Modified mbed TLS headers for AES functionality only to reduce build size
Dependents: BLE_Gateway_Linker_fix BLE_Gateway
Fork of mbedtls by
source/ctr_drbg.c
- Committer:
- Christopher Haster
- Date:
- 2016-01-22
- Revision:
- 1:24750b9ad5ef
File content as of revision 1:24750b9ad5ef:
/* * CTR_DRBG implementation based on AES-256 (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 800-90 DRBGs are described in the following publucation. * * http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_CTR_DRBG_C) #include "mbedtls/ctr_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_PLATFORM_C */ #endif /* MBEDTLS_SELF_TEST */ /* 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; } /* * CTR_DRBG context initialization */ void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx ) { memset( ctx, 0, sizeof( mbedtls_ctr_drbg_context ) ); #if defined(MBEDTLS_THREADING_C) mbedtls_mutex_init( &ctx->mutex ); #endif } /* * Non-public function wrapped by ctr_crbg_init(). Necessary to allow NIST * tests to succeed (which require known length fixed entropy) */ int mbedtls_ctr_drbg_seed_entropy_len( mbedtls_ctr_drbg_context *ctx, int (*f_entropy)(void *, unsigned char *, size_t), void *p_entropy, const unsigned char *custom, size_t len, size_t entropy_len ) { int ret; unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE]; memset( key, 0, MBEDTLS_CTR_DRBG_KEYSIZE ); mbedtls_aes_init( &ctx->aes_ctx ); ctx->f_entropy = f_entropy; ctx->p_entropy = p_entropy; ctx->entropy_len = entropy_len; ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL; /* * Initialize with an empty key */ mbedtls_aes_setkey_enc( &ctx->aes_ctx, key, MBEDTLS_CTR_DRBG_KEYBITS ); if( ( ret = mbedtls_ctr_drbg_reseed( ctx, custom, len ) ) != 0 ) return( ret ); return( 0 ); } int mbedtls_ctr_drbg_seed( mbedtls_ctr_drbg_context *ctx, int (*f_entropy)(void *, unsigned char *, size_t), void *p_entropy, const unsigned char *custom, size_t len ) { return( mbedtls_ctr_drbg_seed_entropy_len( ctx, f_entropy, p_entropy, custom, len, MBEDTLS_CTR_DRBG_ENTROPY_LEN ) ); } void mbedtls_ctr_drbg_free( mbedtls_ctr_drbg_context *ctx ) { if( ctx == NULL ) return; #if defined(MBEDTLS_THREADING_C) mbedtls_mutex_free( &ctx->mutex ); #endif mbedtls_aes_free( &ctx->aes_ctx ); mbedtls_zeroize( ctx, sizeof( mbedtls_ctr_drbg_context ) ); } void mbedtls_ctr_drbg_set_prediction_resistance( mbedtls_ctr_drbg_context *ctx, int resistance ) { ctx->prediction_resistance = resistance; } void mbedtls_ctr_drbg_set_entropy_len( mbedtls_ctr_drbg_context *ctx, size_t len ) { ctx->entropy_len = len; } void mbedtls_ctr_drbg_set_reseed_interval( mbedtls_ctr_drbg_context *ctx, int interval ) { ctx->reseed_interval = interval; } static int block_cipher_df( unsigned char *output, const unsigned char *data, size_t data_len ) { unsigned char buf[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + MBEDTLS_CTR_DRBG_BLOCKSIZE + 16]; unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN]; unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE]; unsigned char chain[MBEDTLS_CTR_DRBG_BLOCKSIZE]; unsigned char *p, *iv; mbedtls_aes_context aes_ctx; int i, j; size_t buf_len, use_len; if( data_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ) return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG ); memset( buf, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + MBEDTLS_CTR_DRBG_BLOCKSIZE + 16 ); mbedtls_aes_init( &aes_ctx ); /* * Construct IV (16 bytes) and