pkcs5.c

00001 /**
00002  * \file pkcs5.c
00003  *
00004  * \brief PKCS#5 functions
00005  *
00006  * \author Mathias Olsson <mathias@kompetensum.com>
00007  *
00008  *  Copyright (C) 2006-2014, Brainspark B.V.
00009  *
00010  *  This file is part of PolarSSL (http://www.polarssl.org)
00011  *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
00012  *
00013  *  All rights reserved.
00014  *
00015  *  This program is free software; you can redistribute it and/or modify
00016  *  it under the terms of the GNU General Public License as published by
00017  *  the Free Software Foundation; either version 2 of the License, or
00018  *  (at your option) any later version.
00019  *
00020  *  This program is distributed in the hope that it will be useful,
00021  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00022  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00023  *  GNU General Public License for more details.
00024  *
00025  *  You should have received a copy of the GNU General Public License along
00026  *  with this program; if not, write to the Free Software Foundation, Inc.,
00027  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00028  */
00029 /*
00030  * PKCS#5 includes PBKDF2 and more
00031  *
00032  * http://tools.ietf.org/html/rfc2898 (Specification)
00033  * http://tools.ietf.org/html/rfc6070 (Test vectors)
00034  */
00035 
00036 #if !defined(POLARSSL_CONFIG_FILE)
00037 #include "polarssl/config.h"
00038 #else
00039 #include POLARSSL_CONFIG_FILE
00040 #endif
00041 
00042 #if defined(POLARSSL_PKCS5_C)
00043 
00044 #include "polarssl/pkcs5.h"
00045 #include "polarssl/asn1.h"
00046 #include "polarssl/cipher.h"
00047 #include "polarssl/oid.h"
00048 
00049 #if defined(POLARSSL_PLATFORM_C)
00050 #include "polarssl/platform.h"
00051 #else
00052 #define polarssl_printf printf
00053 #endif
00054 
00055 static int pkcs5_parse_pbkdf2_params( asn1_buf *params,
00056                                       asn1_buf *salt, int *iterations,
00057                                       int *keylen, md_type_t *md_type )
00058 {
00059     int ret;
00060     asn1_buf prf_alg_oid;
00061     unsigned char **p = &params->p;
00062     const unsigned char *end = params->p + params->len;
00063 
00064     if( params->tag != ( ASN1_CONSTRUCTED | ASN1_SEQUENCE ) )
00065         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT +
00066                 POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
00067     /*
00068      *  PBKDF2-params ::= SEQUENCE {
00069      *    salt              OCTET STRING,
00070      *    iterationCount    INTEGER,
00071      *    keyLength         INTEGER OPTIONAL
00072      *    prf               AlgorithmIdentifier DEFAULT algid-hmacWithSHA1
00073      *  }
00074      *
00075      */
00076     if( ( ret = asn1_get_tag( p, end, &salt->len, ASN1_OCTET_STRING ) ) != 0 )
00077         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00078 
00079     salt->p = *p;
00080     *p += salt->len;
00081 
00082     if( ( ret = asn1_get_int( p, end, iterations ) ) != 0 )
00083         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00084 
00085     if( *p == end )
00086         return( 0 );
00087 
00088     if( ( ret = asn1_get_int( p, end, keylen ) ) != 0 )
00089     {
00090         if( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
00091             return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00092     }
00093 
00094     if( *p == end )
00095         return( 0 );
00096 
