| /* |
| * TLS server tickets callbacks implementation |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_SSL_TICKET_C) |
| |
| #include "mbedtls/platform.h" |
| |
| #include "ssl_misc.h" |
| #include "mbedtls/ssl_ticket.h" |
| #include "mbedtls/error.h" |
| #include "mbedtls/platform_util.h" |
| |
| #include <string.h> |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| /* Define a local translating function to save code size by not using too many |
| * arguments in each translating place. */ |
| static int local_err_translation(psa_status_t status) |
| { |
| return psa_status_to_mbedtls(status, psa_to_ssl_errors, |
| ARRAY_LENGTH(psa_to_ssl_errors), |
| psa_generic_status_to_mbedtls); |
| } |
| #define PSA_TO_MBEDTLS_ERR(status) local_err_translation(status) |
| #endif |
| |
| /* |
| * Initialize context |
| */ |
| void mbedtls_ssl_ticket_init(mbedtls_ssl_ticket_context *ctx) |
| { |
| memset(ctx, 0, sizeof(mbedtls_ssl_ticket_context)); |
| |
| #if defined(MBEDTLS_THREADING_C) |
| mbedtls_mutex_init(&ctx->mutex); |
| #endif |
| } |
| |
| #define MAX_KEY_BYTES MBEDTLS_SSL_TICKET_MAX_KEY_BYTES |
| |
| #define TICKET_KEY_NAME_BYTES MBEDTLS_SSL_TICKET_KEY_NAME_BYTES |
| #define TICKET_IV_BYTES 12 |
| #define TICKET_CRYPT_LEN_BYTES 2 |
| #define TICKET_AUTH_TAG_BYTES 16 |
| |
| #define TICKET_MIN_LEN (TICKET_KEY_NAME_BYTES + \ |
| TICKET_IV_BYTES + \ |
| TICKET_CRYPT_LEN_BYTES + \ |
| TICKET_AUTH_TAG_BYTES) |
| #define TICKET_ADD_DATA_LEN (TICKET_KEY_NAME_BYTES + \ |
| TICKET_IV_BYTES + \ |
| TICKET_CRYPT_LEN_BYTES) |
| |
| /* |
| * Generate/update a key |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_ticket_gen_key(mbedtls_ssl_ticket_context *ctx, |
| unsigned char index) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char buf[MAX_KEY_BYTES] = { 0 }; |
| mbedtls_ssl_ticket_key *key = ctx->keys + index; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| #endif |
| |
| #if defined(MBEDTLS_HAVE_TIME) |
| key->generation_time = mbedtls_time(NULL); |
| #endif |
| /* The lifetime of a key is the configured lifetime of the tickets when |
| * the key is created. |
| */ |
| key->lifetime = ctx->ticket_lifetime; |
| |
| if ((ret = ctx->f_rng(ctx->p_rng, key->name, sizeof(key->name))) != 0) { |
| return ret; |
| } |
| |
| if ((ret = ctx->f_rng(ctx->p_rng, buf, sizeof(buf))) != 0) { |
| return ret; |
| } |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_set_key_usage_flags(&attributes, |
| PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT); |
| psa_set_key_algorithm(&attributes, key->alg); |
| psa_set_key_type(&attributes, key->key_type); |
| psa_set_key_bits(&attributes, key->key_bits); |
| |
| ret = PSA_TO_MBEDTLS_ERR( |
| psa_import_key(&attributes, buf, |
| PSA_BITS_TO_BYTES(key->key_bits), |
| &key->key)); |
| #else |
| /* With GCM and CCM, same context can encrypt & decrypt */ |
| ret = mbedtls_cipher_setkey(&key->ctx, buf, |
| mbedtls_cipher_get_key_bitlen(&key->ctx), |
| MBEDTLS_ENCRYPT); |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| mbedtls_platform_zeroize(buf, sizeof(buf)); |
| |
| return ret; |
| } |
| |
| /* |
| * Rotate/generate keys if necessary |
| */ |
| MBEDTLS_CHECK_RETURN_CRITICAL |
| static int ssl_ticket_update_keys(mbedtls_ssl_ticket_context *ctx) |
| { |
| #if !defined(MBEDTLS_HAVE_TIME) |
| ((void) ctx); |
| #else |
| mbedtls_ssl_ticket_key * const key = ctx->keys + ctx->active; |
| if (key->lifetime != 0) { |
| mbedtls_time_t current_time = mbedtls_time(NULL); |
| mbedtls_time_t key_time = key->generation_time; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| #endif |
| |
| if (current_time >= key_time && |
| (uint64_t) (current_time - key_time) < key->lifetime) { |
| return 0; |
| } |
| |
| ctx->active = 1 - ctx->active; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| if ((status = psa_destroy_key(ctx->keys[ctx->active].key)) != PSA_SUCCESS) { |
