| /* |
| * Generic SSL/TLS messaging layer functions |
| * (record layer + retransmission state machine) |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| /* |
| * http://www.ietf.org/rfc/rfc2246.txt |
| * http://www.ietf.org/rfc/rfc4346.txt |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_SSL_TLS_C) |
| |
| #if defined(MBEDTLS_PLATFORM_C) |
| #include "mbedtls/platform.h" |
| #else |
| #include <stdlib.h> |
| #define mbedtls_calloc calloc |
| #define mbedtls_free free |
| #endif |
| |
| #include "mbedtls/ssl.h" |
| #include "ssl_misc.h" |
| #include "mbedtls/debug.h" |
| #include "mbedtls/error.h" |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/version.h" |
| |
| #include "ssl_invasive.h" |
| |
| #include <string.h> |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| #include "mbedtls/psa_util.h" |
| #include "psa/crypto.h" |
| #endif |
| |
| #if defined(MBEDTLS_X509_CRT_PARSE_C) |
| #include "mbedtls/oid.h" |
| #endif |
| |
| static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl ); |
| |
| /* |
| * Start a timer. |
| * Passing millisecs = 0 cancels a running timer. |
| */ |
| void mbedtls_ssl_set_timer( mbedtls_ssl_context *ssl, uint32_t millisecs ) |
| { |
| if( ssl->f_set_timer == NULL ) |
| return; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "set_timer to %d ms", (int) millisecs ) ); |
| ssl->f_set_timer( ssl->p_timer, millisecs / 4, millisecs ); |
| } |
| |
| /* |
| * Return -1 is timer is expired, 0 if it isn't. |
| */ |
| int mbedtls_ssl_check_timer( mbedtls_ssl_context *ssl ) |
| { |
| if( ssl->f_get_timer == NULL ) |
| return( 0 ); |
| |
| if( ssl->f_get_timer( ssl->p_timer ) == 2 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "timer expired" ) ); |
| return( -1 ); |
| } |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_SSL_RECORD_CHECKING) |
| static int ssl_parse_record_header( mbedtls_ssl_context const *ssl, |
| unsigned char *buf, |
| size_t len, |
| mbedtls_record *rec ); |
| |
| int mbedtls_ssl_check_record( mbedtls_ssl_context const *ssl, |
| unsigned char *buf, |
| size_t buflen ) |
| { |
| int ret = 0; |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "=> mbedtls_ssl_check_record" ) ); |
| MBEDTLS_SSL_DEBUG_BUF( 3, "record buffer", buf, buflen ); |
| |
| /* We don't support record checking in TLS because |
| * (a) there doesn't seem to be a usecase for it, and |
| * (b) In TLS 1.0, CBC record decryption has state |
| * and we'd need to backup the transform here. |
| */ |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM ) |
| { |
| ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; |
| goto exit; |
| } |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| else |
| { |
| mbedtls_record rec; |
| |
| ret = ssl_parse_record_header( ssl, buf, buflen, &rec ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 3, "ssl_parse_record_header", ret ); |
| goto exit; |
| } |
| |
| if( ssl->transform_in != NULL ) |
| { |
| ret = mbedtls_ssl_decrypt_buf( ssl, ssl->transform_in, &rec ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 3, "mbedtls_ssl_decrypt_buf", ret ); |
| goto exit; |
| } |
| } |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| exit: |
| /* On success, we have decrypted the buffer in-place, so make |
| * sure we don't leak any plaintext data. */ |
| mbedtls_platform_zeroize( buf, buflen ); |
| |
| /* For the purpose of this API, treat messages with unexpected CID |
| * as well as such from future epochs as unexpected. */ |
| if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_CID || |
| ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) |
| { |
| ret = MBEDTLS_ERR_SSL_UNEXPECTED_RECORD; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "<= mbedtls_ssl_check_record" ) ); |
| return( ret ); |
| } |
| #endif /* MBEDTLS_SSL_RECORD_CHECKING */ |
| |
| #define SSL_DONT_FORCE_FLUSH 0 |
| #define SSL_FORCE_FLUSH 1 |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| |
| /* Forward declarations for functions related to message buffering. */ |
| static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl, |
| uint8_t slot ); |
| static void ssl_free_buffered_record( mbedtls_ssl_context *ssl ); |
| static int ssl_load_buffered_message( mbedtls_ssl_context *ssl ); |
| static int ssl_load_buffered_record( mbedtls_ssl_context *ssl ); |
| static int ssl_buffer_message( mbedtls_ssl_context *ssl ); |
| static int ssl_buffer_future_record( mbedtls_ssl_context *ssl, |
| mbedtls_record const *rec ); |
| static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl ); |
| |
| static size_t ssl_get_maximum_datagram_size( mbedtls_ssl_context const *ssl ) |
| { |
| size_t mtu = mbedtls_ssl_get_current_mtu( ssl ); |
| #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) |
| size_t out_buf_len = ssl->out_buf_len; |
| #else |
| size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN; |
| #endif |
| |
| if( mtu != 0 && mtu < out_buf_len ) |
| return( mtu ); |
| |
| return( out_buf_len ); |
| } |
| |
| static int ssl_get_remaining_space_in_datagram( mbedtls_ssl_context const *ssl ) |
| { |
| size_t const bytes_written = ssl->out_left; |
| size_t const mtu = ssl_get_maximum_datagram_size( ssl ); |
| |
| /* Double-check that the write-index hasn't gone |
| * past what we can transmit in a single datagram. */ |
| if( bytes_written > mtu ) |
| { |
| /* Should never happen... */ |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| return( (int) ( mtu - bytes_written ) ); |
| } |
| |
| static int ssl_get_remaining_payload_in_datagram( mbedtls_ssl_context const *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t remaining, expansion; |
| size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN; |
| |
| #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) |
| const size_t mfl = mbedtls_ssl_get_output_max_frag_len( ssl ); |
| |
| if( max_len > mfl ) |
| max_len = mfl; |
| |
| /* By the standard (RFC 6066 Sect. 4), the MFL extension |
| * only limits the maximum record payload size, so in theory |
| * we would be allowed to pack multiple records of payload size |
| * MFL into a single datagram. However, this would mean that there's |
| * no way to explicitly communicate MTU restrictions to the peer. |
| * |
| * The following reduction of max_len makes sure that we never |
| * write datagrams larger than MFL + Record Expansion Overhead. |
| */ |
| if( max_len <= ssl->out_left ) |
| return( 0 ); |
| |
| max_len -= ssl->out_left; |
| #endif |
| |
| ret = ssl_get_remaining_space_in_datagram( ssl ); |
| if( ret < 0 ) |
| return( ret ); |
| remaining = (size_t) ret; |
| |
| ret = mbedtls_ssl_get_record_expansion( ssl ); |
| if( ret < 0 ) |
| return( ret ); |
| expansion = (size_t) ret; |
| |
| if( remaining <= expansion ) |
| return( 0 ); |
| |
| remaining -= expansion; |
| if( remaining >= max_len ) |
| remaining = max_len; |
| |
| return( (int) remaining ); |
| } |
| |
| /* |
| * Double the retransmit timeout value, within the allowed range, |
| * returning -1 if the maximum value has already been reached. |
| */ |
| static int ssl_double_retransmit_timeout( mbedtls_ssl_context *ssl ) |
| { |
| uint32_t new_timeout; |
| |
| if( ssl->handshake->retransmit_timeout >= ssl->conf->hs_timeout_max ) |
| return( -1 ); |
| |
| /* Implement the final paragraph of RFC 6347 section 4.1.1.1 |
| * in the following way: after the initial transmission and a first |
| * retransmission, back off to a temporary estimated MTU of 508 bytes. |
| * This value is guaranteed to be deliverable (if not guaranteed to be |
| * delivered) of any compliant IPv4 (and IPv6) network, and should work |
| * on most non-IP stacks too. */ |
| if( ssl->handshake->retransmit_timeout != ssl->conf->hs_timeout_min ) |
| { |
| ssl->handshake->mtu = 508; |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "mtu autoreduction to %d bytes", ssl->handshake->mtu ) ); |
| } |
| |
| new_timeout = 2 * ssl->handshake->retransmit_timeout; |
| |
| /* Avoid arithmetic overflow and range overflow */ |
| if( new_timeout < ssl->handshake->retransmit_timeout || |
| new_timeout > ssl->conf->hs_timeout_max ) |
| { |
| new_timeout = ssl->conf->hs_timeout_max; |
| } |
| |
| ssl->handshake->retransmit_timeout = new_timeout; |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "update timeout value to %lu millisecs", |
| (unsigned long) ssl->handshake->retransmit_timeout ) ); |
| |
| return( 0 ); |
| } |
| |
| static void ssl_reset_retransmit_timeout( mbedtls_ssl_context *ssl ) |
| { |
| ssl->handshake->retransmit_timeout = ssl->conf->hs_timeout_min; |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "update timeout value to %lu millisecs", |
| (unsigned long) ssl->handshake->retransmit_timeout ) ); |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| /* |
| * Encryption/decryption functions |
| */ |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) || \ |
| defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) |
| |
| static size_t ssl_compute_padding_length( size_t len, |
| size_t granularity ) |
| { |
| return( ( granularity - ( len + 1 ) % granularity ) % granularity ); |
| } |
| |
| /* This functions transforms a (D)TLS plaintext fragment and a record content |
| * type into an instance of the (D)TLSInnerPlaintext structure. This is used |
| * in DTLS 1.2 + CID and within TLS 1.3 to allow flexible padding and to protect |
| * a record's content type. |
| * |
| * struct { |
| * opaque content[DTLSPlaintext.length]; |
| * ContentType real_type; |
| * uint8 zeros[length_of_padding]; |
| * } (D)TLSInnerPlaintext; |
| * |
| * Input: |
| * - `content`: The beginning of the buffer holding the |
| * plaintext to be wrapped. |
| * - `*content_size`: The length of the plaintext in Bytes. |
| * - `max_len`: The number of Bytes available starting from |
| * `content`. This must be `>= *content_size`. |
| * - `rec_type`: The desired record content type. |
| * |
| * Output: |
| * - `content`: The beginning of the resulting (D)TLSInnerPlaintext structure. |
| * - `*content_size`: The length of the resulting (D)TLSInnerPlaintext structure. |
| * |
| * Returns: |
| * - `0` on success. |
| * - A negative error code if `max_len` didn't offer enough space |
| * for the expansion. |
| */ |
| static int ssl_build_inner_plaintext( unsigned char *content, |
| size_t *content_size, |
| size_t remaining, |
| uint8_t rec_type, |
| size_t pad ) |
| { |
| size_t len = *content_size; |
| |
| /* Write real content type */ |
| if( remaining == 0 ) |
| return( -1 ); |
| content[ len ] = rec_type; |
| len++; |
| remaining--; |
| |
| if( remaining < pad ) |
| return( -1 ); |
| memset( content + len, 0, pad ); |
| len += pad; |
| remaining -= pad; |
| |
| *content_size = len; |
| return( 0 ); |
| } |
| |
| /* This function parses a (D)TLSInnerPlaintext structure. |
| * See ssl_build_inner_plaintext() for details. */ |
| static int ssl_parse_inner_plaintext( unsigned char const *content, |
| size_t *content_size, |
| uint8_t *rec_type ) |
| { |
| size_t remaining = *content_size; |
| |
| /* Determine length of padding by skipping zeroes from the back. */ |
| do |
| { |
| if( remaining == 0 ) |
| return( -1 ); |
| remaining--; |
| } while( content[ remaining ] == 0 ); |
| |
| *content_size = remaining; |
| *rec_type = content[ remaining ]; |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID || |
| MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ |
| |
| /* `add_data` must have size 13 Bytes if the CID extension is disabled, |
| * and 13 + 1 + CID-length Bytes if the CID extension is enabled. */ |
| static void ssl_extract_add_data_from_record( unsigned char* add_data, |
| size_t *add_data_len, |
| mbedtls_record *rec, |
| unsigned minor_ver ) |
| { |
| /* Quoting RFC 5246 (TLS 1.2): |
| * |
| * additional_data = seq_num + TLSCompressed.type + |
| * TLSCompressed.version + TLSCompressed.length; |
| * |
| * For the CID extension, this is extended as follows |
| * (quoting draft-ietf-tls-dtls-connection-id-05, |
| * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05): |
| * |
| * additional_data = seq_num + DTLSPlaintext.type + |
| * DTLSPlaintext.version + |
| * cid + |
| * cid_length + |
| * length_of_DTLSInnerPlaintext; |
| * |
| * For TLS 1.3, the record sequence number is dropped from the AAD |
| * and encoded within the nonce of the AEAD operation instead. |
| */ |
| |
| unsigned char *cur = add_data; |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) |
| if( minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 ) |
| #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ |
| { |
| ((void) minor_ver); |
| memcpy( cur, rec->ctr, sizeof( rec->ctr ) ); |
| cur += sizeof( rec->ctr ); |
| } |
| |
| *cur = rec->type; |
| cur++; |
| |
| memcpy( cur, rec->ver, sizeof( rec->ver ) ); |
| cur += sizeof( rec->ver ); |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| if( rec->cid_len != 0 ) |
| { |
| memcpy( cur, rec->cid, rec->cid_len ); |
| cur += rec->cid_len; |
| |
| *cur = rec->cid_len; |
| cur++; |
| |
| cur[0] = ( rec->data_len >> 8 ) & 0xFF; |
| cur[1] = ( rec->data_len >> 0 ) & 0xFF; |
| cur += 2; |
| } |
| else |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| { |
| cur[0] = ( rec->data_len >> 8 ) & 0xFF; |
| cur[1] = ( rec->data_len >> 0 ) & 0xFF; |
| cur += 2; |
| } |
| |
| *add_data_len = cur - add_data; |
| } |
| |
| #if defined(MBEDTLS_GCM_C) || \ |
| defined(MBEDTLS_CCM_C) || \ |
| defined(MBEDTLS_CHACHAPOLY_C) |
| static int ssl_transform_aead_dynamic_iv_is_explicit( |
| mbedtls_ssl_transform const *transform ) |
| { |
| return( transform->ivlen != transform->fixed_ivlen ); |
| } |
| |
| /* Compute IV := ( fixed_iv || 0 ) XOR ( 0 || dynamic_IV ) |
| * |
| * Concretely, this occurs in two variants: |
| * |
| * a) Fixed and dynamic IV lengths add up to total IV length, giving |
| * IV = fixed_iv || dynamic_iv |
| * |
| * This variant is used in TLS 1.2 when used with GCM or CCM. |
| * |
| * b) Fixed IV lengths matches total IV length, giving |
| * IV = fixed_iv XOR ( 0 || dynamic_iv ) |
| * |
| * This variant occurs in TLS 1.3 and for TLS 1.2 when using ChaChaPoly. |
| * |
| * See also the documentation of mbedtls_ssl_transform. |
| * |
| * This function has the precondition that |
| * |
| * dst_iv_len >= max( fixed_iv_len, dynamic_iv_len ) |
| * |
| * which has to be ensured by the caller. If this precondition |
| * violated, the behavior of this function is undefined. |
| */ |
| static void ssl_build_record_nonce( unsigned char *dst_iv, |
| size_t dst_iv_len, |
| unsigned char const *fixed_iv, |
| size_t fixed_iv_len, |
| unsigned char const *dynamic_iv, |
| size_t dynamic_iv_len ) |
| { |
| size_t i; |
| |
| /* Start with Fixed IV || 0 */ |
| memset( dst_iv, 0, dst_iv_len ); |
| memcpy( dst_iv, fixed_iv, fixed_iv_len ); |
| |
| dst_iv += dst_iv_len - dynamic_iv_len; |
| for( i = 0; i < dynamic_iv_len; i++ ) |
| dst_iv[i] ^= dynamic_iv[i]; |
| } |
| #endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C || MBEDTLS_CHACHAPOLY_C */ |
| |
| int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl, |
| mbedtls_ssl_transform *transform, |
| mbedtls_record *rec, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng ) |
| { |
| mbedtls_cipher_mode_t mode; |
| int auth_done = 0; |
| unsigned char * data; |
| unsigned char add_data[13 + 1 + MBEDTLS_SSL_CID_OUT_LEN_MAX ]; |
| size_t add_data_len; |
| size_t post_avail; |
| |
| /* The SSL context is only used for debugging purposes! */ |
| #if !defined(MBEDTLS_DEBUG_C) |
| ssl = NULL; /* make sure we don't use it except for debug */ |
| ((void) ssl); |
| #endif |
| |
| /* The PRNG is used for dynamic IV generation that's used |
| * for CBC transformations in TLS 1.1 and TLS 1.2. */ |
| #if !( defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC) && \ |
| ( defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) ) ) |
| ((void) f_rng); |
| ((void) p_rng); |
| #endif |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> encrypt buf" ) ); |
| |
| if( transform == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "no transform provided to encrypt_buf" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| if( rec == NULL |
| || rec->buf == NULL |
| || rec->buf_len < rec->data_offset |
| || rec->buf_len - rec->data_offset < rec->data_len |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| || rec->cid_len != 0 |
| #endif |
| ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad record structure provided to encrypt_buf" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| data = rec->buf + rec->data_offset; |
| post_avail = rec->buf_len - ( rec->data_len + rec->data_offset ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "before encrypt: output payload", |
| data, rec->data_len ); |
| |
| mode = mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_enc ); |
| |
| if( rec->data_len > MBEDTLS_SSL_OUT_CONTENT_LEN ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Record content %" MBEDTLS_PRINTF_SIZET |
| " too large, maximum %" MBEDTLS_PRINTF_SIZET, |
| rec->data_len, |
| (size_t) MBEDTLS_SSL_OUT_CONTENT_LEN ) ); |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| } |
| |
| /* The following two code paths implement the (D)TLSInnerPlaintext |
| * structure present in TLS 1.3 and DTLS 1.2 + CID. |
| * |
| * See ssl_build_inner_plaintext() for more information. |
| * |
| * Note that this changes `rec->data_len`, and hence |
| * `post_avail` needs to be recalculated afterwards. |
| * |
| * Note also that the two code paths cannot occur simultaneously |
| * since they apply to different versions of the protocol. There |
| * is hence no risk of double-addition of the inner plaintext. |
| */ |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) |
| if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 ) |
| { |
| size_t padding = |
| ssl_compute_padding_length( rec->data_len, |
| MBEDTLS_SSL_TLS1_3_PADDING_GRANULARITY ); |
| if( ssl_build_inner_plaintext( data, |
| &rec->data_len, |
| post_avail, |
| rec->type, |
| padding ) != 0 ) |
| { |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| |
| rec->type = MBEDTLS_SSL_MSG_APPLICATION_DATA; |
| } |
| #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| /* |
| * Add CID information |
| */ |
| rec->cid_len = transform->out_cid_len; |
| memcpy( rec->cid, transform->out_cid, transform->out_cid_len ); |
| MBEDTLS_SSL_DEBUG_BUF( 3, "CID", rec->cid, rec->cid_len ); |
| |
| if( rec->cid_len != 0 ) |
| { |
| size_t padding = |
| ssl_compute_padding_length( rec->data_len, |
| MBEDTLS_SSL_CID_PADDING_GRANULARITY ); |
| /* |
| * Wrap plaintext into DTLSInnerPlaintext structure. |
| * See ssl_build_inner_plaintext() for more information. |
| * |
| * Note that this changes `rec->data_len`, and hence |
| * `post_avail` needs to be recalculated afterwards. |
| */ |
| if( ssl_build_inner_plaintext( data, |
| &rec->data_len, |
| post_avail, |
| rec->type, |
| padding ) != 0 ) |
| { |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| |
| rec->type = MBEDTLS_SSL_MSG_CID; |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| |
| post_avail = rec->buf_len - ( rec->data_len + rec->data_offset ); |
| |
| /* |
| * Add MAC before if needed |
| */ |
| #if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) |
| if( mode == MBEDTLS_MODE_STREAM || |
| ( mode == MBEDTLS_MODE_CBC |
| #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) |
| && transform->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED |
| #endif |
| ) ) |
| { |
| if( post_avail < transform->maclen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ |
| defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 ) |
| { |
| unsigned char mac[MBEDTLS_SSL_MAC_ADD]; |
| |
| ssl_extract_add_data_from_record( add_data, &add_data_len, rec, |
| transform->minor_ver ); |
| |
| mbedtls_md_hmac_update( &transform->md_ctx_enc, add_data, |
| add_data_len ); |
| mbedtls_md_hmac_update( &transform->md_ctx_enc, |
| data, rec->data_len ); |
| mbedtls_md_hmac_finish( &transform->md_ctx_enc, mac ); |
| mbedtls_md_hmac_reset( &transform->md_ctx_enc ); |
| |
| memcpy( data + rec->data_len, mac, transform->maclen ); |
| } |
| else |
| #endif |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "computed mac", data + rec->data_len, |
| transform->maclen ); |
| |
| rec->data_len += transform->maclen; |
| post_avail -= transform->maclen; |
| auth_done++; |
| } |
| #endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */ |
| |
| /* |
| * Encrypt |
| */ |
| #if defined(MBEDTLS_CIPHER_NULL_CIPHER) |
| if( mode == MBEDTLS_MODE_STREAM ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t olen; |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %" MBEDTLS_PRINTF_SIZET ", " |
| "including %d bytes of padding", |
| rec->data_len, 0 ) ); |
| |
| if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_enc, |
| transform->iv_enc, transform->ivlen, |
| data, rec->data_len, |
| data, &olen ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); |
| return( ret ); |
| } |
| |
| if( rec->data_len != olen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_CIPHER_NULL_CIPHER */ |
| |
| #if defined(MBEDTLS_GCM_C) || \ |
| defined(MBEDTLS_CCM_C) || \ |
