| /* |
| * Privacy Enhanced Mail (PEM) decoding |
| * |
| * 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. |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_PEM_PARSE_C) || defined(MBEDTLS_PEM_WRITE_C) |
| |
| #include "mbedtls/pem.h" |
| #include "mbedtls/base64.h" |
| #include "mbedtls/des.h" |
| #include "mbedtls/aes.h" |
| #include "mbedtls/md5.h" |
| #include "mbedtls/cipher.h" |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/error.h" |
| |
| #include <string.h> |
| |
| #if defined(MBEDTLS_PLATFORM_C) |
| #include "mbedtls/platform.h" |
| #else |
| #include <stdlib.h> |
| #define mbedtls_calloc calloc |
| #define mbedtls_free free |
| #endif |
| |
| #if defined(MBEDTLS_PEM_PARSE_C) |
| void mbedtls_pem_init( mbedtls_pem_context *ctx ) |
| { |
| memset( ctx, 0, sizeof( mbedtls_pem_context ) ); |
| } |
| |
| #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \ |
| ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) ) |
| /* |
| * Read a 16-byte hex string and convert it to binary |
| */ |
| static int pem_get_iv( const unsigned char *s, unsigned char *iv, |
| size_t iv_len ) |
| { |
| size_t i, j, k; |
| |
| memset( iv, 0, iv_len ); |
| |
| for( i = 0; i < iv_len * 2; i++, s++ ) |
| { |
| if( *s >= '0' && *s <= '9' ) j = *s - '0'; else |
| if( *s >= 'A' && *s <= 'F' ) j = *s - '7'; else |
| if( *s >= 'a' && *s <= 'f' ) j = *s - 'W'; else |
| return( MBEDTLS_ERR_PEM_INVALID_ENC_IV ); |
| |
| k = ( ( i & 1 ) != 0 ) ? j : j << 4; |
| |
| iv[i >> 1] = (unsigned char)( iv[i >> 1] | k ); |
| } |
| |
| return( 0 ); |
| } |
| |
| static int pem_pbkdf1( unsigned char *key, size_t keylen, |
| unsigned char *iv, |
| const unsigned char *pwd, size_t pwdlen ) |
| { |
| mbedtls_md5_context md5_ctx; |
| unsigned char md5sum[16]; |
| size_t use_len; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_md5_init( &md5_ctx ); |
| |
| /* |
| * key[ 0..15] = MD5(pwd || IV) |
| */ |
| if( ( ret = mbedtls_md5_starts( &md5_ctx ) ) != 0 ) |
| goto exit; |
| if( ( ret = mbedtls_md5_update( &md5_ctx, pwd, pwdlen ) ) != 0 ) |
| goto exit; |
| if( ( ret = mbedtls_md5_update( &md5_ctx, iv, 8 ) ) != 0 ) |
| goto exit; |
| if( ( ret = mbedtls_md5_finish( &md5_ctx, md5sum ) ) != 0 ) |
| goto exit; |
| |
| if( keylen <= 16 ) |
| { |
| memcpy( key, md5sum, keylen ); |
| goto exit; |
| } |
| |
| memcpy( key, md5sum, 16 ); |
| |
| /* |
| * key[16..23] = MD5(key[ 0..15] || pwd || IV]) |
| */ |
| if( ( ret = mbedtls_md5_starts( &md5_ctx ) ) != 0 ) |
| goto exit; |
| if( ( ret = mbedtls_md5_update( &md5_ctx, md5sum, 16 ) ) != 0 ) |
| goto exit; |
| if( ( ret = mbedtls_md5_update( &md5_ctx, pwd, pwdlen ) ) != 0 ) |
| goto exit; |
| if( ( ret = mbedtls_md5_update( &md5_ctx, iv, 8 ) ) != 0 ) |
| goto exit; |
| if( ( ret = mbedtls_md5_finish( &md5_ctx, md5sum ) ) != 0 ) |
| goto exit; |
| |
| use_len = 16; |
| if( keylen < 32 ) |
| use_len = keylen - 16; |
| |
| memcpy( key + 16, md5sum, use_len ); |
| |
| exit: |
| mbedtls_md5_free( &md5_ctx ); |
| mbedtls_platform_zeroize( md5sum, 16 ); |
| |
| return( ret ); |
| } |
| |
| #if defined(MBEDTLS_DES_C) |
| /* |
| * Decrypt with DES-CBC, using PBKDF1 for key derivation |
| */ |
| static int pem_des_decrypt( unsigned char des_iv[8], |
| unsigned char *buf, size_t buflen, |
| const unsigned char *pwd, size_t pwdlen ) |
| { |
| mbedtls_des_context des_ctx; |
| unsigned char des_key[8]; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_des_init( &des_ctx ); |
