/* | |
* Privacy Enhanced Mail (PEM) decoding | |
* | |
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved | |
* 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. | |
* | |
* This file is part of mbed TLS (https://tls.mbed.org) | |
*/ | |
#if !defined(MBEDTLS_CONFIG_FILE) | |
#include "mbedtls/config.h" | |
#else | |
#include MBEDTLS_CONFIG_FILE | |
#endif | |
#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 <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_md5_init( &md5_ctx ); | |
/* | |
* key[ 0..15] = MD5(pwd || IV) | |
*/ | |
if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv, 8 ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md5_finish_ret( &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_ret( &md5_ctx ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md5_update_ret( &md5_ctx, md5sum, 16 ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv, 8 ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md5_finish_ret( &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_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_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_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_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_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; | |
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; | |
mbedtls_free( encode_buf ); | |
return( 0 ); | |
} | |
#endif /* MBEDTLS_PEM_WRITE_C */ | |
#endif /* MBEDTLS_PEM_PARSE_C || MBEDTLS_PEM_WRITE_C */ |