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, ARM Limited, All Rights Reserved
00009  *
00010  *  This file is part of mbed TLS (https://tls.mbed.org)
00011  *
00012  *  This program is free software; you can redistribute it and/or modify
00013  *  it under the terms of the GNU General Public License as published by
00014  *  the Free Software Foundation; either version 2 of the License, or
00015  *  (at your option) any later version.
00016  *
00017  *  This program is distributed in the hope that it will be useful,
00018  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00019  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00020  *  GNU General Public License for more details.
00021  *
00022  *  You should have received a copy of the GNU General Public License along
00023  *  with this program; if not, write to the Free Software Foundation, Inc.,
00024  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00025  */
00026 /*
00027  * PKCS#5 includes PBKDF2 and more
00028  *
00029  * http://tools.ietf.org/html/rfc2898 (Specification)
00030  * http://tools.ietf.org/html/rfc6070 (Test vectors)
00031  */
00032 
00033 #if !defined(POLARSSL_CONFIG_FILE)
00034 #include "polarssl/config.h"
00035 #else
00036 #include POLARSSL_CONFIG_FILE
00037 #endif
00038 
00039 #if defined(POLARSSL_PKCS5_C)
00040 
00041 #include "polarssl/pkcs5.h"
00042 #include "polarssl/asn1.h"
00043 #include "polarssl/cipher.h"
00044 #include "polarssl/oid.h"
00045 
00046 #include <string.h>
00047 
00048 #if defined(POLARSSL_PLATFORM_C)
00049 #include "polarssl/platform.h"
00050 #else
00051 #include <stdio.h>
00052 #define polarssl_printf printf
00053 #endif
00054 
00055 static int pkcs5_parse_pbkdf2_params( const 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     /*
00134      *  PBES2-params ::= SEQUENCE {
00135      *    keyDerivationFunc AlgorithmIdentifier {{PBES2-KDFs}},
00136      *    encryptionScheme AlgorithmIdentifier {{PBES2-Encs}}
00137      *  }
00138      */
00139     if( pbe_params->tag != ( ASN1_CONSTRUCTED | ASN1_SEQUENCE ) )
00140         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT +
00141                 POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
00142 
00143     if( ( ret = asn1_get_alg( &p, end, &kdf_alg_oid, &kdf_alg_params ) ) != 0 )
00144         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00145 
00146     // Only PBKDF2 supported at the moment
00147     //
00148     if( !OID_CMP( OID_PKCS5_PBKDF2, &kdf_alg_oid ) )
00149         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00150 
00151     if( ( ret = pkcs5_parse_pbkdf2_params( &kdf_alg_params,
00152                                            &salt, &iterations, &keylen,
00153                                            &md_type ) ) != 0 )
00154     {
00155         return( ret );
00156     }
00157 
00158     md_info = md_info_from_type( md_type );
00159     if( md_info == NULL )
00160         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00161 
00162     if( ( ret = asn1_get_alg( &p, end, &enc_scheme_oid,
00163                               &enc_scheme_params ) ) != 0 )
00164     {
00165         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT + ret );
00166     }
00167 
00168     if( oid_get_cipher_alg( &enc_scheme_oid, &cipher_alg ) != 0 )
00169         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00170 
00171     cipher_info = cipher_info_from_type( cipher_alg );
00172     if( cipher_info == NULL )
