From: Phil Sutter <phil@nwl.cc>
Date: Thu, 5 Dec 2019 15:01:29 +0000 (+0100)
Subject: xtables-translate: Guard strcpy() call in xlate_ifname()
X-Git-Tag: v1.8.5~76
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2861bdbbf062071487a49103513d129ce40e2652;p=thirdparty%2Fiptables.git

xtables-translate: Guard strcpy() call in xlate_ifname()

The function potentially fed overlong strings to strcpy(). Given that
everything needed to avoid this is there, reorder code a bit to prevent
those inputs, too.

Fixes: 0ddd663e9c167 ("iptables-translate: add in/out ifname wildcard match translation to nft")
---

diff --git a/iptables/xtables-translate.c b/iptables/xtables-translate.c
index a42c60a3..77a186b9 100644
--- a/iptables/xtables-translate.c
+++ b/iptables/xtables-translate.c
@@ -32,14 +32,13 @@
 void xlate_ifname(struct xt_xlate *xl, const char *nftmeta, const char *ifname,
 		  bool invert)
 {
+	int ifaclen = strlen(ifname);
 	char iface[IFNAMSIZ];
-	int ifaclen;
 
-	if (ifname[0] == '\0')
+	if (ifaclen < 1 || ifaclen >= IFNAMSIZ)
 		return;
 
 	strcpy(iface, ifname);
-	ifaclen = strlen(iface);
 	if (iface[ifaclen - 1] == '+')
 		iface[ifaclen - 1] = '*';