S in buffer * IV = Counter (in 32-bits) padded to 16 with zeroes * S = Length input string (in 32-bits) || Length of output (in 32-bits) || * data || 0x80 * (Total is padded to a multiple of 16-bytes with zeroes) */ p = buf + MBEDTLS_CTR_DRBG_BLOCKSIZE; *p++ = ( data_len >> 24 ) & 0xff; *p++ = ( data_len >> 16 ) & 0xff; *p++ = ( data_len >> 8 ) & 0xff; *p++ = ( data_len ) & 0xff; p += 3; *p++ = MBEDTLS_CTR_DRBG_SEEDLEN; memcpy( p, data, data_len ); p[data_len] = 0x80; buf_len = MBEDTLS_CTR_DRBG_BLOCKSIZE + 8 + data_len + 1; for( i = 0; i < MBEDTLS_CTR_DRBG_KEYSIZE; i++ ) key[i] = i; mbedtls_aes_setkey_enc( &aes_ctx, key, MBEDTLS_CTR_DRBG_KEYBITS ); /* * Reduce data to MBEDTLS_CTR_DRBG_SEEDLEN bytes of data */ for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE ) { p = buf; memset( chain, 0, MBEDTLS_CTR_DRBG_BLOCKSIZE ); use_len = buf_len; while( use_len > 0 ) { for( i = 0; i < MBEDTLS_CTR_DRBG_BLOCKSIZE; i++ ) chain[i] ^= p[i]; p += MBEDTLS_CTR_DRBG_BLOCKSIZE; use_len -= ( use_len >= MBEDTLS_CTR_DRBG_BLOCKSIZE ) ? MBEDTLS_CTR_DRBG_BLOCKSIZE : use_len; mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT, chain, chain ); } memcpy( tmp + j, chain, MBEDTLS_CTR_DRBG_BLOCKSIZE ); /* * Update IV */ buf[3]++; } /* * Do final encryption with reduced data */ mbedtls_aes_setkey_enc( &aes_ctx, tmp, MBEDTLS_CTR_DRBG_KEYBITS ); iv = tmp + MBEDTLS_CTR_DRBG_KEYSIZE; p = output; for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE ) { mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT, iv, iv ); memcpy( p, iv, MBEDTLS_CTR_DRBG_BLOCKSIZE ); p += MBEDTLS_CTR_DRBG_BLOCKSIZE; } mbedtls_aes_free( &aes_ctx ); return( 0 ); } static int ctr_drbg_update_internal( mbedtls_ctr_drbg_context *ctx, const unsigned char data[MBEDTLS_CTR_DRBG_SEEDLEN] ) { unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN]; unsigned char *p = tmp; int i, j; memset( tmp, 0, MBEDTLS_CTR_DRBG_SEEDLEN ); for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE ) { /* * Increase counter */ for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- ) if( ++ctx->counter[i - 1] != 0 ) break; /* * Crypt counter block */ mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, p ); p += MBEDTLS_CTR_DRBG_BLOCKSIZE; } for( i = 0; i < MBEDTLS_CTR_DRBG_SEEDLEN; i++ ) tmp[i] ^= data[i]; /* * Update key and counter */ mbedtls_aes_setkey_enc( &ctx->aes_ctx, tmp, MBEDTLS_CTR_DRBG_KEYBITS ); memcpy( ctx->counter, tmp + MBEDTLS_CTR_DRBG_KEYSIZE, MBEDTLS_CTR_DRBG_BLOCKSIZE ); return( 0 ); } void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx, const unsigned char *additional, size_t add_len ) { unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN]; if( add_len > 0 ) { /* MAX_INPUT would be more logical here, but we have to match * block_cipher_df()'s limits since we can't propagate errors */ if( add_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ) add_len = MBEDTLS_CTR_DRBG_MAX_SEED_INPUT; block_cipher_df( add_input, additional, add_len ); ctr_drbg_update_internal( ctx, add_input ); } } int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx, const unsigned char *additional, size_t len ) { unsigned char seed[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT]; size_t seedlen = 0; if( ctx->entropy_len + len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ) return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG ); memset( seed, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ); /* * Gather entropy_len