| defined(MBEDTLS_CHACHAPOLY_C) |
| if( mode == MBEDTLS_MODE_GCM || |
| mode == MBEDTLS_MODE_CCM || |
| mode == MBEDTLS_MODE_CHACHAPOLY ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char iv[12]; |
| unsigned char *dynamic_iv; |
| size_t dynamic_iv_len; |
| int dynamic_iv_is_explicit = |
| ssl_transform_aead_dynamic_iv_is_explicit( transform ); |
| |
| /* Check that there's space for the authentication tag. */ |
| if( post_avail < transform->taglen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| |
| /* |
| * Build nonce for AEAD encryption. |
| * |
| * Note: In the case of CCM and GCM in TLS 1.2, the dynamic |
| * part of the IV is prepended to the ciphertext and |
| * can be chosen freely - in particular, it need not |
| * agree with the record sequence number. |
| * However, since ChaChaPoly as well as all AEAD modes |
| * in TLS 1.3 use the record sequence number as the |
| * dynamic part of the nonce, we uniformly use the |
| * record sequence number here in all cases. |
| */ |
| dynamic_iv = rec->ctr; |
| dynamic_iv_len = sizeof( rec->ctr ); |
| |
| ssl_build_record_nonce( iv, sizeof( iv ), |
| transform->iv_enc, |
| transform->fixed_ivlen, |
| dynamic_iv, |
| dynamic_iv_len ); |
| |
| /* |
| * Build additional data for AEAD encryption. |
| * This depends on the TLS version. |
| */ |
| ssl_extract_add_data_from_record( add_data, &add_data_len, rec, |
| transform->minor_ver ); |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "IV used (internal)", |
| iv, transform->ivlen ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "IV used (transmitted)", |
| dynamic_iv, |
| dynamic_iv_is_explicit ? dynamic_iv_len : 0 ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "additional data used for AEAD", |
| add_data, add_data_len ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %" MBEDTLS_PRINTF_SIZET ", " |
| "including 0 bytes of padding", |
| rec->data_len ) ); |
| |
| /* |
| * Encrypt and authenticate |
| */ |
| |
| if( ( ret = mbedtls_cipher_auth_encrypt_ext( &transform->cipher_ctx_enc, |
| iv, transform->ivlen, |
| add_data, add_data_len, |
| data, rec->data_len, /* src */ |
| data, rec->buf_len - (data - rec->buf), /* dst */ |
| &rec->data_len, |
| transform->taglen ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_auth_encrypt", ret ); |
| return( ret ); |
| } |
| MBEDTLS_SSL_DEBUG_BUF( 4, "after encrypt: tag", |
| data + rec->data_len - transform->taglen, |
| transform->taglen ); |
| /* Account for authentication tag. */ |
| post_avail -= transform->taglen; |
| |
| /* |
| * Prefix record content with dynamic IV in case it is explicit. |
| */ |
| if( dynamic_iv_is_explicit != 0 ) |
| { |
| if( rec->data_offset < dynamic_iv_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| |
| memcpy( data - dynamic_iv_len, dynamic_iv, dynamic_iv_len ); |
| rec->data_offset -= dynamic_iv_len; |
| rec->data_len += dynamic_iv_len; |
| } |
| |
| auth_done++; |
| } |
| else |
| #endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C || MBEDTLS_CHACHAPOLY_C */ |
| #if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC) |
| if( mode == MBEDTLS_MODE_CBC ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t padlen, i; |
| size_t olen; |
| |
| /* Currently we're always using minimal padding |
| * (up to 255 bytes would be allowed). */ |
| padlen = transform->ivlen - ( rec->data_len + 1 ) % transform->ivlen; |
| if( padlen == transform->ivlen ) |
| padlen = 0; |
| |
| /* Check there's enough space in the buffer for the padding. */ |
| if( post_avail < padlen + 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| |
| for( i = 0; i <= padlen; i++ ) |
| data[rec->data_len + i] = (unsigned char) padlen; |
| |
| rec->data_len += padlen + 1; |
| post_avail -= padlen + 1; |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| /* |
| * Prepend per-record IV for block cipher in TLS v1.1 and up as per |
| * Method 1 (6.2.3.2. in RFC4346 and RFC5246) |
| */ |
| if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) |
| { |
| if( f_rng == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "No PRNG provided to encrypt_record routine" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| if( rec->data_offset < transform->ivlen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| |
| /* |
| * Generate IV |
| */ |
| ret = f_rng( p_rng, transform->iv_enc, transform->ivlen ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| memcpy( data - transform->ivlen, transform->iv_enc, |
| transform->ivlen ); |
| |
| } |
| #endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */ |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %" MBEDTLS_PRINTF_SIZET ", " |
| "including %" MBEDTLS_PRINTF_SIZET |
| " bytes of IV and %" MBEDTLS_PRINTF_SIZET " bytes of padding", |
| rec->data_len, transform->ivlen, |
| padlen + 1 ) ); |
| |
| if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_enc, |
| transform->iv_enc, |
| transform->ivlen, |
| data, rec->data_len, |
| data, &olen ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); |
| return( ret ); |
| } |
| |
| if( rec->data_len != olen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1) |
| if( transform->minor_ver < MBEDTLS_SSL_MINOR_VERSION_2 ) |
| { |
| /* |
| * Save IV in TLS1 |
| */ |
| memcpy( transform->iv_enc, transform->cipher_ctx_enc.iv, |
| transform->ivlen ); |
| } |
| else |
| #endif |
| { |
| data -= transform->ivlen; |
| rec->data_offset -= transform->ivlen; |
| rec->data_len += transform->ivlen; |
| } |
| |
| #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) |
| if( auth_done == 0 ) |
| { |
| unsigned char mac[MBEDTLS_SSL_MAC_ADD]; |
| |
| /* |
| * MAC(MAC_write_key, seq_num + |
| * TLSCipherText.type + |
| * TLSCipherText.version + |
| * length_of( (IV +) ENC(...) ) + |
| * IV + // except for TLS 1.0 |
| * ENC(content + padding + padding_length)); |
| */ |
| |
| if( post_avail < transform->maclen) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| } |
| |
| ssl_extract_add_data_from_record( add_data, &add_data_len, |
| rec, transform->minor_ver ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "MAC'd meta-data", add_data, |
| add_data_len ); |
| |
| mbedtls_md_hmac_update( &transform->md_ctx_enc, add_data, |
| add_data_len ); |
| mbedtls_md_hmac_update( &transform->md_ctx_enc, |
| data, rec->data_len ); |
| mbedtls_md_hmac_finish( &transform->md_ctx_enc, mac ); |
| mbedtls_md_hmac_reset( &transform->md_ctx_enc ); |
| |
| memcpy( data + rec->data_len, mac, transform->maclen ); |
| |
| rec->data_len += transform->maclen; |
| post_avail -= transform->maclen; |
| auth_done++; |
| } |
| #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ |
| } |
| else |
| #endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC) */ |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| /* Make extra sure authentication was performed, exactly once */ |
| if( auth_done != 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= encrypt buf" ) ); |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC) |
| /* |
| * Turn a bit into a mask: |
| * - if bit == 1, return the all-bits 1 mask, aka (size_t) -1 |
| * - if bit == 0, return the all-bits 0 mask, aka 0 |
| * |
| * This function can be used to write constant-time code by replacing branches |
| * with bit operations using masks. |
| * |
| * This function is implemented without using comparison operators, as those |
| * might be translated to branches by some compilers on some platforms. |
| */ |
| static size_t mbedtls_ssl_cf_mask_from_bit( size_t bit ) |
| { |
| /* MSVC has a warning about unary minus on unsigned integer types, |
| * but this is well-defined and precisely what we want to do here. */ |
| #if defined(_MSC_VER) |
| #pragma warning( push ) |
| #pragma warning( disable : 4146 ) |
| #endif |
| return -bit; |
| #if defined(_MSC_VER) |
| #pragma warning( pop ) |
| #endif |
| } |
| |
| /* |
| * Constant-flow mask generation for "less than" comparison: |
| * - if x < y, return all bits 1, that is (size_t) -1 |
| * - otherwise, return all bits 0, that is 0 |
| * |
| * This function can be used to write constant-time code by replacing branches |
| * with bit operations using masks. |
| * |
| * This function is implemented without using comparison operators, as those |
| * might be translated to branches by some compilers on some platforms. |
| */ |
| static size_t mbedtls_ssl_cf_mask_lt( size_t x, size_t y ) |
| { |
| /* This has the most significant bit set if and only if x < y */ |
| const size_t sub = x - y; |
| |
| /* sub1 = (x < y) ? 1 : 0 */ |
| const size_t sub1 = sub >> ( sizeof( sub ) * 8 - 1 ); |
| |
| /* mask = (x < y) ? 0xff... : 0x00... */ |
| const size_t mask = mbedtls_ssl_cf_mask_from_bit( sub1 ); |
| |
| return( mask ); |
| } |
| |
| /* |
| * Constant-flow mask generation for "greater or equal" comparison: |
| * - if x >= y, return all bits 1, that is (size_t) -1 |
| * - otherwise, return all bits 0, that is 0 |
| * |
| * This function can be used to write constant-time code by replacing branches |
| * with bit operations using masks. |
| * |
| * This function is implemented without using comparison operators, as those |
| * might be translated to branches by some compilers on some platforms. |
| */ |
| static size_t mbedtls_ssl_cf_mask_ge( size_t x, size_t y ) |
| { |
| return( ~mbedtls_ssl_cf_mask_lt( x, y ) ); |
| } |
| |
| /* |
| * Constant-flow boolean "equal" comparison: |
| * return x == y |
| * |
| * This function can be used to write constant-time code by replacing branches |
| * with bit operations - it can be used in conjunction with |
| * mbedtls_ssl_cf_mask_from_bit(). |
| * |
| * This function is implemented without using comparison operators, as those |
| * might be translated to branches by some compilers on some platforms. |
| */ |
| static size_t mbedtls_ssl_cf_bool_eq( size_t x, size_t y ) |
| { |
| /* diff = 0 if x == y, non-zero otherwise */ |
| const size_t diff = x ^ y; |
| |
| /* MSVC has a warning about unary minus on unsigned integer types, |
| * but this is well-defined and precisely what we want to do here. */ |
| #if defined(_MSC_VER) |
| #pragma warning( push ) |
| #pragma warning( disable : 4146 ) |
| #endif |
| |
| /* diff_msb's most significant bit is equal to x != y */ |
| const size_t diff_msb = ( diff | -diff ); |
| |
| #if defined(_MSC_VER) |
| #pragma warning( pop ) |
| #endif |
| |
| /* diff1 = (x != y) ? 1 : 0 */ |
| const size_t diff1 = diff_msb >> ( sizeof( diff_msb ) * 8 - 1 ); |
| |
| return( 1 ^ diff1 ); |
| } |
| |
| /* |
| * Constant-flow conditional memcpy: |
| * - if c1 == c2, equivalent to memcpy(dst, src, len), |
| * - otherwise, a no-op, |
| * but with execution flow independent of the values of c1 and c2. |
| * |
| * This function is implemented without using comparison operators, as those |
| * might be translated to branches by some compilers on some platforms. |
| */ |
| static void mbedtls_ssl_cf_memcpy_if_eq( unsigned char *dst, |
| const unsigned char *src, |
| size_t len, |
| size_t c1, size_t c2 ) |
| { |
| /* mask = c1 == c2 ? 0xff : 0x00 */ |
| const size_t equal = mbedtls_ssl_cf_bool_eq( c1, c2 ); |
| const unsigned char mask = (unsigned char) mbedtls_ssl_cf_mask_from_bit( equal ); |
| |
| /* dst[i] = c1 == c2 ? src[i] : dst[i] */ |
| for( size_t i = 0; i < len; i++ ) |
| dst[i] = ( src[i] & mask ) | ( dst[i] & ~mask ); |
| } |
| |
| /* |
| * Compute HMAC of variable-length data with constant flow. |
| * |
| * Only works with MD-5, SHA-1, SHA-256 and SHA-384. |
| * (Otherwise, computation of block_size needs to be adapted.) |
| */ |
| MBEDTLS_STATIC_TESTABLE int mbedtls_ssl_cf_hmac( |
| mbedtls_md_context_t *ctx, |
| const unsigned char *add_data, size_t add_data_len, |
| const unsigned char *data, size_t data_len_secret, |
| size_t min_data_len, size_t max_data_len, |
| unsigned char *output ) |
| { |
| /* |
| * This function breaks the HMAC abstraction and uses the md_clone() |
| * extension to the MD API in order to get constant-flow behaviour. |
| * |
| * HMAC(msg) is defined as HASH(okey + HASH(ikey + msg)) where + means |
| * concatenation, and okey/ikey are the XOR of the key with some fixed bit |
| * patterns (see RFC 2104, sec. 2), which are stored in ctx->hmac_ctx. |
| * |
| * We'll first compute inner_hash = HASH(ikey + msg) by hashing up to |
| * minlen, then cloning the context, and for each byte up to maxlen |
| * finishing up the hash computation, keeping only the correct result. |
| * |
| * Then we only need to compute HASH(okey + inner_hash) and we're done. |
| */ |
| const mbedtls_md_type_t md_alg = mbedtls_md_get_type( ctx->md_info ); |
| /* TLS 1.0-1.2 only support SHA-384, SHA-256, SHA-1, MD-5, |
| * all of which have the same block size except SHA-384. */ |
| const size_t block_size = md_alg == MBEDTLS_MD_SHA384 ? 128 : 64; |
| const unsigned char * const ikey = ctx->hmac_ctx; |
| const unsigned char * const okey = ikey + block_size; |
| const size_t hash_size = mbedtls_md_get_size( ctx->md_info ); |
| |
| unsigned char aux_out[MBEDTLS_MD_MAX_SIZE]; |
| mbedtls_md_context_t aux; |
| size_t offset; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_md_init( &aux ); |
| |
| #define MD_CHK( func_call ) \ |
| do { \ |
| ret = (func_call); \ |
| if( ret != 0 ) \ |
| goto cleanup; \ |
| } while( 0 ) |
| |
| MD_CHK( mbedtls_md_setup( &aux, ctx->md_info, 0 ) ); |
| |
| /* After hmac_start() of hmac_reset(), ikey has already been hashed, |
| * so we can start directly with the message */ |
| MD_CHK( mbedtls_md_update( ctx, add_data, add_data_len ) ); |
| MD_CHK( mbedtls_md_update( ctx, data, min_data_len ) ); |
| |
| /* For each possible length, compute the hash up to that point */ |
| for( offset = min_data_len; offset <= max_data_len; offset++ ) |
| { |
| MD_CHK( mbedtls_md_clone( &aux, ctx ) ); |
| MD_CHK( mbedtls_md_finish( &aux, aux_out ) ); |
| /* Keep only the correct inner_hash in the output buffer */ |
| mbedtls_ssl_cf_memcpy_if_eq( output, aux_out, hash_size, |
| offset, data_len_secret ); |
| |
| if( offset < max_data_len ) |
| MD_CHK( mbedtls_md_update( ctx, data + offset, 1 ) ); |
| } |
| |
| /* Now compute HASH(okey + inner_hash) */ |
| MD_CHK( mbedtls_md_starts( ctx ) ); |
| MD_CHK( mbedtls_md_update( ctx, okey, block_size ) ); |
| MD_CHK( mbedtls_md_update( ctx, output, hash_size ) ); |
| MD_CHK( mbedtls_md_finish( ctx, output ) ); |
| |
| /* Done, get ready for next time */ |
| MD_CHK( mbedtls_md_hmac_reset( ctx ) ); |
| |
| #undef MD_CHK |
| |
| cleanup: |
| mbedtls_md_free( &aux ); |
| return( ret ); |
| } |
| |
| /* |
| * Constant-flow memcpy from variable position in buffer. |
| * - functionally equivalent to memcpy(dst, src + offset_secret, len) |
| * - but with execution flow independent from the value of offset_secret. |
| */ |
| MBEDTLS_STATIC_TESTABLE void mbedtls_ssl_cf_memcpy_offset( |
| unsigned char *dst, |
| const unsigned char *src_base, |
| size_t offset_secret, |
| size_t offset_min, size_t offset_max, |
| size_t len ) |
| { |
| size_t offset; |
| |
| for( offset = offset_min; offset <= offset_max; offset++ ) |
| { |
| mbedtls_ssl_cf_memcpy_if_eq( dst, src_base + offset, len, |
| offset, offset_secret ); |
| } |
| } |
| #endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */ |
| |
| int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl, |
| mbedtls_ssl_transform *transform, |
| mbedtls_record *rec ) |
| { |
| size_t olen; |
| mbedtls_cipher_mode_t mode; |
| int ret, auth_done = 0; |
| #if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) |
| size_t padlen = 0, correct = 1; |
| #endif |
| unsigned char* data; |
| unsigned char add_data[13 + 1 + MBEDTLS_SSL_CID_IN_LEN_MAX ]; |
| size_t add_data_len; |
| |
| #if !defined(MBEDTLS_DEBUG_C) |
| ssl = NULL; /* make sure we don't use it except for debug */ |
| ((void) ssl); |
| #endif |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> decrypt buf" ) ); |
| if( rec == NULL || |
| rec->buf == NULL || |
| rec->buf_len < rec->data_offset || |
| rec->buf_len - rec->data_offset < rec->data_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad record structure provided to decrypt_buf" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| data = rec->buf + rec->data_offset; |
| mode = mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_dec ); |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| /* |
| * Match record's CID with incoming CID. |
| */ |
| if( rec->cid_len != transform->in_cid_len || |
| memcmp( rec->cid, transform->in_cid, rec->cid_len ) != 0 ) |
| { |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_CID ); |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| |
| #if defined(MBEDTLS_CIPHER_NULL_CIPHER) |
| if( mode == MBEDTLS_MODE_STREAM ) |
| { |
| padlen = 0; |
| if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_dec, |
| transform->iv_dec, |
| transform->ivlen, |
| data, rec->data_len, |
| data, &olen ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); |
| return( ret ); |
| } |
| |
| if( rec->data_len != olen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_CIPHER_NULL_CIPHER */ |
| #if defined(MBEDTLS_GCM_C) || \ |
| defined(MBEDTLS_CCM_C) || \ |
| defined(MBEDTLS_CHACHAPOLY_C) |
| if( mode == MBEDTLS_MODE_GCM || |
| mode == MBEDTLS_MODE_CCM || |
| mode == MBEDTLS_MODE_CHACHAPOLY ) |
| { |
| unsigned char iv[12]; |
| unsigned char *dynamic_iv; |
| size_t dynamic_iv_len; |
| |
| /* |
| * Extract dynamic part of nonce for AEAD decryption. |
| * |
| * Note: In the case of CCM and GCM in TLS 1.2, the dynamic |
| * part of the IV is prepended to the ciphertext and |
| * can be chosen freely - in particular, it need not |
| * agree with the record sequence number. |
| */ |
| dynamic_iv_len = sizeof( rec->ctr ); |
| if( ssl_transform_aead_dynamic_iv_is_explicit( transform ) == 1 ) |
| { |
| if( rec->data_len < dynamic_iv_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET |
| " ) < explicit_iv_len (%" MBEDTLS_PRINTF_SIZET ") ", |
| rec->data_len, |
| dynamic_iv_len ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| } |
| dynamic_iv = data; |
| |
| data += dynamic_iv_len; |
| rec->data_offset += dynamic_iv_len; |
| rec->data_len -= dynamic_iv_len; |
| } |
| else |
| { |
| dynamic_iv = rec->ctr; |
| } |
| |
| /* Check that there's space for the authentication tag. */ |
| if( rec->data_len < transform->taglen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET |
| ") < taglen (%" MBEDTLS_PRINTF_SIZET ") ", |
| rec->data_len, |
| transform->taglen ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| } |
| rec->data_len -= transform->taglen; |
| |
| /* |
| * Prepare nonce from dynamic and static parts. |
| */ |
| ssl_build_record_nonce( iv, sizeof( iv ), |
| transform->iv_dec, |
| transform->fixed_ivlen, |
| dynamic_iv, |
| dynamic_iv_len ); |
| |
| /* |
| * Build additional data for AEAD encryption. |
| * This depends on the TLS version. |
| */ |
| ssl_extract_add_data_from_record( add_data, &add_data_len, rec, |
| transform->minor_ver ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "additional data used for AEAD", |
| add_data, add_data_len ); |
| |
| /* Because of the check above, we know that there are |
| * explicit_iv_len Bytes preceeding data, and taglen |
| * bytes following data + data_len. This justifies |
| * the debug message and the invocation of |
| * mbedtls_cipher_auth_decrypt() below. */ |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "IV used", iv, transform->ivlen ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "TAG used", data + rec->data_len, |
| transform->taglen ); |
| |
| /* |
| * Decrypt and authenticate |
| */ |
| if( ( ret = mbedtls_cipher_auth_decrypt_ext( &transform->cipher_ctx_dec, |
| iv, transform->ivlen, |
| add_data, add_data_len, |
| data, rec->data_len + transform->taglen, /* src */ |
| data, rec->buf_len - (data - rec->buf), &olen, /* dst */ |
| transform->taglen ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_auth_decrypt", ret ); |
| |
| if( ret == MBEDTLS_ERR_CIPHER_AUTH_FAILED ) |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| |
| return( ret ); |
| } |
| auth_done++; |
| |
| /* Double-check that AEAD decryption doesn't change content length. */ |
| if( olen != rec->data_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C */ |
| #if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC) |
| if( mode == MBEDTLS_MODE_CBC ) |
| { |
| size_t minlen = 0; |
| |
| /* |
| * Check immediate ciphertext sanity |
| */ |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) |
| { |
| /* The ciphertext is prefixed with the CBC IV. */ |
| minlen += transform->ivlen; |
| } |
| #endif |
| |
| /* Size considerations: |
| * |
| * - The CBC cipher text must not be empty and hence |
| * at least of size transform->ivlen. |
| * |
| * Together with the potential IV-prefix, this explains |
| * the first of the two checks below. |
| * |
| * - The record must contain a MAC, either in plain or |
| * encrypted, depending on whether Encrypt-then-MAC |
| * is used or not. |
| * - If it is, the message contains the IV-prefix, |
| * the CBC ciphertext, and the MAC. |
| * - If it is not, the padded plaintext, and hence |
| * the CBC ciphertext, has at least length maclen + 1 |