| |
| if( ( ret = pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen ) ) != 0 ) |
| goto exit; |
| |
| if( ( ret = mbedtls_des_setkey_dec( &des_ctx, des_key ) ) != 0 ) |
| goto exit; |
| ret = mbedtls_des_crypt_cbc( &des_ctx, MBEDTLS_DES_DECRYPT, buflen, |
| des_iv, buf, buf ); |
| |
| exit: |
| mbedtls_des_free( &des_ctx ); |
| mbedtls_platform_zeroize( des_key, 8 ); |
| |
| return( ret ); |
| } |
| |
| /* |
| * Decrypt with 3DES-CBC, using PBKDF1 for key derivation |
| */ |
| static int pem_des3_decrypt( unsigned char des3_iv[8], |
| unsigned char *buf, size_t buflen, |
| const unsigned char *pwd, size_t pwdlen ) |
| { |
| mbedtls_des3_context des3_ctx; |
| unsigned char des3_key[24]; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_des3_init( &des3_ctx ); |
| |
| if( ( ret = pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen ) ) != 0 ) |
| goto exit; |
| |
| if( ( ret = mbedtls_des3_set3key_dec( &des3_ctx, des3_key ) ) != 0 ) |
| goto exit; |
| ret = mbedtls_des3_crypt_cbc( &des3_ctx, MBEDTLS_DES_DECRYPT, buflen, |
| des3_iv, buf, buf ); |
| |
| exit: |
| mbedtls_des3_free( &des3_ctx ); |
| mbedtls_platform_zeroize( des3_key, 24 ); |
| |
| return( ret ); |
| } |
| #endif /* MBEDTLS_DES_C */ |
| |
| #if defined(MBEDTLS_AES_C) |
| /* |
| * Decrypt with AES-XXX-CBC, using PBKDF1 for key derivation |
| */ |
| static int pem_aes_decrypt( unsigned char aes_iv[16], unsigned int keylen, |
| unsigned char *buf, size_t buflen, |
| const unsigned char *pwd, size_t pwdlen ) |
| { |
| mbedtls_aes_context aes_ctx; |
| unsigned char aes_key[32]; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| mbedtls_aes_init( &aes_ctx ); |
| |
| if( ( ret = pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen ) ) != 0 ) |
| goto exit; |
| |
| if( ( ret = mbedtls_aes_setkey_dec( &aes_ctx, aes_key, keylen * 8 ) ) != 0 ) |
| goto exit; |
| ret = mbedtls_aes_crypt_cbc( &aes_ctx, MBEDTLS_AES_DECRYPT, buflen, |
| aes_iv, buf, buf ); |
| |
| exit: |
| mbedtls_aes_free( &aes_ctx ); |
| mbedtls_platform_zeroize( aes_key, keylen ); |
| |
| return( ret ); |
| } |
| #endif /* MBEDTLS_AES_C */ |
| |
| #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC && |
| ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */ |
| |
| int mbedtls_pem_read_buffer( mbedtls_pem_context *ctx, const char *header, const char *footer, |
| const unsigned char *data, const unsigned char *pwd, |
| size_t pwdlen, size_t *use_len ) |
| { |
| int ret, enc; |
| size_t len; |
| unsigned char *buf; |
| const unsigned char *s1, *s2, *end; |
| #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \ |
| ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) ) |
| unsigned char pem_iv[16]; |
| mbedtls_cipher_type_t enc_alg = MBEDTLS_CIPHER_NONE; |
| #else |
| ((void) pwd); |
| ((void) pwdlen); |
| #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC && |
| ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */ |
| |
| if( ctx == NULL ) |
| return( MBEDTLS_ERR_PEM_BAD_INPUT_DATA ); |
| |
| s1 = (unsigned char *) strstr( (const char *) data, header ); |
| |
| if( s1 == NULL ) |
| return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ); |
| |
| s2 = (unsigned char *) strstr( (const char *) data, footer ); |
| |
| if( s2 == NULL || s2 <= s1 ) |
| return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ); |
| |
| s1 += strlen( header ); |
| if( *s1 == ' ' ) s1++; |
| if( *s1 == '\r' ) s1++; |
