summaryrefslogtreecommitdiffstats
path: root/net/ipv4
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2015-10-01 14:39:26 +0200
committerDavid S. Miller <davem@davemloft.net>2015-10-05 13:04:09 +0200
commit2306c704ce280c97a60d1f45333b822b40281dea (patch)
tree0a5f2c82541f1c99b09081d60f70fe64794a07b4 /net/ipv4
parenttcp/dccp: fix old style declarations (diff)
downloadlinux-2306c704ce280c97a60d1f45333b822b40281dea.tar.xz
linux-2306c704ce280c97a60d1f45333b822b40281dea.zip
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.c19
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);