| * because there is at least the padding length byte. |
| * |
| * As the CBC ciphertext is not empty, both cases give the |
| * lower bound minlen + maclen + 1 on the record size, which |
| * we test for in the second check below. |
| */ |
| if( rec->data_len < minlen + transform->ivlen || |
| rec->data_len < minlen + transform->maclen + 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET |
| ") < max( ivlen(%" MBEDTLS_PRINTF_SIZET |
| "), maclen (%" MBEDTLS_PRINTF_SIZET ") " |
| "+ 1 ) ( + expl IV )", rec->data_len, |
| transform->ivlen, |
| transform->maclen ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| } |
| |
| /* |
| * Authenticate before decrypt if enabled |
| */ |
| #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) |
| if( transform->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED ) |
| { |
| unsigned char mac_expect[MBEDTLS_SSL_MAC_ADD]; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) ); |
| |
| /* Update data_len in tandem with add_data. |
| * |
| * The subtraction is safe because of the previous check |
| * data_len >= minlen + maclen + 1. |
| * |
| * Afterwards, we know that data + data_len is followed by at |
| * least maclen Bytes, which justifies the call to |
| * mbedtls_ssl_safer_memcmp() below. |
| * |
| * Further, we still know that data_len > minlen */ |
| rec->data_len -= transform->maclen; |
| ssl_extract_add_data_from_record( add_data, &add_data_len, rec, |
| transform->minor_ver ); |
| |
| /* Calculate expected MAC. */ |
| MBEDTLS_SSL_DEBUG_BUF( 4, "MAC'd meta-data", add_data, |
| add_data_len ); |
| mbedtls_md_hmac_update( &transform->md_ctx_dec, add_data, |
| add_data_len ); |
| mbedtls_md_hmac_update( &transform->md_ctx_dec, |
| data, rec->data_len ); |
| mbedtls_md_hmac_finish( &transform->md_ctx_dec, mac_expect ); |
| mbedtls_md_hmac_reset( &transform->md_ctx_dec ); |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", data + rec->data_len, |
| transform->maclen ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "expected mac", mac_expect, |
| transform->maclen ); |
| |
| /* Compare expected MAC with MAC at the end of the record. */ |
| if( mbedtls_ssl_safer_memcmp( data + rec->data_len, mac_expect, |
| transform->maclen ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| } |
| auth_done++; |
| } |
| #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ |
| |
| /* |
| * Check length sanity |
| */ |
| |
| /* We know from above that data_len > minlen >= 0, |
| * so the following check in particular implies that |
| * data_len >= minlen + ivlen ( = minlen or 2 * minlen ). */ |
| if( rec->data_len % transform->ivlen != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET |
| ") %% ivlen (%" MBEDTLS_PRINTF_SIZET ") != 0", |
| rec->data_len, transform->ivlen ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| /* |
| * Initialize for prepended IV for block cipher in TLS v1.1 and up |
| */ |
| if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) |
| { |
| /* Safe because data_len >= minlen + ivlen = 2 * ivlen. */ |
| memcpy( transform->iv_dec, data, transform->ivlen ); |
| |
| data += transform->ivlen; |
| rec->data_offset += transform->ivlen; |
| rec->data_len -= transform->ivlen; |
| } |
| #endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */ |
| |
| /* We still have data_len % ivlen == 0 and data_len >= ivlen here. */ |
| |
| if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_dec, |
| transform->iv_dec, transform->ivlen, |
| data, rec->data_len, data, &olen ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); |
| return( ret ); |
| } |
| |
| /* Double-check that length hasn't changed during decryption. */ |
| if( rec->data_len != olen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1) |
| if( transform->minor_ver < MBEDTLS_SSL_MINOR_VERSION_2 ) |
| { |
| /* |
| * Save IV in TLS1, where CBC decryption of consecutive |
| * records is equivalent to CBC decryption of the concatenation |
| * of the records; in other words, IVs are maintained across |
| * record decryptions. |
| */ |
| memcpy( transform->iv_dec, transform->cipher_ctx_dec.iv, |
| transform->ivlen ); |
| } |
| #endif |
| |
| /* Safe since data_len >= minlen + maclen + 1, so after having |
| * subtracted at most minlen and maclen up to this point, |
| * data_len > 0 (because of data_len % ivlen == 0, it's actually |
| * >= ivlen ). */ |
| padlen = data[rec->data_len - 1]; |
| |
| if( auth_done == 1 ) |
| { |
| const size_t mask = mbedtls_ssl_cf_mask_ge( |
| rec->data_len, |
| padlen + 1 ); |
| correct &= mask; |
| padlen &= mask; |
| } |
| else |
| { |
| #if defined(MBEDTLS_SSL_DEBUG_ALL) |
| if( rec->data_len < transform->maclen + padlen + 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET |
| ") < maclen (%" MBEDTLS_PRINTF_SIZET |
| ") + padlen (%" MBEDTLS_PRINTF_SIZET ")", |
| rec->data_len, |
| transform->maclen, |
| padlen + 1 ) ); |
| } |
| #endif |
| |
| const size_t mask = mbedtls_ssl_cf_mask_ge( |
| rec->data_len, |
| transform->maclen + padlen + 1 ); |
| correct &= mask; |
| padlen &= mask; |
| } |
| |
| padlen++; |
| |
| /* Regardless of the validity of the padding, |
| * we have data_len >= padlen here. */ |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ |
| defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| /* The padding check involves a series of up to 256 |
| * consecutive memory reads at the end of the record |
| * plaintext buffer. In order to hide the length and |
| * validity of the padding, always perform exactly |
| * `min(256,plaintext_len)` reads (but take into account |
| * only the last `padlen` bytes for the padding check). */ |
| size_t pad_count = 0; |
| volatile unsigned char* const check = data; |
| |
| /* Index of first padding byte; it has been ensured above |
| * that the subtraction is safe. */ |
| size_t const padding_idx = rec->data_len - padlen; |
| size_t const num_checks = rec->data_len <= 256 ? rec->data_len : 256; |
| size_t const start_idx = rec->data_len - num_checks; |
| size_t idx; |
| |
| for( idx = start_idx; idx < rec->data_len; idx++ ) |
| { |
| /* pad_count += (idx >= padding_idx) && |
| * (check[idx] == padlen - 1); |
| */ |
| const size_t mask = mbedtls_ssl_cf_mask_ge( idx, padding_idx ); |
| const size_t equal = mbedtls_ssl_cf_bool_eq( check[idx], |
| padlen - 1 ); |
| pad_count += mask & equal; |
| } |
| correct &= mbedtls_ssl_cf_bool_eq( pad_count, padlen ); |
| |
| #if defined(MBEDTLS_SSL_DEBUG_ALL) |
| if( padlen > 0 && correct == 0 ) |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad padding byte detected" ) ); |
| #endif |
| padlen &= mbedtls_ssl_cf_mask_from_bit( correct ); |
| |
| #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \ |
| MBEDTLS_SSL_PROTO_TLS1_2 */ |
| |
| /* If the padding was found to be invalid, padlen == 0 |
| * and the subtraction is safe. If the padding was found valid, |
| * padlen hasn't been changed and the previous assertion |
| * data_len >= padlen still holds. */ |
| rec->data_len -= padlen; |
| } |
| else |
| #endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC */ |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| #if defined(MBEDTLS_SSL_DEBUG_ALL) |
| MBEDTLS_SSL_DEBUG_BUF( 4, "raw buffer after decryption", |
| data, rec->data_len ); |
| #endif |
| |
| /* |
| * Authenticate if not done yet. |
| * Compute the MAC regardless of the padding result (RFC4346, CBCTIME). |
| */ |
| #if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) |
| if( auth_done == 0 ) |
| { |
| unsigned char mac_expect[MBEDTLS_SSL_MAC_ADD]; |
| unsigned char mac_peer[MBEDTLS_SSL_MAC_ADD]; |
| |
| /* If the initial value of padlen was such that |
| * data_len < maclen + padlen + 1, then padlen |
| * got reset to 1, and the initial check |
| * data_len >= minlen + maclen + 1 |
| * guarantees that at this point we still |
| * have at least data_len >= maclen. |
| * |
| * If the initial value of padlen was such that |
| * data_len >= maclen + padlen + 1, then we have |
| * subtracted either padlen + 1 (if the padding was correct) |
| * or 0 (if the padding was incorrect) since then, |
| * hence data_len >= maclen in any case. |
| */ |
| rec->data_len -= transform->maclen; |
| ssl_extract_add_data_from_record( add_data, &add_data_len, rec, |
| transform->minor_ver ); |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ |
| defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| /* |
| * The next two sizes are the minimum and maximum values of |
| * data_len over all padlen values. |
| * |
| * They're independent of padlen, since we previously did |
| * data_len -= padlen. |
| * |
| * Note that max_len + maclen is never more than the buffer |
| * length, as we previously did in_msglen -= maclen too. |
| */ |
| const size_t max_len = rec->data_len + padlen; |
| const size_t min_len = ( max_len > 256 ) ? max_len - 256 : 0; |
| |
| ret = mbedtls_ssl_cf_hmac( &transform->md_ctx_dec, |
| add_data, add_data_len, |
| data, rec->data_len, min_len, max_len, |
| mac_expect ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_cf_hmac", ret ); |
| return( ret ); |
| } |
| |
| mbedtls_ssl_cf_memcpy_offset( mac_peer, data, |
| rec->data_len, |
| min_len, max_len, |
| transform->maclen ); |
| #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \ |
| MBEDTLS_SSL_PROTO_TLS1_2 */ |
| |
| #if defined(MBEDTLS_SSL_DEBUG_ALL) |
| MBEDTLS_SSL_DEBUG_BUF( 4, "expected mac", mac_expect, transform->maclen ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", mac_peer, transform->maclen ); |
| #endif |
| |
| if( mbedtls_ssl_safer_memcmp( mac_peer, mac_expect, |
| transform->maclen ) != 0 ) |
| { |
| #if defined(MBEDTLS_SSL_DEBUG_ALL) |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) ); |
| #endif |
| correct = 0; |
| } |
| auth_done++; |
| } |
| |
| /* |
| * Finally check the correct flag |
| */ |
| if( correct == 0 ) |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| #endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */ |
| |
| /* Make extra sure authentication was performed, exactly once */ |
| if( auth_done != 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) |
| if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 ) |
| { |
| /* Remove inner padding and infer true content type. */ |
| ret = ssl_parse_inner_plaintext( data, &rec->data_len, |
| &rec->type ); |
| |
| if( ret != 0 ) |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| if( rec->cid_len != 0 ) |
| { |
| ret = ssl_parse_inner_plaintext( data, &rec->data_len, |
| &rec->type ); |
| if( ret != 0 ) |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= decrypt buf" ) ); |
| |
| return( 0 ); |
| } |
| |
| #undef MAC_NONE |
| #undef MAC_PLAINTEXT |
| #undef MAC_CIPHERTEXT |
| |
| /* |
| * Fill the input message buffer by appending data to it. |
| * The amount of data already fetched is in ssl->in_left. |
| * |
| * If we return 0, is it guaranteed that (at least) nb_want bytes are |
| * available (from this read and/or a previous one). Otherwise, an error code |
| * is returned (possibly EOF or WANT_READ). |
| * |
| * With stream transport (TLS) on success ssl->in_left == nb_want, but |
| * with datagram transport (DTLS) on success ssl->in_left >= nb_want, |
| * since we always read a whole datagram at once. |
| * |
| * For DTLS, it is up to the caller to set ssl->next_record_offset when |
| * they're done reading a record. |
| */ |
| int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t len; |
| #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) |
| size_t in_buf_len = ssl->in_buf_len; |
| #else |
| size_t in_buf_len = MBEDTLS_SSL_IN_BUFFER_LEN; |
| #endif |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> fetch input" ) ); |
| |
| if( ssl->f_recv == NULL && ssl->f_recv_timeout == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Bad usage of mbedtls_ssl_set_bio() " |
| "or mbedtls_ssl_set_bio()" ) ); |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| } |
| |
| if( nb_want > in_buf_len - (size_t)( ssl->in_hdr - ssl->in_buf ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "requesting more data than fits" ) ); |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| uint32_t timeout; |
| |
| /* |
| * The point is, we need to always read a full datagram at once, so we |
| * sometimes read more then requested, and handle the additional data. |
| * It could be the rest of the current record (while fetching the |
| * header) and/or some other records in the same datagram. |
| */ |
| |
| /* |
| * Move to the next record in the already read datagram if applicable |
| */ |
| if( ssl->next_record_offset != 0 ) |
| { |
| if( ssl->in_left < ssl->next_record_offset ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| ssl->in_left -= ssl->next_record_offset; |
| |
| if( ssl->in_left != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "next record in same datagram, offset: %" |
| MBEDTLS_PRINTF_SIZET, |
| ssl->next_record_offset ) ); |
| memmove( ssl->in_hdr, |
| ssl->in_hdr + ssl->next_record_offset, |
| ssl->in_left ); |
| } |
| |
| ssl->next_record_offset = 0; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "in_left: %" MBEDTLS_PRINTF_SIZET |
| ", nb_want: %" MBEDTLS_PRINTF_SIZET, |
| ssl->in_left, nb_want ) ); |
| |
| /* |
| * Done if we already have enough data. |
| */ |
| if( nb_want <= ssl->in_left) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= fetch input" ) ); |
| return( 0 ); |
| } |
| |
| /* |
| * A record can't be split across datagrams. If we need to read but |
| * are not at the beginning of a new record, the caller did something |
| * wrong. |
| */ |
| if( ssl->in_left != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| /* |
| * Don't even try to read if time's out already. |
| * This avoids by-passing the timer when repeatedly receiving messages |
| * that will end up being dropped. |
| */ |
| if( mbedtls_ssl_check_timer( ssl ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "timer has expired" ) ); |
| ret = MBEDTLS_ERR_SSL_TIMEOUT; |
| } |
| else |
| { |
| len = in_buf_len - ( ssl->in_hdr - ssl->in_buf ); |
| |
| if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) |
| timeout = ssl->handshake->retransmit_timeout; |
| else |
| timeout = ssl->conf->read_timeout; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "f_recv_timeout: %lu ms", (unsigned long) timeout ) ); |
| |
| if( ssl->f_recv_timeout != NULL ) |
| ret = ssl->f_recv_timeout( ssl->p_bio, ssl->in_hdr, len, |
| timeout ); |
| else |
| ret = ssl->f_recv( ssl->p_bio, ssl->in_hdr, len ); |
| |
| MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_recv(_timeout)", ret ); |
| |
| if( ret == 0 ) |
| return( MBEDTLS_ERR_SSL_CONN_EOF ); |
| } |
| |
| if( ret == MBEDTLS_ERR_SSL_TIMEOUT ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "timeout" ) ); |
| mbedtls_ssl_set_timer( ssl, 0 ); |
| |
| if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) |
| { |
| if( ssl_double_retransmit_timeout( ssl ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake timeout" ) ); |
| return( MBEDTLS_ERR_SSL_TIMEOUT ); |
| } |
| |
| if( ( ret = mbedtls_ssl_resend( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend", ret ); |
| return( ret ); |
| } |
| |
| return( MBEDTLS_ERR_SSL_WANT_READ ); |
| } |
| #if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_RENEGOTIATION) |
| else if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && |
| ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING ) |
| { |
| if( ( ret = mbedtls_ssl_resend_hello_request( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend_hello_request", |
| ret ); |
| return( ret ); |
| } |
| |
| return( MBEDTLS_ERR_SSL_WANT_READ ); |
| } |
| #endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_RENEGOTIATION */ |
| } |
| |
| if( ret < 0 ) |
| return( ret ); |
| |
| ssl->in_left = ret; |
| } |
| else |
| #endif |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "in_left: %" MBEDTLS_PRINTF_SIZET |
| ", nb_want: %" MBEDTLS_PRINTF_SIZET, |
| ssl->in_left, nb_want ) ); |
| |
| while( ssl->in_left < nb_want ) |
| { |
| len = nb_want - ssl->in_left; |
| |
| if( mbedtls_ssl_check_timer( ssl ) != 0 ) |
| ret = MBEDTLS_ERR_SSL_TIMEOUT; |
| else |
| { |
| if( ssl->f_recv_timeout != NULL ) |
| { |
| ret = ssl->f_recv_timeout( ssl->p_bio, |
| ssl->in_hdr + ssl->in_left, len, |
| ssl->conf->read_timeout ); |
| } |
| else |
| { |
| ret = ssl->f_recv( ssl->p_bio, |
| ssl->in_hdr + ssl->in_left, len ); |
| } |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "in_left: %" MBEDTLS_PRINTF_SIZET |
| ", nb_want: %" MBEDTLS_PRINTF_SIZET, |
| ssl->in_left, nb_want ) ); |
| MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_recv(_timeout)", ret ); |
| |
| if( ret == 0 ) |
| return( MBEDTLS_ERR_SSL_CONN_EOF ); |
| |
| if( ret < 0 ) |
| return( ret ); |
| |
| if ( (size_t)ret > len || ( INT_MAX > SIZE_MAX && ret > (int)SIZE_MAX ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, |
| ( "f_recv returned %d bytes but only %" MBEDTLS_PRINTF_SIZET " were requested", |
| ret, len ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| ssl->in_left += ret; |
| } |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= fetch input" ) ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Flush any data not yet written |
| */ |
| int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *buf; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> flush output" ) ); |
| |
| if( ssl->f_send == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Bad usage of mbedtls_ssl_set_bio() " |
| "or mbedtls_ssl_set_bio()" ) ); |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| } |
| |
| /* Avoid incrementing counter if data is flushed */ |
| if( ssl->out_left == 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= flush output" ) ); |
| return( 0 ); |
| } |
| |
| while( ssl->out_left > 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "message length: %" MBEDTLS_PRINTF_SIZET |
| ", out_left: %" MBEDTLS_PRINTF_SIZET, |
| mbedtls_ssl_out_hdr_len( ssl ) + ssl->out_msglen, ssl->out_left ) ); |
| |
| buf = ssl->out_hdr - ssl->out_left; |
| ret = ssl->f_send( ssl->p_bio, buf, ssl->out_left ); |
| |
| MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_send", ret ); |
| |
| if( ret <= 0 ) |
| return( ret ); |
| |
| if( (size_t)ret > ssl->out_left || ( INT_MAX > SIZE_MAX && ret > (int)SIZE_MAX ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, |
| ( "f_send returned %d bytes but only %" MBEDTLS_PRINTF_SIZET " bytes were sent", |
| ret, ssl->out_left ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| ssl->out_left -= ret; |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| ssl->out_hdr = ssl->out_buf; |
| } |
| else |
| #endif |
| { |
| ssl->out_hdr = ssl->out_buf + 8; |
| } |
| mbedtls_ssl_update_out_pointers( ssl, ssl->transform_out ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= flush output" ) ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Functions to handle the DTLS retransmission state machine |
| */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| /* |
| * Append current handshake message to current outgoing flight |
| */ |
| static int ssl_flight_append( mbedtls_ssl_context *ssl ) |
| { |
| mbedtls_ssl_flight_item *msg; |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_flight_append" ) ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "message appended to flight", |
| ssl->out_msg, ssl->out_msglen ); |
| |
| /* Allocate space for current message */ |
| if( ( msg = mbedtls_calloc( 1, sizeof( mbedtls_ssl_flight_item ) ) ) == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc %" MBEDTLS_PRINTF_SIZET " bytes failed", |
| sizeof( mbedtls_ssl_flight_item ) ) ); |
| return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); |
| } |
| |
| if( ( msg->p = mbedtls_calloc( 1, ssl->out_msglen ) ) == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc %" MBEDTLS_PRINTF_SIZET " bytes failed", |
| ssl->out_msglen ) ); |
| mbedtls_free( msg ); |
| return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); |
| } |
| |
| /* Copy current handshake message with headers */ |
| memcpy( msg->p, ssl->out_msg, ssl->out_msglen ); |
| msg->len = ssl->out_msglen; |
| msg->type = ssl->out_msgtype; |
| msg->next = NULL; |
| |
| /* Append to the current flight */ |
| if( ssl->handshake->flight == NULL ) |
| ssl->handshake->flight = msg; |
| else |
| { |
| mbedtls_ssl_flight_item *cur = ssl->handshake->flight; |
| while( cur->next != NULL ) |
| cur = cur->next; |
| cur->next = msg; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_flight_append" ) ); |
| return( 0 ); |
| } |
| |
| /* |
| * Free the current flight of handshake messages |
| */ |
| void mbedtls_ssl_flight_free( mbedtls_ssl_flight_item *flight ) |
| { |
| mbedtls_ssl_flight_item *cur = flight; |
| mbedtls_ssl_flight_item *next; |
| |
| while( cur != NULL ) |
| { |
| next = cur->next; |
| |
| mbedtls_free( cur->p ); |
| mbedtls_free( cur ); |
| |
| cur = next; |
| } |
| } |
| |
| /* |
| * Swap transform_out and out_ctr with the alternative ones |
| */ |
| static int ssl_swap_epochs( mbedtls_ssl_context *ssl ) |
| { |
| mbedtls_ssl_transform *tmp_transform; |
| unsigned char tmp_out_ctr[8]; |
