From d324c5954a53cf1cb5da416cdeffe918210e5732 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Tue, 11 Sep 2018 15:34:17 +0200 Subject: [PATCH 1/7] CTR_DRBG: clean stack buffers Wipe stack buffers that may contain sensitive data (data that contributes to the DRBG state. --- library/ctr_drbg.c | 44 ++++++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 26 deletions(-) diff --git a/library/ctr_drbg.c b/library/ctr_drbg.c index ff532a013..fc3188eb3 100644 --- a/library/ctr_drbg.c +++ b/library/ctr_drbg.c @@ -283,9 +283,7 @@ static int ctr_drbg_update_internal( mbedtls_ctr_drbg_context *ctx, * Crypt counter block */ if( ( ret = mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, p ) ) != 0 ) - { - return( ret ); - } + goto exit; p += MBEDTLS_CTR_DRBG_BLOCKSIZE; } @@ -297,12 +295,12 @@ static int ctr_drbg_update_internal( mbedtls_ctr_drbg_context *ctx, * Update key and counter */ if( ( ret = mbedtls_aes_setkey_enc( &ctx->aes_ctx, tmp, MBEDTLS_CTR_DRBG_KEYBITS ) ) != 0 ) - { - return( ret ); - } + goto exit; memcpy( ctx->counter, tmp + MBEDTLS_CTR_DRBG_KEYSIZE, MBEDTLS_CTR_DRBG_BLOCKSIZE ); - return( 0 ); +exit: + mbedtls_zeroize( tmp, sizeof( tmp ) ); + return( ret ); } void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx, @@ -319,6 +317,7 @@ void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx, block_cipher_df( add_input, additional, add_len ); ctr_drbg_update_internal( ctx, add_input ); + mbedtls_zeroize( add_input, sizeof( add_input ) ); } } @@ -359,20 +358,18 @@ int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx, * Reduce to 384 bits */ if( ( ret = block_cipher_df( seed, seed, seedlen ) ) != 0 ) - { - return( ret ); - } + goto exit; /* * Update state */ if( ( ret = ctr_drbg_update_internal( ctx, seed ) ) != 0 ) - { - return( ret ); - } + goto exit; ctx->reseed_counter = 1; - return( 0 ); +exit: + mbedtls_zeroize( seed, sizeof( seed ) ); + return( ret ); } int mbedtls_ctr_drbg_random_with_add( void *p_rng, @@ -408,13 +405,9 @@ int mbedtls_ctr_drbg_random_with_add( void *p_rng, if( add_len > 0 ) { if( ( ret = block_cipher_df( add_input, additional, add_len ) ) != 0 ) - { - return( ret ); - } + goto exit; if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 ) - { - return( ret ); - } + goto exit; } while( output_len > 0 ) @@ -430,9 +423,7 @@ int mbedtls_ctr_drbg_random_with_add( void *p_rng, * Crypt counter block */ if( ( ret = mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, tmp ) ) != 0 ) - { - return( ret ); - } + goto exit; use_len = ( output_len > MBEDTLS_CTR_DRBG_BLOCKSIZE ) ? MBEDTLS_CTR_DRBG_BLOCKSIZE : output_len; @@ -445,12 +436,13 @@ int mbedtls_ctr_drbg_random_with_add( void *p_rng, } if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 ) - { - return( ret ); - } + goto exit; ctx->reseed_counter++; +exit: + mbedtls_zeroize( add_input, sizeof( add_input ) ); + mbedtls_zeroize( tmp, sizeof( tmp ) ); return( 0 ); } From 1da7776bd722b9739d9dc46bb7e4415da18f3443 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Tue, 11 Sep 2018 15:35:41 +0200 Subject: [PATCH 2/7] HMAC_DRBG: clean stack buffers Wipe stack buffers that may contain sensitive data (data that contributes to the DRBG state. --- library/hmac_drbg.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/library/hmac_drbg.c b/library/hmac_drbg.c index 24c609e9c..40e2b0ad6 100644 --- a/library/hmac_drbg.c +++ b/library/hmac_drbg.c @@ -93,6 +93,8 @@ void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx, mbedtls_md_hmac_update( &ctx->md_ctx, ctx->V, md_len ); mbedtls_md_hmac_finish( &ctx->md_ctx, ctx->V ); } + + mbedtls_zeroize( K, sizeof( K ) ); } /* @@ -158,6 +160,7 @@ int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, ctx->reseed_counter = 1; /* 4. Done */ + mbedtls_zeroize( seed, seedlen ); return( 0 ); } From f249e37e86b3fdd374eae36e96581ea723886b10 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Tue, 11 Sep 2018 18:53:58 +0200 Subject: [PATCH 3/7] Add ChangeLog entry for wiping sensitive buffers --- ChangeLog | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/ChangeLog b/ChangeLog index 1f21f5e25..7bea29d86 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ mbed TLS ChangeLog (Sorted per branch, date) += mbed TLS 2.7.x branch released xxxx-xx-xx + +Security + * Wipe sensitive buffers on the stack in the CTR_DRBG and HMAC_DRBG + modules. + = mbed TLS 2.7.6 branch released 2018-08-31 Security From 9ce2972399430c8086fe5c192ac3a64431eb9adb Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Tue, 11 Sep 2018 16:41:54 +0200 Subject: [PATCH 4/7] CTR_DRBG: add mbedtls_ctr_drbg_update_ret Deprecate mbedtls_ctr_drbg_update (which returns void) in favor of a new function mbedtls_ctr_drbg_update_ret which reports error. The old function is not officially marked as deprecated in this branch because this is a stable maintenance branch. --- include/mbedtls/ctr_drbg.h | 33 ++++++++++++++++--- library/ctr_drbg.c | 40 +++++++++++++++-------- tests/suites/test_suite_ctr_drbg.function | 8 +++-- 3 files changed, 60 insertions(+), 21 deletions(-) diff --git a/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h index e554a0aff..2b4dc73d3 100644 --- a/include/mbedtls/ctr_drbg.h +++ b/include/mbedtls/ctr_drbg.h @@ -227,14 +227,37 @@ int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx, * * \param ctx The CTR_DRBG context. * \param additional The data to update the state with. - * \param add_len Length of \p additional data. + * \param add_len Length of \p additional in bytes. This must be at + * most #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT. * - * \note If \p add_len is greater than #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT, - * only the first #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT Bytes are used. - * The remaining Bytes are silently discarded. + * \return \c 0 on success. + * \return #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG if + * \p add_len is more than + * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT. + * \return An error from the underlying AES cipher on failure. + */ +int mbedtls_ctr_drbg_update_ret( mbedtls_ctr_drbg_context *ctx, + const unsigned char *additional, + size_t add_len ); + +/** + * \brief This function updates the state of the CTR_DRBG context. + * + * \warning This function cannot report errors. You should use + * mbedtls_ctr_drbg_update_ret() instead. + * + * \note If \p add_len is greater than + * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT, only the first + * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT Bytes are used. + * The remaining Bytes are silently discarded. + * + * \param ctx The CTR_DRBG context. + * \param additional The data to update the state with. + * \param add_len Length of \p additional data. */ void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx, - const unsigned char *additional, size_t add_len ); + const unsigned char *additional, + size_t add_len ); /** * \brief This function updates a CTR_DRBG instance with additional diff --git a/library/ctr_drbg.c b/library/ctr_drbg.c index fc3188eb3..d7a94840c 100644 --- a/library/ctr_drbg.c +++ b/library/ctr_drbg.c @@ -303,22 +303,36 @@ exit: return( ret ); } -void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx, - const unsigned char *additional, size_t add_len ) +int mbedtls_ctr_drbg_update_ret( mbedtls_ctr_drbg_context *ctx, + const unsigned char *additional, + size_t add_len ) { unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN]; + int ret; - 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; + if( add_len == 0 ) + return( 0 ); - block_cipher_df( add_input, additional, add_len ); - ctr_drbg_update_internal( ctx, add_input ); - mbedtls_zeroize( add_input, sizeof( add_input ) ); - } + if( ( ret = block_cipher_df( add_input, additional, add_len ) ) != 0 ) + goto exit; + if( ( ret = ctr_drbg_update_internal( ctx, add_input ) ) != 0 ) + goto exit; + +exit: + mbedtls_zeroize( add_input, sizeof( add_input ) ); + return( ret ); +} + +/* Deprecated function, kept for backward compatibility. */ +void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx, + const unsigned char *additional, + size_t add_len ) +{ + /* 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; + (void) mbedtls_ctr_drbg_update_ret( ctx, additional, add_len ); } int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx, @@ -514,7 +528,7 @@ int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx, const char if( fread( buf, 1, n, f ) != n ) ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR; else - mbedtls_ctr_drbg_update( ctx, buf, n ); + ret = mbedtls_ctr_drbg_update_ret( ctx, buf, n ); fclose( f ); diff --git a/tests/suites/test_suite_ctr_drbg.function b/tests/suites/test_suite_ctr_drbg.function index d8ffebe46..f17bd3be0 100644 --- a/tests/suites/test_suite_ctr_drbg.function +++ b/tests/suites/test_suite_ctr_drbg.function @@ -177,9 +177,11 @@ void ctr_drbg_entropy_usage( ) } TEST_ASSERT( last_idx == test_offset_idx ); - /* Call update with too much data (sizeof entropy > MAX(_SEED)_INPUT) - * (just make sure it doesn't cause memory corruption) */ - mbedtls_ctr_drbg_update( &ctx, entropy, sizeof( entropy ) ); + /* Call update with too much data (sizeof entropy > MAX(_SEED)_INPUT). + * Make sure it's detected as an error and doesn't cause memory + * corruption. */ + TEST_ASSERT( mbedtls_ctr_drbg_update_ret( + &ctx, entropy, sizeof( entropy ) ) != 0 ); /* Now enable PR, so the next few calls should all reseed */ mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON ); From 4d23757fad055de7b19207388b59dde55ce5deaa Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Thu, 13 Sep 2018 22:19:57 +0200 Subject: [PATCH 5/7] HMAC_DRBG: deprecate mbedtls_hmac_drbg_update because it ignores errors Deprecate mbedtls_hmac_drbg_update (which returns void) in favor of a new function mbedtls_hmac_drbg_update_ret which reports error. The old function is not officially marked as deprecated in this branch because this is a stable maintenance branch. --- include/mbedtls/hmac_drbg.h | 22 +++++++++++- library/hmac_drbg.c | 71 +++++++++++++++++++++++++++---------- 2 files changed, 74 insertions(+), 19 deletions(-) diff --git a/include/mbedtls/hmac_drbg.h b/include/mbedtls/hmac_drbg.h index 2608de859..dd31fc8fd 100644 --- a/include/mbedtls/hmac_drbg.h +++ b/include/mbedtls/hmac_drbg.h @@ -195,11 +195,31 @@ void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx, * \param additional Additional data to update state with, or NULL * \param add_len Length of additional data, or 0 * + * \return \c 0 on success, or an error from the underlying + * hash calculation. + * + * \note Additional data is optional, pass NULL and 0 as second + * third argument if no additional data is being used. + */ +int mbedtls_hmac_drbg_update_ret( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, size_t add_len ); + +/** + * \brief HMAC_DRBG update state + * + * \warning This function cannot report errors. You should use + * mbedtls_hmac_drbg_update_ret() instead. + * + * \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 ); + const unsigned char *additional, + size_t add_len ); /** * \brief HMAC_DRBG reseeding (extracts data from entropy source) diff --git a/library/hmac_drbg.c b/library/hmac_drbg.c index 40e2b0ad6..11cf2de0d 100644 --- a/library/hmac_drbg.c +++ b/library/hmac_drbg.c @@ -70,31 +70,56 @@ void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx ) /* * 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 ) +int mbedtls_hmac_drbg_update_ret( 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]; + int ret; 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( ( ret = mbedtls_md_hmac_reset( &ctx->md_ctx ) ) != 0 ) + goto exit; + if( ( ret = mbedtls_md_hmac_update( &ctx->md_ctx, + ctx->V, md_len ) ) != 0 ) + goto exit; + if( ( ret = mbedtls_md_hmac_update( &ctx->md_ctx, + sep, 1 ) ) != 0 ) + goto exit; if( rounds == 2 ) - mbedtls_md_hmac_update( &ctx->md_ctx, additional, add_len ); - mbedtls_md_hmac_finish( &ctx->md_ctx, K ); + { + if( ( ret = mbedtls_md_hmac_update( &ctx->md_ctx, + additional, add_len ) ) != 0 ) + goto exit; + } + if( ( ret = mbedtls_md_hmac_finish( &ctx->md_ctx, K ) ) != 0 ) + goto exit; /* 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 ); + if( ( ret = mbedtls_md_hmac_starts( &ctx->md_ctx, K, md_len ) ) != 0 ) + goto exit; + if( ( ret = mbedtls_md_hmac_update( &ctx->md_ctx, + ctx->V, md_len ) ) != 0 ) + goto exit; + if( ( ret = mbedtls_md_hmac_finish( &ctx->md_ctx, ctx->V ) ) != 0 ) + goto exit; } +exit: mbedtls_zeroize( K, sizeof( K ) ); + return( ret ); +} + +void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx, + const unsigned char *additional, + size_t add_len ) +{ + (void) mbedtls_hmac_drbg_update_ret( ctx, additional, add_len ); } /* @@ -117,7 +142,8 @@ int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx, 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 ); + if( ( ret = mbedtls_hmac_drbg_update_ret( ctx, data, data_len ) ) != 0 ) + return( ret ); return( 0 ); } @@ -130,6 +156,7 @@ int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, { unsigned char seed[MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT]; size_t seedlen; + int ret; /* III. Check input length */ if( len > MBEDTLS_HMAC_DRBG_MAX_INPUT || @@ -154,14 +181,16 @@ int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, } /* 2. Update state */ - mbedtls_hmac_drbg_update( ctx, seed, seedlen ); + if( ( ret = mbedtls_hmac_drbg_update_ret( ctx, seed, seedlen ) ) != 0 ) + goto exit; /* 3. Reset reseed_counter */ ctx->reseed_counter = 1; +exit: /* 4. Done */ mbedtls_zeroize( seed, seedlen ); - return( 0 ); + return( ret ); } /* @@ -280,7 +309,11 @@ int mbedtls_hmac_drbg_random_with_add( void *p_rng, /* 2. Use additional data if any */ if( additional != NULL && add_len != 0 ) - mbedtls_hmac_drbg_update( ctx, additional, add_len ); + { + if( ( ret = mbedtls_hmac_drbg_update_ret( ctx, + additional, add_len ) ) != 0 ) + goto exit; + } /* 3, 4, 5. Generate bytes */ while( left != 0 ) @@ -297,13 +330,16 @@ int mbedtls_hmac_drbg_random_with_add( void *p_rng, } /* 6. Update */ - mbedtls_hmac_drbg_update( ctx, additional, add_len ); + if( ( ret = mbedtls_hmac_drbg_update_ret( ctx, + additional, add_len ) ) != 0 ) + goto exit; /* 7. Update reseed counter */ ctx->reseed_counter++; +exit: /* 8. Done */ - return( 0 ); + return( ret ); } /* @@ -395,8 +431,7 @@ int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const ch if( fread( buf, 1, n, f ) != n ) ret = MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR; else - mbedtls_hmac_drbg_update( ctx, buf, n ); - + ret = mbedtls_hmac_drbg_update_ret( ctx, buf, n ); fclose( f ); mbedtls_zeroize( buf, sizeof( buf ) ); From aadc81812681e66b460ace6d28c709657323c79e Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Tue, 11 Sep 2018 16:54:57 +0200 Subject: [PATCH 6/7] HMAC_DRBG: report all errors from HMAC functions Make sure that any error from mbedtls_md_hmac_xxx is propagated. --- library/hmac_drbg.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/library/hmac_drbg.c b/library/hmac_drbg.c index 11cf2de0d..9801bc50d 100644 --- a/library/hmac_drbg.c +++ b/library/hmac_drbg.c @@ -139,7 +139,9 @@ int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx, * 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 ) ); + if( ( ret = mbedtls_md_hmac_starts( &ctx->md_ctx, ctx->V, + mbedtls_md_get_size( md_info ) ) ) != 0 ) + return( ret ); memset( ctx->V, 0x01, mbedtls_md_get_size( md_info ) ); if( ( ret = mbedtls_hmac_drbg_update_ret( ctx, data, data_len ) ) != 0 ) @@ -168,7 +170,8 @@ int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, 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 ) + if( ( ret = ctx->f_entropy( ctx->p_entropy, + seed, ctx->entropy_len ) ) != 0 ) return( MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED ); seedlen = ctx->entropy_len; @@ -216,7 +219,8 @@ int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx, * 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 ); + if( ( ret = mbedtls_md_hmac_starts( &ctx->md_ctx, ctx->V, md_size ) ) != 0 ) + return( ret ); memset( ctx->V, 0x01, md_size ); ctx->f_entropy = f_entropy; @@ -320,9 +324,13 @@ int mbedtls_hmac_drbg_random_with_add( void *p_rng, { 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 ); + if( ( ret = mbedtls_md_hmac_reset( &ctx->md_ctx ) ) != 0 ) + goto exit; + if( ( ret = mbedtls_md_hmac_update( &ctx->md_ctx, + ctx->V, md_len ) ) != 0 ) + goto exit; + if( ( ret = mbedtls_md_hmac_finish( &ctx->md_ctx, ctx->V ) ) != 0 ) + goto exit; memcpy( out, ctx->V, use_len ); out += use_len; @@ -432,6 +440,7 @@ int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const ch ret = MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR; else ret = mbedtls_hmac_drbg_update_ret( ctx, buf, n ); + fclose( f ); mbedtls_zeroize( buf, sizeof( buf ) ); From 94a779b2c2267db419863dcdd7ff6a0d72ed39e8 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Thu, 13 Sep 2018 22:27:12 +0200 Subject: [PATCH 7/7] Add ChangeLog entry for deprecation of mbedtls_xxx_drbg_update --- ChangeLog | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/ChangeLog b/ChangeLog index 7bea29d86..7a497b05c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -6,6 +6,13 @@ Security * Wipe sensitive buffers on the stack in the CTR_DRBG and HMAC_DRBG modules. +API Changes + * The new functions mbedtls_ctr_drbg_update_ret() and + mbedtls_hmac_drbg_update_ret() are similar to mbedtls_ctr_drbg_update() + and mbedtls_hmac_drbg_update() respectively, but the new functions + report errors whereas the old functions return void. We recommend that + applications use the new functions. + = mbed TLS 2.7.6 branch released 2018-08-31 Security