commit 74fd868ca67bdeefdb588046b1ee948a8661eaa3
author Gilles Peskine <Gilles.Peskine@arm.com> Fri May 05 19:24:06 2017 +0200
committer Gilles Peskine <Gilles.Peskine@arm.com> Fri May 05 19:28:38 2017 +0200
tree aaf0856ec36f98cba6fbe2482f61af462cc6927f
parent 8877ec23a30cce26dd50fb4727f6c212c989ba32

RSA: wipe more stack buffers

MGF mask and PSS salt are not highly sensitive, but wipe them anyway
for good hygiene.

library/rsa.c

diff --git a/library/rsa.c b/library/rsa.c
index 250f96f..ca99ccb 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -496,6 +496,8 @@
 
         dlen -= use_len;
     }
+
+    mbedtls_zeroize( mask, sizeof( mask ) );
 }
 #endif /* MBEDTLS_PKCS1_V21 */
 
@@ -1010,6 +1012,7 @@
     if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
     {
         mbedtls_md_free( &md_ctx );
+        /* No need to zeroize salt: we didn't use it. */
         return( ret );
     }
 
@@ -1020,6 +1023,7 @@
     mbedtls_md_update( &md_ctx, hash, hashlen );
     mbedtls_md_update( &md_ctx, salt, slen );
     mbedtls_md_finish( &md_ctx, p );
+    mbedtls_zeroize( salt, sizeof( salt ) );
 
     // Compensate for boundary condition when applying mask
     //