00097     if( ( ret = asn1_get_alg_null( p, end, &prf_alg_oid ) ) != 0 )
00098         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00099 
00100     if( !OID_CMP( OID_HMAC_SHA1, &prf_alg_oid ) )
00101         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00102 
00103     *md_type = POLARSSL_MD_SHA1;
00104 
00105     if( *p != end )
00106         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT +
00107                 POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
00108 
00109     return( 0 );
00110 }
00111 
00112 int pkcs5_pbes2( asn1_buf *pbe_params, int mode,
00113                  const unsigned char *pwd,  size_t pwdlen,
00114                  const unsigned char *data, size_t datalen,
00115                  unsigned char *output )
00116 {
00117     int ret, iterations = 0, keylen = 0;
00118     unsigned char *p, *end;
00119     asn1_buf kdf_alg_oid, enc_scheme_oid, kdf_alg_params, enc_scheme_params;
00120     asn1_buf salt;
00121     md_type_t md_type = POLARSSL_MD_SHA1;
00122     unsigned char key[32], iv[32];
00123     size_t olen = 0;
00124     const md_info_t *md_info;
00125     const cipher_info_t *cipher_info;
00126     md_context_t md_ctx;
00127     cipher_type_t cipher_alg;
00128     cipher_context_t cipher_ctx;
00129 
00130     p = pbe_params->p;
00131     end = p + pbe_params->len;
00132 
00133     memset( &md_ctx, 0, sizeof(md_context_t) );
00134     memset( &cipher_ctx, 0, sizeof(cipher_context_t) );
00135 
00136     /*
00137      *  PBES2-params ::= SEQUENCE {
00138      *    keyDerivationFunc AlgorithmIdentifier {{PBES2-KDFs}},
00139      *    encryptionScheme AlgorithmIdentifier {{PBES2-Encs}}
00140      *  }
00141      */
00142     if( pbe_params->tag != ( ASN1_CONSTRUCTED | ASN1_SEQUENCE ) )
00143         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT +
00144                 POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
00145 
00146     if( ( ret = asn1_get_alg( &p, end, &kdf_alg_oid, &kdf_alg_params ) ) != 0 )
00147         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00148 
00149     // Only PBKDF2 supported at the moment
00150     //
00151     if( !OID_CMP( OID_PKCS5_PBKDF2, &kdf_alg_oid ) )
00152         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00153 
00154     if( ( ret = pkcs5_parse_pbkdf2_params( &kdf_alg_params,
00155                                            &salt, &iterations, &keylen,
00156                                            &md_type ) ) != 0 )
00157     {
00158         return( ret );
00159     }
00160 
00161     md_info = md_info_from_type( md_type );
00162     if( md_info == NULL )
00163         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00164 
00165     if( ( ret = asn1_get_alg( &p, end, &enc_scheme_oid,
00166                               &enc_scheme_params ) ) != 0 )
00167     {
00168         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00169     }
00170 
00171     if ( oid_get_cipher_alg( &enc_scheme_oid, &cipher_alg ) != 0 )
00172         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00173 
00174     cipher_info = cipher_info_from_type( cipher_alg );
00175     if( cipher_info == NULL )
00176         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00177 
00178     keylen = cipher_info->key_length / 8;
00179 
00180     if( enc_scheme_params.tag != ASN1_OCTET_STRING ||
00181         enc_scheme_params.len != cipher_info->iv_size )
00182     {
00183         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT );
00184     }
00185 