bytes of entropy to seed state */ if( 0 != ctx->f_entropy( ctx->p_entropy, seed, ctx->entropy_len ) ) { return( MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED ); } seedlen += ctx->entropy_len; /* * Add additional data */ if( additional && len ) { memcpy( seed + seedlen, additional, len ); seedlen += len; } /* * Reduce to 384 bits */ block_cipher_df( seed, seed, seedlen ); /* * Update state */ ctr_drbg_update_internal( ctx, seed ); ctx->reseed_counter = 1; return( 0 ); } int mbedtls_ctr_drbg_random_with_add( void *p_rng, unsigned char *output, size_t output_len, const unsigned char *additional, size_t add_len ) { int ret = 0; mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng; unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN]; unsigned char *p = output; unsigned char tmp[MBEDTLS_CTR_DRBG_BLOCKSIZE]; int i; size_t use_len; if( output_len > MBEDTLS_CTR_DRBG_MAX_REQUEST ) return( MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG ); if( add_len > MBEDTLS_CTR_DRBG_MAX_INPUT ) return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG ); memset( add_input, 0, MBEDTLS_CTR_DRBG_SEEDLEN ); if( ctx->reseed_counter > ctx->reseed_interval || ctx->prediction_resistance ) { if( ( ret = mbedtls_ctr_drbg_reseed( ctx, additional, add_len ) ) != 0 ) return( ret ); add_len = 0; } if( add_len > 0 ) { block_cipher_df( add_input, additional, add_len ); ctr_drbg_update_internal( ctx, add_input ); } while( output_len > 0 ) { /* * Increase counter */ for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- ) if( ++ctx->counter[i - 1] != 0 ) break; /* * Crypt counter block */ mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, tmp ); use_len = ( output_len > MBEDTLS_CTR_DRBG_BLOCKSIZE ) ? MBEDTLS_CTR_DRBG_BLOCKSIZE : output_len; /* * Copy random block to destination */ memcpy( p, tmp, use_len ); p += use_len; output_len -= use_len; } ctr_drbg_update_internal( ctx, add_input ); ctx->reseed_counter++; return( 0 ); } int mbedtls_ctr_drbg_random( void *p_rng, unsigned char *output, size_t output_len ) { int ret; mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng; #if defined(MBEDTLS_THREADING_C) if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) return( ret ); #endif ret = mbedtls_ctr_drbg_random_with_add( ctx, output, output_len, NULL, 0 ); #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); #endif return( ret ); } #if defined(MBEDTLS_FS_IO) int mbedtls_ctr_drbg_write_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path ) { int ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR; FILE *f; unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ]; if( ( f = fopen( path, "wb" ) ) == NULL ) return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR ); if( ( ret = mbedtls_ctr_drbg_random( ctx, buf, MBEDTLS_CTR_DRBG_MAX_INPUT ) ) != 0 ) goto exit; if( fwrite( buf, 1, MBEDTLS_CTR_DRBG_MAX_INPUT, f ) != MBEDTLS_CTR_DRBG_MAX_INPUT ) { ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR; goto exit; } ret = 0; exit: fclose( f ); return( ret ); } int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path ) { FILE *f; size_t n; unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ]; if( ( f = fopen( path, "rb" ) ) == NULL ) return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR ); fseek( f, 0, SEEK_END ); n = (size_t) ftell( f ); fseek( f, 0, SEEK_SET ); if( n > MBEDTLS_CTR_DRBG_MAX_INPUT ) { fclose( f ); return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG ); } if( fread( buf, 1, n, f ) != n ) { fclose( f ); return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR ); } fclose( f ); mbedtls_ctr_drbg_update( ctx, buf, n ); return( mbedtls_ctr_drbg_write_seed_file( ctx, path ) ); } #endif /* MBEDTLS_FS_IO */ #if defined(MBEDTLS_SELF_TEST) static const unsigned char entropy_source_pr[96] = { 0xc1, 0x80, 0x81, 0xa6, 0x5d, 0x44, 0x02, 0x16, 0x19, 0xb3, 0xf1, 0x80, 0xb1, 0xc9, 0x20, 0x02, 0x6a, 0x54, 0x6f, 0x0c, 0x70, 0x81, 0x49, 0x8b, 0x6e, 0xa6, 0x62, 0x52, 0x6d, 0x51, 0xb1, 0xcb, 0x58, 0x3b, 0xfa, 0xd5, 0x37, 0x5f, 0xfb, 0xc9, 0xff, 0x46, 0xd2, 0x19, 0xc7, 0x22, 0x3e, 0x95, 0x45, 0x9d, 0x82, 0xe1, 0xe7, 0x22, 0x9f, 0x63, 0x31, 0x69, 0xd2, 0x6b, 0x57, 0x47, 0x4f, 0xa3, 0x37, 0xc9, 0x98, 0x1c, 0x0b, 0xfb, 0x91, 0x31, 0x4d, 0x55, 0xb9, 0xe9, 0x1c, 0x5a, 0x5e, 0xe4, 0x93, 0x92, 0xcf, 0xc5, 0x23, 0x12, 0xd5, 0x56, 0x2c, 0x4a, 0x6e, 0xff, 0xdc, 0x10, 0xd0, 0x68 }; static const unsigned char entropy_source_nopr[64] = { 0x5a, 0x19, 0x4d, 0x5e, 0x2b, 0x31, 0x58, 0x14, 0x54, 0xde, 0xf6, 0x75, 0xfb, 0x79, 0x58, 0xfe, 0xc7, 0xdb, 0x87, 0x3e, 0x56, 0x89, 0xfc, 0x9d, 0x03, 0x21, 0x7c, 0x68, 0xd8, 0x03, 0x38, 0x20, 0xf9, 0xe6, 0x5e, 0x04, 0xd8, 0x56, 0xf3, 0xa9, 0xc4, 0x4a, 0x4c, 0xbd, 0xc1, 0xd0, 0x08, 0x46, 0xf5, 0x98, 0x3d, 0x77, 0x1c, 0x1b, 0x13, 0x7e, 0x4e, 0x0f, 0x9d, 0x8e, 0xf4, 0x09, 0xf9, 0x2e }; static const unsigned char nonce_pers_pr[16] = { 0xd2, 0x54, 0xfc, 0xff, 0x02, 0x1e, 0x69, 0xd2, 0x29, 0xc9, 0xcf, 0xad, 0x85, 0xfa, 0x48, 0x6c }; static const unsigned char nonce_pers_nopr[16] = { 0x1b, 0x54, 0xb8, 0xff, 0x06, 0x42, 0xbf, 0xf5, 0x21, 0xf1, 0x5c, 0x1c, 0x0b, 0x66, 0x5f, 0x3f }; static const unsigned char result_pr[16] = { 0x34, 0x01, 0x16, 0x56, 0xb4, 0x29, 0x00, 0x8f, 0x35, 0x63, 0xec, 0xb5, 0xf2, 0x59, 0x07, 0x23 }; static const unsigned char result_nopr[16] = { 0xa0, 0x54, 0x30, 0x3d, 0x8a, 0x7e, 0xa9, 0x88, 0x9d, 0x90, 0x3e, 0x07, 0x7c, 0x6f, 0x21, 0x8f }; static size_t test_offset; static int ctr_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 */ int mbedtls_ctr_drbg_self_test( int verbose ) { mbedtls_ctr_drbg_context ctx; unsigned char buf[16]; mbedtls_ctr_drbg_init( &ctx ); /* * Based on a NIST CTR_DRBG test vector (PR = True) */ if( verbose != 0 ) mbedtls_printf( " CTR_DRBG (PR = TRUE) : " ); test_offset = 0; CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy, (void *) entropy_source_pr, nonce_pers_pr, 16, 32 ) ); mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON ); CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) ); CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) ); CHK( memcmp( buf, result_pr, MBEDTLS_CTR_DRBG_BLOCKSIZE ) ); mbedtls_ctr_drbg_free( &ctx ); if( verbose != 0 ) mbedtls_printf( "passed\n" ); /* * Based on a NIST CTR_DRBG test vector (PR = FALSE) */ if( verbose != 0 ) mbedtls_printf( " CTR_DRBG (PR = FALSE): " ); mbedtls_ctr_drbg_init( &ctx ); test_offset = 0; CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy, (void *) entropy_source_nopr, nonce_pers_nopr, 16, 32 ) ); CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) ); CHK( mbedtls_ctr_drbg_reseed( &ctx, NULL, 0 ) ); CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) ); CHK( memcmp( buf, result_nopr, 16 ) ); mbedtls_ctr_drbg_free( &ctx ); if( verbose != 0 ) mbedtls_printf( "passed\n" ); if( verbose != 0 ) mbedtls_printf( "\n" ); return( 0 ); } #endif /* MBEDTLS_SELF_TEST */ #endif /* MBEDTLS_CTR_DRBG_C */