@@ -361,23 +361,6 @@ static void evict_oldest_expect(struct nf_conn *master,
}
}
-static inline int refresh_timer(struct nf_conntrack_expect *i)
-{
- struct nf_conn_help *master_help = nfct_help(i->master);
- const struct nf_conntrack_expect_policy *p;
-
- if (!del_timer(&i->timeout))
- return 0;
-
- p = &rcu_dereference_protected(
- master_help->helper,
- lockdep_is_held(&nf_conntrack_lock)
- )->expect_policy[i->class];
- i->timeout.expires = jiffies + p->timeout * HZ;
- add_timer(&i->timeout);
- return 1;
-}
-
static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect)
{
const struct nf_conntrack_expect_policy *p;
@@ -386,7 +369,7 @@ static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect)
struct nf_conn_help *master_help = nfct_help(master);
struct nf_conntrack_helper *helper;
struct net *net = nf_ct_exp_net(expect);
- struct hlist_node *n;
+ struct hlist_node *n, *next;
unsigned int h;
int ret = 1;
@@ -395,12 +378,12 @@ static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect)
goto out;
}
h = nf_ct_expect_dst_hash(&expect->tuple);
- hlist_for_each_entry(i, n, &net->ct.expect_hash[h], hnode) {
+ hlist_for_each_entry_safe(i, n, next, &net->ct.expect_hash[h], hnode) {
if (expect_matches(i, expect)) {
- /* Refresh timer: if it's dying, ignore.. */
- if (refresh_timer(i)) {
- ret = 0;
- goto out;
+ if (del_timer(&i->timeout)) {
+ nf_ct_unlink_expect(i);
+ nf_ct_expect_put(i);
+ break;
}
} else if (expect_clash(i, expect)) {
ret = -EBUSY;
This is a note to let you know that I have just added a patch titled netfilter: nf_ct_expect: fix possible access to to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.yuz tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From c732a539bc4a58f3ed5609e1db13734a50b93875 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso <pablo@netfilter.org> Date: Thu, 16 Aug 2012 02:25:24 +0200 Subject: [PATCH] netfilter: nf_ct_expect: fix possible access to uninitialized timer commit 2614f86490122bf51eb7c12ec73927f1900f4e7d upstream. In __nf_ct_expect_check, the function refresh_timer returns 1 if a matching expectation is found and its timer is successfully refreshed. This results in nf_ct_expect_related returning 0. Note that at this point: - the passed expectation is not inserted in the expectation table and its timer was not initialized, since we have refreshed one matching/existing expectation. - nf_ct_expect_alloc uses kmem_cache_alloc, so the expectation timer is in some undefined state just after the allocation, until it is appropriately initialized. This can be a problem for the SIP helper during the expectation addition: ... if (nf_ct_expect_related(rtp_exp) == 0) { if (nf_ct_expect_related(rtcp_exp) != 0) nf_ct_unexpect_related(rtp_exp); ... Note that nf_ct_expect_related(rtp_exp) may return 0 for the timer refresh case that is detailed above. Then, if nf_ct_unexpect_related(rtcp_exp) returns != 0, nf_ct_unexpect_related(rtp_exp) is called, which does: spin_lock_bh(&nf_conntrack_lock); if (del_timer(&exp->timeout)) { nf_ct_unlink_expect(exp); nf_ct_expect_put(exp); } spin_unlock_bh(&nf_conntrack_lock); Note that del_timer always returns false if the timer has been initialized. However, the timer was not initialized since setup_timer was not called, therefore, the expectation timer remains in some undefined state. If I'm not missing anything, this may lead to the removal an unexistent expectation. To fix this, the optimization that allows refreshing an expectation is removed. Now nf_conntrack_expect_related looks more consistent to me since it always add the expectation in case that it returns success. Thanks to Patrick McHardy for participating in the discussion of this patch. I think this may be the source of the problem described by: http://marc.info/?l=netfilter-devel&m=134073514719421&w=2 Reported-by: Rafal Fitt <rafalf@aplusc.com.pl> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- net/netfilter/nf_conntrack_expect.c | 29 ++++++----------------------- 1 file changed, 6 insertions(+), 23 deletions(-) -- 1.7.9.5