| return PSA_TO_MBEDTLS_ERR(status); |
| } |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| return ssl_ticket_gen_key(ctx, ctx->active); |
| } else |
| #endif /* MBEDTLS_HAVE_TIME */ |
| return 0; |
| } |
| |
| /* |
| * Rotate active session ticket encryption key |
| */ |
| int mbedtls_ssl_ticket_rotate(mbedtls_ssl_ticket_context *ctx, |
| const unsigned char *name, size_t nlength, |
| const unsigned char *k, size_t klength, |
| uint32_t lifetime) |
| { |
| const unsigned char idx = 1 - ctx->active; |
| mbedtls_ssl_ticket_key * const key = ctx->keys + idx; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT; |
| const size_t bitlen = key->key_bits; |
| #else |
| const int bitlen = mbedtls_cipher_get_key_bitlen(&key->ctx); |
| #endif |
| |
| if (nlength < TICKET_KEY_NAME_BYTES || klength * 8 < (size_t) bitlen) { |
| return MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA; |
| } |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| if ((status = psa_destroy_key(key->key)) != PSA_SUCCESS) { |
| ret = PSA_TO_MBEDTLS_ERR(status); |
| return ret; |
| } |
| |
| psa_set_key_usage_flags(&attributes, |
| PSA_KEY_USAGE_ENCRYPT | PSA_KEY_USAGE_DECRYPT); |
| psa_set_key_algorithm(&attributes, key->alg); |
| psa_set_key_type(&attributes, key->key_type); |
| psa_set_key_bits(&attributes, key->key_bits); |
| |
| if ((status = psa_import_key(&attributes, k, |
| PSA_BITS_TO_BYTES(key->key_bits), |
| &key->key)) != PSA_SUCCESS) { |
| ret = PSA_TO_MBEDTLS_ERR(status); |
| return ret; |
| } |
| #else |
| ret = mbedtls_cipher_setkey(&key->ctx, k, bitlen, MBEDTLS_ENCRYPT); |
| if (ret != 0) { |
| return ret; |
| } |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| ctx->active = idx; |
| ctx->ticket_lifetime = lifetime; |
| memcpy(key->name, name, TICKET_KEY_NAME_BYTES); |
| #if defined(MBEDTLS_HAVE_TIME) |
| key->generation_time = mbedtls_time(NULL); |
| #endif |
| key->lifetime = lifetime; |
| |
| return 0; |
| } |
| |
| /* |
| * Setup context for actual use |
| */ |
| int mbedtls_ssl_ticket_setup(mbedtls_ssl_ticket_context *ctx, |
| int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, |
| mbedtls_cipher_type_t cipher, |
| uint32_t lifetime) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t key_bits; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_algorithm_t alg; |
| psa_key_type_t key_type; |
| #else |
| const mbedtls_cipher_info_t *cipher_info; |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| if (mbedtls_ssl_cipher_to_psa(cipher, TICKET_AUTH_TAG_BYTES, |
| &alg, &key_type, &key_bits) != PSA_SUCCESS) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| |
| if (PSA_ALG_IS_AEAD(alg) == 0) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| #else |
| cipher_info = mbedtls_cipher_info_from_type(cipher); |
| |
| if (mbedtls_cipher_info_get_mode(cipher_info) != MBEDTLS_MODE_GCM && |
| mbedtls_cipher_info_get_mode(cipher_info) != MBEDTLS_MODE_CCM && |
| mbedtls_cipher_info_get_mode(cipher_info) != MBEDTLS_MODE_CHACHAPOLY) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| |
| key_bits = mbedtls_cipher_info_get_key_bitlen(cipher_info); |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| if (key_bits > 8 * MAX_KEY_BYTES) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| |
| ctx->f_rng = f_rng; |
| ctx->p_rng = p_rng; |
| |
| ctx->ticket_lifetime = lifetime; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| ctx->keys[0].alg = alg; |
| ctx->keys[0].key_type = key_type; |
| ctx->keys[0].key_bits = key_bits; |
| |
| ctx->keys[1].alg = alg; |
| ctx->keys[1].key_type = key_type; |
| ctx->keys[1].key_bits = key_bits; |
| #else |
| if ((ret = mbedtls_cipher_setup(&ctx->keys[0].ctx, cipher_info)) != 0) { |
| return ret; |
| } |
| |
| if ((ret = mbedtls_cipher_setup(&ctx->keys[1].ctx, cipher_info)) != 0) { |
