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| author | Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> | 2008-07-07 15:57:03 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-07-24 09:14:07 -0700 |
| commit | ea1bb944a0a2f98350648dcc801c64b11fd7c186 (patch) | |
| tree | 9e40ef227b10dbb05e93bef04a91c09cfd448e70 /drivers | |
| parent | 3fa6bcb587adefb2ed2391297529cbead8f03e0a (diff) | |
netfilter: nf_conntrack_tcp: fixing to check the lower bound of valid ACK
Upstream commit 84ebe1c:
Lost connections was reported by Thomas Bätzler (running 2.6.25 kernel) on
the netfilter mailing list (see the thread "Weird nat/conntrack Problem
with PASV FTP upload"). He provided tcpdump recordings which helped to
find a long lingering bug in conntrack.
In TCP connection tracking, checking the lower bound of valid ACK could
lead to mark valid packets as INVALID because:
- We have got a "higher or equal" inequality, but the test checked
the "higher" condition only; fixed.
- If the packet contains a SACK option, it could occur that the ACK
value was before the left edge of our (S)ACK "window": if a previous
packet from the other party intersected the right edge of the window
of the receiver, we could move forward the window parameters beyond
accepting a valid ack. Therefore in this patch we check the rightmost
SACK edge instead of the ACK value in the lower bound of valid (S)ACK
test.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
0 files changed, 0 insertions, 0 deletions