commit 092f2c48c467f29de6f350bc2fec88281b50f99c
author Janos Follath <janos.follath@arm.com> Thu Feb 11 11:08:18 2016 +0000
committer Simon Butcher <simon.butcher@arm.com> Wed May 18 19:58:41 2016 +0100
tree 96a972d85d535c7fece3a88d6c6c6058b1a35359
parent 574b118bf83170e1a9e94e82cf8006e628f29bf0

Move underflow test to make time constant

library/rsa.c

diff --git a/library/rsa.c b/library/rsa.c
index 154fa58..0a28812 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -702,6 +702,12 @@
     if( md_info == NULL )
         return( POLARSSL_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
      */