Blame SOURCES/0051-nft-Don-t-assume-NFTNL_RULE_USERDATA-holds-a-comment.patch

1dc35b
From e78321d1a719a5dc1b340292fc1971d4daf7e472 Mon Sep 17 00:00:00 2001
8cce6c
From: Phil Sutter <phil@nwl.cc>
8cce6c
Date: Thu, 7 Feb 2019 22:08:53 +0100
8cce6c
Subject: [PATCH] nft: Don't assume NFTNL_RULE_USERDATA holds a comment
8cce6c
8cce6c
If this rule attribute is present but does not contain a comment,
8cce6c
get_comment() returns NULL which is then fed into strncpy() causing a
8cce6c
crash.
8cce6c
8cce6c
Signed-off-by: Phil Sutter <phil@nwl.cc>
8cce6c
Signed-off-by: Florian Westphal <fw@strlen.de>
8cce6c
(cherry picked from commit d1df0a36b0486c780211cfa574301132bf55f194)
8cce6c
Signed-off-by: Phil Sutter <psutter@redhat.com>
8cce6c
---
8cce6c
 iptables/nft-shared.c | 39 ++++++++++++++++++++++-----------------
8cce6c
 1 file changed, 22 insertions(+), 17 deletions(-)
8cce6c
8cce6c
diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c
8cce6c
index ce40787f92f7d..fc484b49e2318 100644
8cce6c
--- a/iptables/nft-shared.c
8cce6c
+++ b/iptables/nft-shared.c
8cce6c
@@ -639,25 +639,30 @@ void nft_rule_to_iptables_command_state(const struct nftnl_rule *r,
8cce6c
 	if (nftnl_rule_is_set(r, NFTNL_RULE_USERDATA)) {
8cce6c
 		const void *data;
8cce6c
 		uint32_t len, size;
8cce6c
-		struct xtables_match *match;
8cce6c
-		struct xt_entry_match *m;
8cce6c
+		const char *comment;
8cce6c
 
8cce6c
 		data = nftnl_rule_get_data(r, NFTNL_RULE_USERDATA, &len;;
8cce6c
-		match = xtables_find_match("comment", XTF_TRY_LOAD,
8cce6c
-					   &cs->matches);
8cce6c
-		if (match == NULL)
8cce6c
-			return;
8cce6c
-
8cce6c
-		size = XT_ALIGN(sizeof(struct xt_entry_match)) + match->size;
8cce6c
-		m = xtables_calloc(1, size);
8cce6c
-
8cce6c
-		strncpy((char *)m->data, get_comment(data, len),
8cce6c
-			match->size - 1);
8cce6c
-		m->u.match_size = size;
8cce6c
-		m->u.user.revision = 0;
8cce6c
-		strcpy(m->u.user.name, match->name);
8cce6c
-
8cce6c
-		match->m = m;
8cce6c
+		comment = get_comment(data, len);
8cce6c
+		if (comment) {
8cce6c
+			struct xtables_match *match;
8cce6c
+			struct xt_entry_match *m;
8cce6c
+
8cce6c
+			match = xtables_find_match("comment", XTF_TRY_LOAD,
8cce6c
+						   &cs->matches);
8cce6c
+			if (match == NULL)
8cce6c
+				return;
8cce6c
+
8cce6c
+			size = XT_ALIGN(sizeof(struct xt_entry_match))
8cce6c
+				+ match->size;
8cce6c
+			m = xtables_calloc(1, size);
8cce6c
+
8cce6c
+			strncpy((char *)m->data, comment, match->size - 1);
8cce6c
+			m->u.match_size = size;
8cce6c
+			m->u.user.revision = 0;
8cce6c
+			strcpy(m->u.user.name, match->name);
8cce6c
+
8cce6c
+			match->m = m;
8cce6c
+		}
8cce6c
 	}
8cce6c
 
8cce6c
 	if (cs->target != NULL) {
8cce6c
-- 
1dc35b
2.21.0
8cce6c