| |
| if( ssl->transform_out == ssl->handshake->alt_transform_out ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip swap epochs" ) ); |
| return( 0 ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "swap epochs" ) ); |
| |
| /* Swap transforms */ |
| tmp_transform = ssl->transform_out; |
| ssl->transform_out = ssl->handshake->alt_transform_out; |
| ssl->handshake->alt_transform_out = tmp_transform; |
| |
| /* Swap epoch + sequence_number */ |
| memcpy( tmp_out_ctr, ssl->cur_out_ctr, 8 ); |
| memcpy( ssl->cur_out_ctr, ssl->handshake->alt_out_ctr, 8 ); |
| memcpy( ssl->handshake->alt_out_ctr, tmp_out_ctr, 8 ); |
| |
| /* Adjust to the newly activated transform */ |
| mbedtls_ssl_update_out_pointers( ssl, ssl->transform_out ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Retransmit the current flight of messages. |
| */ |
| int mbedtls_ssl_resend( mbedtls_ssl_context *ssl ) |
| { |
| int ret = 0; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_resend" ) ); |
| |
| ret = mbedtls_ssl_flight_transmit( ssl ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_resend" ) ); |
| |
| return( ret ); |
| } |
| |
| /* |
| * Transmit or retransmit the current flight of messages. |
| * |
| * Need to remember the current message in case flush_output returns |
| * WANT_WRITE, causing us to exit this function and come back later. |
| * This function must be called until state is no longer SENDING. |
| */ |
| int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_flight_transmit" ) ); |
| |
| if( ssl->handshake->retransmit_state != MBEDTLS_SSL_RETRANS_SENDING ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialise flight transmission" ) ); |
| |
| ssl->handshake->cur_msg = ssl->handshake->flight; |
| ssl->handshake->cur_msg_p = ssl->handshake->flight->p + 12; |
| ret = ssl_swap_epochs( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_SENDING; |
| } |
| |
| while( ssl->handshake->cur_msg != NULL ) |
| { |
| size_t max_frag_len; |
| const mbedtls_ssl_flight_item * const cur = ssl->handshake->cur_msg; |
| |
| int const is_finished = |
| ( cur->type == MBEDTLS_SSL_MSG_HANDSHAKE && |
| cur->p[0] == MBEDTLS_SSL_HS_FINISHED ); |
| |
| uint8_t const force_flush = ssl->disable_datagram_packing == 1 ? |
| SSL_FORCE_FLUSH : SSL_DONT_FORCE_FLUSH; |
| |
| /* Swap epochs before sending Finished: we can't do it after |
| * sending ChangeCipherSpec, in case write returns WANT_READ. |
| * Must be done before copying, may change out_msg pointer */ |
| if( is_finished && ssl->handshake->cur_msg_p == ( cur->p + 12 ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "swap epochs to send finished message" ) ); |
| ret = ssl_swap_epochs( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| } |
| |
| ret = ssl_get_remaining_payload_in_datagram( ssl ); |
| if( ret < 0 ) |
| return( ret ); |
| max_frag_len = (size_t) ret; |
| |
| /* CCS is copied as is, while HS messages may need fragmentation */ |
| if( cur->type == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) |
| { |
| if( max_frag_len == 0 ) |
| { |
| if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) |
| return( ret ); |
| |
| continue; |
| } |
| |
| memcpy( ssl->out_msg, cur->p, cur->len ); |
| ssl->out_msglen = cur->len; |
| ssl->out_msgtype = cur->type; |
| |
| /* Update position inside current message */ |
| ssl->handshake->cur_msg_p += cur->len; |
| } |
| else |
| { |
| const unsigned char * const p = ssl->handshake->cur_msg_p; |
| const size_t hs_len = cur->len - 12; |
| const size_t frag_off = p - ( cur->p + 12 ); |
| const size_t rem_len = hs_len - frag_off; |
| size_t cur_hs_frag_len, max_hs_frag_len; |
| |
| if( ( max_frag_len < 12 ) || ( max_frag_len == 12 && hs_len != 0 ) ) |
| { |
| if( is_finished ) |
| { |
| ret = ssl_swap_epochs( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| } |
| |
| if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) |
| return( ret ); |
| |
| continue; |
| } |
| max_hs_frag_len = max_frag_len - 12; |
| |
| cur_hs_frag_len = rem_len > max_hs_frag_len ? |
| max_hs_frag_len : rem_len; |
| |
| if( frag_off == 0 && cur_hs_frag_len != hs_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "fragmenting handshake message (%u > %u)", |
| (unsigned) cur_hs_frag_len, |
| (unsigned) max_hs_frag_len ) ); |
| } |
| |
| /* Messages are stored with handshake headers as if not fragmented, |
| * copy beginning of headers then fill fragmentation fields. |
| * Handshake headers: type(1) len(3) seq(2) f_off(3) f_len(3) */ |
| memcpy( ssl->out_msg, cur->p, 6 ); |
| |
| ssl->out_msg[6] = ( ( frag_off >> 16 ) & 0xff ); |
| ssl->out_msg[7] = ( ( frag_off >> 8 ) & 0xff ); |
| ssl->out_msg[8] = ( ( frag_off ) & 0xff ); |
| |
| ssl->out_msg[ 9] = ( ( cur_hs_frag_len >> 16 ) & 0xff ); |
| ssl->out_msg[10] = ( ( cur_hs_frag_len >> 8 ) & 0xff ); |
| ssl->out_msg[11] = ( ( cur_hs_frag_len ) & 0xff ); |
| |
| MBEDTLS_SSL_DEBUG_BUF( 3, "handshake header", ssl->out_msg, 12 ); |
| |
| /* Copy the handshake message content and set records fields */ |
| memcpy( ssl->out_msg + 12, p, cur_hs_frag_len ); |
| ssl->out_msglen = cur_hs_frag_len + 12; |
| ssl->out_msgtype = cur->type; |
| |
| /* Update position inside current message */ |
| ssl->handshake->cur_msg_p += cur_hs_frag_len; |
| } |
| |
| /* If done with the current message move to the next one if any */ |
| if( ssl->handshake->cur_msg_p >= cur->p + cur->len ) |
| { |
| if( cur->next != NULL ) |
| { |
| ssl->handshake->cur_msg = cur->next; |
| ssl->handshake->cur_msg_p = cur->next->p + 12; |
| } |
| else |
| { |
| ssl->handshake->cur_msg = NULL; |
| ssl->handshake->cur_msg_p = NULL; |
| } |
| } |
| |
| /* Actually send the message out */ |
| if( ( ret = mbedtls_ssl_write_record( ssl, force_flush ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); |
| return( ret ); |
| } |
| } |
| |
| if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) |
| return( ret ); |
| |
| /* Update state and set timer */ |
| if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) |
| ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED; |
| else |
| { |
| ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_WAITING; |
| mbedtls_ssl_set_timer( ssl, ssl->handshake->retransmit_timeout ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_flight_transmit" ) ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * To be called when the last message of an incoming flight is received. |
| */ |
| void mbedtls_ssl_recv_flight_completed( mbedtls_ssl_context *ssl ) |
| { |
| /* We won't need to resend that one any more */ |
| mbedtls_ssl_flight_free( ssl->handshake->flight ); |
| ssl->handshake->flight = NULL; |
| ssl->handshake->cur_msg = NULL; |
| |
| /* The next incoming flight will start with this msg_seq */ |
| ssl->handshake->in_flight_start_seq = ssl->handshake->in_msg_seq; |
| |
| /* We don't want to remember CCS's across flight boundaries. */ |
| ssl->handshake->buffering.seen_ccs = 0; |
| |
| /* Clear future message buffering structure. */ |
| mbedtls_ssl_buffering_free( ssl ); |
| |
| /* Cancel timer */ |
| mbedtls_ssl_set_timer( ssl, 0 ); |
| |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && |
| ssl->in_msg[0] == MBEDTLS_SSL_HS_FINISHED ) |
| { |
| ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED; |
| } |
| else |
| ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_PREPARING; |
| } |
| |
| /* |
| * To be called when the last message of an outgoing flight is send. |
| */ |
| void mbedtls_ssl_send_flight_completed( mbedtls_ssl_context *ssl ) |
| { |
| ssl_reset_retransmit_timeout( ssl ); |
| mbedtls_ssl_set_timer( ssl, ssl->handshake->retransmit_timeout ); |
| |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && |
| ssl->in_msg[0] == MBEDTLS_SSL_HS_FINISHED ) |
| { |
| ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED; |
| } |
| else |
| ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_WAITING; |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| /* |
| * Handshake layer functions |
| */ |
| |
| /* |
| * Write (DTLS: or queue) current handshake (including CCS) message. |
| * |
| * - fill in handshake headers |
| * - update handshake checksum |
| * - DTLS: save message for resending |
| * - then pass to the record layer |
| * |
| * DTLS: except for HelloRequest, messages are only queued, and will only be |
| * actually sent when calling flight_transmit() or resend(). |
| * |
| * Inputs: |
| * - ssl->out_msglen: 4 + actual handshake message len |
| * (4 is the size of handshake headers for TLS) |
| * - ssl->out_msg[0]: the handshake type (ClientHello, ServerHello, etc) |
| * - ssl->out_msg + 4: the handshake message body |
| * |
| * Outputs, ie state before passing to flight_append() or write_record(): |
| * - ssl->out_msglen: the length of the record contents |
| * (including handshake headers but excluding record headers) |
| * - ssl->out_msg: the record contents (handshake headers + content) |
| */ |
| int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| const size_t hs_len = ssl->out_msglen - 4; |
| const unsigned char hs_type = ssl->out_msg[0]; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write handshake message" ) ); |
| |
| /* |
| * Sanity checks |
| */ |
| if( ssl->out_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE && |
| ssl->out_msgtype != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| /* Whenever we send anything different from a |
| * HelloRequest we should be in a handshake - double check. */ |
| if( ! ( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && |
| hs_type == MBEDTLS_SSL_HS_HELLO_REQUEST ) && |
| ssl->handshake == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ssl->handshake != NULL && |
| ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| #endif |
| |
| /* Double-check that we did not exceed the bounds |
| * of the outgoing record buffer. |
| * This should never fail as the various message |
| * writing functions must obey the bounds of the |
| * outgoing record buffer, but better be safe. |
| * |
| * Note: We deliberately do not check for the MTU or MFL here. |
| */ |
| if( ssl->out_msglen > MBEDTLS_SSL_OUT_CONTENT_LEN ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Record too large: " |
| "size %" MBEDTLS_PRINTF_SIZET |
| ", maximum %" MBEDTLS_PRINTF_SIZET, |
| ssl->out_msglen, |
| (size_t) MBEDTLS_SSL_OUT_CONTENT_LEN ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| /* |
| * Fill handshake headers |
| */ |
| if( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) |
| { |
| ssl->out_msg[1] = (unsigned char)( hs_len >> 16 ); |
| ssl->out_msg[2] = (unsigned char)( hs_len >> 8 ); |
| ssl->out_msg[3] = (unsigned char)( hs_len ); |
| |
| /* |
| * DTLS has additional fields in the Handshake layer, |
| * between the length field and the actual payload: |
| * uint16 message_seq; |
| * uint24 fragment_offset; |
| * uint24 fragment_length; |
| */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| /* Make room for the additional DTLS fields */ |
| if( MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen < 8 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS handshake message too large: " |
| "size %" MBEDTLS_PRINTF_SIZET ", maximum %" MBEDTLS_PRINTF_SIZET, |
| hs_len, |
| (size_t) ( MBEDTLS_SSL_OUT_CONTENT_LEN - 12 ) ) ); |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| } |
| |
| memmove( ssl->out_msg + 12, ssl->out_msg + 4, hs_len ); |
| ssl->out_msglen += 8; |
| |
| /* Write message_seq and update it, except for HelloRequest */ |
| if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST ) |
| { |
| ssl->out_msg[4] = ( ssl->handshake->out_msg_seq >> 8 ) & 0xFF; |
| ssl->out_msg[5] = ( ssl->handshake->out_msg_seq ) & 0xFF; |
| ++( ssl->handshake->out_msg_seq ); |
| } |
| else |
| { |
| ssl->out_msg[4] = 0; |
| ssl->out_msg[5] = 0; |
| } |
| |
| /* Handshake hashes are computed without fragmentation, |
| * so set frag_offset = 0 and frag_len = hs_len for now */ |
| memset( ssl->out_msg + 6, 0x00, 3 ); |
| memcpy( ssl->out_msg + 9, ssl->out_msg + 1, 3 ); |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| /* Update running hashes of handshake messages seen */ |
| if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST ) |
| ssl->handshake->update_checksum( ssl, ssl->out_msg, ssl->out_msglen ); |
| } |
| |
| /* Either send now, or just save to be sent (and resent) later */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ! ( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && |
| hs_type == MBEDTLS_SSL_HS_HELLO_REQUEST ) ) |
| { |
| if( ( ret = ssl_flight_append( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_flight_append", ret ); |
| return( ret ); |
| } |
| } |
| else |
| #endif |
| { |
| if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_write_record", ret ); |
| return( ret ); |
| } |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write handshake message" ) ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Record layer functions |
| */ |
| |
| /* |
| * Write current record. |
| * |
| * Uses: |
| * - ssl->out_msgtype: type of the message (AppData, Handshake, Alert, CCS) |
| * - ssl->out_msglen: length of the record content (excl headers) |
| * - ssl->out_msg: record content |
| */ |
| int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush ) |
| { |
| int ret, done = 0; |
| size_t len = ssl->out_msglen; |
| uint8_t flush = force_flush; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write record" ) ); |
| |
| if( !done ) |
| { |
| unsigned i; |
| size_t protected_record_size; |
| #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) |
| size_t out_buf_len = ssl->out_buf_len; |
| #else |
| size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN; |
| #endif |
| /* Skip writing the record content type to after the encryption, |
| * as it may change when using the CID extension. */ |
| |
| mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver, |
| ssl->conf->transport, ssl->out_hdr + 1 ); |
| |
| memcpy( ssl->out_ctr, ssl->cur_out_ctr, 8 ); |
| ssl->out_len[0] = (unsigned char)( len >> 8 ); |
| ssl->out_len[1] = (unsigned char)( len ); |
| |
| if( ssl->transform_out != NULL ) |
| { |
| mbedtls_record rec; |
| |
| rec.buf = ssl->out_iv; |
| rec.buf_len = out_buf_len - ( ssl->out_iv - ssl->out_buf ); |
| rec.data_len = ssl->out_msglen; |
| rec.data_offset = ssl->out_msg - rec.buf; |
| |
| memcpy( &rec.ctr[0], ssl->out_ctr, 8 ); |
| mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver, |
| ssl->conf->transport, rec.ver ); |
| rec.type = ssl->out_msgtype; |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| /* The CID is set by mbedtls_ssl_encrypt_buf(). */ |
| rec.cid_len = 0; |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| |
| if( ( ret = mbedtls_ssl_encrypt_buf( ssl, ssl->transform_out, &rec, |
| ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_encrypt_buf", ret ); |
| return( ret ); |
| } |
| |
| if( rec.data_offset != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| /* Update the record content type and CID. */ |
| ssl->out_msgtype = rec.type; |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID ) |
| memcpy( ssl->out_cid, rec.cid, rec.cid_len ); |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| ssl->out_msglen = len = rec.data_len; |
| ssl->out_len[0] = (unsigned char)( rec.data_len >> 8 ); |
| ssl->out_len[1] = (unsigned char)( rec.data_len ); |
| } |
| |
| protected_record_size = len + mbedtls_ssl_out_hdr_len( ssl ); |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| /* In case of DTLS, double-check that we don't exceed |
| * the remaining space in the datagram. */ |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| ret = ssl_get_remaining_space_in_datagram( ssl ); |
| if( ret < 0 ) |
| return( ret ); |
| |
| if( protected_record_size > (size_t) ret ) |
| { |
| /* Should never happen */ |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| /* Now write the potentially updated record content type. */ |
| ssl->out_hdr[0] = (unsigned char) ssl->out_msgtype; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "output record: msgtype = %u, " |
| "version = [%u:%u], msglen = %" MBEDTLS_PRINTF_SIZET, |
| ssl->out_hdr[0], ssl->out_hdr[1], |
| ssl->out_hdr[2], len ) ); |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network", |
| ssl->out_hdr, protected_record_size ); |
| |
| ssl->out_left += protected_record_size; |
| ssl->out_hdr += protected_record_size; |
| mbedtls_ssl_update_out_pointers( ssl, ssl->transform_out ); |
| |
| for( i = 8; i > mbedtls_ssl_ep_len( ssl ); i-- ) |
| if( ++ssl->cur_out_ctr[i - 1] != 0 ) |
| break; |
| |
| /* The loop goes to its end iff the counter is wrapping */ |
| if( i == mbedtls_ssl_ep_len( ssl ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "outgoing message counter would wrap" ) ); |
| return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING ); |
| } |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| flush == SSL_DONT_FORCE_FLUSH ) |
| { |
| size_t remaining; |
| ret = ssl_get_remaining_payload_in_datagram( ssl ); |
| if( ret < 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_get_remaining_payload_in_datagram", |
| ret ); |
| return( ret ); |
| } |
| |
| remaining = (size_t) ret; |
| if( remaining == 0 ) |
| { |
| flush = SSL_FORCE_FLUSH; |
| } |
| else |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Still %u bytes available in current datagram", (unsigned) remaining ) ); |
| } |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| if( ( flush == SSL_FORCE_FLUSH ) && |
| ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flush_output", ret ); |
| return( ret ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write record" ) ); |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| |
| static int ssl_hs_is_proper_fragment( mbedtls_ssl_context *ssl ) |
| { |
| if( ssl->in_msglen < ssl->in_hslen || |
| memcmp( ssl->in_msg + 6, "\0\0\0", 3 ) != 0 || |
| memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 ) |
| { |
| return( 1 ); |
| } |
| return( 0 ); |
| } |
| |
| static uint32_t ssl_get_hs_frag_len( mbedtls_ssl_context const *ssl ) |
| { |
| return( ( ssl->in_msg[9] << 16 ) | |
| ( ssl->in_msg[10] << 8 ) | |
| ssl->in_msg[11] ); |
| } |
| |
| static uint32_t ssl_get_hs_frag_off( mbedtls_ssl_context const *ssl ) |
| { |
| return( ( ssl->in_msg[6] << 16 ) | |
| ( ssl->in_msg[7] << 8 ) | |
| ssl->in_msg[8] ); |
| } |
| |
| static int ssl_check_hs_header( mbedtls_ssl_context const *ssl ) |
| { |
| uint32_t msg_len, frag_off, frag_len; |
| |
| msg_len = ssl_get_hs_total_len( ssl ); |
| frag_off = ssl_get_hs_frag_off( ssl ); |
| frag_len = ssl_get_hs_frag_len( ssl ); |
| |
| if( frag_off > msg_len ) |
| return( -1 ); |
| |
| if( frag_len > msg_len - frag_off ) |
| return( -1 ); |
| |
| if( frag_len + 12 > ssl->in_msglen ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Mark bits in bitmask (used for DTLS HS reassembly) |
| */ |
| static void ssl_bitmask_set( unsigned char *mask, size_t offset, size_t len ) |
| { |
| unsigned int start_bits, end_bits; |
| |
| start_bits = 8 - ( offset % 8 ); |
| if( start_bits != 8 ) |
| { |
| size_t first_byte_idx = offset / 8; |
| |
| /* Special case */ |
| if( len <= start_bits ) |
| { |
| for( ; len != 0; len-- ) |
| mask[first_byte_idx] |= 1 << ( start_bits - len ); |
| |
| /* Avoid potential issues with offset or len becoming invalid */ |
| return; |
| } |
| |
| offset += start_bits; /* Now offset % 8 == 0 */ |
| len -= start_bits; |
| |
| for( ; start_bits != 0; start_bits-- ) |
| mask[first_byte_idx] |= 1 << ( start_bits - 1 ); |
| } |
| |
| end_bits = len % 8; |
| if( end_bits != 0 ) |
| { |
| size_t last_byte_idx = ( offset + len ) / 8; |
| |
| len -= end_bits; /* Now len % 8 == 0 */ |
| |
| for( ; end_bits != 0; end_bits-- ) |
| mask[last_byte_idx] |= 1 << ( 8 - end_bits ); |
| } |
| |
| memset( mask + offset / 8, 0xFF, len / 8 ); |
| } |
| |
| /* |
| * Check that bitmask is full |
| */ |
| static int ssl_bitmask_check( unsigned char *mask, size_t len ) |
| { |
| size_t i; |
| |
| for( i = 0; i < len / 8; i++ ) |
| if( mask[i] != 0xFF ) |
| return( -1 ); |
| |
| for( i = 0; i < len % 8; i++ ) |
| if( ( mask[len / 8] & ( 1 << ( 7 - i ) ) ) == 0 ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |
| |
| /* msg_len does not include the handshake header */ |
| static size_t ssl_get_reassembly_buffer_size( size_t msg_len, |
| unsigned add_bitmap ) |
| { |
| size_t alloc_len; |
| |
| alloc_len = 12; /* Handshake header */ |
| alloc_len += msg_len; /* Content buffer */ |
| |
| if( add_bitmap ) |
| alloc_len += msg_len / 8 + ( msg_len % 8 != 0 ); /* Bitmap */ |
| |
| return( alloc_len ); |
| } |
| |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl ) |
| { |
| return( ( ssl->in_msg[1] << 16 ) | |
| ( ssl->in_msg[2] << 8 ) | |
| ssl->in_msg[3] ); |
| } |
| |
| int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) |
| { |
| if( ssl->in_msglen < mbedtls_ssl_hs_hdr_len( ssl ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake message too short: %" MBEDTLS_PRINTF_SIZET, |
| ssl->in_msglen ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + ssl_get_hs_total_len( ssl ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "handshake message: msglen =" |
