mirror of
https://github.com/Mbed-TLS/mbedtls.git
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9d781407bc
- The error codes have been remapped and combining error codes is now done with a PLUS instead of an OR as error codes used are negative. - Descriptions to all error codes have been added. - Generation script for error.c has been created to automatically generate error.c from the available error definitions in the headers.
351 lines
9.9 KiB
C
351 lines
9.9 KiB
C
/*
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* Privacy Enhanced Mail (PEM) decoding
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*
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* Copyright (C) 2006-2010, Brainspark B.V.
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*
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* This file is part of PolarSSL (http://www.polarssl.org)
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* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "polarssl/config.h"
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#if defined(POLARSSL_PEM_C)
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#include "polarssl/pem.h"
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#include "polarssl/base64.h"
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#include "polarssl/des.h"
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#include "polarssl/aes.h"
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#include "polarssl/md5.h"
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#include "polarssl/cipher.h"
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#include <stdlib.h>
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void pem_init( pem_context *ctx )
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{
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memset( ctx, 0, sizeof( pem_context ) );
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}
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#if defined(POLARSSL_MD5_C) && (defined(POLARSSL_DES_C) || defined(POLARSSL_AES_C))
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/*
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* Read a 16-byte hex string and convert it to binary
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*/
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static int pem_get_iv( const unsigned char *s, unsigned char *iv, size_t iv_len )
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{
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size_t i, j, k;
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memset( iv, 0, iv_len );
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for( i = 0; i < iv_len * 2; i++, s++ )
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{
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if( *s >= '0' && *s <= '9' ) j = *s - '0'; else
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if( *s >= 'A' && *s <= 'F' ) j = *s - '7'; else
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if( *s >= 'a' && *s <= 'f' ) j = *s - 'W'; else
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return( POLARSSL_ERR_PEM_INVALID_ENC_IV );
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k = ( ( i & 1 ) != 0 ) ? j : j << 4;
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iv[i >> 1] = (unsigned char)( iv[i >> 1] | k );
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}
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return( 0 );
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}
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static void pem_pbkdf1( unsigned char *key, size_t keylen,
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unsigned char *iv,
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const unsigned char *pwd, size_t pwdlen )
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{
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md5_context md5_ctx;
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unsigned char md5sum[16];
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size_t use_len;
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/*
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* key[ 0..15] = MD5(pwd || IV)
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*/
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md5_starts( &md5_ctx );
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md5_update( &md5_ctx, pwd, pwdlen );
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md5_update( &md5_ctx, iv, 8 );
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md5_finish( &md5_ctx, md5sum );
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if( keylen <= 16 )
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{
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memcpy( key, md5sum, keylen );
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memset( &md5_ctx, 0, sizeof( md5_ctx ) );
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memset( md5sum, 0, 16 );
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return;
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}
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memcpy( key, md5sum, 16 );
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/*
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* key[16..23] = MD5(key[ 0..15] || pwd || IV])
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*/
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md5_starts( &md5_ctx );
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md5_update( &md5_ctx, md5sum, 16 );
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md5_update( &md5_ctx, pwd, pwdlen );
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md5_update( &md5_ctx, iv, 8 );
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md5_finish( &md5_ctx, md5sum );
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use_len = 16;
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if( keylen < 32 )
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use_len = keylen - 16;
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memcpy( key + 16, md5sum, use_len );
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memset( &md5_ctx, 0, sizeof( md5_ctx ) );
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memset( md5sum, 0, 16 );
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}
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#if defined(POLARSSL_DES_C)
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/*
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* Decrypt with DES-CBC, using PBKDF1 for key derivation
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*/
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static void pem_des_decrypt( unsigned char des_iv[8],
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unsigned char *buf, size_t buflen,
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const unsigned char *pwd, size_t pwdlen )
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{
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des_context des_ctx;
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unsigned char des_key[8];
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pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen );
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des_setkey_dec( &des_ctx, des_key );
