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| author | Joerg Marx <joerg.marx@secunet.com> | 2010-05-20 15:55:30 +0200 |
|---|---|---|
| committer | Patrick McHardy <kaber@trash.net> | 2010-05-20 15:55:30 +0200 |
| commit | fc350777c705a39a312728ac5e8a6f164a828f5d (patch) | |
| tree | 62aa121cd62e416a505d35de9b5d77ab8ae89f66 /net/netfilter | |
| parent | a1d7c1b4b8dfbc5ecadcff9284d64bb6ad4c0196 (diff) | |
| download | linux-fc350777c705a39a312728ac5e8a6f164a828f5d.tar.gz linux-fc350777c705a39a312728ac5e8a6f164a828f5d.tar.bz2 linux-fc350777c705a39a312728ac5e8a6f164a828f5d.zip | |
netfilter: nf_conntrack: fix a race in __nf_conntrack_confirm against nf_ct_get_next_corpse()
This race was triggered by a 'conntrack -F' command running in parallel
to the insertion of a hash for a new connection. Losing this race led to
a dead conntrack entry effectively blocking traffic for a particular
connection until timeout or flushing the conntrack hashes again.
Now the check for an already dying connection is done inside the lock.
Signed-off-by: Joerg Marx <joerg.marx@secunet.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/nf_conntrack_core.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index b83c530c5e0a..eeeb8bc73982 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -424,6 +424,16 @@ __nf_conntrack_confirm(struct sk_buff *skb) spin_lock_bh(&nf_conntrack_lock); + /* We have to check the DYING flag inside the lock to prevent + a race against nf_ct_get_next_corpse() possibly called from + user context, else we insert an already 'dead' hash, blocking + further use of that particular connection -JM */ + + if (unlikely(nf_ct_is_dying(ct))) { + spin_unlock_bh(&nf_conntrack_lock); + return NF_ACCEPT; + } + /* See if there's one in the list already, including reverse: NAT could have grabbed it without realizing, since we're not in the hash. If there is, we lost race. */ |