| " %" MBEDTLS_PRINTF_SIZET ", type = %u, hslen = %" MBEDTLS_PRINTF_SIZET, |
| ssl->in_msglen, ssl->in_msg[0], ssl->in_hslen ) ); |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned int recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; |
| |
| if( ssl_check_hs_header( ssl ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid handshake header" ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| if( ssl->handshake != NULL && |
| ( ( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && |
| recv_msg_seq != ssl->handshake->in_msg_seq ) || |
| ( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER && |
| ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) ) ) |
| { |
| if( recv_msg_seq > ssl->handshake->in_msg_seq ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "received future handshake message of sequence number %u (next %u)", |
| recv_msg_seq, |
| ssl->handshake->in_msg_seq ) ); |
| return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); |
| } |
| |
| /* Retransmit only on last message from previous flight, to avoid |
| * too many retransmissions. |
| * Besides, No sane server ever retransmits HelloVerifyRequest */ |
| if( recv_msg_seq == ssl->handshake->in_flight_start_seq - 1 && |
| ssl->in_msg[0] != MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "received message from last flight, " |
| "message_seq = %u, start_of_flight = %u", |
| recv_msg_seq, |
| ssl->handshake->in_flight_start_seq ) ); |
| |
| if( ( ret = mbedtls_ssl_resend( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend", ret ); |
| return( ret ); |
| } |
| } |
| else |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "dropping out-of-sequence message: " |
| "message_seq = %u, expected = %u", |
| recv_msg_seq, |
| ssl->handshake->in_msg_seq ) ); |
| } |
| |
| return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); |
| } |
| /* Wait until message completion to increment in_msg_seq */ |
| |
| /* Message reassembly is handled alongside buffering of future |
| * messages; the commonality is that both handshake fragments and |
| * future messages cannot be forwarded immediately to the |
| * handshake logic layer. */ |
| if( ssl_hs_is_proper_fragment( ssl ) == 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "found fragmented DTLS handshake message" ) ); |
| return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| /* With TLS we don't handle fragmentation (for now) */ |
| if( ssl->in_msglen < ssl->in_hslen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLS handshake fragmentation not supported" ) ); |
| return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); |
| } |
| |
| return( 0 ); |
| } |
| |
| void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl ) |
| { |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| |
| if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && hs != NULL ) |
| { |
| ssl->handshake->update_checksum( ssl, ssl->in_msg, ssl->in_hslen ); |
| } |
| |
| /* Handshake message is complete, increment counter */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ssl->handshake != NULL ) |
| { |
| unsigned offset; |
| mbedtls_ssl_hs_buffer *hs_buf; |
| |
| /* Increment handshake sequence number */ |
| hs->in_msg_seq++; |
| |
| /* |
| * Clear up handshake buffering and reassembly structure. |
| */ |
| |
| /* Free first entry */ |
| ssl_buffering_free_slot( ssl, 0 ); |
| |
| /* Shift all other entries */ |
| for( offset = 0, hs_buf = &hs->buffering.hs[0]; |
| offset + 1 < MBEDTLS_SSL_MAX_BUFFERED_HS; |
| offset++, hs_buf++ ) |
| { |
| *hs_buf = *(hs_buf + 1); |
| } |
| |
| /* Create a fresh last entry */ |
| memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) ); |
| } |
| #endif |
| } |
| |
| /* |
| * DTLS anti-replay: RFC 6347 4.1.2.6 |
| * |
| * in_window is a field of bits numbered from 0 (lsb) to 63 (msb). |
| * Bit n is set iff record number in_window_top - n has been seen. |
| * |
| * Usually, in_window_top is the last record number seen and the lsb of |
| * in_window is set. The only exception is the initial state (record number 0 |
| * not seen yet). |
| */ |
| #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) |
| void mbedtls_ssl_dtls_replay_reset( mbedtls_ssl_context *ssl ) |
| { |
| ssl->in_window_top = 0; |
| ssl->in_window = 0; |
| } |
| |
| static inline uint64_t ssl_load_six_bytes( unsigned char *buf ) |
| { |
| return( ( (uint64_t) buf[0] << 40 ) | |
| ( (uint64_t) buf[1] << 32 ) | |
| ( (uint64_t) buf[2] << 24 ) | |
| ( (uint64_t) buf[3] << 16 ) | |
| ( (uint64_t) buf[4] << 8 ) | |
| ( (uint64_t) buf[5] ) ); |
| } |
| |
| static int mbedtls_ssl_dtls_record_replay_check( mbedtls_ssl_context *ssl, uint8_t *record_in_ctr ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *original_in_ctr; |
| |
| // save original in_ctr |
| original_in_ctr = ssl->in_ctr; |
| |
| // use counter from record |
| ssl->in_ctr = record_in_ctr; |
| |
| ret = mbedtls_ssl_dtls_replay_check( (mbedtls_ssl_context const *) ssl ); |
| |
| // restore the counter |
| ssl->in_ctr = original_in_ctr; |
| |
| return ret; |
| } |
| |
| /* |
| * Return 0 if sequence number is acceptable, -1 otherwise |
| */ |
| int mbedtls_ssl_dtls_replay_check( mbedtls_ssl_context const *ssl ) |
| { |
| uint64_t rec_seqnum = ssl_load_six_bytes( ssl->in_ctr + 2 ); |
| uint64_t bit; |
| |
| if( ssl->conf->anti_replay == MBEDTLS_SSL_ANTI_REPLAY_DISABLED ) |
| return( 0 ); |
| |
| if( rec_seqnum > ssl->in_window_top ) |
| return( 0 ); |
| |
| bit = ssl->in_window_top - rec_seqnum; |
| |
| if( bit >= 64 ) |
| return( -1 ); |
| |
| if( ( ssl->in_window & ( (uint64_t) 1 << bit ) ) != 0 ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Update replay window on new validated record |
| */ |
| void mbedtls_ssl_dtls_replay_update( mbedtls_ssl_context *ssl ) |
| { |
| uint64_t rec_seqnum = ssl_load_six_bytes( ssl->in_ctr + 2 ); |
| |
| if( ssl->conf->anti_replay == MBEDTLS_SSL_ANTI_REPLAY_DISABLED ) |
| return; |
| |
| if( rec_seqnum > ssl->in_window_top ) |
| { |
| /* Update window_top and the contents of the window */ |
| uint64_t shift = rec_seqnum - ssl->in_window_top; |
| |
| if( shift >= 64 ) |
| ssl->in_window = 1; |
| else |
| { |
| ssl->in_window <<= shift; |
| ssl->in_window |= 1; |
| } |
| |
| ssl->in_window_top = rec_seqnum; |
| } |
| else |
| { |
| /* Mark that number as seen in the current window */ |
| uint64_t bit = ssl->in_window_top - rec_seqnum; |
| |
| if( bit < 64 ) /* Always true, but be extra sure */ |
| ssl->in_window |= (uint64_t) 1 << bit; |
| } |
| } |
| #endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */ |
| |
| #if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C) |
| /* |
| * Without any SSL context, check if a datagram looks like a ClientHello with |
| * a valid cookie, and if it doesn't, generate a HelloVerifyRequest message. |
| * Both input and output include full DTLS headers. |
| * |
| * - if cookie is valid, return 0 |
| * - if ClientHello looks superficially valid but cookie is not, |
| * fill obuf and set olen, then |
| * return MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED |
| * - otherwise return a specific error code |
| */ |
| static int ssl_check_dtls_clihlo_cookie( |
| mbedtls_ssl_cookie_write_t *f_cookie_write, |
| mbedtls_ssl_cookie_check_t *f_cookie_check, |
| void *p_cookie, |
| const unsigned char *cli_id, size_t cli_id_len, |
| const unsigned char *in, size_t in_len, |
| unsigned char *obuf, size_t buf_len, size_t *olen ) |
| { |
| size_t sid_len, cookie_len; |
| unsigned char *p; |
| |
| /* |
| * Structure of ClientHello with record and handshake headers, |
| * and expected values. We don't need to check a lot, more checks will be |
| * done when actually parsing the ClientHello - skipping those checks |
| * avoids code duplication and does not make cookie forging any easier. |
| * |
| * 0-0 ContentType type; copied, must be handshake |
| * 1-2 ProtocolVersion version; copied |
| * 3-4 uint16 epoch; copied, must be 0 |
| * 5-10 uint48 sequence_number; copied |
| * 11-12 uint16 length; (ignored) |
| * |
| * 13-13 HandshakeType msg_type; (ignored) |
| * 14-16 uint24 length; (ignored) |
| * 17-18 uint16 message_seq; copied |
| * 19-21 uint24 fragment_offset; copied, must be 0 |
| * 22-24 uint24 fragment_length; (ignored) |
| * |
| * 25-26 ProtocolVersion client_version; (ignored) |
| * 27-58 Random random; (ignored) |
| * 59-xx SessionID session_id; 1 byte len + sid_len content |
| * 60+ opaque cookie<0..2^8-1>; 1 byte len + content |
| * ... |
| * |
| * Minimum length is 61 bytes. |
| */ |
| if( in_len < 61 || |
| in[0] != MBEDTLS_SSL_MSG_HANDSHAKE || |
| in[3] != 0 || in[4] != 0 || |
| in[19] != 0 || in[20] != 0 || in[21] != 0 ) |
| { |
| return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); |
| } |
| |
| sid_len = in[59]; |
| if( sid_len > in_len - 61 ) |
| return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); |
| |
| cookie_len = in[60 + sid_len]; |
| if( cookie_len > in_len - 60 ) |
| return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); |
| |
| if( f_cookie_check( p_cookie, in + sid_len + 61, cookie_len, |
| cli_id, cli_id_len ) == 0 ) |
| { |
| /* Valid cookie */ |
| return( 0 ); |
| } |
| |
| /* |
| * If we get here, we've got an invalid cookie, let's prepare HVR. |
| * |
| * 0-0 ContentType type; copied |
| * 1-2 ProtocolVersion version; copied |
| * 3-4 uint16 epoch; copied |
| * 5-10 uint48 sequence_number; copied |
| * 11-12 uint16 length; olen - 13 |
| * |
| * 13-13 HandshakeType msg_type; hello_verify_request |
| * 14-16 uint24 length; olen - 25 |
| * 17-18 uint16 message_seq; copied |
| * 19-21 uint24 fragment_offset; copied |
| * 22-24 uint24 fragment_length; olen - 25 |
| * |
| * 25-26 ProtocolVersion server_version; 0xfe 0xff |
| * 27-27 opaque cookie<0..2^8-1>; cookie_len = olen - 27, cookie |
| * |
| * Minimum length is 28. |
| */ |
| if( buf_len < 28 ) |
| return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); |
| |
| /* Copy most fields and adapt others */ |
| memcpy( obuf, in, 25 ); |
| obuf[13] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST; |
| obuf[25] = 0xfe; |
| obuf[26] = 0xff; |
| |
| /* Generate and write actual cookie */ |
| p = obuf + 28; |
| if( f_cookie_write( p_cookie, |
| &p, obuf + buf_len, cli_id, cli_id_len ) != 0 ) |
| { |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| *olen = p - obuf; |
| |
| /* Go back and fill length fields */ |
| obuf[27] = (unsigned char)( *olen - 28 ); |
| |
| obuf[14] = obuf[22] = (unsigned char)( ( *olen - 25 ) >> 16 ); |
| obuf[15] = obuf[23] = (unsigned char)( ( *olen - 25 ) >> 8 ); |
| obuf[16] = obuf[24] = (unsigned char)( ( *olen - 25 ) ); |
| |
| obuf[11] = (unsigned char)( ( *olen - 13 ) >> 8 ); |
| obuf[12] = (unsigned char)( ( *olen - 13 ) ); |
| |
| return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED ); |
| } |
| |
| /* |
| * Handle possible client reconnect with the same UDP quadruplet |
| * (RFC 6347 Section 4.2.8). |
| * |
| * Called by ssl_parse_record_header() in case we receive an epoch 0 record |
| * that looks like a ClientHello. |
| * |
| * - if the input looks like a ClientHello without cookies, |
| * send back HelloVerifyRequest, then return 0 |
| * - if the input looks like a ClientHello with a valid cookie, |
| * reset the session of the current context, and |
| * return MBEDTLS_ERR_SSL_CLIENT_RECONNECT |
| * - if anything goes wrong, return a specific error code |
| * |
| * This function is called (through ssl_check_client_reconnect()) when an |
| * unexpected record is found in ssl_get_next_record(), which will discard the |
| * record if we return 0, and bubble up the return value otherwise (this |
| * includes the case of MBEDTLS_ERR_SSL_CLIENT_RECONNECT and of unexpected |
| * errors, and is the right thing to do in both cases). |
| */ |
| static int ssl_handle_possible_reconnect( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t len; |
| |
| if( ssl->conf->f_cookie_write == NULL || |
| ssl->conf->f_cookie_check == NULL ) |
| { |
| /* If we can't use cookies to verify reachability of the peer, |
| * drop the record. */ |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "no cookie callbacks, " |
| "can't check reconnect validity" ) ); |
| return( 0 ); |
| } |
| |
| ret = ssl_check_dtls_clihlo_cookie( |
| ssl->conf->f_cookie_write, |
| ssl->conf->f_cookie_check, |
| ssl->conf->p_cookie, |
| ssl->cli_id, ssl->cli_id_len, |
| ssl->in_buf, ssl->in_left, |
| ssl->out_buf, MBEDTLS_SSL_OUT_CONTENT_LEN, &len ); |
| |
| MBEDTLS_SSL_DEBUG_RET( 2, "ssl_check_dtls_clihlo_cookie", ret ); |
| |
| if( ret == MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED ) |
| { |
| int send_ret; |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "sending HelloVerifyRequest" ) ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network", |
| ssl->out_buf, len ); |
| /* Don't check write errors as we can't do anything here. |
| * If the error is permanent we'll catch it later, |
| * if it's not, then hopefully it'll work next time. */ |
| send_ret = ssl->f_send( ssl->p_bio, ssl->out_buf, len ); |
| MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_send", send_ret ); |
| (void) send_ret; |
| |
| return( 0 ); |
| } |
| |
| if( ret == 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "cookie is valid, resetting context" ) ); |
| if( ( ret = mbedtls_ssl_session_reset_int( ssl, 1 ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "reset", ret ); |
| return( ret ); |
| } |
| |
| return( MBEDTLS_ERR_SSL_CLIENT_RECONNECT ); |
| } |
| |
| return( ret ); |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */ |
| |
| static int ssl_check_record_type( uint8_t record_type ) |
| { |
| if( record_type != MBEDTLS_SSL_MSG_HANDSHAKE && |
| record_type != MBEDTLS_SSL_MSG_ALERT && |
| record_type != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC && |
| record_type != MBEDTLS_SSL_MSG_APPLICATION_DATA ) |
| { |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| return( 0 ); |
| } |
| |
| /* |
| * ContentType type; |
| * ProtocolVersion version; |
| * uint16 epoch; // DTLS only |
| * uint48 sequence_number; // DTLS only |
| * uint16 length; |
| * |
| * Return 0 if header looks sane (and, for DTLS, the record is expected) |
| * MBEDTLS_ERR_SSL_INVALID_RECORD if the header looks bad, |
| * MBEDTLS_ERR_SSL_UNEXPECTED_RECORD (DTLS only) if sane but unexpected. |
| * |
| * With DTLS, mbedtls_ssl_read_record() will: |
| * 1. proceed with the record if this function returns 0 |
| * 2. drop only the current record if this function returns UNEXPECTED_RECORD |
| * 3. return CLIENT_RECONNECT if this function return that value |
| * 4. drop the whole datagram if this function returns anything else. |
| * Point 2 is needed when the peer is resending, and we have already received |
| * the first record from a datagram but are still waiting for the others. |
| */ |
| static int ssl_parse_record_header( mbedtls_ssl_context const *ssl, |
| unsigned char *buf, |
| size_t len, |
| mbedtls_record *rec ) |
| { |
| int major_ver, minor_ver; |
| |
| size_t const rec_hdr_type_offset = 0; |
| size_t const rec_hdr_type_len = 1; |
| |
| size_t const rec_hdr_version_offset = rec_hdr_type_offset + |
| rec_hdr_type_len; |
| size_t const rec_hdr_version_len = 2; |
| |
| size_t const rec_hdr_ctr_len = 8; |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| uint32_t rec_epoch; |
| size_t const rec_hdr_ctr_offset = rec_hdr_version_offset + |
| rec_hdr_version_len; |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| size_t const rec_hdr_cid_offset = rec_hdr_ctr_offset + |
| rec_hdr_ctr_len; |
| size_t rec_hdr_cid_len = 0; |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| size_t rec_hdr_len_offset; /* To be determined */ |
| size_t const rec_hdr_len_len = 2; |
| |
| /* |
| * Check minimum lengths for record header. |
| */ |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| rec_hdr_len_offset = rec_hdr_ctr_offset + rec_hdr_ctr_len; |
| } |
| else |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| { |
| rec_hdr_len_offset = rec_hdr_version_offset + rec_hdr_version_len; |
| } |
| |
| if( len < rec_hdr_len_offset + rec_hdr_len_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "datagram of length %u too small to hold DTLS record header of length %u", |
| (unsigned) len, |
| (unsigned)( rec_hdr_len_len + rec_hdr_len_len ) ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| /* |
| * Parse and validate record content type |
| */ |
| |
| rec->type = buf[ rec_hdr_type_offset ]; |
| |
| /* Check record content type */ |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| rec->cid_len = 0; |
| |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ssl->conf->cid_len != 0 && |
| rec->type == MBEDTLS_SSL_MSG_CID ) |
| { |
| /* Shift pointers to account for record header including CID |
| * struct { |
| * ContentType special_type = tls12_cid; |
| * ProtocolVersion version; |
| * uint16 epoch; |
| * uint48 sequence_number; |
| * opaque cid[cid_length]; // Additional field compared to |
| * // default DTLS record format |
| * uint16 length; |
| * opaque enc_content[DTLSCiphertext.length]; |
| * } DTLSCiphertext; |
| */ |
| |
| /* So far, we only support static CID lengths |
| * fixed in the configuration. */ |
| rec_hdr_cid_len = ssl->conf->cid_len; |
| rec_hdr_len_offset += rec_hdr_cid_len; |
| |
| if( len < rec_hdr_len_offset + rec_hdr_len_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "datagram of length %u too small to hold DTLS record header including CID, length %u", |
| (unsigned) len, |
| (unsigned)( rec_hdr_len_offset + rec_hdr_len_len ) ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| /* configured CID len is guaranteed at most 255, see |
| * MBEDTLS_SSL_CID_OUT_LEN_MAX in check_config.h */ |
| rec->cid_len = (uint8_t) rec_hdr_cid_len; |
| memcpy( rec->cid, buf + rec_hdr_cid_offset, rec_hdr_cid_len ); |
| } |
| else |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| { |
| if( ssl_check_record_type( rec->type ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "unknown record type %u", |
| (unsigned) rec->type ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| } |
| |
| /* |
| * Parse and validate record version |
| */ |
| |
| rec->ver[0] = buf[ rec_hdr_version_offset + 0 ]; |
| rec->ver[1] = buf[ rec_hdr_version_offset + 1 ]; |
| mbedtls_ssl_read_version( &major_ver, &minor_ver, |
| ssl->conf->transport, |
| &rec->ver[0] ); |
| |
| if( major_ver != ssl->major_ver ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "major version mismatch" ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| if( minor_ver > ssl->conf->max_minor_ver ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "minor version mismatch" ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| /* |
| * Parse/Copy record sequence number. |
| */ |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| /* Copy explicit record sequence number from input buffer. */ |
| memcpy( &rec->ctr[0], buf + rec_hdr_ctr_offset, |
| rec_hdr_ctr_len ); |
| } |
| else |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| { |
| /* Copy implicit record sequence number from SSL context structure. */ |
| memcpy( &rec->ctr[0], ssl->in_ctr, rec_hdr_ctr_len ); |
| } |
| |
| /* |
| * Parse record length. |
| */ |
| |
| rec->data_offset = rec_hdr_len_offset + rec_hdr_len_len; |
| rec->data_len = ( (size_t) buf[ rec_hdr_len_offset + 0 ] << 8 ) | |
| ( (size_t) buf[ rec_hdr_len_offset + 1 ] << 0 ); |
| MBEDTLS_SSL_DEBUG_BUF( 4, "input record header", buf, rec->data_offset ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "input record: msgtype = %u, " |
| "version = [%d:%d], msglen = %" MBEDTLS_PRINTF_SIZET, |
| rec->type, |
| major_ver, minor_ver, rec->data_len ) ); |
| |
| rec->buf = buf; |
| rec->buf_len = rec->data_offset + rec->data_len; |
| |
| if( rec->data_len == 0 ) |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| |
| /* |
| * DTLS-related tests. |
| * Check epoch before checking length constraint because |
| * the latter varies with the epoch. E.g., if a ChangeCipherSpec |
| * message gets duplicated before the corresponding Finished message, |
| * the second ChangeCipherSpec should be discarded because it belongs |
| * to an old epoch, but not because its length is shorter than |
| * the minimum record length for packets using the new record transform. |
| * Note that these two kinds of failures are handled differently, |
| * as an unexpected record is silently skipped but an invalid |
| * record leads to the entire datagram being dropped. |
| */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| rec_epoch = ( rec->ctr[0] << 8 ) | rec->ctr[1]; |
| |
| /* Check that the datagram is large enough to contain a record |
| * of the advertised length. */ |
| if( len < rec->data_offset + rec->data_len ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Datagram of length %u too small to contain record of advertised length %u.", |
| (unsigned) len, |
| (unsigned)( rec->data_offset + rec->data_len ) ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| /* Records from other, non-matching epochs are silently discarded. |
