From cadd480c74b11f0510aa56d9ee9f58c7fd7c094d Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Tue, 4 Apr 2017 16:21:45 +0200
Subject: [PATCH] tc: m_xt: Prevent segfault with standard targets

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1326726
Upstream Status: iproute2.git commit 445745221a21e

commit 445745221a21ecb4111c19cfa7f4c2cf4796337f
Author: Phil Sutter <phil@nwl.cc>
Date:   Fri Jun 10 13:42:00 2016 +0200

    tc: m_xt: Prevent segfault with standard targets

    Iptables standard targets like DROP or REJECT don't implement the print
    callback in libxtables. Hence the following command would segfault:

    | tc filter add dev d0 parent ffff: u32 match u32 0 0 action xt -j DROP

    With this patch standard targets still can't be used (and are not really
    useful anyway), but at least it doesn't crash anymore.

    Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 tc/m_xt.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tc/m_xt.c b/tc/m_xt.c
index 537daf8..aa83061 100644
--- a/tc/m_xt.c
+++ b/tc/m_xt.c
@@ -248,8 +248,12 @@ static int parse_ipt(struct action_util *a,int *argc_p,
 	fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 	fprintf(stdout, "\ttarget: ");
 
-	if (m)
-		m->print(NULL, m->t, 0);
+	if (m) {
+		if (m->print)
+			m->print(NULL, m->t, 0);
+		else
+			printf("%s ", m->name);
+	}
 	fprintf(stdout, " index %d\n", index);
 
 	if (strlen(tname) > 16) {
-- 
1.8.3.1