00173         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
00174 
00175     /*
00176      * The value of keylen from pkcs5_parse_pbkdf2_params() is ignored
00177      * since it is optional and we don't know if it was set or not
00178      */
00179     keylen = cipher_info->key_length / 8;
00180 
00181     if( enc_scheme_params.tag != ASN1_OCTET_STRING ||
00182         enc_scheme_params.len != cipher_info->iv_size )
00183     {
00184         return( POLARSSL_ERR_PKCS5_INVALID_FORMAT );
00185     }
00186 
00187     md_init( &md_ctx );
00188     cipher_init( &cipher_ctx );
00189 
00190     memcpy( iv, enc_scheme_params.p, enc_scheme_params.len );
00191 
00192     if( ( ret = md_init_ctx( &md_ctx, md_info ) ) != 0 )
00193         goto exit;
00194 
00195     if( ( ret = pkcs5_pbkdf2_hmac( &md_ctx, pwd, pwdlen, salt.p, salt.len,
00196                                    iterations, keylen, key ) ) != 0 )
00197     {
00198         goto exit;
00199     }
00200 
00201     if( ( ret = cipher_init_ctx( &cipher_ctx, cipher_info ) ) != 0 )
00202         goto exit;
00203 
00204     if( ( ret = cipher_setkey( &cipher_ctx, key, 8 * keylen, (operation_t) mode ) ) != 0 )
00205         goto exit;
00206 
00207     if( ( ret = cipher_crypt( &cipher_ctx, iv, enc_scheme_params.len,
00208                               data, datalen, output, &olen ) ) != 0 )
00209         ret = POLARSSL_ERR_PKCS5_PASSWORD_MISMATCH;
00210 
00211 exit:
00212     md_free( &md_ctx );
00213     cipher_free( &cipher_ctx );
00214 
00215     return( ret );
00216 }
00217 
00218 int pkcs5_pbkdf2_hmac( md_context_t *ctx, const unsigned char *password,
00219                        size_t plen, const unsigned char *salt, size_t slen,
00220                        unsigned int iteration_count,
00221                        uint32_t key_length, unsigned char *output )
00222 {
00223     int ret, j;
00224     unsigned int i;
00225     unsigned char md1[POLARSSL_MD_MAX_SIZE];
00226     unsigned char work[POLARSSL_MD_MAX_SIZE];
00227     unsigned char md_size = md_get_size( ctx->md_info );
00228     size_t use_len;
00229     unsigned char *out_p = output;
00230     unsigned char counter[4];
00231 
00232     memset( counter, 0, 4 );
00233     counter[3] = 1;
00234 
00235     if( iteration_count > 0xFFFFFFFF )
00236         return( POLARSSL_ERR_PKCS5_BAD_INPUT_DATA );
00237 
00238     while( key_length )
00239     {
00240         // U1 ends up in work
00241         //
00242         if( ( ret = md_hmac_starts( ctx, password, plen ) ) != 0 )
00243             return( ret );
00244 
00245         if( ( ret = md_hmac_update( ctx, salt, slen ) ) != 0 )
00246             return( ret );
00247 
00248         if( ( ret = md_hmac_update( ctx, counter, 4 ) ) != 0 )
00249             return( ret );
00250 
00251         if( ( ret = md_hmac_finish( ctx, work ) ) != 0 )
00252             return( ret );
00253 
00254         memcpy( md1, work, md_size );
00255 
00256         for( i = 1; i < iteration_count; i++ )
00257         {
00258             // U2 ends up in md1
00259             //
00260             if( ( ret = md_hmac_starts( ctx, password, plen ) ) != 0 )
00261                 return( ret );
00262 
00263             if( ( ret = md_hmac_update( ctx, md1, md_size ) ) != 0 )
00264                 return( ret );
00265 
00266             if( ( ret = md_hmac_finish( ctx, md1 ) ) != 0 )
00267                 return( ret );
00268 
00269             // U1 xor U2
00270             //