| * (The case of same-port Client reconnects must be considered in |
| * the caller). */ |
| if( rec_epoch != ssl->in_epoch ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "record from another epoch: " |
| "expected %u, received %lu", |
| ssl->in_epoch, (unsigned long) rec_epoch ) ); |
| |
| /* Records from the next epoch are considered for buffering |
| * (concretely: early Finished messages). */ |
| if( rec_epoch == (unsigned) ssl->in_epoch + 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Consider record for buffering" ) ); |
| return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); |
| } |
| |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); |
| } |
| #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) |
| /* For records from the correct epoch, check whether their |
| * sequence number has been seen before. */ |
| else if( mbedtls_ssl_dtls_record_replay_check( (mbedtls_ssl_context *) ssl, |
| &rec->ctr[0] ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record" ) ); |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); |
| } |
| #endif |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| return( 0 ); |
| } |
| |
| |
| #if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C) |
| static int ssl_check_client_reconnect( mbedtls_ssl_context *ssl ) |
| { |
| unsigned int rec_epoch = ( ssl->in_ctr[0] << 8 ) | ssl->in_ctr[1]; |
| |
| /* |
| * Check for an epoch 0 ClientHello. We can't use in_msg here to |
| * access the first byte of record content (handshake type), as we |
| * have an active transform (possibly iv_len != 0), so use the |
| * fact that the record header len is 13 instead. |
| */ |
| if( rec_epoch == 0 && |
| ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && |
| ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER && |
| ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && |
| ssl->in_left > 13 && |
| ssl->in_buf[13] == MBEDTLS_SSL_HS_CLIENT_HELLO ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "possible client reconnect " |
| "from the same port" ) ); |
| return( ssl_handle_possible_reconnect( ssl ) ); |
| } |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */ |
| |
| /* |
| * If applicable, decrypt record content |
| */ |
| static int ssl_prepare_record_content( mbedtls_ssl_context *ssl, |
| mbedtls_record *rec ) |
| { |
| int ret, done = 0; |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "input record from network", |
| rec->buf, rec->buf_len ); |
| |
| if( !done && ssl->transform_in != NULL ) |
| { |
| unsigned char const old_msg_type = rec->type; |
| |
| if( ( ret = mbedtls_ssl_decrypt_buf( ssl, ssl->transform_in, |
| rec ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_decrypt_buf", ret ); |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_CID && |
| ssl->conf->ignore_unexpected_cid |
| == MBEDTLS_SSL_UNEXPECTED_CID_IGNORE ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "ignoring unexpected CID" ) ); |
| ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING; |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| |
| return( ret ); |
| } |
| |
| if( old_msg_type != rec->type ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 4, ( "record type after decrypt (before %d): %d", |
| old_msg_type, rec->type ) ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "input payload after decrypt", |
| rec->buf + rec->data_offset, rec->data_len ); |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| /* We have already checked the record content type |
| * in ssl_parse_record_header(), failing or silently |
| * dropping the record in the case of an unknown type. |
| * |
| * Since with the use of CIDs, the record content type |
| * might change during decryption, re-check the record |
| * content type, but treat a failure as fatal this time. */ |
| if( ssl_check_record_type( rec->type ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "unknown record type" ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| |
| if( rec->data_len == 0 ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 |
| && rec->type != MBEDTLS_SSL_MSG_APPLICATION_DATA ) |
| { |
| /* TLS v1.2 explicitly disallows zero-length messages which are not application data */ |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid zero-length message type: %d", ssl->in_msgtype ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ |
| |
| ssl->nb_zero++; |
| |
| /* |
| * Three or more empty messages may be a DoS attack |
| * (excessive CPU consumption). |
| */ |
| if( ssl->nb_zero > 3 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "received four consecutive empty " |
| "messages, possible DoS attack" ) ); |
| /* Treat the records as if they were not properly authenticated, |
| * thereby failing the connection if we see more than allowed |
| * by the configured bad MAC threshold. */ |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| } |
| } |
| else |
| ssl->nb_zero = 0; |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| ; /* in_ctr read from peer, not maintained internally */ |
| } |
| else |
| #endif |
| { |
| unsigned i; |
| for( i = 8; i > mbedtls_ssl_ep_len( ssl ); i-- ) |
| if( ++ssl->in_ctr[i - 1] != 0 ) |
| break; |
| |
| /* The loop goes to its end iff the counter is wrapping */ |
| if( i == mbedtls_ssl_ep_len( ssl ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "incoming message counter would wrap" ) ); |
| return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING ); |
| } |
| } |
| |
| } |
| |
| #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| mbedtls_ssl_dtls_replay_update( ssl ); |
| } |
| #endif |
| |
| /* Check actual (decrypted) record content length against |
| * configured maximum. */ |
| if( ssl->in_msglen > MBEDTLS_SSL_IN_CONTENT_LEN ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Read a record. |
| * |
| * Silently ignore non-fatal alert (and for DTLS, invalid records as well, |
| * RFC 6347 4.1.2.7) and continue reading until a valid record is found. |
| * |
| */ |
| |
| /* Helper functions for mbedtls_ssl_read_record(). */ |
| static int ssl_consume_current_message( mbedtls_ssl_context *ssl ); |
| static int ssl_get_next_record( mbedtls_ssl_context *ssl ); |
| static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl ); |
| |
| int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl, |
| unsigned update_hs_digest ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> read record" ) ); |
| |
| if( ssl->keep_current_message == 0 ) |
| { |
| do { |
| |
| ret = ssl_consume_current_message( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| if( ssl_record_is_in_progress( ssl ) == 0 ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| int have_buffered = 0; |
| |
| /* We only check for buffered messages if the |
| * current datagram is fully consumed. */ |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ssl_next_record_is_in_datagram( ssl ) == 0 ) |
| { |
| if( ssl_load_buffered_message( ssl ) == 0 ) |
| have_buffered = 1; |
| } |
| |
| if( have_buffered == 0 ) |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| { |
| ret = ssl_get_next_record( ssl ); |
| if( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ) |
| continue; |
| |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_get_next_record" ), ret ); |
| return( ret ); |
| } |
| } |
| } |
| |
| ret = mbedtls_ssl_handle_message_type( ssl ); |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) |
| { |
| /* Buffer future message */ |
| ret = ssl_buffer_message( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING; |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| } while( MBEDTLS_ERR_SSL_NON_FATAL == ret || |
| MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret ); |
| |
| if( 0 != ret ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_handle_message_type" ), ret ); |
| return( ret ); |
| } |
| |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && |
| update_hs_digest == 1 ) |
| { |
| mbedtls_ssl_update_handshake_status( ssl ); |
| } |
| } |
| else |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "reuse previously read message" ) ); |
| ssl->keep_current_message = 0; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= read record" ) ); |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl ) |
| { |
| if( ssl->in_left > ssl->next_record_offset ) |
| return( 1 ); |
| |
| return( 0 ); |
| } |
| |
| static int ssl_load_buffered_message( mbedtls_ssl_context *ssl ) |
| { |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| mbedtls_ssl_hs_buffer * hs_buf; |
| int ret = 0; |
| |
| if( hs == NULL ) |
| return( -1 ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_messsage" ) ); |
| |
| if( ssl->state == MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC || |
| ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC ) |
| { |
| /* Check if we have seen a ChangeCipherSpec before. |
| * If yes, synthesize a CCS record. */ |
| if( !hs->buffering.seen_ccs ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "CCS not seen in the current flight" ) ); |
| ret = -1; |
| goto exit; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Injecting buffered CCS message" ) ); |
| ssl->in_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC; |
| ssl->in_msglen = 1; |
| ssl->in_msg[0] = 1; |
| |
| /* As long as they are equal, the exact value doesn't matter. */ |
| ssl->in_left = 0; |
| ssl->next_record_offset = 0; |
| |
| hs->buffering.seen_ccs = 0; |
| goto exit; |
| } |
| |
| #if defined(MBEDTLS_DEBUG_C) |
| /* Debug only */ |
| { |
| unsigned offset; |
| for( offset = 1; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ ) |
| { |
| hs_buf = &hs->buffering.hs[offset]; |
| if( hs_buf->is_valid == 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Future message with sequence number %u %s buffered.", |
| hs->in_msg_seq + offset, |
| hs_buf->is_complete ? "fully" : "partially" ) ); |
| } |
| } |
| } |
| #endif /* MBEDTLS_DEBUG_C */ |
| |
| /* Check if we have buffered and/or fully reassembled the |
| * next handshake message. */ |
| hs_buf = &hs->buffering.hs[0]; |
| if( ( hs_buf->is_valid == 1 ) && ( hs_buf->is_complete == 1 ) ) |
| { |
| /* Synthesize a record containing the buffered HS message. */ |
| size_t msg_len = ( hs_buf->data[1] << 16 ) | |
| ( hs_buf->data[2] << 8 ) | |
| hs_buf->data[3]; |
| |
| /* Double-check that we haven't accidentally buffered |
| * a message that doesn't fit into the input buffer. */ |
| if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message has been buffered - load" ) ); |
| MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered handshake message (incl. header)", |
| hs_buf->data, msg_len + 12 ); |
| |
| ssl->in_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; |
| ssl->in_hslen = msg_len + 12; |
| ssl->in_msglen = msg_len + 12; |
| memcpy( ssl->in_msg, hs_buf->data, ssl->in_hslen ); |
| |
| ret = 0; |
| goto exit; |
| } |
| else |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message %u not or only partially bufffered", |
| hs->in_msg_seq ) ); |
| } |
| |
| ret = -1; |
| |
| exit: |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_message" ) ); |
| return( ret ); |
| } |
| |
| static int ssl_buffer_make_space( mbedtls_ssl_context *ssl, |
| size_t desired ) |
| { |
| int offset; |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Attempt to free buffered messages to have %u bytes available", |
| (unsigned) desired ) ); |
| |
| /* Get rid of future records epoch first, if such exist. */ |
| ssl_free_buffered_record( ssl ); |
| |
| /* Check if we have enough space available now. */ |
| if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - |
| hs->buffering.total_bytes_buffered ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing future epoch record" ) ); |
| return( 0 ); |
| } |
| |
| /* We don't have enough space to buffer the next expected handshake |
| * message. Remove buffers used for future messages to gain space, |
| * starting with the most distant one. */ |
| for( offset = MBEDTLS_SSL_MAX_BUFFERED_HS - 1; |
| offset >= 0; offset-- ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Free buffering slot %d to make space for reassembly of next handshake message", |
| offset ) ); |
| |
| ssl_buffering_free_slot( ssl, (uint8_t) offset ); |
| |
| /* Check if we have enough space available now. */ |
| if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - |
| hs->buffering.total_bytes_buffered ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing buffered HS messages" ) ); |
| return( 0 ); |
| } |
| } |
| |
| return( -1 ); |
| } |
| |
| static int ssl_buffer_message( mbedtls_ssl_context *ssl ) |
| { |
| int ret = 0; |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| |
| if( hs == NULL ) |
| return( 0 ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_buffer_message" ) ); |
| |
| switch( ssl->in_msgtype ) |
| { |
| case MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC: |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Remember CCS message" ) ); |
| |
| hs->buffering.seen_ccs = 1; |
| break; |
| |
| case MBEDTLS_SSL_MSG_HANDSHAKE: |
| { |
| unsigned recv_msg_seq_offset; |
| unsigned recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; |
| mbedtls_ssl_hs_buffer *hs_buf; |
| size_t msg_len = ssl->in_hslen - 12; |
| |
| /* We should never receive an old handshake |
| * message - double-check nonetheless. */ |
| if( recv_msg_seq < ssl->handshake->in_msg_seq ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| recv_msg_seq_offset = recv_msg_seq - ssl->handshake->in_msg_seq; |
| if( recv_msg_seq_offset >= MBEDTLS_SSL_MAX_BUFFERED_HS ) |
| { |
| /* Silently ignore -- message too far in the future */ |
| MBEDTLS_SSL_DEBUG_MSG( 2, |
| ( "Ignore future HS message with sequence number %u, " |
| "buffering window %u - %u", |
| recv_msg_seq, ssl->handshake->in_msg_seq, |
| ssl->handshake->in_msg_seq + MBEDTLS_SSL_MAX_BUFFERED_HS - 1 ) ); |
| |
| goto exit; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering HS message with sequence number %u, offset %u ", |
| recv_msg_seq, recv_msg_seq_offset ) ); |
| |
| hs_buf = &hs->buffering.hs[ recv_msg_seq_offset ]; |
| |
| /* Check if the buffering for this seq nr has already commenced. */ |
| if( !hs_buf->is_valid ) |
| { |
| size_t reassembly_buf_sz; |
| |
| hs_buf->is_fragmented = |
| ( ssl_hs_is_proper_fragment( ssl ) == 1 ); |
| |
| /* We copy the message back into the input buffer |
| * after reassembly, so check that it's not too large. |
| * This is an implementation-specific limitation |
| * and not one from the standard, hence it is not |
| * checked in ssl_check_hs_header(). */ |
| if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN ) |
| { |
| /* Ignore message */ |
| goto exit; |
| } |
| |
| /* Check if we have enough space to buffer the message. */ |
| if( hs->buffering.total_bytes_buffered > |
| MBEDTLS_SSL_DTLS_MAX_BUFFERING ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| reassembly_buf_sz = ssl_get_reassembly_buffer_size( msg_len, |
| hs_buf->is_fragmented ); |
| |
| if( reassembly_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - |
| hs->buffering.total_bytes_buffered ) ) |
| { |
| if( recv_msg_seq_offset > 0 ) |
| { |
| /* If we can't buffer a future message because |
| * of space limitations -- ignore. */ |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %" MBEDTLS_PRINTF_SIZET |
| " would exceed the compile-time limit %" MBEDTLS_PRINTF_SIZET |
| " (already %" MBEDTLS_PRINTF_SIZET |
| " bytes buffered) -- ignore\n", |
| msg_len, (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, |
| hs->buffering.total_bytes_buffered ) ); |
| goto exit; |
| } |
| else |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %" MBEDTLS_PRINTF_SIZET |
| " would exceed the compile-time limit %" MBEDTLS_PRINTF_SIZET |
| " (already %" MBEDTLS_PRINTF_SIZET |
| " bytes buffered) -- attempt to make space by freeing buffered future messages\n", |
| msg_len, (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, |
| hs->buffering.total_bytes_buffered ) ); |
| } |
| |
| if( ssl_buffer_make_space( ssl, reassembly_buf_sz ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Reassembly of next message of size %" MBEDTLS_PRINTF_SIZET |
| " (%" MBEDTLS_PRINTF_SIZET " with bitmap) would exceed" |
| " the compile-time limit %" MBEDTLS_PRINTF_SIZET |
| " (already %" MBEDTLS_PRINTF_SIZET |
| " bytes buffered) -- fail\n", |
| msg_len, |
| reassembly_buf_sz, |
| (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, |
| hs->buffering.total_bytes_buffered ) ); |
| ret = MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL; |
| goto exit; |
| } |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %" MBEDTLS_PRINTF_SIZET, |
| msg_len ) ); |
| |
| hs_buf->data = mbedtls_calloc( 1, reassembly_buf_sz ); |
| if( hs_buf->data == NULL ) |
| { |
| ret = MBEDTLS_ERR_SSL_ALLOC_FAILED; |
| goto exit; |
| } |
| hs_buf->data_len = reassembly_buf_sz; |
| |
| /* Prepare final header: copy msg_type, length and message_seq, |
| * then add standardised fragment_offset and fragment_length */ |
| memcpy( hs_buf->data, ssl->in_msg, 6 ); |
| memset( hs_buf->data + 6, 0, 3 ); |
| memcpy( hs_buf->data + 9, hs_buf->data + 1, 3 ); |
| |
| hs_buf->is_valid = 1; |
| |
| hs->buffering.total_bytes_buffered += reassembly_buf_sz; |
| } |
| else |
| { |
| /* Make sure msg_type and length are consistent */ |
| if( memcmp( hs_buf->data, ssl->in_msg, 4 ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "Fragment header mismatch - ignore" ) ); |
| /* Ignore */ |
| goto exit; |
| } |
| } |
| |
| if( !hs_buf->is_complete ) |
| { |
| size_t frag_len, frag_off; |
| unsigned char * const msg = hs_buf->data + 12; |
| |
| /* |
| * Check and copy current fragment |
| */ |
| |
| /* Validation of header fields already done in |
| * mbedtls_ssl_prepare_handshake_record(). */ |
| frag_off = ssl_get_hs_frag_off( ssl ); |
| frag_len = ssl_get_hs_frag_len( ssl ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %" MBEDTLS_PRINTF_SIZET |
| ", length = %" MBEDTLS_PRINTF_SIZET, |
| frag_off, frag_len ) ); |
| memcpy( msg + frag_off, ssl->in_msg + 12, frag_len ); |
| |
| if( hs_buf->is_fragmented ) |
| { |
| unsigned char * const bitmask = msg + msg_len; |
| ssl_bitmask_set( bitmask, frag_off, frag_len ); |
| hs_buf->is_complete = ( ssl_bitmask_check( bitmask, |
| msg_len ) == 0 ); |
| } |
| else |
| { |
| hs_buf->is_complete = 1; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "message %scomplete", |
| hs_buf->is_complete ? "" : "not yet " ) ); |
| } |
| |
| break; |
| } |
| |
| default: |
| /* We don't buffer other types of messages. */ |
| break; |
| } |
| |
| exit: |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_buffer_message" ) ); |
| return( ret ); |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| static int ssl_consume_current_message( mbedtls_ssl_context *ssl ) |
| { |
| /* |
| * Consume last content-layer message and potentially |
| * update in_msglen which keeps track of the contents' |
| * consumption state. |
| * |
| * (1) Handshake messages: |
| * Remove last handshake message, move content |
| * and adapt in_msglen. |
| * |
| * (2) Alert messages: |
| * Consume whole record content, in_msglen = 0. |
| * |
| * (3) Change cipher spec: |
| * Consume whole record content, in_msglen = 0. |
| * |
| * (4) Application data: |
| * Don't do anything - the record layer provides |
| * the application data as a stream transport |
| * and consumes through mbedtls_ssl_read only. |
| * |
| */ |
| |
| /* Case (1): Handshake messages */ |
| if( ssl->in_hslen != 0 ) |
| { |
| /* Hard assertion to be sure that no application data |
| * is in flight, as corrupting ssl->in_msglen during |
| * ssl->in_offt != NULL is fatal. */ |
| if( ssl->in_offt != NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| /* |
| * Get next Handshake message in the current record |
| */ |
| |
| /* Notes: |
| * (1) in_hslen is not necessarily the size of the |
| * current handshake content: If DTLS handshake |
| * fragmentation is used, that's the fragment |
| * size instead. Using the total handshake message |
| * size here is faulty and should be changed at |
| * some point. |
| * (2) While it doesn't seem to cause problems, one |
| * has to be very careful not to assume that in_hslen |
| * is always <= in_msglen in a sensible communication. |
| * Again, it's wrong for DTLS handshake fragmentation. |
| * The following check is therefore mandatory, and |
| * should not be treated as a silently corrected assertion. |
| * Additionally, ssl->in_hslen might be arbitrarily out of |
| * bounds after handling a DTLS message with an unexpected |
| * sequence number, see mbedtls_ssl_prepare_handshake_record. |
| */ |
| if( ssl->in_hslen < ssl->in_msglen ) |
| { |
| ssl->in_msglen -= ssl->in_hslen; |
| memmove( ssl->in_msg, ssl->in_msg + ssl->in_hslen, |
| ssl->in_msglen ); |
| |
| MBEDTLS_SSL_DEBUG_BUF( 4, "remaining content in record", |
| ssl->in_msg, ssl->in_msglen ); |
| } |
| else |
| { |
| ssl->in_msglen = 0; |
| } |
| |
| ssl->in_hslen = 0; |
| } |
| /* Case (4): Application data */ |
| else if( ssl->in_offt != NULL ) |
| { |
