From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Date: Fri, 17 Sep 2021 20:37:24 +0000 (-0400)
Subject: lib/x509: Avoid memcpy when string is empty
X-Git-Tag: 3.7.3~37^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a00a79ddf41eb14d56bdea076b5c252029896431;p=thirdparty%2Fgnutls.git

lib/x509: Avoid memcpy when string is empty

This fixes an ASAN warning in fuzz/gnutls_private_key_parser_fuzzer
when run against the malformed private key
fuzz/gnutls_private_key_parser_fuzzer.in/10a5c92fa30ddb6cbb4286d7699b2b7a7e032b17

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---

diff --git a/lib/x509/common.c b/lib/x509/common.c
index c156bd96a9..94d206ff75 100644
--- a/lib/x509/common.c
+++ b/lib/x509/common.c
@@ -630,7 +630,8 @@ _gnutls_x509_decode_string(unsigned int etype,
 	if (td.data == NULL)
 		return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
 
-	memcpy(td.data, str, str_size);
+        if (str_size > 0)
+                memcpy(td.data, str, str_size);
 	td.data[str_size] = 0;
 
 	if (allow_ber)