| return ret; |
| } |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| if ((ret = ssl_ticket_gen_key(ctx, 0)) != 0 || |
| (ret = ssl_ticket_gen_key(ctx, 1)) != 0) { |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Create session ticket, with the following structure: |
| * |
| * struct { |
| * opaque key_name[4]; |
| * opaque iv[12]; |
| * opaque encrypted_state<0..2^16-1>; |
| * opaque tag[16]; |
| * } ticket; |
| * |
| * The key_name, iv, and length of encrypted_state are the additional |
| * authenticated data. |
| */ |
| |
| int mbedtls_ssl_ticket_write(void *p_ticket, |
| const mbedtls_ssl_session *session, |
| unsigned char *start, |
| const unsigned char *end, |
| size_t *tlen, |
| uint32_t *ticket_lifetime) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ssl_ticket_context *ctx = p_ticket; |
| mbedtls_ssl_ticket_key *key; |
| unsigned char *key_name = start; |
| unsigned char *iv = start + TICKET_KEY_NAME_BYTES; |
| unsigned char *state_len_bytes = iv + TICKET_IV_BYTES; |
| unsigned char *state = state_len_bytes + TICKET_CRYPT_LEN_BYTES; |
| size_t clear_len, ciph_len; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| #endif |
| |
| *tlen = 0; |
| |
| if (ctx == NULL || ctx->f_rng == NULL) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| |
| /* We need at least 4 bytes for key_name, 12 for IV, 2 for len 16 for tag, |
| * in addition to session itself, that will be checked when writing it. */ |
| MBEDTLS_SSL_CHK_BUF_PTR(start, end, TICKET_MIN_LEN); |
| |
| #if defined(MBEDTLS_THREADING_C) |
| if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) { |
| return ret; |
| } |
| #endif |
| |
| if ((ret = ssl_ticket_update_keys(ctx)) != 0) { |
| goto cleanup; |
| } |
| |
| key = &ctx->keys[ctx->active]; |
| |
| *ticket_lifetime = key->lifetime; |
| |
| memcpy(key_name, key->name, TICKET_KEY_NAME_BYTES); |
| |
| if ((ret = ctx->f_rng(ctx->p_rng, iv, TICKET_IV_BYTES)) != 0) { |
| goto cleanup; |
| } |
| |
| /* Dump session state */ |
| if ((ret = mbedtls_ssl_session_save(session, |
| state, (size_t) (end - state), |
| &clear_len)) != 0 || |
| (unsigned long) clear_len > 65535) { |
| goto cleanup; |
| } |
| MBEDTLS_PUT_UINT16_BE(clear_len, state_len_bytes, 0); |
| |
| /* Encrypt and authenticate */ |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| if ((status = psa_aead_encrypt(key->key, key->alg, iv, TICKET_IV_BYTES, |
| key_name, TICKET_ADD_DATA_LEN, |
| state, clear_len, |
| state, end - state, |
| &ciph_len)) != PSA_SUCCESS) { |
| ret = PSA_TO_MBEDTLS_ERR(status); |
| goto cleanup; |
| } |
| #else |
| if ((ret = mbedtls_cipher_auth_encrypt_ext(&key->ctx, |
| iv, TICKET_IV_BYTES, |
| /* Additional data: key name, IV and length */ |
| key_name, TICKET_ADD_DATA_LEN, |
| state, clear_len, |
| state, (size_t) (end - state), &ciph_len, |
| TICKET_AUTH_TAG_BYTES)) != 0) { |
| goto cleanup; |
| } |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| if (ciph_len != clear_len + TICKET_AUTH_TAG_BYTES) { |
| ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| goto cleanup; |
| } |
| |
| *tlen = TICKET_MIN_LEN + ciph_len - TICKET_AUTH_TAG_BYTES; |
| |
| cleanup: |
| #if defined(MBEDTLS_THREADING_C) |
| if (mbedtls_mutex_unlock(&ctx->mutex) != 0) { |
| return MBEDTLS_ERR_THREADING_MUTEX_ERROR; |
| } |
| #endif |
| |
| return ret; |
| } |
| |
| /* |
| * Select key based on name |
| */ |
| static mbedtls_ssl_ticket_key *ssl_ticket_select_key( |
| mbedtls_ssl_ticket_context *ctx, |
| const unsigned char name[4]) |
| { |
| unsigned char i; |
| |
| for (i = 0; i < sizeof(ctx->keys) / sizeof(*ctx->keys); i++) { |
| if (memcmp(name, ctx->keys[i].name, 4) == 0) { |
| return &ctx->keys[i]; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /* |
| * Load session ticket (see mbedtls_ssl_ticket_write for structure) |
| */ |
