diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-10-01 05:39:26 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-10-05 04:04:09 -0700 |
| commit | 2306c704ce280c97a60d1f45333b822b40281dea (patch) | |
| tree | 0a5f2c82541f1c99b09081d60f70fe64794a07b4 /net/ipv4 | |
| parent | 8695a144da9e500a5a60fa34c06694346ec1048f (diff) | |
inet: fix race in reqsk_queue_unlink()
reqsk_timer_handler() tests if icsk_accept_queue.listen_opt
is NULL at its beginning.
By the time it calls inet_csk_reqsk_queue_drop() and
reqsk_queue_unlink(), listener might have been closed and
inet_csk_listen_stop() had called reqsk_queue_yank_acceptq()
which sets icsk_accept_queue.listen_opt to NULL
We therefore need to correctly check listen_opt being NULL
after holding syn_wait_lock for proper synchronization.
Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer")
Fixes: b357a364c57c ("inet: fix possible panic in reqsk_queue_unlink()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/inet_connection_sock.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 7bb9c39e0a4d..61b45a17fc73 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -577,21 +577,22 @@ EXPORT_SYMBOL(inet_rtx_syn_ack); static bool reqsk_queue_unlink(struct request_sock_queue *queue, struct request_sock *req) { - struct listen_sock *lopt = queue->listen_opt; struct request_sock **prev; + struct listen_sock *lopt; bool found = false; spin_lock(&queue->syn_wait_lock); - - for (prev = &lopt->syn_table[req->rsk_hash]; *prev != NULL; - prev = &(*prev)->dl_next) { - if (*prev == req) { - *prev = req->dl_next; - found = true; - break; + lopt = queue->listen_opt; + if (lopt) { + for (prev = &lopt->syn_table[req->rsk_hash]; *prev != NULL; + prev = &(*prev)->dl_next) { + if (*prev == req) { + *prev = req->dl_next; + found = true; + break; + } } } - spin_unlock(&queue->syn_wait_lock); if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer)) reqsk_put(req); |