Added sppecific test cases for mbedtls_rsa_rsassa_pss_sign_ext()
- all positibe test cases were sampled from the CAVP test suite
(SigGenPSS_186-2.txt, SigGenPSS_186-3.txt)
Only kept one representative for each triple (modlen, sha, saltlen)
- two extra test cases were added to cover the maximum salt length
(slen=olen-slen-2 and slen=(olen-slen-2)-1)
- in rsa.c, the salt intermediate buffer was too small to cover cases
where slen > hlen. So reworked the code to generate the salt in the
encoded message directly. This has the advantage to remove a memcpy
and a memset.
Signed-off-by: Cédric Meuter <cedric.meuter@gmail.com>
diff --git a/library/rsa.c b/library/rsa.c
index 02423c0..7e75b2b 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1799,7 +1799,7 @@
{
size_t olen;
unsigned char *p = sig;
- unsigned char salt[MBEDTLS_MD_MAX_SIZE];
+ unsigned char *salt = NULL;
size_t slen, min_slen, hlen, offset = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t msb;
@@ -1867,15 +1867,16 @@
memset( sig, 0, olen );
- /* Generate salt of length slen */
- if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 )
- return( MBEDTLS_ERR_RSA_RNG_FAILED + ret );
-
/* Note: EMSA-PSS encoding is over the length of N - 1 bits */
msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
p += olen - hlen - slen - 2;
*p++ = 0x01;
- memcpy( p, salt, slen );
+
+ /* Generate salt of length slen in place in the encoded message */
+ salt = p;
+ if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 )
+ return( MBEDTLS_ERR_RSA_RNG_FAILED + ret );
+
p += slen;
mbedtls_md_init( &md_ctx );
@@ -1909,8 +1910,6 @@
p += hlen;
*p++ = 0xBC;
- mbedtls_platform_zeroize( salt, sizeof( salt ) );
-
exit:
mbedtls_md_free( &md_ctx );