diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-08-15 02:44:43 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-15 07:31:27 +0200 |
| commit | d624d276d1ddacbcb12ad96832ce0c7b82cd25db (patch) | |
| tree | b78aa1f2060bf2aa70b13af5d58a7bca994af306 /net/ipv4 | |
| parent | dccp: purge write queue in dccp_destroy_sock() (diff) | |
| download | linux-d624d276d1ddacbcb12ad96832ce0c7b82cd25db.tar.xz linux-d624d276d1ddacbcb12ad96832ce0c7b82cd25db.zip | |
tcp: fix possible deadlock in TCP stack vs BPF filter
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: 8fac365f63c8 ("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>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a20e7f03d5f7..e9252c7df809 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1722,6 +1722,8 @@ process: */ sock_hold(sk); refcounted = true; + if (tcp_filter(sk, skb)) + goto discard_and_relse; nsk = tcp_check_req(sk, skb, req, false); if (!nsk) { reqsk_put(req); @@ -1729,8 +1731,6 @@ process: } if (nsk == sk) { reqsk_put(req); - } else if (tcp_filter(sk, skb)) { - goto discard_and_relse; } else if (tcp_child_process(sk, nsk, skb)) { tcp_v4_send_reset(nsk, skb); goto discard_and_relse; |