| return( 0 ); |
| } |
| /* Everything else (CCS & Alerts) */ |
| else |
| { |
| ssl->in_msglen = 0; |
| } |
| |
| return( 0 ); |
| } |
| |
| static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl ) |
| { |
| if( ssl->in_msglen > 0 ) |
| return( 1 ); |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| |
| static void ssl_free_buffered_record( mbedtls_ssl_context *ssl ) |
| { |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| if( hs == NULL ) |
| return; |
| |
| if( hs->buffering.future_record.data != NULL ) |
| { |
| hs->buffering.total_bytes_buffered -= |
| hs->buffering.future_record.len; |
| |
| mbedtls_free( hs->buffering.future_record.data ); |
| hs->buffering.future_record.data = NULL; |
| } |
| } |
| |
| static int ssl_load_buffered_record( mbedtls_ssl_context *ssl ) |
| { |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| unsigned char * rec; |
| size_t rec_len; |
| unsigned rec_epoch; |
| #if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) |
| size_t in_buf_len = ssl->in_buf_len; |
| #else |
| size_t in_buf_len = MBEDTLS_SSL_IN_BUFFER_LEN; |
| #endif |
| if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| return( 0 ); |
| |
| if( hs == NULL ) |
| return( 0 ); |
| |
| rec = hs->buffering.future_record.data; |
| rec_len = hs->buffering.future_record.len; |
| rec_epoch = hs->buffering.future_record.epoch; |
| |
| if( rec == NULL ) |
| return( 0 ); |
| |
| /* Only consider loading future records if the |
| * input buffer is empty. */ |
| if( ssl_next_record_is_in_datagram( ssl ) == 1 ) |
| return( 0 ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_record" ) ); |
| |
| if( rec_epoch != ssl->in_epoch ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffered record not from current epoch." ) ); |
| goto exit; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Found buffered record from current epoch - load" ) ); |
| |
| /* Double-check that the record is not too large */ |
| if( rec_len > in_buf_len - (size_t)( ssl->in_hdr - ssl->in_buf ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| memcpy( ssl->in_hdr, rec, rec_len ); |
| ssl->in_left = rec_len; |
| ssl->next_record_offset = 0; |
| |
| ssl_free_buffered_record( ssl ); |
| |
| exit: |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_record" ) ); |
| return( 0 ); |
| } |
| |
| static int ssl_buffer_future_record( mbedtls_ssl_context *ssl, |
| mbedtls_record const *rec ) |
| { |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| |
| /* Don't buffer future records outside handshakes. */ |
| if( hs == NULL ) |
| return( 0 ); |
| |
| /* Only buffer handshake records (we are only interested |
| * in Finished messages). */ |
| if( rec->type != MBEDTLS_SSL_MSG_HANDSHAKE ) |
| return( 0 ); |
| |
| /* Don't buffer more than one future epoch record. */ |
| if( hs->buffering.future_record.data != NULL ) |
| return( 0 ); |
| |
| /* Don't buffer record if there's not enough buffering space remaining. */ |
| if( rec->buf_len > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - |
| hs->buffering.total_bytes_buffered ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future epoch record of size %" MBEDTLS_PRINTF_SIZET |
| " would exceed the compile-time limit %" MBEDTLS_PRINTF_SIZET |
| " (already %" MBEDTLS_PRINTF_SIZET |
| " bytes buffered) -- ignore\n", |
| rec->buf_len, (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, |
| hs->buffering.total_bytes_buffered ) ); |
| return( 0 ); |
| } |
| |
| /* Buffer record */ |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffer record from epoch %u", |
| ssl->in_epoch + 1U ) ); |
| MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered record", rec->buf, rec->buf_len ); |
| |
| /* ssl_parse_record_header() only considers records |
| * of the next epoch as candidates for buffering. */ |
| hs->buffering.future_record.epoch = ssl->in_epoch + 1; |
| hs->buffering.future_record.len = rec->buf_len; |
| |
| hs->buffering.future_record.data = |
| mbedtls_calloc( 1, hs->buffering.future_record.len ); |
| if( hs->buffering.future_record.data == NULL ) |
| { |
| /* If we run out of RAM trying to buffer a |
| * record from the next epoch, just ignore. */ |
| return( 0 ); |
| } |
| |
| memcpy( hs->buffering.future_record.data, rec->buf, rec->buf_len ); |
| |
| hs->buffering.total_bytes_buffered += rec->buf_len; |
| return( 0 ); |
| } |
| |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| static int ssl_get_next_record( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_record rec; |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| /* We might have buffered a future record; if so, |
| * and if the epoch matches now, load it. |
| * On success, this call will set ssl->in_left to |
| * the length of the buffered record, so that |
| * the calls to ssl_fetch_input() below will |
| * essentially be no-ops. */ |
| ret = ssl_load_buffered_record( ssl ); |
| if( ret != 0 ) |
| return( ret ); |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| /* Ensure that we have enough space available for the default form |
| * of TLS / DTLS record headers (5 Bytes for TLS, 13 Bytes for DTLS, |
| * with no space for CIDs counted in). */ |
| ret = mbedtls_ssl_fetch_input( ssl, mbedtls_ssl_in_hdr_len( ssl ) ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret ); |
| return( ret ); |
| } |
| |
| ret = ssl_parse_record_header( ssl, ssl->in_hdr, ssl->in_left, &rec ); |
| if( ret != 0 ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) |
| { |
| ret = ssl_buffer_future_record( ssl, &rec ); |
| if( ret != 0 ) |
| return( ret ); |
| |
| /* Fall through to handling of unexpected records */ |
| ret = MBEDTLS_ERR_SSL_UNEXPECTED_RECORD; |
| } |
| |
| if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ) |
| { |
| #if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C) |
| /* Reset in pointers to default state for TLS/DTLS records, |
| * assuming no CID and no offset between record content and |
| * record plaintext. */ |
| mbedtls_ssl_update_in_pointers( ssl ); |
| |
| /* Setup internal message pointers from record structure. */ |
| ssl->in_msgtype = rec.type; |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| ssl->in_len = ssl->in_cid + rec.cid_len; |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| ssl->in_iv = ssl->in_msg = ssl->in_len + 2; |
| ssl->in_msglen = rec.data_len; |
| |
| ret = ssl_check_client_reconnect( ssl ); |
| MBEDTLS_SSL_DEBUG_RET( 2, "ssl_check_client_reconnect", ret ); |
| if( ret != 0 ) |
| return( ret ); |
| #endif |
| |
| /* Skip unexpected record (but not whole datagram) */ |
| ssl->next_record_offset = rec.buf_len; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "discarding unexpected record " |
| "(header)" ) ); |
| } |
| else |
| { |
| /* Skip invalid record and the rest of the datagram */ |
| ssl->next_record_offset = 0; |
| ssl->in_left = 0; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "discarding invalid record " |
| "(header)" ) ); |
| } |
| |
| /* Get next record */ |
| return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); |
| } |
| else |
| #endif |
| { |
| return( ret ); |
| } |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| /* Remember offset of next record within datagram. */ |
| ssl->next_record_offset = rec.buf_len; |
| if( ssl->next_record_offset < ssl->in_left ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "more than one record within datagram" ) ); |
| } |
| } |
| else |
| #endif |
| { |
| /* |
| * Fetch record contents from underlying transport. |
| */ |
| ret = mbedtls_ssl_fetch_input( ssl, rec.buf_len ); |
| if( ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret ); |
| return( ret ); |
| } |
| |
| ssl->in_left = 0; |
| } |
| |
| /* |
| * Decrypt record contents. |
| */ |
| |
| if( ( ret = ssl_prepare_record_content( ssl, &rec ) ) != 0 ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| /* Silently discard invalid records */ |
| if( ret == MBEDTLS_ERR_SSL_INVALID_MAC ) |
| { |
| /* Except when waiting for Finished as a bad mac here |
| * probably means something went wrong in the handshake |
| * (eg wrong psk used, mitm downgrade attempt, etc.) */ |
| if( ssl->state == MBEDTLS_SSL_CLIENT_FINISHED || |
| ssl->state == MBEDTLS_SSL_SERVER_FINISHED ) |
| { |
| #if defined(MBEDTLS_SSL_ALL_ALERT_MESSAGES) |
| if( ret == MBEDTLS_ERR_SSL_INVALID_MAC ) |
| { |
| mbedtls_ssl_send_alert_message( ssl, |
| MBEDTLS_SSL_ALERT_LEVEL_FATAL, |
| MBEDTLS_SSL_ALERT_MSG_BAD_RECORD_MAC ); |
| } |
| #endif |
| return( ret ); |
| } |
| |
| #if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT) |
| if( ssl->conf->badmac_limit != 0 && |
| ++ssl->badmac_seen >= ssl->conf->badmac_limit ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "too many records with bad MAC" ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_MAC ); |
| } |
| #endif |
| |
| /* As above, invalid records cause |
| * dismissal of the whole datagram. */ |
| |
| ssl->next_record_offset = 0; |
| ssl->in_left = 0; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "discarding invalid record (mac)" ) ); |
| return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); |
| } |
| |
| return( ret ); |
| } |
| else |
| #endif |
| { |
| /* Error out (and send alert) on invalid records */ |
| #if defined(MBEDTLS_SSL_ALL_ALERT_MESSAGES) |
| if( ret == MBEDTLS_ERR_SSL_INVALID_MAC ) |
| { |
| mbedtls_ssl_send_alert_message( ssl, |
| MBEDTLS_SSL_ALERT_LEVEL_FATAL, |
| MBEDTLS_SSL_ALERT_MSG_BAD_RECORD_MAC ); |
| } |
| #endif |
| return( ret ); |
| } |
| } |
| |
| |
| /* Reset in pointers to default state for TLS/DTLS records, |
| * assuming no CID and no offset between record content and |
| * record plaintext. */ |
| mbedtls_ssl_update_in_pointers( ssl ); |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| ssl->in_len = ssl->in_cid + rec.cid_len; |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| ssl->in_iv = ssl->in_len + 2; |
| |
| /* The record content type may change during decryption, |
| * so re-read it. */ |
| ssl->in_msgtype = rec.type; |
| /* Also update the input buffer, because unfortunately |
| * the server-side ssl_parse_client_hello() reparses the |
| * record header when receiving a ClientHello initiating |
| * a renegotiation. */ |
| ssl->in_hdr[0] = rec.type; |
| ssl->in_msg = rec.buf + rec.data_offset; |
| ssl->in_msglen = rec.data_len; |
| ssl->in_len[0] = (unsigned char)( rec.data_len >> 8 ); |
| ssl->in_len[1] = (unsigned char)( rec.data_len ); |
| |
| return( 0 ); |
| } |
| |
| int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| /* |
| * Handle particular types of records |
| */ |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) |
| { |
| if( ( ret = mbedtls_ssl_prepare_handshake_record( ssl ) ) != 0 ) |
| { |
| return( ret ); |
| } |
| } |
| |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) |
| { |
| if( ssl->in_msglen != 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, len: %" MBEDTLS_PRINTF_SIZET, |
| ssl->in_msglen ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| if( ssl->in_msg[0] != 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, content: %02x", |
| ssl->in_msg[0] ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC && |
| ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC ) |
| { |
| if( ssl->handshake == NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping ChangeCipherSpec outside handshake" ) ); |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "received out-of-order ChangeCipherSpec - remember" ) ); |
| return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); |
| } |
| #endif |
| } |
| |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT ) |
| { |
| if( ssl->in_msglen != 2 ) |
| { |
| /* Note: Standard allows for more than one 2 byte alert |
| to be packed in a single message, but Mbed TLS doesn't |
| currently support this. */ |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid alert message, len: %" MBEDTLS_PRINTF_SIZET, |
| ssl->in_msglen ) ); |
| return( MBEDTLS_ERR_SSL_INVALID_RECORD ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "got an alert message, type: [%u:%u]", |
| ssl->in_msg[0], ssl->in_msg[1] ) ); |
| |
| /* |
| * Ignore non-fatal alerts, except close_notify and no_renegotiation |
| */ |
| if( ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_FATAL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "is a fatal alert message (msg %d)", |
| ssl->in_msg[1] ) ); |
| return( MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE ); |
| } |
| |
| if( ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_WARNING && |
| ssl->in_msg[1] == MBEDTLS_SSL_ALERT_MSG_CLOSE_NOTIFY ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "is a close notify message" ) ); |
| return( MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY ); |
| } |
| |
| #if defined(MBEDTLS_SSL_RENEGOTIATION_ENABLED) |
| if( ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_WARNING && |
| ssl->in_msg[1] == MBEDTLS_SSL_ALERT_MSG_NO_RENEGOTIATION ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "is a no renegotiation alert" ) ); |
| /* Will be handled when trying to parse ServerHello */ |
| return( 0 ); |
| } |
| #endif |
| /* Silently ignore: fetch new message */ |
| return MBEDTLS_ERR_SSL_NON_FATAL; |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| /* Drop unexpected ApplicationData records, |
| * except at the beginning of renegotiations */ |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA && |
| ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER |
| #if defined(MBEDTLS_SSL_RENEGOTIATION) |
| && ! ( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && |
| ssl->state == MBEDTLS_SSL_SERVER_HELLO ) |
| #endif |
| ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping unexpected ApplicationData" ) ); |
| return( MBEDTLS_ERR_SSL_NON_FATAL ); |
| } |
| |
| if( ssl->handshake != NULL && |
| ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) |
| { |
| mbedtls_ssl_handshake_wrapup_free_hs_transform( ssl ); |
| } |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| return( 0 ); |
| } |
| |
| int mbedtls_ssl_send_fatal_handshake_failure( mbedtls_ssl_context *ssl ) |
| { |
| return( mbedtls_ssl_send_alert_message( ssl, |
| MBEDTLS_SSL_ALERT_LEVEL_FATAL, |
| MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ) ); |
| } |
| |
| int mbedtls_ssl_send_alert_message( mbedtls_ssl_context *ssl, |
| unsigned char level, |
| unsigned char message ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if( ssl == NULL || ssl->conf == NULL ) |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> send alert message" ) ); |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "send alert level=%u message=%u", level, message )); |
| |
| ssl->out_msgtype = MBEDTLS_SSL_MSG_ALERT; |
| ssl->out_msglen = 2; |
| ssl->out_msg[0] = level; |
| ssl->out_msg[1] = message; |
| |
| if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); |
| return( ret ); |
| } |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= send alert message" ) ); |
| |
| return( 0 ); |
| } |
| |
| int mbedtls_ssl_write_change_cipher_spec( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write change cipher spec" ) ); |
| |
| ssl->out_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC; |
| ssl->out_msglen = 1; |
| ssl->out_msg[0] = 1; |
| |
| ssl->state++; |
| |
| if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret ); |
| return( ret ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write change cipher spec" ) ); |
| |
| return( 0 ); |
| } |
| |
| int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) ); |
| |
| if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); |
| return( ret ); |
| } |
| |
| if( ssl->in_msgtype != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) ); |
| mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, |
| MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE ); |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); |
| } |
| |
| /* CCS records are only accepted if they have length 1 and content '1', |
| * so we don't need to check this here. */ |
| |
| /* |
| * Switch to our negotiated transform and session parameters for inbound |
| * data. |
| */ |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "switching to new transform spec for inbound data" ) ); |
| ssl->transform_in = ssl->transform_negotiate; |
| ssl->session_in = ssl->session_negotiate; |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) |
| mbedtls_ssl_dtls_replay_reset( ssl ); |
| #endif |
| |
| /* Increment epoch */ |
| if( ++ssl->in_epoch == 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS epoch would wrap" ) ); |
| /* This is highly unlikely to happen for legitimate reasons, so |
| treat it as an attack and don't send an alert. */ |
| return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| memset( ssl->in_ctr, 0, 8 ); |
| |
| mbedtls_ssl_update_in_pointers( ssl ); |
| |
| ssl->state++; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse change cipher spec" ) ); |
| |
| return( 0 ); |
| } |
| |
| /* Once ssl->out_hdr as the address of the beginning of the |
| * next outgoing record is set, deduce the other pointers. |
| * |
| * Note: For TLS, we save the implicit record sequence number |
| * (entering MAC computation) in the 8 bytes before ssl->out_hdr, |
| * and the caller has to make sure there's space for this. |
| */ |
| |
| static size_t ssl_transform_get_explicit_iv_len( |
| mbedtls_ssl_transform const *transform ) |
| { |
| if( transform->minor_ver < MBEDTLS_SSL_MINOR_VERSION_2 ) |
| return( 0 ); |
| |
| return( transform->ivlen - transform->fixed_ivlen ); |
| } |
| |
| void mbedtls_ssl_update_out_pointers( mbedtls_ssl_context *ssl, |
| mbedtls_ssl_transform *transform ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| ssl->out_ctr = ssl->out_hdr + 3; |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| ssl->out_cid = ssl->out_ctr + 8; |
| ssl->out_len = ssl->out_cid; |
| if( transform != NULL ) |
| ssl->out_len += transform->out_cid_len; |
| #else /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| ssl->out_len = ssl->out_ctr + 8; |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| ssl->out_iv = ssl->out_len + 2; |
| } |
| else |
| #endif |
| { |
| ssl->out_len = ssl->out_hdr + 3; |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| ssl->out_cid = ssl->out_len; |
| #endif |
| ssl->out_iv = ssl->out_hdr + 5; |
| } |
| |
| ssl->out_msg = ssl->out_iv; |
| /* Adjust out_msg to make space for explicit IV, if used. */ |
| if( transform != NULL ) |
| ssl->out_msg += ssl_transform_get_explicit_iv_len( transform ); |
| } |
| |
| /* Once ssl->in_hdr as the address of the beginning of the |
| * next incoming record is set, deduce the other pointers. |
| * |
| * Note: For TLS, we save the implicit record sequence number |
| * (entering MAC computation) in the 8 bytes before ssl->in_hdr, |
| * and the caller has to make sure there's space for this. |
| */ |
| |
| void mbedtls_ssl_update_in_pointers( mbedtls_ssl_context *ssl ) |
| { |
| /* This function sets the pointers to match the case |
| * of unprotected TLS/DTLS records, with both ssl->in_iv |
| * and ssl->in_msg pointing to the beginning of the record |
| * content. |
| * |
| * When decrypting a protected record, ssl->in_msg |
| * will be shifted to point to the beginning of the |
| * record plaintext. |
| */ |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| /* This sets the header pointers to match records |
| * without CID. When we receive a record containing |
| * a CID, the fields are shifted accordingly in |
| * ssl_parse_record_header(). */ |
| ssl->in_ctr = ssl->in_hdr + 3; |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| ssl->in_cid = ssl->in_ctr + 8; |
| ssl->in_len = ssl->in_cid; /* Default: no CID */ |
| #else /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| ssl->in_len = ssl->in_ctr + 8; |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| ssl->in_iv = ssl->in_len + 2; |
| } |
| else |
| #endif |
| { |
| ssl->in_ctr = ssl->in_hdr - 8; |
| ssl->in_len = ssl->in_hdr + 3; |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| ssl->in_cid = ssl->in_len; |
| #endif |
| ssl->in_iv = ssl->in_hdr + 5; |
| } |
| |
| /* This will be adjusted at record decryption time. */ |
| ssl->in_msg = ssl->in_iv; |
| } |
| |
| /* |
| * Setup an SSL context |
| */ |
| |
| void mbedtls_ssl_reset_in_out_pointers( mbedtls_ssl_context *ssl ) |
| { |
| /* Set the incoming and outgoing record pointers. */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| ssl->out_hdr = ssl->out_buf; |
| ssl->in_hdr = ssl->in_buf; |
| } |
| else |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| { |
| ssl->out_ctr = ssl->out_buf; |
| ssl->out_hdr = ssl->out_buf + 8; |
| ssl->in_hdr = ssl->in_buf + 8; |
| } |
| |
| /* Derive other internal pointers. */ |
| mbedtls_ssl_update_out_pointers( ssl, NULL /* no transform enabled */ ); |
| mbedtls_ssl_update_in_pointers ( ssl ); |
| } |
| |
| /* |
| * SSL get accessors |
| */ |
| size_t mbedtls_ssl_get_bytes_avail( const mbedtls_ssl_context *ssl ) |
| { |
| return( ssl->in_offt == NULL ? 0 : ssl->in_msglen ); |
| } |
| |