| if( *s1 == '\n' ) s1++; |
| else return( MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ); |
| |
| end = s2; |
| end += strlen( footer ); |
| if( *end == ' ' ) end++; |
| if( *end == '\r' ) end++; |
| if( *end == '\n' ) end++; |
| *use_len = end - data; |
| |
| enc = 0; |
| |
| if( s2 - s1 >= 22 && memcmp( s1, "Proc-Type: 4,ENCRYPTED", 22 ) == 0 ) |
| { |
| #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \ |
| ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) ) |
| enc++; |
| |
| s1 += 22; |
| if( *s1 == '\r' ) s1++; |
| if( *s1 == '\n' ) s1++; |
| else return( MBEDTLS_ERR_PEM_INVALID_DATA ); |
| |
| |
| #if defined(MBEDTLS_DES_C) |
| if( s2 - s1 >= 23 && memcmp( s1, "DEK-Info: DES-EDE3-CBC,", 23 ) == 0 ) |
| { |
| enc_alg = MBEDTLS_CIPHER_DES_EDE3_CBC; |
| |
| s1 += 23; |
| if( s2 - s1 < 16 || pem_get_iv( s1, pem_iv, 8 ) != 0 ) |
| return( MBEDTLS_ERR_PEM_INVALID_ENC_IV ); |
| |
| s1 += 16; |
| } |
| else if( s2 - s1 >= 18 && memcmp( s1, "DEK-Info: DES-CBC,", 18 ) == 0 ) |
| { |
| enc_alg = MBEDTLS_CIPHER_DES_CBC; |
| |
| s1 += 18; |
| if( s2 - s1 < 16 || pem_get_iv( s1, pem_iv, 8) != 0 ) |
| return( MBEDTLS_ERR_PEM_INVALID_ENC_IV ); |
| |
| s1 += 16; |
| } |
| #endif /* MBEDTLS_DES_C */ |
| |
| #if defined(MBEDTLS_AES_C) |
| if( s2 - s1 >= 14 && memcmp( s1, "DEK-Info: AES-", 14 ) == 0 ) |
| { |
| if( s2 - s1 < 22 ) |
| return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG ); |
| else if( memcmp( s1, "DEK-Info: AES-128-CBC,", 22 ) == 0 ) |
| enc_alg = MBEDTLS_CIPHER_AES_128_CBC; |
| else if( memcmp( s1, "DEK-Info: AES-192-CBC,", 22 ) == 0 ) |
| enc_alg = MBEDTLS_CIPHER_AES_192_CBC; |
| else if( memcmp( s1, "DEK-Info: AES-256-CBC,", 22 ) == 0 ) |
| enc_alg = MBEDTLS_CIPHER_AES_256_CBC; |
| else |
| return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG ); |
| |
| s1 += 22; |
| if( s2 - s1 < 32 || pem_get_iv( s1, pem_iv, 16 ) != 0 ) |
| return( MBEDTLS_ERR_PEM_INVALID_ENC_IV ); |
| |
| s1 += 32; |
| } |
| #endif /* MBEDTLS_AES_C */ |
| |
| if( enc_alg == MBEDTLS_CIPHER_NONE ) |
| return( MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG ); |
| |
| if( *s1 == '\r' ) s1++; |
| if( *s1 == '\n' ) s1++; |
| else return( MBEDTLS_ERR_PEM_INVALID_DATA ); |
| #else |
| return( MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE ); |
| #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC && |
| ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */ |
| } |
| |
| if( s1 >= s2 ) |
| return( MBEDTLS_ERR_PEM_INVALID_DATA ); |
| |
| ret = mbedtls_base64_decode( NULL, 0, &len, s1, s2 - s1 ); |
| |
| if( ret == MBEDTLS_ERR_BASE64_INVALID_CHARACTER ) |
| return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PEM_INVALID_DATA, ret ) ); |
| |
| if( ( buf = mbedtls_calloc( 1, len ) ) == NULL ) |
| return( MBEDTLS_ERR_PEM_ALLOC_FAILED ); |
| |
| if( ( ret = mbedtls_base64_decode( buf, len, &len, s1, s2 - s1 ) ) != 0 ) |
| { |
| mbedtls_platform_zeroize( buf, len ); |
| mbedtls_free( buf ); |
| return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PEM_INVALID_DATA, ret ) ); |
| } |
| |
| if( enc != 0 ) |
| { |
| #if defined(MBEDTLS_MD5_C) && defined(MBEDTLS_CIPHER_MODE_CBC) && \ |
| ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) ) |
| if( pwd == NULL ) |
| { |
| mbedtls_platform_zeroize( buf, len ); |
| mbedtls_free( buf ); |
| return( MBEDTLS_ERR_PEM_PASSWORD_REQUIRED ); |
| } |
| |
| ret = 0; |
| |
| #if defined(MBEDTLS_DES_C) |
