Netfilter-Devel Archive on lore.kernel.org
 help / color / Atom feed
From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net
Subject: [PATCH 1/9] netfilter: nf_ct_h323: do not re-activate already expired timer
Date: Wed, 10 Aug 2016 20:56:26 +0200
Message-ID: <1470855394-7234-2-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1470855394-7234-1-git-send-email-pablo@netfilter.org>

From: Liping Zhang <liping.zhang@spreadtrum.com>

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>
---
 net/netfilter/nf_conntrack_h323_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
index bb77a97..5c0db5c 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);
 	}
-- 
2.1.4


  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-10 18:56 [PATCH 0/9] Netfilter fixes for net Pablo Neira Ayuso
2016-08-10 18:56 ` Pablo Neira Ayuso [this message]
2016-08-10 18:56 ` [PATCH 2/9] netfilter: nf_tables: s/MFT_REG32_01/NFT_REG32_01 Pablo Neira Ayuso
2016-08-10 18:56 ` [PATCH 3/9] netfilter: nft_rbtree: ignore inactive matching element with no descendants Pablo Neira Ayuso
2016-08-10 18:56 ` [PATCH 4/9] netfilter: nf_conntrack_sip: CSeq 0 is a valid CSeq Pablo Neira Ayuso
2016-08-10 18:56 ` [PATCH 5/9] netfilter: nf_ct_expect: remove the redundant slash when policy name is empty Pablo Neira Ayuso
2016-08-10 18:56 ` [PATCH 6/9] netfilter: nfnetlink_queue: fix memory leak when attach expectation successfully Pablo Neira Ayuso
2016-08-10 18:56 ` [PATCH 7/9] netfilter: nfnetlink_queue: reject verdict request from different portid Pablo Neira Ayuso
2016-08-10 18:56 ` [PATCH 8/9] netfilter: ctnetlink: reject new conntrack request with different l4proto Pablo Neira Ayuso
2016-08-10 18:56 ` [PATCH 9/9] netfilter: nft_exthdr: Add size check on u8 nft_exthdr attributes Pablo Neira Ayuso
2016-08-10 21:54 ` [PATCH 0/9] Netfilter fixes for net David Miller
2016-08-10 19:16 Pablo Neira Ayuso
2016-08-10 19:16 ` [PATCH 1/9] netfilter: nf_ct_h323: do not re-activate already expired timer Pablo Neira Ayuso

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1470855394-7234-2-git-send-email-pablo@netfilter.org \
    --to=pablo@netfilter.org \
    --cc=davem@davemloft.net \
    --cc=netfilter-devel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Netfilter-Devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/netfilter-devel/0 netfilter-devel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 netfilter-devel netfilter-devel/ https://lore.kernel.org/netfilter-devel \
		netfilter-devel@vger.kernel.org
	public-inbox-index netfilter-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.netfilter-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git