| int mbedtls_ssl_check_pending( const mbedtls_ssl_context *ssl ) |
| { |
| /* |
| * Case A: We're currently holding back |
| * a message for further processing. |
| */ |
| |
| if( ssl->keep_current_message == 1 ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: record held back for processing" ) ); |
| return( 1 ); |
| } |
| |
| /* |
| * Case B: Further records are pending in the current datagram. |
| */ |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ssl->in_left > ssl->next_record_offset ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: more records within current datagram" ) ); |
| return( 1 ); |
| } |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| /* |
| * Case C: A handshake message is being processed. |
| */ |
| |
| if( ssl->in_hslen > 0 && ssl->in_hslen < ssl->in_msglen ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: more handshake messages within current record" ) ); |
| return( 1 ); |
| } |
| |
| /* |
| * Case D: An application data message is being processed |
| */ |
| if( ssl->in_offt != NULL ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: application data record is being processed" ) ); |
| return( 1 ); |
| } |
| |
| /* |
| * In all other cases, the rest of the message can be dropped. |
| * As in ssl_get_next_record, this needs to be adapted if |
| * we implement support for multiple alerts in single records. |
| */ |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: nothing pending" ) ); |
| return( 0 ); |
| } |
| |
| |
| int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl ) |
| { |
| size_t transform_expansion = 0; |
| const mbedtls_ssl_transform *transform = ssl->transform_out; |
| unsigned block_size; |
| |
| size_t out_hdr_len = mbedtls_ssl_out_hdr_len( ssl ); |
| |
| if( transform == NULL ) |
| return( (int) out_hdr_len ); |
| |
| switch( mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_enc ) ) |
| { |
| case MBEDTLS_MODE_GCM: |
| case MBEDTLS_MODE_CCM: |
| case MBEDTLS_MODE_CHACHAPOLY: |
| case MBEDTLS_MODE_STREAM: |
| transform_expansion = transform->minlen; |
| break; |
| |
| case MBEDTLS_MODE_CBC: |
| |
| block_size = mbedtls_cipher_get_block_size( |
| &transform->cipher_ctx_enc ); |
| |
| /* Expansion due to the addition of the MAC. */ |
| transform_expansion += transform->maclen; |
| |
| /* Expansion due to the addition of CBC padding; |
| * Theoretically up to 256 bytes, but we never use |
| * more than the block size of the underlying cipher. */ |
| transform_expansion += block_size; |
| |
| /* For TLS 1.1 or higher, an explicit IV is added |
| * after the record header. */ |
| #if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) |
| transform_expansion += block_size; |
| #endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */ |
| |
| break; |
| |
| default: |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| |
| #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) |
| if( transform->out_cid_len != 0 ) |
| transform_expansion += MBEDTLS_SSL_MAX_CID_EXPANSION; |
| #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ |
| |
| return( (int)( out_hdr_len + transform_expansion ) ); |
| } |
| |
| #if defined(MBEDTLS_SSL_RENEGOTIATION) |
| /* |
| * Check record counters and renegotiate if they're above the limit. |
| */ |
| static int ssl_check_ctr_renegotiate( mbedtls_ssl_context *ssl ) |
| { |
| size_t ep_len = mbedtls_ssl_ep_len( ssl ); |
| int in_ctr_cmp; |
| int out_ctr_cmp; |
| |
| if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER || |
| ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING || |
| ssl->conf->disable_renegotiation == MBEDTLS_SSL_RENEGOTIATION_DISABLED ) |
| { |
| return( 0 ); |
| } |
| |
| in_ctr_cmp = memcmp( ssl->in_ctr + ep_len, |
| ssl->conf->renego_period + ep_len, 8 - ep_len ); |
| out_ctr_cmp = memcmp( ssl->cur_out_ctr + ep_len, |
| ssl->conf->renego_period + ep_len, 8 - ep_len ); |
| |
| if( in_ctr_cmp <= 0 && out_ctr_cmp <= 0 ) |
| { |
| return( 0 ); |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "record counter limit reached: renegotiate" ) ); |
| return( mbedtls_ssl_renegotiate( ssl ) ); |
| } |
| #endif /* MBEDTLS_SSL_RENEGOTIATION */ |
| |
| /* |
| * Receive application data decrypted from the SSL layer |
| */ |
| int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t n; |
| |
| if( ssl == NULL || ssl->conf == NULL ) |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> read" ) ); |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) |
| return( ret ); |
| |
| if( ssl->handshake != NULL && |
| ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING ) |
| { |
| if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 ) |
| return( ret ); |
| } |
| } |
| #endif |
| |
| /* |
| * Check if renegotiation is necessary and/or handshake is |
| * in process. If yes, perform/continue, and fall through |
| * if an unexpected packet is received while the client |
| * is waiting for the ServerHello. |
| * |
| * (There is no equivalent to the last condition on |
| * the server-side as it is not treated as within |
| * a handshake while waiting for the ClientHello |
| * after a renegotiation request.) |
| */ |
| |
| #if defined(MBEDTLS_SSL_RENEGOTIATION) |
| ret = ssl_check_ctr_renegotiate( ssl ); |
| if( ret != MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO && |
| ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_check_ctr_renegotiate", ret ); |
| return( ret ); |
| } |
| #endif |
| |
| if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) |
| { |
| ret = mbedtls_ssl_handshake( ssl ); |
| if( ret != MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO && |
| ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_handshake", ret ); |
| return( ret ); |
| } |
| } |
| |
| /* Loop as long as no application data record is available */ |
| while( ssl->in_offt == NULL ) |
| { |
| /* Start timer if not already running */ |
| if( ssl->f_get_timer != NULL && |
| ssl->f_get_timer( ssl->p_timer ) == -1 ) |
| { |
| mbedtls_ssl_set_timer( ssl, ssl->conf->read_timeout ); |
| } |
| |
| if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) |
| { |
| if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) |
| return( 0 ); |
| |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); |
| return( ret ); |
| } |
| |
| if( ssl->in_msglen == 0 && |
| ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA ) |
| { |
| /* |
| * OpenSSL sends empty messages to randomize the IV |
| */ |
| if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) |
| { |
| if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) |
| return( 0 ); |
| |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); |
| return( ret ); |
| } |
| } |
| |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "received handshake message" ) ); |
| |
| /* |
| * - For client-side, expect SERVER_HELLO_REQUEST. |
| * - For server-side, expect CLIENT_HELLO. |
| * - Fail (TLS) or silently drop record (DTLS) in other cases. |
| */ |
| |
| #if defined(MBEDTLS_SSL_CLI_C) |
| if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT && |
| ( ssl->in_msg[0] != MBEDTLS_SSL_HS_HELLO_REQUEST || |
| ssl->in_hslen != mbedtls_ssl_hs_hdr_len( ssl ) ) ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake received (not HelloRequest)" ) ); |
| |
| /* With DTLS, drop the packet (probably from last handshake) */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| continue; |
| } |
| #endif |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); |
| } |
| #endif /* MBEDTLS_SSL_CLI_C */ |
| |
| #if defined(MBEDTLS_SSL_SRV_C) |
| if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && |
| ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake received (not ClientHello)" ) ); |
| |
| /* With DTLS, drop the packet (probably from last handshake) */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| continue; |
| } |
| #endif |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); |
| } |
| #endif /* MBEDTLS_SSL_SRV_C */ |
| |
| #if defined(MBEDTLS_SSL_RENEGOTIATION) |
| /* Determine whether renegotiation attempt should be accepted */ |
| if( ! ( ssl->conf->disable_renegotiation == MBEDTLS_SSL_RENEGOTIATION_DISABLED || |
| ( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && |
| ssl->conf->allow_legacy_renegotiation == |
| MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION ) ) ) |
| { |
| /* |
| * Accept renegotiation request |
| */ |
| |
| /* DTLS clients need to know renego is server-initiated */ |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && |
| ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT ) |
| { |
| ssl->renego_status = MBEDTLS_SSL_RENEGOTIATION_PENDING; |
| } |
| #endif |
| ret = mbedtls_ssl_start_renegotiation( ssl ); |
| if( ret != MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO && |
| ret != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_start_renegotiation", |
| ret ); |
| return( ret ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_SSL_RENEGOTIATION */ |
| { |
| /* |
| * Refuse renegotiation |
| */ |
| |
| MBEDTLS_SSL_DEBUG_MSG( 3, ( "refusing renegotiation, sending alert" ) ); |
| |
| #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ |
| defined(MBEDTLS_SSL_PROTO_TLS1_2) |
| if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 ) |
| { |
| if( ( ret = mbedtls_ssl_send_alert_message( ssl, |
| MBEDTLS_SSL_ALERT_LEVEL_WARNING, |
| MBEDTLS_SSL_ALERT_MSG_NO_RENEGOTIATION ) ) != 0 ) |
| { |
| return( ret ); |
| } |
| } |
| else |
| #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || |
| MBEDTLS_SSL_PROTO_TLS1_2 */ |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); |
| return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); |
| } |
| } |
| |
| /* At this point, we don't know whether the renegotiation has been |
| * completed or not. The cases to consider are the following: |
| * 1) The renegotiation is complete. In this case, no new record |
| * has been read yet. |
| * 2) The renegotiation is incomplete because the client received |
| * an application data record while awaiting the ServerHello. |
| * 3) The renegotiation is incomplete because the client received |
| * a non-handshake, non-application data message while awaiting |
| * the ServerHello. |
| * In each of these case, looping will be the proper action: |
| * - For 1), the next iteration will read a new record and check |
| * if it's application data. |
| * - For 2), the loop condition isn't satisfied as application data |
| * is present, hence continue is the same as break |
| * - For 3), the loop condition is satisfied and read_record |
| * will re-deliver the message that was held back by the client |
| * when expecting the ServerHello. |
| */ |
| continue; |
| } |
| #if defined(MBEDTLS_SSL_RENEGOTIATION) |
| else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING ) |
| { |
| if( ssl->conf->renego_max_records >= 0 ) |
| { |
| if( ++ssl->renego_records_seen > ssl->conf->renego_max_records ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation requested, " |
| "but not honored by client" ) ); |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); |
| } |
| } |
| } |
| #endif /* MBEDTLS_SSL_RENEGOTIATION */ |
| |
| /* Fatal and closure alerts handled by mbedtls_ssl_read_record() */ |
| if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "ignoring non-fatal non-closure alert" ) ); |
| return( MBEDTLS_ERR_SSL_WANT_READ ); |
| } |
| |
| if( ssl->in_msgtype != MBEDTLS_SSL_MSG_APPLICATION_DATA ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad application data message" ) ); |
| return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); |
| } |
| |
| ssl->in_offt = ssl->in_msg; |
| |
| /* We're going to return something now, cancel timer, |
| * except if handshake (renegotiation) is in progress */ |
| if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) |
| mbedtls_ssl_set_timer( ssl, 0 ); |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| /* If we requested renego but received AppData, resend HelloRequest. |
| * Do it now, after setting in_offt, to avoid taking this branch |
| * again if ssl_write_hello_request() returns WANT_WRITE */ |
| #if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_RENEGOTIATION) |
| if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && |
| ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING ) |
| { |
| if( ( ret = mbedtls_ssl_resend_hello_request( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend_hello_request", |
| ret ); |
| return( ret ); |
| } |
| } |
| #endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_RENEGOTIATION */ |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| } |
| |
| n = ( len < ssl->in_msglen ) |
| ? len : ssl->in_msglen; |
| |
| memcpy( buf, ssl->in_offt, n ); |
| ssl->in_msglen -= n; |
| |
| /* Zeroising the plaintext buffer to erase unused application data |
| from the memory. */ |
| mbedtls_platform_zeroize( ssl->in_offt, n ); |
| |
| if( ssl->in_msglen == 0 ) |
| { |
| /* all bytes consumed */ |
| ssl->in_offt = NULL; |
| ssl->keep_current_message = 0; |
| } |
| else |
| { |
| /* more data available */ |
| ssl->in_offt += n; |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= read" ) ); |
| |
| return( (int) n ); |
| } |
| |
| /* |
| * Send application data to be encrypted by the SSL layer, taking care of max |
| * fragment length and buffer size. |
| * |
| * According to RFC 5246 Section 6.2.1: |
| * |
| * Zero-length fragments of Application data MAY be sent as they are |
| * potentially useful as a traffic analysis countermeasure. |
| * |
| * Therefore, it is possible that the input message length is 0 and the |
| * corresponding return code is 0 on success. |
| */ |
| static int ssl_write_real( mbedtls_ssl_context *ssl, |
| const unsigned char *buf, size_t len ) |
| { |
| int ret = mbedtls_ssl_get_max_out_record_payload( ssl ); |
| const size_t max_len = (size_t) ret; |
| |
| if( ret < 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_get_max_out_record_payload", ret ); |
| return( ret ); |
| } |
| |
| if( len > max_len ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| MBEDTLS_SSL_DEBUG_MSG( 1, ( "fragment larger than the (negotiated) " |
| "maximum fragment length: %" MBEDTLS_PRINTF_SIZET |
| " > %" MBEDTLS_PRINTF_SIZET, |
| len, max_len ) ); |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| } |
| else |
| #endif |
| len = max_len; |
| } |
| |
| if( ssl->out_left != 0 ) |
| { |
| /* |
| * The user has previously tried to send the data and |
| * MBEDTLS_ERR_SSL_WANT_WRITE or the message was only partially |
| * written. In this case, we expect the high-level write function |
| * (e.g. mbedtls_ssl_write()) to be called with the same parameters |
| */ |
| if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flush_output", ret ); |
| return( ret ); |
| } |
| } |
| else |
| { |
| /* |
| * The user is trying to send a message the first time, so we need to |
| * copy the data into the internal buffers and setup the data structure |
| * to keep track of partial writes |
| */ |
| ssl->out_msglen = len; |
| ssl->out_msgtype = MBEDTLS_SSL_MSG_APPLICATION_DATA; |
| memcpy( ssl->out_msg, buf, len ); |
| |
| if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); |
| return( ret ); |
| } |
| } |
| |
| return( (int) len ); |
| } |
| |
| /* |
| * Write application data, doing 1/n-1 splitting if necessary. |
| * |
| * With non-blocking I/O, ssl_write_real() may return WANT_WRITE, |
| * then the caller will call us again with the same arguments, so |
| * remember whether we already did the split or not. |
| */ |
| #if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING) |
| static int ssl_write_split( mbedtls_ssl_context *ssl, |
| const unsigned char *buf, size_t len ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if( ssl->conf->cbc_record_splitting == |
| MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED || |
| len <= 1 || |
| ssl->minor_ver > MBEDTLS_SSL_MINOR_VERSION_1 || |
| mbedtls_cipher_get_cipher_mode( &ssl->transform_out->cipher_ctx_enc ) |
| != MBEDTLS_MODE_CBC ) |
| { |
| return( ssl_write_real( ssl, buf, len ) ); |
| } |
| |
| if( ssl->split_done == 0 ) |
| { |
| if( ( ret = ssl_write_real( ssl, buf, 1 ) ) <= 0 ) |
| return( ret ); |
| ssl->split_done = 1; |
| } |
| |
| if( ( ret = ssl_write_real( ssl, buf + 1, len - 1 ) ) <= 0 ) |
| return( ret ); |
| ssl->split_done = 0; |
| |
| return( ret + 1 ); |
| } |
| #endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */ |
| |
| /* |
| * Write application data (public-facing wrapper) |
| */ |
| int mbedtls_ssl_write( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write" ) ); |
| |
| if( ssl == NULL || ssl->conf == NULL ) |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| |
| #if defined(MBEDTLS_SSL_RENEGOTIATION) |
| if( ( ret = ssl_check_ctr_renegotiate( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "ssl_check_ctr_renegotiate", ret ); |
| return( ret ); |
| } |
| #endif |
| |
| if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) |
| { |
| if( ( ret = mbedtls_ssl_handshake( ssl ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_handshake", ret ); |
| return( ret ); |
| } |
| } |
| |
| #if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING) |
| ret = ssl_write_split( ssl, buf, len ); |
| #else |
| ret = ssl_write_real( ssl, buf, len ); |
| #endif |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write" ) ); |
| |
| return( ret ); |
| } |
| |
| /* |
| * Notify the peer that the connection is being closed |
| */ |
| int mbedtls_ssl_close_notify( mbedtls_ssl_context *ssl ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if( ssl == NULL || ssl->conf == NULL ) |
| return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write close notify" ) ); |
| |
| if( ssl->out_left != 0 ) |
| return( mbedtls_ssl_flush_output( ssl ) ); |
| |
| if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) |
| { |
| if( ( ret = mbedtls_ssl_send_alert_message( ssl, |
| MBEDTLS_SSL_ALERT_LEVEL_WARNING, |
| MBEDTLS_SSL_ALERT_MSG_CLOSE_NOTIFY ) ) != 0 ) |
| { |
| MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_send_alert_message", ret ); |
| return( ret ); |
| } |
| } |
| |
| MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write close notify" ) ); |
| |
| return( 0 ); |
| } |
| |
| void mbedtls_ssl_transform_free( mbedtls_ssl_transform *transform ) |
| { |
| if( transform == NULL ) |
| return; |
| |
| mbedtls_cipher_free( &transform->cipher_ctx_enc ); |
| mbedtls_cipher_free( &transform->cipher_ctx_dec ); |
| |
| #if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) |
| mbedtls_md_free( &transform->md_ctx_enc ); |
| mbedtls_md_free( &transform->md_ctx_dec ); |
| #endif |
| |
| mbedtls_platform_zeroize( transform, sizeof( mbedtls_ssl_transform ) ); |
| } |
| |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| |
| void mbedtls_ssl_buffering_free( mbedtls_ssl_context *ssl ) |
| { |
| unsigned offset; |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| |
| if( hs == NULL ) |
| return; |
| |
| ssl_free_buffered_record( ssl ); |
| |
| for( offset = 0; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ ) |
| ssl_buffering_free_slot( ssl, offset ); |
| } |
| |
| static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl, |
| uint8_t slot ) |
| { |
| mbedtls_ssl_handshake_params * const hs = ssl->handshake; |
| mbedtls_ssl_hs_buffer * const hs_buf = &hs->buffering.hs[slot]; |
| |
| if( slot >= MBEDTLS_SSL_MAX_BUFFERED_HS ) |
| return; |
| |
| if( hs_buf->is_valid == 1 ) |
| { |
| hs->buffering.total_bytes_buffered -= hs_buf->data_len; |
| mbedtls_platform_zeroize( hs_buf->data, hs_buf->data_len ); |
| mbedtls_free( hs_buf->data ); |
| memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) ); |
| } |
| } |
| |
| #endif /* MBEDTLS_SSL_PROTO_DTLS */ |
| |
| /* |
| * Convert version numbers to/from wire format |
| * and, for DTLS, to/from TLS equivalent. |
| * |
| * For TLS this is the identity. |
| * For DTLS, use 1's complement (v -> 255 - v, and then map as follows: |
| * 1.0 <-> 3.2 (DTLS 1.0 is based on TLS 1.1) |
| * 1.x <-> 3.x+1 for x != 0 (DTLS 1.2 based on TLS 1.2) |
| */ |
| void mbedtls_ssl_write_version( int major, int minor, int transport, |
| unsigned char ver[2] ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| if( minor == MBEDTLS_SSL_MINOR_VERSION_2 ) |
| --minor; /* DTLS 1.0 stored as TLS 1.1 internally */ |
| |
| ver[0] = (unsigned char)( 255 - ( major - 2 ) ); |
| ver[1] = (unsigned char)( 255 - ( minor - 1 ) ); |
| } |
| else |
| #else |
| ((void) transport); |
| #endif |
| { |
| ver[0] = (unsigned char) major; |
| ver[1] = (unsigned char) minor; |
| } |
| } |
| |
| void mbedtls_ssl_read_version( int *major, int *minor, int transport, |
| const unsigned char ver[2] ) |
| { |
| #if defined(MBEDTLS_SSL_PROTO_DTLS) |
| if( transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) |
| { |
| *major = 255 - ver[0] + 2; |
| *minor = 255 - ver[1] + 1; |
| |
| if( *minor == MBEDTLS_SSL_MINOR_VERSION_1 ) |
| ++*minor; /* DTLS 1.0 stored as TLS 1.1 internally */ |
| } |
| else |
| #else |
| ((void) transport); |
| #endif |
| { |
| *major = ver[0]; |
| *minor = ver[1]; |
| } |
| } |
| |
| #endif /* MBEDTLS_SSL_TLS_C */ |