| int mbedtls_ssl_ticket_parse(void *p_ticket, |
| mbedtls_ssl_session *session, |
| unsigned char *buf, |
| size_t len) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ssl_ticket_context *ctx = p_ticket; |
| mbedtls_ssl_ticket_key *key; |
| unsigned char *key_name = buf; |
| unsigned char *iv = buf + TICKET_KEY_NAME_BYTES; |
| unsigned char *enc_len_p = iv + TICKET_IV_BYTES; |
| unsigned char *ticket = enc_len_p + TICKET_CRYPT_LEN_BYTES; |
| size_t enc_len, clear_len; |
| |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; |
| #endif |
| |
| if (ctx == NULL || ctx->f_rng == NULL) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| |
| if (len < TICKET_MIN_LEN) { |
| return MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| } |
| |
| #if defined(MBEDTLS_THREADING_C) |
| if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) { |
| return ret; |
| } |
| #endif |
| |
| if ((ret = ssl_ticket_update_keys(ctx)) != 0) { |
| goto cleanup; |
| } |
| |
| enc_len = MBEDTLS_GET_UINT16_BE(enc_len_p, 0); |
| |
| if (len != TICKET_MIN_LEN + enc_len) { |
| ret = MBEDTLS_ERR_SSL_BAD_INPUT_DATA; |
| goto cleanup; |
| } |
| |
| /* Select key */ |
| if ((key = ssl_ticket_select_key(ctx, key_name)) == NULL) { |
| /* We can't know for sure but this is a likely option unless we're |
| * under attack - this is only informative anyway */ |
| ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED; |
| goto cleanup; |
| } |
| |
| /* Decrypt and authenticate */ |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| if ((status = psa_aead_decrypt(key->key, key->alg, iv, TICKET_IV_BYTES, |
| key_name, TICKET_ADD_DATA_LEN, |
| ticket, enc_len + TICKET_AUTH_TAG_BYTES, |
| ticket, enc_len, &clear_len)) != PSA_SUCCESS) { |
| ret = PSA_TO_MBEDTLS_ERR(status); |
| goto cleanup; |
| } |
| #else |
| if ((ret = mbedtls_cipher_auth_decrypt_ext(&key->ctx, |
| iv, TICKET_IV_BYTES, |
| /* Additional data: key name, IV and length */ |
| key_name, TICKET_ADD_DATA_LEN, |
| ticket, enc_len + TICKET_AUTH_TAG_BYTES, |
| ticket, enc_len, &clear_len, |
| TICKET_AUTH_TAG_BYTES)) != 0) { |
| if (ret == MBEDTLS_ERR_CIPHER_AUTH_FAILED) { |
| ret = MBEDTLS_ERR_SSL_INVALID_MAC; |
| } |
| |
| goto cleanup; |
| } |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| if (clear_len != enc_len) { |
| ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR; |
| goto cleanup; |
| } |
| |
| /* Actually load session */ |
| if ((ret = mbedtls_ssl_session_load(session, ticket, clear_len)) != 0) { |
| goto cleanup; |
| } |
| |
| #if defined(MBEDTLS_HAVE_TIME) |
| mbedtls_ms_time_t ticket_creation_time, ticket_age; |
| mbedtls_ms_time_t ticket_lifetime = |
| (mbedtls_ms_time_t) key->lifetime * 1000; |
| |
| ret = mbedtls_ssl_session_get_ticket_creation_time(session, |
| &ticket_creation_time); |
| if (ret != 0) { |
| goto cleanup; |
| } |
| |
| ticket_age = mbedtls_ms_time() - ticket_creation_time; |
| if (ticket_age < 0 || ticket_age > ticket_lifetime) { |
| ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED; |
| goto cleanup; |
| } |
| #endif |
| |
| cleanup: |
| #if defined(MBEDTLS_THREADING_C) |
| if (mbedtls_mutex_unlock(&ctx->mutex) != 0) { |
| return MBEDTLS_ERR_THREADING_MUTEX_ERROR; |
| } |
| #endif |
| |
| return ret; |
| } |
| |
| /* |
| * Free context |
| */ |
| void mbedtls_ssl_ticket_free(mbedtls_ssl_ticket_context *ctx) |
| { |
| #if defined(MBEDTLS_USE_PSA_CRYPTO) |
| psa_destroy_key(ctx->keys[0].key); |
| psa_destroy_key(ctx->keys[1].key); |
| #else |
| mbedtls_cipher_free(&ctx->keys[0].ctx); |
| mbedtls_cipher_free(&ctx->keys[1].ctx); |
| #endif /* MBEDTLS_USE_PSA_CRYPTO */ |
| |
| #if defined(MBEDTLS_THREADING_C) |
| mbedtls_mutex_free(&ctx->mutex); |
| #endif |
| |
| mbedtls_platform_zeroize(ctx, sizeof(mbedtls_ssl_ticket_context)); |
| } |
| |
| #endif /* MBEDTLS_SSL_TICKET_C */ |