00271             for( j = 0; j < md_size; j++ )
00272                 work[j] ^= md1[j];
00273         }
00274 
00275         use_len = ( key_length < md_size ) ? key_length : md_size;
00276         memcpy( out_p, work, use_len );
00277 
00278         key_length -= (uint32_t) use_len;
00279         out_p += use_len;
00280 
00281         for( i = 4; i > 0; i-- )
00282             if( ++counter[i - 1] != 0 )
00283                 break;
00284     }
00285 
00286     return( 0 );
00287 }
00288 
00289 #if defined(POLARSSL_SELF_TEST)
00290 
00291 #if !defined(POLARSSL_SHA1_C)
00292 int pkcs5_self_test( int verbose )
00293 {
00294     if( verbose != 0 )
00295         polarssl_printf( "  PBKDF2 (SHA1): skipped\n\n" );
00296 
00297     return( 0 );
00298 }
00299 #else
00300 
00301 #define MAX_TESTS   6
00302 
00303 static const size_t plen[MAX_TESTS] =
00304     { 8, 8, 8, 24, 9 };
00305 
00306 static const unsigned char password[MAX_TESTS][32] =
00307 {
00308     "password",
00309     "password",
00310     "password",
00311     "passwordPASSWORDpassword",
00312     "pass\0word",
00313 };
00314 
00315 static const size_t slen[MAX_TESTS] =
00316     { 4, 4, 4, 36, 5 };
00317 
00318 static const unsigned char salt[MAX_TESTS][40] =
00319 {
00320     "salt",
00321     "salt",
00322     "salt",
00323     "saltSALTsaltSALTsaltSALTsaltSALTsalt",
00324     "sa\0lt",
00325 };
00326 
00327 static const uint32_t it_cnt[MAX_TESTS] =
00328     { 1, 2, 4096, 4096, 4096 };
00329 
00330 static const uint32_t key_len[MAX_TESTS] =
00331     { 20, 20, 20, 25, 16 };
00332 
00333 static const unsigned char result_key[MAX_TESTS][32] =
00334 {
00335     { 0x0c, 0x60, 0xc8, 0x0f, 0x96, 0x1f, 0x0e, 0x71,
00336       0xf3, 0xa9, 0xb5, 0x24, 0xaf, 0x60, 0x12, 0x06,
00337       0x2f, 0xe0, 0x37, 0xa6 },
00338     { 0xea, 0x6c, 0x01, 0x4d, 0xc7, 0x2d, 0x6f, 0x8c,
00339       0xcd, 0x1e, 0xd9, 0x2a, 0xce, 0x1d, 0x41, 0xf0,
00340       0xd8, 0xde, 0x89, 0x57 },
00341     { 0x4b, 0x00, 0x79, 0x01, 0xb7, 0x65, 0x48, 0x9a,
00342       0xbe, 0xad, 0x49, 0xd9, 0x26, 0xf7, 0x21, 0xd0,
00343       0x65, 0xa4, 0x29, 0xc1 },
00344     { 0x3d, 0x2e, 0xec, 0x4f, 0xe4, 0x1c, 0x84, 0x9b,
00345       0x80, 0xc8, 0xd8, 0x36, 0x62, 0xc0, 0xe4, 0x4a,
00346       0x8b, 0x29, 0x1a, 0x96, 0x4c, 0xf2, 0xf0, 0x70,
00347       0x38 },
00348     { 0x56, 0xfa, 0x6a, 0xa7, 0x55, 0x48, 0x09, 0x9d,
00349       0xcc, 0x37, 0xd7, 0xf0, 0x34, 0x25, 0xe0, 0xc3 },
00350 };
00351 
00352 int pkcs5_self_test( int verbose )
00353 {
00354     md_context_t sha1_ctx;
00355     const md_info_t *info_sha1;
00356     int ret, i;
00357     unsigned char key[64];
00358 
00359     md_init( &sha1_ctx );
00360 
00361     info_sha1 = md_info_from_type( POLARSSL_MD_SHA1 );
00362     if( info_sha1 == NULL )
00363     {
00364         ret = 1;
00365         goto exit;
00366     }
00367 
00368     if( ( ret = md_init_ctx( &sha1_ctx, info_sha1 ) ) != 0 )
00369     {
00370         ret = 1;
00371         goto exit;
00372     }
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             ret = 1;
00388             goto exit;
00389         }
00390 
00391         if( verbose != 0 )
00392             polarssl_printf( "passed\n" );
00393     }
00394 
00395     polarssl_printf( "\n" );
00396 
00397 exit:
00398     md_free( &sha1_ctx );
00399 
00400     return( ret );
00401 }
00402 #endif /* POLARSSL_SHA1_C */
00403 
00404 #endif /* POLARSSL_SELF_TEST */
00405 
00406 #endif /* POLARSSL_PKCS5_C */
00407