From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 3/4] netfilter: nat: use atomic bit op to clear the _SRC_NAT_DONE_BIT
Date: Mon, 29 May 2017 13:34:31 +0200 [thread overview]
Message-ID: <1496057672-6751-4-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1496057672-6751-1-git-send-email-pablo@netfilter.org>
From: Liping Zhang <zlpnobody@gmail.com>
We need to clear the IPS_SRC_NAT_DONE_BIT to indicate that the ct has
been removed from nat_bysource table. But unfortunately, we use the
non-atomic bit operation: "ct->status &= ~IPS_NAT_DONE_MASK". So
there's a race condition that we may clear the _DYING_BIT set by
another CPU unexpectedly.
Since we don't care about the IPS_DST_NAT_DONE_BIT, so just using
clear_bit to clear the IPS_SRC_NAT_DONE_BIT is enough.
Also note, this is the last user which use the non-atomic bit operation
to update the confirmed ct->status.
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_nat_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index ef0be325a0c6..6c72922d20ca 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -566,7 +566,7 @@ static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
* Else, when the conntrack is destoyed, nf_nat_cleanup_conntrack()
* will delete entry from already-freed table.
*/
- ct->status &= ~IPS_NAT_DONE_MASK;
+ clear_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
nf_nat_bysource_params);
--
2.1.4
next prev parent reply other threads:[~2017-05-29 11:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-29 11:34 [PATCH 0/4] Netfilter fixes for net Pablo Neira Ayuso
2017-05-29 11:34 ` [PATCH 1/4] netfilter: conntrack: fix false CRC32c mismatch using paged skb Pablo Neira Ayuso
2017-05-29 11:34 ` [PATCH 2/4] netfilter: nft_set_rbtree: handle element re-addition after deletion Pablo Neira Ayuso
2017-05-29 11:34 ` Pablo Neira Ayuso [this message]
2017-05-29 11:34 ` [PATCH 4/4] netfilter: ctnetlink: fix incorrect nf_ct_put during hash resize Pablo Neira Ayuso
2017-05-30 3:20 ` [PATCH 0/4] Netfilter fixes for net David Miller
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