tcp: fix possible deadlock in TCP stack vs BPF filter

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Filtering the ACK packet was not put at the right place.

At this place, we already allocated a child and put it
into accept queue.

We absolutely need to call tcp_child_process() to release
its spinlock, or we will deadlock at accept() or close() time.

Found by syzkaller team (Thanks a lot !)

Fixes: 8fac365f63 ("tcp: Add a tcp_filter hook before handle ack packet")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Chenbo Feng <fengc@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Eric Dumazet 2017-08-14 17:44:43 -07:00 • committed by David S. Miller

parent 7749d4ff88

commit d624d276d1

2 changed files with 4 additions and 4 deletions

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4

net/ipv4/tcp_ipv4.c

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4

net/ipv6/tcp_ipv6.c

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