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Tune API of internal function mgf_mask in RSA

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This is a first step towards making a version of this function that
uses PSA when MD is not available.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This commit is contained in:
Manuel Pégourié-Gonnard 2022-07-15 12:09:08 +02:00 committed by Przemek Stekiel
parent f421d45869
commit 259c213545
1 changed files with 25 additions and 13 deletions
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38
library/rsa.c
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@ -1095,11 +1095,13 @@ cleanup:
* \param dlen length of destination buffer
* \param src source of the mask generation
* \param slen length of the source buffer
* \param md_ctx message digest context to use
* \param md_alg message digest to use
*/
static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
size_t slen, mbedtls_md_context_t *md_ctx )
size_t slen, mbedtls_md_type_t md_alg )
{
const mbedtls_md_info_t *md_info;
mbedtls_md_context_t md_ctx;
unsigned char mask[MBEDTLS_MD_MAX_SIZE];
unsigned char counter[4];
unsigned char *p;
@ -1107,10 +1109,19 @@ static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
size_t i, use_len;
int ret = 0;
mbedtls_md_init( &md_ctx );
memset( mask, 0, MBEDTLS_MD_MAX_SIZE );
memset( counter, 0, 4 );
hlen = mbedtls_md_get_size( md_ctx->md_info );
md_info = mbedtls_md_info_from_type( md_alg );
if( md_info == NULL )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
mbedtls_md_init( &md_ctx );
if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
goto exit;
hlen = mbedtls_md_get_size( md_info );
/* Generate and apply dbMask */
p = dst;
@ -1121,13 +1132,13 @@ static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
if( dlen < hlen )
use_len = dlen;
if( ( ret = mbedtls_md_starts( md_ctx ) ) != 0 )
if( ( ret = mbedtls_md_starts( &md_ctx ) ) != 0 )
goto exit;
if( ( ret = mbedtls_md_update( md_ctx, src, slen ) ) != 0 )
if( ( ret = mbedtls_md_update( &md_ctx, src, slen ) ) != 0 )
goto exit;
if( ( ret = mbedtls_md_update( md_ctx, counter, 4 ) ) != 0 )
if( ( ret = mbedtls_md_update( &md_ctx, counter, 4 ) ) != 0 )
goto exit;
if( ( ret = mbedtls_md_finish( md_ctx, mask ) ) != 0 )
if( ( ret = mbedtls_md_finish( &md_ctx, mask ) ) != 0 )
goto exit;
for( i = 0; i < use_len; ++i )
@ -1139,6 +1150,7 @@ static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
}
exit:
mbedtls_md_free( &md_ctx );
mbedtls_platform_zeroize( mask, sizeof( mask ) );
return( ret );
@ -1208,12 +1220,12 @@ int mbedtls_rsa_rsaes_oaep_encrypt( mbedtls_rsa_context *ctx,
/* maskedDB: Apply dbMask to DB */
if( ( ret = mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen,
&md_ctx ) ) != 0 )
ctx->hash_id ) ) != 0 )
goto exit;
/* maskedSeed: Apply seedMask to seed */
if( ( ret = mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,
&md_ctx ) ) != 0 )
ctx->hash_id ) ) != 0 )
goto exit;
exit:
@ -1384,10 +1396,10 @@ int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
/* seed: Apply seedMask to maskedSeed */
if( ( ret = mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,
&md_ctx ) ) != 0 ||
ctx->hash_id ) ) != 0 ||
/* DB: Apply dbMask to maskedDB */
( ret = mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,
&md_ctx ) ) != 0 )
ctx->hash_id ) ) != 0 )
{
mbedtls_md_free( &md_ctx );
goto cleanup;
@ -1648,7 +1660,7 @@ static int rsa_rsassa_pss_sign( mbedtls_rsa_context *ctx,
/* maskedDB: Apply dbMask to DB */
if( ( ret = mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen,
&md_ctx ) ) != 0 )
ctx->hash_id ) ) != 0 )
goto exit;
msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
@ -2029,7 +2041,7 @@ int mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_rsa_context *ctx,
if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
goto exit;
ret = mgf_mask( p, siglen - hlen - 1, hash_start, hlen, &md_ctx );
ret = mgf_mask( p, siglen - hlen - 1, hash_start, hlen, mgf1_hash_id );
if( ret != 0 )
goto exit;