| if( enc_alg == MBEDTLS_CIPHER_DES_EDE3_CBC ) |
| ret = pem_des3_decrypt( pem_iv, buf, len, pwd, pwdlen ); |
| else if( enc_alg == MBEDTLS_CIPHER_DES_CBC ) |
| ret = pem_des_decrypt( pem_iv, buf, len, pwd, pwdlen ); |
| #endif /* MBEDTLS_DES_C */ |
| |
| #if defined(MBEDTLS_AES_C) |
| if( enc_alg == MBEDTLS_CIPHER_AES_128_CBC ) |
| ret = pem_aes_decrypt( pem_iv, 16, buf, len, pwd, pwdlen ); |
| else if( enc_alg == MBEDTLS_CIPHER_AES_192_CBC ) |
| ret = pem_aes_decrypt( pem_iv, 24, buf, len, pwd, pwdlen ); |
| else if( enc_alg == MBEDTLS_CIPHER_AES_256_CBC ) |
| ret = pem_aes_decrypt( pem_iv, 32, buf, len, pwd, pwdlen ); |
| #endif /* MBEDTLS_AES_C */ |
| |
| if( ret != 0 ) |
| { |
| mbedtls_free( buf ); |
| return( ret ); |
| } |
| |
| /* |
| * The result will be ASN.1 starting with a SEQUENCE tag, with 1 to 3 |
| * length bytes (allow 4 to be sure) in all known use cases. |
| * |
| * Use that as a heuristic to try to detect password mismatches. |
| */ |
| if( len <= 2 || buf[0] != 0x30 || buf[1] > 0x83 ) |
| { |
| mbedtls_platform_zeroize( buf, len ); |
| mbedtls_free( buf ); |
| return( MBEDTLS_ERR_PEM_PASSWORD_MISMATCH ); |
| } |
| #else |
| mbedtls_platform_zeroize( buf, len ); |
| mbedtls_free( buf ); |
| return( MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE ); |
| #endif /* MBEDTLS_MD5_C && MBEDTLS_CIPHER_MODE_CBC && |
| ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */ |
| } |
| |
| ctx->buf = buf; |
| ctx->buflen = len; |
| |
| return( 0 ); |
| } |
| |
| void mbedtls_pem_free( mbedtls_pem_context *ctx ) |
| { |
| if ( ctx->buf != NULL ) |
| { |
| mbedtls_platform_zeroize( ctx->buf, ctx->buflen ); |
| mbedtls_free( ctx->buf ); |
| } |
| mbedtls_free( ctx->info ); |
| |
| mbedtls_platform_zeroize( ctx, sizeof( mbedtls_pem_context ) ); |
| } |
| #endif /* MBEDTLS_PEM_PARSE_C */ |
| |
| #if defined(MBEDTLS_PEM_WRITE_C) |
| int mbedtls_pem_write_buffer( const char *header, const char *footer, |
| const unsigned char *der_data, size_t der_len, |
| unsigned char *buf, size_t buf_len, size_t *olen ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *encode_buf = NULL, *c, *p = buf; |
| size_t len = 0, use_len, add_len = 0; |
| |
| mbedtls_base64_encode( NULL, 0, &use_len, der_data, der_len ); |
| add_len = strlen( header ) + strlen( footer ) + ( use_len / 64 ) + 1; |
| |
| if( use_len + add_len > buf_len ) |
| { |
| *olen = use_len + add_len; |
| return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL ); |
| } |
| |
| if( use_len != 0 && |
| ( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL ) ) |
| return( MBEDTLS_ERR_PEM_ALLOC_FAILED ); |
| |
| if( ( ret = mbedtls_base64_encode( encode_buf, use_len, &use_len, der_data, |
| der_len ) ) != 0 ) |
| { |
| mbedtls_free( encode_buf ); |
| return( ret ); |
| } |
| |
| memcpy( p, header, strlen( header ) ); |
| p += strlen( header ); |
| c = encode_buf; |
| |
| while( use_len ) |
| { |
| len = ( use_len > 64 ) ? 64 : use_len; |
| memcpy( p, c, len ); |
| use_len -= len; |
| p += len; |
| c += len; |
| *p++ = '\n'; |
| } |
| |
| memcpy( p, footer, strlen( footer ) ); |
| p += strlen( footer ); |
| |
| *p++ = '\0'; |
| *olen = p - buf; |
| |
| /* Clean any remaining data previously written to the buffer */ |
| memset( buf + *olen, 0, buf_len - *olen ); |
| |
| mbedtls_free( encode_buf ); |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_PEM_WRITE_C */ |
| #endif /* MBEDTLS_PEM_PARSE_C || MBEDTLS_PEM_WRITE_C */ |
| |