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des_crypt_cbc( &des_ctx, DES_DECRYPT, buflen,
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des_iv, buf, buf );
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memset( &des_ctx, 0, sizeof( des_ctx ) );
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memset( des_key, 0, 8 );
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}
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/*
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* Decrypt with 3DES-CBC, using PBKDF1 for key derivation
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*/
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static void pem_des3_decrypt( unsigned char des3_iv[8],
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unsigned char *buf, size_t buflen,
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const unsigned char *pwd, size_t pwdlen )
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{
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des3_context des3_ctx;
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unsigned char des3_key[24];
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pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen );
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des3_set3key_dec( &des3_ctx, des3_key );
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des3_crypt_cbc( &des3_ctx, DES_DECRYPT, buflen,
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des3_iv, buf, buf );
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memset( &des3_ctx, 0, sizeof( des3_ctx ) );
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memset( des3_key, 0, 24 );
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}
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#endif /* POLARSSL_DES_C */
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#if defined(POLARSSL_AES_C)
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/*
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* Decrypt with AES-XXX-CBC, using PBKDF1 for key derivation
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*/
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static void pem_aes_decrypt( unsigned char aes_iv[16], unsigned int keylen,
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unsigned char *buf, size_t buflen,
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const unsigned char *pwd, size_t pwdlen )
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{
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aes_context aes_ctx;
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unsigned char aes_key[32];
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pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen );
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aes_setkey_dec( &aes_ctx, aes_key, keylen * 8 );
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aes_crypt_cbc( &aes_ctx, AES_DECRYPT, buflen,
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aes_iv, buf, buf );
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memset( &aes_ctx, 0, sizeof( aes_ctx ) );
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memset( aes_key, 0, keylen );
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}
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#endif /* POLARSSL_AES_C */
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#endif /* POLARSSL_MD5_C && (POLARSSL_AES_C || POLARSSL_DES_C) */
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int pem_read_buffer( pem_context *ctx, char *header, char *footer, const unsigned char *data, const unsigned char *pwd, size_t pwdlen, size_t *use_len )
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{
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int ret, enc;
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size_t len;
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unsigned char *buf;
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unsigned char *s1, *s2;
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#if defined(POLARSSL_MD5_C) && (defined(POLARSSL_DES_C) || defined(POLARSSL_AES_C))
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unsigned char pem_iv[16];
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cipher_type_t enc_alg = POLARSSL_CIPHER_NONE;
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#else
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((void) pwd);
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((void) pwdlen);
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#endif /* POLARSSL_MD5_C && (POLARSSL_AES_C || POLARSSL_DES_C) */
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if( ctx == NULL )
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return( POLARSSL_ERR_PEM_INVALID_DATA );
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s1 = (unsigned char *) strstr( (char *) data, header );
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if( s1 == NULL )
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return( POLARSSL_ERR_PEM_NO_HEADER_PRESENT );
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s2 = (unsigned char *) strstr( (char *) data, footer );
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if( s2 == NULL || s2 <= s1 )
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return( POLARSSL_ERR_PEM_INVALID_DATA );
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s1 += strlen( header );
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if( *s1 == '\r' ) s1++;
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if( *s1 == '\n' ) s1++;
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else return( POLARSSL_ERR_PEM_INVALID_DATA );
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enc = 0;
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if( memcmp( s1, "Proc-Type: 4,ENCRYPTED", 22 ) == 0 )
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{
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#if defined(POLARSSL_MD5_C) && (defined(POLARSSL_DES_C) || defined(POLARSSL_AES_C))
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enc++;
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s1 += 22;
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if( *s1 == '\r' ) s1++;
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if( *s1 == '\n' ) s1++;
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else return( POLARSSL_ERR_PEM_INVALID_DATA );
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#if defined(POLARSSL_DES_C)
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if( memcmp( s1, "DEK-Info: DES-EDE3-CBC,", 23 ) == 0 )
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{
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enc_alg = POLARSSL_CIPHER_DES_EDE3_CBC;
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s1 += 23;
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if( pem_get_iv( s1, pem_iv, 8 ) != 0 )
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return( POLARSSL_ERR_PEM_INVALID_ENC_IV );
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s1 += 16;
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}
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else if( memcmp( s1, "DEK-Info: DES-CBC,", 18 ) == 0 )
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{
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enc_alg = POLARSSL_CIPHER_DES_CBC;
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s1 += 18;