00186     memcpy( iv, enc_scheme_params.p, enc_scheme_params.len );
00187 
00188     if( ( ret = md_init_ctx( &md_ctx, md_info ) ) != 0 )
00189         goto exit;
00190 
00191     if ( ( ret = pkcs5_pbkdf2_hmac( &md_ctx, pwd, pwdlen, salt.p, salt.len,
00192                                     iterations, keylen, key ) ) != 0 )
00193     {
00194         goto exit;
00195     }
00196 
00197     if( ( ret = cipher_init_ctx( &cipher_ctx, cipher_info ) ) != 0 )
00198         goto exit;
00199 
00200     if( ( ret = cipher_setkey( &cipher_ctx, key, 8 * keylen, mode ) ) != 0 )
00201         goto exit;
00202 
00203     if( ( ret = cipher_set_iv( &cipher_ctx, iv, enc_scheme_params.len ) ) != 0 )
00204         goto exit;
00205 
00206     if( ( ret = cipher_reset( &cipher_ctx ) ) != 0 )
00207         goto exit;
00208 
00209     if( ( ret = cipher_update( &cipher_ctx, data, datalen,
00210                                 output, &olen ) ) != 0 )
00211     {
00212         goto exit;
00213     }
00214 
00215     if( ( ret = cipher_finish( &cipher_ctx, output + olen, &olen ) ) != 0 )
00216         ret = POLARSSL_ERR_PKCS5_PASSWORD_MISMATCH;
00217 
00218 exit:
00219     md_free_ctx( &md_ctx );
00220     cipher_free_ctx( &cipher_ctx );
00221 
00222     return( ret );
00223 }
00224 
00225 int pkcs5_pbkdf2_hmac( md_context_t *ctx, const unsigned char *password,
00226                        size_t plen, const unsigned char *salt, size_t slen,
00227                        unsigned int iteration_count,
00228                        uint32_t key_length, unsigned char *output )
00229 {
00230     int ret, j;
00231     unsigned int i;
00232     unsigned char md1[POLARSSL_MD_MAX_SIZE];
00233     unsigned char work[POLARSSL_MD_MAX_SIZE];
00234     unsigned char md_size = md_get_size( ctx->md_info );
00235     size_t use_len;
00236     unsigned char *out_p = output;
00237     unsigned char counter[4];
00238 
00239     memset( counter, 0, 4 );
00240     counter[3] = 1;
00241 
00242     if( iteration_count > 0xFFFFFFFF )
00243         return( POLARSSL_ERR_PKCS5_BAD_INPUT_DATA );
00244 
00245     while( key_length )
00246     {
00247         // U1 ends up in work
00248         //
00249         if( ( ret = md_hmac_starts( ctx, password, plen ) ) != 0 )
00250             return( ret );
00251 
00252         if( ( ret = md_hmac_update( ctx, salt, slen ) ) != 0 )
00253             return( ret );
00254 
00255         if( ( ret = md_hmac_update( ctx, counter, 4 ) ) != 0 )
00256             return( ret );
00257 
00258         if( ( ret = md_hmac_finish( ctx, work ) ) != 0 )
00259             return( ret );
00260 
00261         memcpy( md1, work, md_size );
00262 
00263         for ( i = 1; i < iteration_count; i++ )
00264         {
00265             // U2 ends up in md1
00266             //
00267             if( ( ret = md_hmac_starts( ctx, password, plen ) ) != 0 )
00268                 return( ret );
00269 
00270             if( ( ret = md_hmac_update( ctx, md1, md_size ) ) != 0 )
00271                 return( ret );
00272 
00273             if( ( ret = md_hmac_finish( ctx, md1 ) ) != 0 )
00274                 return( ret );
00275 
00276             // U1 xor U2
00277             //
00278             for( j = 0; j < md_size; j++ )
00279                 work[j] ^= md1[j];
00280         }
00281 
00282         use_len = ( key_length < md_size ) ? key_length : md_size;
00283         memcpy( out_p, work, use_len );
00284 
00285         key_length -= (uint32_t) use_len;
00286         out_p += use_len;
00287 
