From 480416af9d4acb874d5f60bb725334f71103daf7 Mon Sep 17 00:00:00 2001
From: Gilles Peskine <Gilles.Peskine@arm.com>
Date: Thu, 28 Jun 2018 19:04:07 +0200
Subject: [PATCH] Fix argument validation in asn1_write_10x

1 << bits doesn't work when bits is too large. Found by ASan.
---
 tests/suites/test_suite_psa_crypto.function | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index 0d1a25c82..5f705e3e3 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -46,7 +46,9 @@ static int asn1_write_10x( unsigned char **p,
 {
     int ret;
     int len = bits / 8 + 1;
-    if( x >= 1 << bits )
+    if( bits == 0 )
+        return( MBEDTLS_ERR_ASN1_INVALID_DATA );
+    if( bits <= 8 && x >= 1 << ( bits - 1 ) )
         return( MBEDTLS_ERR_ASN1_INVALID_DATA );
     if( *p < start || *p - start < (ssize_t) len )
         return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );