netdev - [iproute PATCH 2/9] tc: m_xt: Fix segfault when adding multiple actions at once

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Date:	Fri, 10 Jun 2016 13:42:01 +0200
From:	Phil Sutter <phil@....cc>
To:	Stephen Hemminger <shemming@...cade.com>
Cc:	netdev@...r.kernel.org
Subject: [iproute PATCH 2/9] tc: m_xt: Fix segfault when adding multiple actions at once

Without this, the following call to tc would segfault:

| tc filter add dev d0 parent ffff: u32 match u32 0 0 \
| 	action xt -j MARK --set-mark 0x1 \
| 	action xt -j MARK --set-mark 0x1

The reason is basically the same as for 6e2e5ec28bad4 ("fix print_ipt:
segfault if more then one filter with action -j MARK.") but in
parse_ipt() instead of print_ipt().

Signed-off-by: Phil Sutter <phil@....cc>
---
 tc/m_xt.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/tc/m_xt.c b/tc/m_xt.c
index 62ec6d7f18e73..45d86d66248d4 100644
--- a/tc/m_xt.c
+++ b/tc/m_xt.c
@@ -133,7 +133,9 @@ static int parse_ipt(struct action_util *a, int *argc_p,
 	__u32 hook = 0, index = 0;
 	struct option *opts = NULL;
 
-	xtables_init_all(&tcipt_globals, NFPROTO_IPV4);
+	/* copy tcipt_globals because .opts will be modified by iptables */
+	struct xtables_globals tmp_tcipt_globals = tcipt_globals;
+	xtables_init_all(&tmp_tcipt_globals, NFPROTO_IPV4);
 	set_lib_dir();
 
 	{
@@ -153,7 +155,7 @@ static int parse_ipt(struct action_util *a, int *argc_p,
 	}
 
 	while (1) {
-		c = getopt_long(argc, argv, "j:", tcipt_globals.opts, NULL);
+		c = getopt_long(argc, argv, "j:", tmp_tcipt_globals.opts, NULL);
 		if (c == -1)
 			break;
 		switch (c) {
@@ -166,12 +168,12 @@ static int parse_ipt(struct action_util *a, int *argc_p,
 					return -1;
 				}
 #if (XTABLES_VERSION_CODE >= 6)
-			opts = xtables_options_xfrm(tcipt_globals.orig_opts,
-						    tcipt_globals.opts,
+			opts = xtables_options_xfrm(tmp_tcipt_globals.orig_opts,
+						    tmp_tcipt_globals.opts,
 						    m->x6_options,
 						    &m->option_offset);
 #else
-			opts = xtables_merge_options(tcipt_globals.opts,
+			opts = xtables_merge_options(tmp_tcipt_globals.opts,
 						     m->extra_opts,
 						     &m->option_offset);
 #endif
@@ -179,7 +181,7 @@ static int parse_ipt(struct action_util *a, int *argc_p,
 				fprintf(stderr, " failed to find additional options for target %s\n\n", optarg);
 				return -1;
 			} else
-				tcipt_globals.opts = opts;
+				tmp_tcipt_globals.opts = opts;
 			} else {
 				fprintf(stderr, " failed to find target %s\n\n", optarg);
 				return -1;
-- 
2.8.2