commit b6e81bc3d7ba726a9dbc72b4127e31be2fc1ab41
author Andrzej Kurek <andrzej.kurek@arm.com> Tue Feb 20 11:20:09 2018 -0500
committer Andrzej Kurek <andrzej.kurek@arm.com> Tue Feb 20 11:20:09 2018 -0500
tree f6de6104e3c6ed9bdeaa29e630e66a6ba987691a
parent 0044ab12b7099457a24930aa80bd85d9724431dc

ECP: Add a sanity check to mbedtls_ecp_ansi_write_group

Check for p != q at the end to ensure that everything went as it should.

library/ecp.c

diff --git a/library/ecp.c b/library/ecp.c
index 477ed0d..89b0af4 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -2082,6 +2082,8 @@
         return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
     q = p + 2 + oid_length;
     *olen = mbedtls_asn1_write_oid( &q, p, oid, oid_length );
+    if ( p != q )
+        return ( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
     return ( 0 );
 }