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Diff: mbedtls/source/hmac_drbg.c
- Revision:
- 11:cada08fc8a70
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbedtls/source/hmac_drbg.c Thu Jun 09 17:08:36 2016 +0000 @@ -0,0 +1,529 @@ +/* + * HMAC_DRBG implementation (NIST SP 800-90) + * + * 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) + */ + +/* + * The NIST SP 800-90A DRBGs are described in the following publication. + * http://csrc.nist.gov/publications/nistpubs/800-90A/SP800-90A.pdf + * References below are based on rev. 1 (January 2012). + */ + +#if !defined(MBEDTLS_CONFIG_FILE) +#include "mbedtls/config.h" +#else +#include MBEDTLS_CONFIG_FILE +#endif + +#if defined(MBEDTLS_HMAC_DRBG_C) + +#include "mbedtls/hmac_drbg.h" + +#include <string.h> + +#if defined(MBEDTLS_FS_IO) +#include <stdio.h> +#endif + +#if defined(MBEDTLS_SELF_TEST) +#if defined(MBEDTLS_PLATFORM_C) +#include "mbedtls/platform.h" +#else +#include <stdio.h> +#define mbedtls_printf printf +#endif /* MBEDTLS_SELF_TEST */ +#endif /* MBEDTLS_PLATFORM_C */ + +/* Implementation that should never be optimized out by the compiler */ +static void mbedtls_zeroize( void *v, size_t n ) { + volatile unsigned char *p = v; while( n-- ) *p++ = 0; +} + +/* + * HMAC_DRBG context initialization + */ +void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx ) +{ + memset( ctx, 0, sizeof( mbedtls_hmac_drbg_context ) ); + +#if defined(MBEDTLS_THREADING_C) + mbedtls_mutex_init( &ctx->mutex ); +#endif +} + +/* + * HMAC_DRBG update, using optional additional data (10.1.2.2) + */ +void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, size_t add_len ) +{ + size_t md_len = mbedtls_md_get_size( ctx->md_ctx.md_info ); + unsigned char rounds = ( additional != NULL && add_len != 0 ) ? 2 : 1; + unsigned char sep[1]; + unsigned char K[MBEDTLS_MD_MAX_SIZE]; + + for( sep[0] = 0; sep[0] < rounds; sep[0]++ ) + { + /* Step 1 or 4 */ + mbedtls_md_hmac_reset( &ctx->md_ctx ); + mbedtls_md_hmac_update( &ctx->md_ctx, ctx->V, md_len ); + mbedtls_md_hmac_update( &ctx->md_ctx, sep, 1 ); + if( rounds == 2 ) + mbedtls_md_hmac_update( &ctx->md_ctx, additional, add_len ); + mbedtls_md_hmac_finish( &ctx->md_ctx, K ); + + /* Step 2 or 5 */ + mbedtls_md_hmac_starts( &ctx->md_ctx, K, md_len ); + mbedtls_md_hmac_update( &ctx->md_ctx, ctx->V, md_len ); + mbedtls_md_hmac_finish( &ctx->md_ctx, ctx->V ); + } +} + +/* + * Simplified HMAC_DRBG initialisation (for use with deterministic ECDSA) + */ +int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx, + const mbedtls_md_info_t * md_info, + const unsigned char *data, size_t data_len ) +{ + int ret; + + if( ( ret = mbedtls_md_setup( &ctx->md_ctx, md_info, 1 ) ) != 0 ) + return( ret ); + + /* + * Set initial working state. + * Use the V memory location, which is currently all 0, to initialize the + * MD context with an all-zero key. Then set V to its initial value. + */ + mbedtls_md_hmac_starts( &ctx->md_ctx, ctx->V, mbedtls_md_get_size( md_info ) ); + memset( ctx->V, 0x01, mbedtls_md_get_size( md_info ) ); + + mbedtls_hmac_drbg_update( ctx, data, data_len ); + + return( 0 ); +} + +/* + * HMAC_DRBG reseeding: 10.1.2.4 (arabic) + 9.2 (Roman) + */ +int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, size_t len ) +{ + unsigned char seed[MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT]; + size_t seedlen; + + /* III. Check input length */ + if( len > MBEDTLS_HMAC_DRBG_MAX_INPUT || + ctx->entropy_len + len > MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT ) + { + return( MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG ); + } + + memset( seed, 0, MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT ); + + /* IV. Gather entropy_len bytes of entropy for the seed */ + if( ctx->f_entropy( ctx->p_entropy, seed, ctx->entropy_len ) != 0 ) + return( MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED ); + + seedlen = ctx->entropy_len; + + /* 1. Concatenate entropy and additional data if any */ + if( additional != NULL && len != 0 ) + { + memcpy( seed + seedlen, additional, len ); + seedlen += len; + } + + /* 2. Update state */ + mbedtls_hmac_drbg_update( ctx, seed, seedlen ); + + /* 3. Reset reseed_counter */ + ctx->reseed_counter = 1; + + /* 4. Done */ + return( 0 ); +} + +/* + * HMAC_DRBG initialisation (10.1.2.3 + 9.1) + */ +int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx, + const mbedtls_md_info_t * md_info, + int (*f_entropy)(void *, unsigned char *, size_t), + void *p_entropy, + const unsigned char *custom, + size_t len ) +{ + int ret; + size_t entropy_len, md_size; + + if( ( ret = mbedtls_md_setup( &ctx->md_ctx, md_info, 1 ) ) != 0 ) + return( ret ); + + md_size = mbedtls_md_get_size( md_info ); + + /* + * Set initial working state. + * Use the V memory location, which is currently all 0, to initialize the + * MD context with an all-zero key. Then set V to its initial value. + */ + mbedtls_md_hmac_starts( &ctx->md_ctx, ctx->V, md_size ); + memset( ctx->V, 0x01, md_size ); + + ctx->f_entropy = f_entropy; + ctx->p_entropy = p_entropy; + + ctx->reseed_interval = MBEDTLS_HMAC_DRBG_RESEED_INTERVAL; + + /* + * See SP800-57 5.6.1 (p. 65-66) for the security strength provided by + * each hash function, then according to SP800-90A rev1 10.1 table 2, + * min_entropy_len (in bits) is security_strength. + * + * (This also matches the sizes used in the NIST test vectors.) + */ + entropy_len = md_size <= 20 ? 16 : /* 160-bits hash -> 128 bits */ + md_size <= 28 ? 24 : /* 224-bits hash -> 192 bits */ + 32; /* better (256+) -> 256 bits */ + + /* + * For initialisation, use more entropy to emulate a nonce + * (Again, matches test vectors.) + */ + ctx->entropy_len = entropy_len * 3 / 2; + + if( ( ret = mbedtls_hmac_drbg_reseed( ctx, custom, len ) ) != 0 ) + return( ret ); + + ctx->entropy_len = entropy_len; + + return( 0 ); +} + +/* + * Set prediction resistance + */ +void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx, + int resistance ) +{ + ctx->prediction_resistance = resistance; +} + +/* + * Set entropy length grabbed for reseeds + */ +void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx, size_t len ) +{ + ctx->entropy_len = len; +} + +/* + * Set reseed interval + */ +void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx, int interval ) +{ + ctx->reseed_interval = interval; +} + +/* + * HMAC_DRBG random function with optional additional data: + * 10.1.2.5 (arabic) + 9.3 (Roman) + */ +int mbedtls_hmac_drbg_random_with_add( void *p_rng, + unsigned char *output, size_t out_len, + const unsigned char *additional, size_t add_len ) +{ + int ret; + mbedtls_hmac_drbg_context *ctx = (mbedtls_hmac_drbg_context *) p_rng; + size_t md_len = mbedtls_md_get_size( ctx->md_ctx.md_info ); + size_t left = out_len; + unsigned char *out = output; + + /* II. Check request length */ + if( out_len > MBEDTLS_HMAC_DRBG_MAX_REQUEST ) + return( MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG ); + + /* III. Check input length */ + if( add_len > MBEDTLS_HMAC_DRBG_MAX_INPUT ) + return( MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG ); + + /* 1. (aka VII and IX) Check reseed counter and PR */ + if( ctx->f_entropy != NULL && /* For no-reseeding instances */ + ( ctx->prediction_resistance == MBEDTLS_HMAC_DRBG_PR_ON || + ctx->reseed_counter > ctx->reseed_interval ) ) + { + if( ( ret = mbedtls_hmac_drbg_reseed( ctx, additional, add_len ) ) != 0 ) + return( ret ); + + add_len = 0; /* VII.4 */ + } + + /* 2. Use additional data if any */ + if( additional != NULL && add_len != 0 ) + mbedtls_hmac_drbg_update( ctx, additional, add_len ); + + /* 3, 4, 5. Generate bytes */ + while( left != 0 ) + { + size_t use_len = left > md_len ? md_len : left; + + mbedtls_md_hmac_reset( &ctx->md_ctx ); + mbedtls_md_hmac_update( &ctx->md_ctx, ctx->V, md_len ); + mbedtls_md_hmac_finish( &ctx->md_ctx, ctx->V ); + + memcpy( out, ctx->V, use_len ); + out += use_len; + left -= use_len; + } + + /* 6. Update */ + mbedtls_hmac_drbg_update( ctx, additional, add_len ); + + /* 7. Update reseed counter */ + ctx->reseed_counter++; + + /* 8. Done */ + return( 0 ); +} + +/* + * HMAC_DRBG random function + */ +int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len ) +{ + int ret; + mbedtls_hmac_drbg_context *ctx = (mbedtls_hmac_drbg_context *) p_rng; + +#if defined(MBEDTLS_THREADING_C) + if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) + return( ret ); +#endif + + ret = mbedtls_hmac_drbg_random_with_add( ctx, output, out_len, NULL, 0 ); + +#if defined(MBEDTLS_THREADING_C) + if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) + return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); +#endif + + return( ret ); +} + +/* + * Free an HMAC_DRBG context + */ +void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx ) +{ + if( ctx == NULL ) + return; + +#if defined(MBEDTLS_THREADING_C) + mbedtls_mutex_free( &ctx->mutex ); +#endif + mbedtls_md_free( &ctx->md_ctx ); + mbedtls_zeroize( ctx, sizeof( mbedtls_hmac_drbg_context ) ); +} + +#if defined(MBEDTLS_FS_IO) +int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ) +{ + int ret; + FILE *f; + unsigned char buf[ MBEDTLS_HMAC_DRBG_MAX_INPUT ]; + + if( ( f = fopen( path, "wb" ) ) == NULL ) + return( MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR ); + + if( ( ret = mbedtls_hmac_drbg_random( ctx, buf, sizeof( buf ) ) ) != 0 ) + goto exit; + + if( fwrite( buf, 1, sizeof( buf ), f ) != sizeof( buf ) ) + { + ret = MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR; + goto exit; + } + + ret = 0; + +exit: + fclose( f ); + return( ret ); +} + +int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ) +{ + FILE *f; + size_t n; + unsigned char buf[ MBEDTLS_HMAC_DRBG_MAX_INPUT ]; + + if( ( f = fopen( path, "rb" ) ) == NULL ) + return( MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR ); + + fseek( f, 0, SEEK_END ); + n = (size_t) ftell( f ); + fseek( f, 0, SEEK_SET ); + + if( n > MBEDTLS_HMAC_DRBG_MAX_INPUT ) + { + fclose( f ); + return( MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG ); + } + + if( fread( buf, 1, n, f ) != n ) + { + fclose( f ); + return( MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR ); + } + + fclose( f ); + + mbedtls_hmac_drbg_update( ctx, buf, n ); + + return( mbedtls_hmac_drbg_write_seed_file( ctx, path ) ); +} +#endif /* MBEDTLS_FS_IO */ + + +#if defined(MBEDTLS_SELF_TEST) + +#if !defined(MBEDTLS_SHA1_C) +/* Dummy checkup routine */ +int mbedtls_hmac_drbg_self_test( int verbose ) +{ + (void) verbose; + return( 0 ); +} +#else + +#define OUTPUT_LEN 80 + +/* From a NIST PR=true test vector */ +static const unsigned char entropy_pr[] = { + 0xa0, 0xc9, 0xab, 0x58, 0xf1, 0xe2, 0xe5, 0xa4, 0xde, 0x3e, 0xbd, 0x4f, + 0xf7, 0x3e, 0x9c, 0x5b, 0x64, 0xef, 0xd8, 0xca, 0x02, 0x8c, 0xf8, 0x11, + 0x48, 0xa5, 0x84, 0xfe, 0x69, 0xab, 0x5a, 0xee, 0x42, 0xaa, 0x4d, 