00288         for( i = 4; i > 0; i-- )
00289             if( ++counter[i - 1] != 0 )
00290                 break;
00291     }
00292 
00293     return( 0 );
00294 }
00295 
00296 #if defined(POLARSSL_SELF_TEST)
00297 
00298 #include <stdio.h>
00299 
00300 #define MAX_TESTS   6
00301 
00302 size_t plen[MAX_TESTS] =
00303     { 8, 8, 8, 8, 24, 9 };
00304 
00305 unsigned char password[MAX_TESTS][32] =
00306 {
00307     "password",
00308     "password",
00309     "password",
00310     "password",
00311     "passwordPASSWORDpassword",
00312     "pass\0word",
00313 };
00314 
00315 size_t slen[MAX_TESTS] =
00316     { 4, 4, 4, 4, 36, 5 };
00317 
00318 unsigned char salt[MAX_TESTS][40] =
00319 {
00320     "salt",
00321     "salt",
00322     "salt",
00323     "salt",
00324     "saltSALTsaltSALTsaltSALTsaltSALTsalt",
00325     "sa\0lt",
00326 };
00327 
00328 uint32_t it_cnt[MAX_TESTS] =
00329     { 1, 2, 4096, 16777216, 4096, 4096 };
00330 
00331 uint32_t key_len[MAX_TESTS] =
00332     { 20, 20, 20, 20, 25, 16 };
00333 
00334 
00335 unsigned char result_key[MAX_TESTS][32] =
00336 {
00337     { 0x0c, 0x60, 0xc8, 0x0f, 0x96, 0x1f, 0x0e, 0x71,
00338       0xf3, 0xa9, 0xb5, 0x24, 0xaf, 0x60, 0x12, 0x06,
00339       0x2f, 0xe0, 0x37, 0xa6 },
00340     { 0xea, 0x6c, 0x01, 0x4d, 0xc7, 0x2d, 0x6f, 0x8c,
00341       0xcd, 0x1e, 0xd9, 0x2a, 0xce, 0x1d, 0x41, 0xf0,
00342       0xd8, 0xde, 0x89, 0x57 },
00343     { 0x4b, 0x00, 0x79, 0x01, 0xb7, 0x65, 0x48, 0x9a,
00344       0xbe, 0xad, 0x49, 0xd9, 0x26, 0xf7, 0x21, 0xd0,
00345       0x65, 0xa4, 0x29, 0xc1 },
00346     { 0xee, 0xfe, 0x3d, 0x61, 0xcd, 0x4d, 0xa4, 0xe4,
00347       0xe9, 0x94, 0x5b, 0x3d, 0x6b, 0xa2, 0x15, 0x8c,
00348       0x26, 0x34, 0xe9, 0x84 },
00349     { 0x3d, 0x2e, 0xec, 0x4f, 0xe4, 0x1c, 0x84, 0x9b,
00350       0x80, 0xc8, 0xd8, 0x36, 0x62, 0xc0, 0xe4, 0x4a,
00351       0x8b, 0x29, 0x1a, 0x96, 0x4c, 0xf2, 0xf0, 0x70,
00352       0x38 },
00353     { 0x56, 0xfa, 0x6a, 0xa7, 0x55, 0x48, 0x09, 0x9d,
00354       0xcc, 0x37, 0xd7, 0xf0, 0x34, 0x25, 0xe0, 0xc3 },
00355 };
00356 
00357 int pkcs5_self_test( int verbose )
00358 {
00359     md_context_t sha1_ctx;
00360     const md_info_t *info_sha1;
00361     int ret, i;
00362     unsigned char key[64];
00363 
00364     info_sha1 = md_info_from_type( POLARSSL_MD_SHA1 );
00365     if( info_sha1 == NULL )
00366         return( 1 );
00367 
00368     if( ( ret = md_init_ctx( &sha1_ctx, info_sha1 ) ) != 0 )
00369         return( 1 );
00370 
00371     if( verbose != 0 )
00372         polarssl_printf( "  PBKDF2 note: test #3 may be slow!\n" );
00373 
00374     for( i = 0; i < MAX_TESTS; i++ )
00375     {
00376         if( verbose != 0 )
00377             polarssl_printf( "  PBKDF2 (SHA1) #%d: ", i );
00378 
00379         ret = pkcs5_pbkdf2_hmac( &sha1_ctx, password[i], plen[i], salt[i],
00380                                   slen[i], it_cnt[i], key_len[i], key );
00381         if( ret != 0 ||
00382             memcmp( result_key[i], key, key_len[i] ) != 0 )
00383         {
00384             if( verbose != 0 )
00385                 polarssl_printf( "failed\n" );
00386 
00387             return( 1 );
00388         }
00389 
00390         if( verbose != 0 )
00391             polarssl_printf( "passed\n" );
00392     }
00393 
00394     polarssl_printf( "\n" );
00395 
00396     if( ( ret = md_free_ctx( &sha1_ctx ) ) != 0 )
00397         return( 1 );
00398 
00399     return( 0 );
00400 }
00401 
00402 #endif /* POLARSSL_SELF_TEST */
00403 
00404 #endif /* POLARSSL_PKCS5_C */
00405 
00406