diff --git a/common/polarssl/hmac_drbg.c b/common/polarssl/hmac_drbg.c new file mode 100644 index 000000000..5c4ee6def --- /dev/null +++ b/common/polarssl/hmac_drbg.c @@ -0,0 +1,533 @@ +/* + * HMAC_DRBG implementation (NIST SP 800-90) + * + * Copyright (C) 2014, ARM Limited, All Rights Reserved + * + * This file is part of mbed TLS (https://tls.mbed.org) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* + * 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 + +#if defined(MBEDTLS_FS_IO) +#include +#endif + +#if defined(MBEDTLS_SELF_TEST) +#if defined(MBEDTLS_PLATFORM_C) +#include "mbedtls/platform.h" +#else +#include +#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 ) +{ + + if( verbose != 0 ) + mbedtls_printf( "\n" ); + + 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 */ diff --git a/common/polarssl/hmac_drbg.h b/common/polarssl/hmac_drbg.h new file mode 100644 index 000000000..eeac3e320 --- /dev/null +++ b/common/polarssl/hmac_drbg.h @@ -0,0 +1,300 @@ +/** + * \file hmac_drbg.h + * + * \brief HMAC_DRBG (NIST SP 800-90A) + * + * Copyright (C) 2014, ARM Limited, All Rights Reserved + * + * This file is part of mbed TLS (https://tls.mbed.org) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ +#ifndef MBEDTLS_HMAC_DRBG_H +#define MBEDTLS_HMAC_DRBG_H + +#include "md.h" + +#if defined(MBEDTLS_THREADING_C) +#include "mbedtls/threading.h" +#endif + +/* + * Error codes + */ +#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */ +#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */ +#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */ +#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED -0x0009 /**< The entropy source failed. */ + +/** + * \name SECTION: Module settings + * + * The configuration options you can set for this module are in this section. + * Either change them in config.h or define them on the compiler command line. + * \{ + */ + +#if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL) +#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */ +#endif + +#if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT) +#define MBEDTLS_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */ +#endif + +#if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST) +#define MBEDTLS_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */ +#endif + +#if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT) +#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */ +#endif + +/* \} name SECTION: Module settings */ + +#define MBEDTLS_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */ +#define MBEDTLS_HMAC_DRBG_PR_ON 1 /**< Prediction resistance enabled */ + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * HMAC_DRBG context. + */ +typedef struct +{ + /* Working state: the key K is not stored explicitely, + * but is implied by the HMAC context */ + mbedtls_md_context_t md_ctx; /*!< HMAC context (inc. K) */ + unsigned char V[MBEDTLS_MD_MAX_SIZE]; /*!< V in the spec */ + int reseed_counter; /*!< reseed counter */ + + /* Administrative state */ + size_t entropy_len; /*!< entropy bytes grabbed on each (re)seed */ + int prediction_resistance; /*!< enable prediction resistance (Automatic + reseed before every random generation) */ + int reseed_interval; /*!< reseed interval */ + + /* Callbacks */ + int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */ + void *p_entropy; /*!< context for the entropy function */ + +#if defined(MBEDTLS_THREADING_C) + mbedtls_threading_mutex_t mutex; +#endif +} mbedtls_hmac_drbg_context; + +/** + * \brief HMAC_DRBG context initialization + * Makes the context ready for mbetls_hmac_drbg_seed(), + * mbedtls_hmac_drbg_seed_buf() or + * mbedtls_hmac_drbg_free(). + * + * \param ctx HMAC_DRBG context to be initialized + */ +void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx ); + +/** + * \brief HMAC_DRBG initial seeding + * Seed and setup entropy source for future reseeds. + * + * \param ctx HMAC_DRBG context to be seeded + * \param md_info MD algorithm to use for HMAC_DRBG + * \param f_entropy Entropy callback (p_entropy, buffer to fill, buffer + * length) + * \param p_entropy Entropy context + * \param custom Personalization data (Device specific identifiers) + * (Can be NULL) + * \param len Length of personalization data + * + * \note The "security strength" as defined by NIST is set to: + * 128 bits if md_alg is SHA-1, + * 192 bits if md_alg is SHA-224, + * 256 bits if md_alg is SHA-256 or higher. + * Note that SHA-256 is just as efficient as SHA-224. + * + * \return 0 if successful, or + * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or + * MBEDTLS_ERR_MD_ALLOC_FAILED, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED. + */ +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 ); + +/** + * \brief Initilisation of simpified HMAC_DRBG (never reseeds). + * (For use with deterministic ECDSA.) + * + * \param ctx HMAC_DRBG context to be initialised + * \param md_info MD algorithm to use for HMAC_DRBG + * \param data Concatenation of entropy string and additional data + * \param data_len Length of data in bytes + * + * \return 0 if successful, or + * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or + * MBEDTLS_ERR_MD_ALLOC_FAILED. + */ +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 ); + +/** + * \brief Enable / disable prediction resistance (Default: Off) + * + * Note: If enabled, entropy is used for ctx->entropy_len before each call! + * Only use this if you have ample supply of good entropy! + * + * \param ctx HMAC_DRBG context + * \param resistance MBEDTLS_HMAC_DRBG_PR_ON or MBEDTLS_HMAC_DRBG_PR_OFF + */ +void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx, + int resistance ); + +/** + * \brief Set the amount of entropy grabbed on each reseed + * (Default: given by the security strength, which + * depends on the hash used, see \c mbedtls_hmac_drbg_init() ) + * + * \param ctx HMAC_DRBG context + * \param len Amount of entropy to grab, in bytes + */ +void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx, + size_t len ); + +/** + * \brief Set the reseed interval + * (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL) + * + * \param ctx HMAC_DRBG context + * \param interval Reseed interval + */ +void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx, + int interval ); + +/** + * \brief HMAC_DRBG update state + * + * \param ctx HMAC_DRBG context + * \param additional Additional data to update state with, or NULL + * \param add_len Length of additional data, or 0 + * + * \note Additional data is optional, pass NULL and 0 as second + * third argument if no additional data is being used. + */ +void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, size_t add_len ); + +/** + * \brief HMAC_DRBG reseeding (extracts data from entropy source) + * + * \param ctx HMAC_DRBG context + * \param additional Additional data to add to state (Can be NULL) + * \param len Length of additional data + * + * \return 0 if successful, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED + */ +int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, size_t len ); + +/** + * \brief HMAC_DRBG generate random with additional update input + * + * Note: Automatically reseeds if reseed_counter is reached or PR is enabled. + * + * \param p_rng HMAC_DRBG context + * \param output Buffer to fill + * \param output_len Length of the buffer + * \param additional Additional data to update with (can be NULL) + * \param add_len Length of additional data (can be 0) + * + * \return 0 if successful, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or + * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or + * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG. + */ +int mbedtls_hmac_drbg_random_with_add( void *p_rng, + unsigned char *output, size_t output_len, + const unsigned char *additional, + size_t add_len ); + +/** + * \brief HMAC_DRBG generate random + * + * Note: Automatically reseeds if reseed_counter is reached or PR is enabled. + * + * \param p_rng HMAC_DRBG context + * \param output Buffer to fill + * \param out_len Length of the buffer + * + * \return 0 if successful, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or + * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG + */ +int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len ); + +/** + * \brief Free an HMAC_DRBG context + * + * \param ctx HMAC_DRBG context to free. + */ +void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx ); + +#if defined(MBEDTLS_FS_IO) +/** + * \brief Write a seed file + * + * \param ctx HMAC_DRBG context + * \param path Name of the file + * + * \return 0 if successful, 1 on file error, or + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED + */ +int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ); + +/** + * \brief Read and update a seed file. Seed is added to this + * instance + * + * \param ctx HMAC_DRBG context + * \param path Name of the file + * + * \return 0 if successful, 1 on file error, + * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or + * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG + */ +int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ); +#endif /* MBEDTLS_FS_IO */ + + +#if defined(MBEDTLS_SELF_TEST) +/** + * \brief Checkup routine + * + * \return 0 if successful, or 1 if the test failed + */ +int mbedtls_hmac_drbg_self_test( int verbose ); +#endif + +#ifdef __cplusplus +} +#endif + +#endif /* hmac_drbg.h */