diff options
| author |   Eric Dumazet <edumazet@google.com> | 2017-08-14 17:44:43 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-08-14 22:31:27 -0700 |
| commit | d624d276d1ddacbcb12ad96832ce0c7b82cd25db (patch) | |
| tree | b78aa1f2060bf2aa70b13af5d58a7bca994af306 | |
| parent | dccp: purge write queue in dccp_destroy_sock() (diff) | |
| download | linux-dev-d624d276d1ddacbcb12ad96832ce0c7b82cd25db.tar.xz linux-dev-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>
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 4 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 4 |
2 files changed, 4 insertions, 4 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; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 2521690d62d6..206210125fd7 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1456,6 +1456,8 @@ 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); @@ -1464,8 +1466,6 @@ process: if (nsk == sk) { reqsk_put(req); tcp_v6_restore_cb(skb); - } else if (tcp_filter(sk, skb)) { - goto discard_and_relse; } else if (tcp_child_process(sk, nsk, skb)) { tcp_v6_send_reset(nsk, skb); goto discard_and_relse; |