diff options
author | Liping Zhang <liping.zhang@spreadtrum.com> | 2016-07-23 22:16:56 +0800 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-08-08 09:26:40 +0200 |
commit | 707e6835f89419ff1c05e828c2d9939fd95a7ad8 (patch) | |
tree | faaf3c1d830f7ad39dad6effc862aeec0ef49663 /net | |
parent | c518189567eaf42b2ec50a4d982484c8e38799f8 (diff) | |
download | linux-707e6835f89419ff1c05e828c2d9939fd95a7ad8.tar.bz2 |
netfilter: nf_ct_h323: do not re-activate already expired timer
Commit 96d1327ac2e3 ("netfilter: h323: Use mod_timer instead of
set_expect_timeout") just simplify the source codes
if (!del_timer(&exp->timeout))
return 0;
add_timer(&exp->timeout);
to mod_timer(&exp->timeout, jiffies + info->timeout * HZ);
This is not correct, and introduce a race codition:
CPU0 CPU1
- timer expire
process_rcf expectation_timed_out
lock(exp_lock) -
find_exp waiting exp_lock...
re-activate timer!! waiting exp_lock...
unlock(exp_lock) lock(exp_lock)
- unlink expect
- free(expect)
- unlock(exp_lock)
So when the timer expires again, we will access the memory that
was already freed.
Replace mod_timer with mod_timer_pending here to fix this problem.
Fixes: 96d1327ac2e3 ("netfilter: h323: Use mod_timer instead of set_expect_timeout")
Cc: Gao Feng <fgao@ikuai8.com>
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r-- | net/netfilter/nf_conntrack_h323_main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c index bb77a97961bf..5c0db5c64734 100644 --- a/net/netfilter/nf_conntrack_h323_main.c +++ b/net/netfilter/nf_conntrack_h323_main.c @@ -1473,7 +1473,8 @@ static int process_rcf(struct sk_buff *skb, struct nf_conn *ct, "timeout to %u seconds for", info->timeout); nf_ct_dump_tuple(&exp->tuple); - mod_timer(&exp->timeout, jiffies + info->timeout * HZ); + mod_timer_pending(&exp->timeout, + jiffies + info->timeout * HZ); } spin_unlock_bh(&nf_conntrack_expect_lock); } |