[PATCH 4.12 78/99] netfilter: expect: fix crash when putting uninited expectation

Greg Kroah-Hartman
2017-08-28T09:01:38Z

From: Florian Westphal <fw@strlen.de>

commit 36ac344e16e04e3e55e8fed7446095a6458c64e6 upstream.

We crash in __nf_ct_expect_check, it calls nf_ct_remove_expect on the
uninitialised expectation instead of existing one, so del_timer chokes
on random memory address.

Fixes: ec0e3f01114ad32711243 ("netfilter: nf_ct_expect: Add nf_ct_remove_expect()")
Reported-by: Sergey Kvachonok <ravenexp@gmail.com>
Tested-by: Sergey Kvachonok <ravenexp@gmail.com>
Cc: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/netfilter/nf_conntrack_expect.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/netfilter/nf_conntrack_expect.c
+++ b/net/netfilter/nf_conntrack_expect.c
@@ -422,7 +422,7 @@ static inline int __nf_ct_expect_check(s
h = nf_ct_expect_dst_hash(net, &expect->tuple);
hlist_for_each_entry_safe(i, next, &nf_ct_expect_hash[h], hnode) {
if (expect_matches(i, expect)) {
- if (nf_ct_remove_expect(expect))
+ if (nf_ct_remove_expect(i))
break;
} else if (expect_clash(i, expect)) {
ret = -EBUSY;