Moved underflow test to better reflect time constant behaviour.

This commit is contained in:
Janos Follath 2016-02-11 11:08:18 +00:00 committed by Simon Butcher
parent 3cbdbf918f
commit e75f8c32c5

View File

@ -699,6 +699,12 @@ int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
if( md_info == NULL ) if( md_info == NULL )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
hlen = mbedtls_md_get_size( md_info );
// checking for integer underflow
if( 2 * hlen + 2 > ilen )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
/* /*
* RSA operation * RSA operation
*/ */
@ -712,12 +718,6 @@ int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
/* /*
* Unmask data and generate lHash * Unmask data and generate lHash
*/ */
hlen = mbedtls_md_get_size( md_info );
// checking for integer underflow
if( 2 * hlen + 2 > ilen )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
mbedtls_md_init( &md_ctx ); mbedtls_md_init( &md_ctx );
mbedtls_md_setup( &md_ctx, md_info, 0 ); mbedtls_md_setup( &md_ctx, md_info, 0 );