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if( pem_get_iv( s1, pem_iv, 8) != 0 )
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return( POLARSSL_ERR_PEM_INVALID_ENC_IV );
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s1 += 16;
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}
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#endif /* POLARSSL_DES_C */
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#if defined(POLARSSL_AES_C)
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if( memcmp( s1, "DEK-Info: AES-", 14 ) == 0 )
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{
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if( memcmp( s1, "DEK-Info: AES-128-CBC,", 22 ) == 0 )
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enc_alg = POLARSSL_CIPHER_AES_128_CBC;
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else if( memcmp( s1, "DEK-Info: AES-192-CBC,", 22 ) == 0 )
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enc_alg = POLARSSL_CIPHER_AES_192_CBC;
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else if( memcmp( s1, "DEK-Info: AES-256-CBC,", 22 ) == 0 )
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enc_alg = POLARSSL_CIPHER_AES_256_CBC;
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else
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return( POLARSSL_ERR_PEM_UNKNOWN_ENC_ALG );
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s1 += 22;
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if( pem_get_iv( s1, pem_iv, 16 ) != 0 )
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return( POLARSSL_ERR_PEM_INVALID_ENC_IV );
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s1 += 32;
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}
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#endif /* POLARSSL_AES_C */
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if( enc_alg == POLARSSL_CIPHER_NONE )
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return( POLARSSL_ERR_PEM_UNKNOWN_ENC_ALG );
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if( *s1 == '\r' ) s1++;
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if( *s1 == '\n' ) s1++;
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else return( POLARSSL_ERR_PEM_INVALID_DATA );
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#else
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return( POLARSSL_ERR_PEM_FEATURE_UNAVAILABLE );
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#endif /* POLARSSL_MD5_C && (POLARSSL_AES_C || POLARSSL_DES_C) */
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}
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len = 0;
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ret = base64_decode( NULL, &len, s1, s2 - s1 );
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if( ret == POLARSSL_ERR_BASE64_INVALID_CHARACTER )
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return( POLARSSL_ERR_PEM_INVALID_DATA + ret );
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if( ( buf = (unsigned char *) malloc( len ) ) == NULL )
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return( POLARSSL_ERR_PEM_MALLOC_FAILED );
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if( ( ret = base64_decode( buf, &len, s1, s2 - s1 ) ) != 0 )
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{
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free( buf );
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return( POLARSSL_ERR_PEM_INVALID_DATA + ret );
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}
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if( enc != 0 )
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{
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#if defined(POLARSSL_MD5_C) && (defined(POLARSSL_DES_C) || defined(POLARSSL_AES_C))
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if( pwd == NULL )
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{
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free( buf );
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return( POLARSSL_ERR_PEM_PASSWORD_REQUIRED );
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}
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#if defined(POLARSSL_DES_C)
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if( enc_alg == POLARSSL_CIPHER_DES_EDE3_CBC )
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pem_des3_decrypt( pem_iv, buf, len, pwd, pwdlen );
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else if( enc_alg == POLARSSL_CIPHER_DES_CBC )
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pem_des_decrypt( pem_iv, buf, len, pwd, pwdlen );
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#endif /* POLARSSL_DES_C */
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#if defined(POLARSSL_AES_C)
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if( enc_alg == POLARSSL_CIPHER_AES_128_CBC )
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pem_aes_decrypt( pem_iv, 16, buf, len, pwd, pwdlen );
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else if( enc_alg == POLARSSL_CIPHER_AES_192_CBC )
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pem_aes_decrypt( pem_iv, 24, buf, len, pwd, pwdlen );
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else if( enc_alg == POLARSSL_CIPHER_AES_256_CBC )
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pem_aes_decrypt( pem_iv, 32, buf, len, pwd, pwdlen );
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#endif /* POLARSSL_AES_C */
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if( buf[0] != 0x30 || buf[1] != 0x82 ||
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buf[4] != 0x02 || buf[5] != 0x01 )
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{
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free( buf );
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return( POLARSSL_ERR_PEM_PASSWORD_MISMATCH );
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}
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#else
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return( POLARSSL_ERR_PEM_FEATURE_UNAVAILABLE );
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#endif
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}
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ctx->buf = buf;
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ctx->buflen = len;
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s2 += strlen( footer );
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if( *s2 == '\r' ) s2++;
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if( *s2 == '\n' ) s2++;
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*use_len = s2 - data;
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return( 0 );
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}
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void pem_free( pem_context *ctx )
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{
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if( ctx->buf )
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free( ctx->buf );
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if( ctx->info )
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free( ctx->info );
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}
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#endif
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