diff options
Diffstat (limited to 'library/pem.c')
| -rw-r--r-- | library/pem.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/library/pem.c b/library/pem.c new file mode 100644 index 000000000..e8abba13c --- /dev/null +++ b/library/pem.c @@ -0,0 +1,569 @@ +/* + * 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 "hash_info.h" + +#include <string.h> + +#include "mbedtls/platform.h" + +#if defined(MBEDTLS_USE_PSA_CRYPTO) +#include "psa/crypto.h" +#endif + +#include "mbedtls/legacy_or_psa.h" + +#if defined(MBEDTLS_HAS_ALG_MD5_VIA_MD_OR_PSA_BASED_ON_USE_PSA) && \ + defined(MBEDTLS_CIPHER_MODE_CBC) && \ + ( defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C) ) +#define PEM_RFC1421 +#endif /* MBEDTLS_HAS_ALG_MD5_VIA_MD_OR_PSA_BASED_ON_USE_PSA && + MBEDTLS_CIPHER_MODE_CBC && + ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */ + +#if defined(MBEDTLS_PEM_PARSE_C) +void mbedtls_pem_init( mbedtls_pem_context *ctx ) +{ + memset( ctx, 0, sizeof( mbedtls_pem_context ) ); +} + +#if defined(PEM_RFC1421) +/* + * 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 ); +} + +#if defined(MBEDTLS_MD5_C) +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 ); +} +#else +static int pem_pbkdf1( unsigned char *key, size_t keylen, + unsigned char *iv, + const unsigned char *pwd, size_t pwdlen ) +{ + unsigned char md5sum[16]; + psa_hash_operation_t operation = PSA_HASH_OPERATION_INIT; + size_t output_length = 0; + psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED; + + + if( ( status = psa_hash_setup( &operation, PSA_ALG_MD5 ) ) != PSA_SUCCESS ) + goto exit; + + if( ( status = psa_hash_update( &operation, pwd, pwdlen ) ) != PSA_SUCCESS ) + goto exit; + + if( ( status = psa_hash_update( &operation, iv, 8 ) ) != PSA_SUCCESS ) + goto exit; + + if( ( status = psa_hash_finish( &operation, md5sum, + PSA_HASH_LENGTH( PSA_ALG_MD5 ), + &output_length ) ) != PSA_SUCCESS ) + { + goto exit; + } + + if( ( status = psa_hash_abort( &operation ) ) != PSA_SUCCESS ) + goto exit; + + /* + * key[ 0..15] = MD5(pwd || IV) + */ + if( keylen <= 16 ) + { + memcpy( key, md5sum, keylen ); + goto exit; + } + + memcpy( key, md5sum, 16 ); + + /* + * key[16..23] = MD5(key[ 0..15] || pwd || IV]) + */ + if( ( status = psa_hash_setup( &operation, PSA_ALG_MD5 ) ) != PSA_SUCCESS ) + goto exit; + + if( ( status = psa_hash_update( &operation, md5sum, 16 ) ) != PSA_SUCCESS ) + goto exit; + + if( ( status = psa_hash_update( &operation, pwd, pwdlen ) ) != PSA_SUCCESS ) + goto exit; + + if( ( status = psa_hash_update( &operation, iv, 8 ) ) != PSA_SUCCESS ) + goto exit; + + if( ( status = psa_hash_finish( &operation, md5sum, + PSA_HASH_LENGTH( PSA_ALG_MD5 ), + &output_length ) ) != PSA_SUCCESS ) + { + goto exit; + } + + if( ( status = psa_hash_abort( &operation ) ) != PSA_SUCCESS ) + goto exit; + + size_t use_len = 16; + if( keylen < 32 ) + use_len = keylen - 16; + + memcpy( key + 16, md5sum, use_len ); + +exit: + mbedtls_platform_zeroize( md5sum, 16 ); + + return( mbedtls_md_error_from_psa ( status ) ); +} +#endif /* MBEDTLS_MD5_C */ + +#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 /* PEM_RFC1421 */ + +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(PEM_RFC1421) + unsigned char pem_iv[16]; + mbedtls_cipher_type_t enc_alg = MBEDTLS_CIPHER_NONE; +#else + ((void) pwd); + ((void) pwdlen); +#endif /* PEM_RFC1421 */ + + 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(PEM_RFC1421) + 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 /* PEM_RFC1421 */ + } + + 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(PEM_RFC1421) + 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 /* PEM_RFC1421 */ + } + + 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 */ + |