0x42, + 0x17, 0x60, 0x99, 0xd4, 0x5e, 0x13, 0x97, 0xdc, 0x40, 0x4d, 0x86, 0xa3, + 0x7b, 0xf5, 0x59, 0x54, 0x75, 0x69, 0x51, 0xe4 }; +static const unsigned char result_pr[OUTPUT_LEN] = { + 0x9a, 0x00, 0xa2, 0xd0, 0x0e, 0xd5, 0x9b, 0xfe, 0x31, 0xec, 0xb1, 0x39, + 0x9b, 0x60, 0x81, 0x48, 0xd1, 0x96, 0x9d, 0x25, 0x0d, 0x3c, 0x1e, 0x94, + 0x10, 0x10, 0x98, 0x12, 0x93, 0x25, 0xca, 0xb8, 0xfc, 0xcc, 0x2d, 0x54, + 0x73, 0x19, 0x70, 0xc0, 0x10, 0x7a, 0xa4, 0x89, 0x25, 0x19, 0x95, 0x5e, + 0x4b, 0xc6, 0x00, 0x1d, 0x7f, 0x4e, 0x6a, 0x2b, 0xf8, 0xa3, 0x01, 0xab, + 0x46, 0x05, 0x5c, 0x09, 0xa6, 0x71, 0x88, 0xf1, 0xa7, 0x40, 0xee, 0xf3, + 0xe1, 0x5c, 0x02, 0x9b, 0x44, 0xaf, 0x03, 0x44 }; + +/* From a NIST PR=false test vector */ +static const unsigned char entropy_nopr[] = { + 0x79, 0x34, 0x9b, 0xbf, 0x7c, 0xdd, 0xa5, 0x79, 0x95, 0x57, 0x86, 0x66, + 0x21, 0xc9, 0x13, 0x83, 0x11, 0x46, 0x73, 0x3a, 0xbf, 0x8c, 0x35, 0xc8, + 0xc7, 0x21, 0x5b, 0x5b, 0x96, 0xc4, 0x8e, 0x9b, 0x33, 0x8c, 0x74, 0xe3, + 0xe9, 0x9d, 0xfe, 0xdf }; +static const unsigned char result_nopr[OUTPUT_LEN] = { + 0xc6, 0xa1, 0x6a, 0xb8, 0xd4, 0x20, 0x70, 0x6f, 0x0f, 0x34, 0xab, 0x7f, + 0xec, 0x5a, 0xdc, 0xa9, 0xd8, 0xca, 0x3a, 0x13, 0x3e, 0x15, 0x9c, 0xa6, + 0xac, 0x43, 0xc6, 0xf8, 0xa2, 0xbe, 0x22, 0x83, 0x4a, 0x4c, 0x0a, 0x0a, + 0xff, 0xb1, 0x0d, 0x71, 0x94, 0xf1, 0xc1, 0xa5, 0xcf, 0x73, 0x22, 0xec, + 0x1a, 0xe0, 0x96, 0x4e, 0xd4, 0xbf, 0x12, 0x27, 0x46, 0xe0, 0x87, 0xfd, + 0xb5, 0xb3, 0xe9, 0x1b, 0x34, 0x93, 0xd5, 0xbb, 0x98, 0xfa, 0xed, 0x49, + 0xe8, 0x5f, 0x13, 0x0f, 0xc8, 0xa4, 0x59, 0xb7 }; + +/* "Entropy" from buffer */ +static size_t test_offset; +static int hmac_drbg_self_test_entropy( void *data, + unsigned char *buf, size_t len ) +{ + const unsigned char *p = data; + memcpy( buf, p + test_offset, len ); + test_offset += len; + return( 0 ); +} + +#define CHK( c ) if( (c) != 0 ) \ + { \ + if( verbose != 0 ) \ + mbedtls_printf( "failed\n" ); \ + return( 1 ); \ + } + +/* + * Checkup routine for HMAC_DRBG with SHA-1 + */ +int mbedtls_hmac_drbg_self_test( int verbose ) +{ + mbedtls_hmac_drbg_context ctx; + unsigned char buf[OUTPUT_LEN]; + const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( MBEDTLS_MD_SHA1 ); + + mbedtls_hmac_drbg_init( &ctx ); + + /* + * PR = True + */ + if( verbose != 0 ) + mbedtls_printf( " HMAC_DRBG (PR = True) : " ); + + test_offset = 0; + CHK( mbedtls_hmac_drbg_seed( &ctx, md_info, + hmac_drbg_self_test_entropy, (void *) entropy_pr, + NULL, 0 ) ); + mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON ); + CHK( mbedtls_hmac_drbg_random( &ctx, buf, OUTPUT_LEN ) ); + CHK( mbedtls_hmac_drbg_random( &ctx, buf, OUTPUT_LEN ) ); + CHK( memcmp( buf, result_pr, OUTPUT_LEN ) ); + mbedtls_hmac_drbg_free( &ctx ); + + mbedtls_hmac_drbg_free( &ctx ); + + if( verbose != 0 ) + mbedtls_printf( "passed\n" ); + + /* + * PR = False + */ + if( verbose != 0 ) + mbedtls_printf( " HMAC_DRBG (PR = False) : " ); + + mbedtls_hmac_drbg_init( &ctx ); + + test_offset = 0; + CHK( mbedtls_hmac_drbg_seed( &ctx, md_info, + hmac_drbg_self_test_entropy, (void *) entropy_nopr, + NULL, 0 ) ); + CHK( mbedtls_hmac_drbg_reseed( &ctx, NULL, 0 ) ); + CHK( mbedtls_hmac_drbg_random( &ctx, buf, OUTPUT_LEN ) ); + CHK( mbedtls_hmac_drbg_random( &ctx, buf, OUTPUT_LEN ) ); + CHK( memcmp( buf, result_nopr, OUTPUT_LEN ) ); + mbedtls_hmac_drbg_free( &ctx ); + + mbedtls_hmac_drbg_free( &ctx ); + + if( verbose != 0 ) + mbedtls_printf( "passed\n" ); + + if( verbose != 0 ) + mbedtls_printf( "\n" ); + + return( 0 ); +} +#endif /* MBEDTLS_SHA1_C */ +#endif /* MBEDTLS_SELF_TEST */ + +#endif /* MBEDTLS_HMAC_DRBG_C */