diff --git a/library/ctr_drbg.c b/library/ctr_drbg.c index fead18f72..559538121 100644 --- a/library/ctr_drbg.c +++ b/library/ctr_drbg.c @@ -299,9 +299,7 @@ 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; } @@ -313,12 +311,12 @@ 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_platform_zeroize( tmp, sizeof( tmp ) ); + return( ret ); } /* CTR_DRBG_Instantiate with derivation function (SP 800-90A §10.2.1.3.2) @@ -347,6 +345,7 @@ 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_platform_zeroize( add_input, sizeof( add_input ) ); } } @@ -399,20 +398,18 @@ 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_platform_zeroize( seed, sizeof( seed ) ); + return( ret ); } /* CTR_DRBG_Generate with derivation function (SP 800-90A §10.2.1.5.2) @@ -467,13 +464,9 @@ 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 ) @@ -489,9 +482,7 @@ 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; @@ -504,12 +495,13 @@ 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_platform_zeroize( add_input, sizeof( add_input ) ); + mbedtls_platform_zeroize( tmp, sizeof( tmp ) ); return( 0 ); }