Zeroize internal buffers and variables in PKCS and SHA

Zeroising of local buffers and variables which are used for calculations in
mbedtls_pkcs5_pbkdf2_hmac() and mbedtls_internal_sha*_process() functions
to erase sensitive data from memory.
Checked all function for possible missing zeroisation in PKCS and SHA.

Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
This commit is contained in:
gabor-mezei-arm 2020-07-30 16:41:25 +02:00
parent fa3b3e0d88
commit d5253bba32
No known key found for this signature in database
GPG Key ID: 106F5A41ECC305BD
5 changed files with 37 additions and 0 deletions

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@ -0,0 +1,5 @@
Security
* Zeroising of local buffers and variables which are used for calculations
in mbedtls_pkcs5_pbkdf2_hmac() and mbedtls_internal_sha*_process()
functions to erase sensitive data from memory. Reported by
Johan Malmgren and Johan Uppman Bruce from Sectra.

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@ -312,6 +312,10 @@ int mbedtls_pkcs5_pbkdf2_hmac( mbedtls_md_context_t *ctx, const unsigned char *p
break; break;
} }
/* Zeroise buffers to clear sensitive data from memory. */
mbedtls_platform_zeroize( work, MBEDTLS_MD_MAX_SIZE );
mbedtls_platform_zeroize( md1, MBEDTLS_MD_MAX_SIZE );
return( 0 ); return( 0 );
} }

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@ -313,6 +313,15 @@ int mbedtls_internal_sha1_process( mbedtls_sha1_context *ctx,
ctx->state[3] += D; ctx->state[3] += D;
ctx->state[4] += E; ctx->state[4] += E;
/* Zeroise buffers and variables to clear sensitive data from memory. */
mbedtls_platform_zeroize( &A, sizeof( A ) );
mbedtls_platform_zeroize( &B, sizeof( B ) );
mbedtls_platform_zeroize( &C, sizeof( C ) );
mbedtls_platform_zeroize( &D, sizeof( D ) );
mbedtls_platform_zeroize( &E, sizeof( E ) );
mbedtls_platform_zeroize( &W, sizeof( W ) );
mbedtls_platform_zeroize( &temp, sizeof( temp ) );
return( 0 ); return( 0 );
} }

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@ -281,6 +281,12 @@ int mbedtls_internal_sha256_process( mbedtls_sha256_context *ctx,
for( i = 0; i < 8; i++ ) for( i = 0; i < 8; i++ )
ctx->state[i] += A[i]; ctx->state[i] += A[i];
/* Zeroise buffers and variables to clear sensitive data from memory. */
mbedtls_platform_zeroize( &A, sizeof( A ) );
mbedtls_platform_zeroize( &W, sizeof( W ) );
mbedtls_platform_zeroize( &temp1, sizeof( temp1 ) );
mbedtls_platform_zeroize( &temp2, sizeof( temp2 ) );
return( 0 ); return( 0 );
} }

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@ -312,6 +312,19 @@ int mbedtls_internal_sha512_process( mbedtls_sha512_context *ctx,
ctx->state[6] += G; ctx->state[6] += G;
ctx->state[7] += H; ctx->state[7] += H;
/* Zeroise buffers and variables to clear sensitive data from memory. */
mbedtls_platform_zeroize( &A, sizeof( A ) );
mbedtls_platform_zeroize( &B, sizeof( B ) );
mbedtls_platform_zeroize( &C, sizeof( C ) );
mbedtls_platform_zeroize( &D, sizeof( D ) );
mbedtls_platform_zeroize( &E, sizeof( E ) );
mbedtls_platform_zeroize( &F, sizeof( F ) );
mbedtls_platform_zeroize( &G, sizeof( G ) );
mbedtls_platform_zeroize( &H, sizeof( H ) );
mbedtls_platform_zeroize( &W, sizeof( W ) );
mbedtls_platform_zeroize( &temp1, sizeof( temp1 ) );
mbedtls_platform_zeroize( &temp2, sizeof( temp2 ) );
return( 0 ); return( 0 );
} }