In sctp_listen_start() invoked by sctp_inet_listen(), it should set the
sk_state back to CLOSED if sctp_autobind() fails due to whatever reason.
Otherwise, next time when calling sctp_inet_listen(), if sctp_sk(sk)->reuse
is already set via setsockopt(SCTP_REUSE_PORT), sctp_sk(sk)->bind_hash will
be dereferenced as sk_state is LISTENING, which causes a crash as bind_hash
is NULL.
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:sctp_inet_listen+0x7f0/0xa20 net/sctp/socket.c:8617
Call Trace:
<TASK>
__sys_listen_socket net/socket.c:1883 [inline]
__sys_listen+0x1b7/0x230 net/socket.c:1894
__do_sys_listen net/socket.c:1902 [inline]
Fixes: 5e8f3f703ae4 ("sctp: simplify sctp listening code")
Reported-by: syzbot+f4e0f821e3a3b7cee51d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
---
net/sctp/socket.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 32f76f1298da..078bcb3858c7 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -8557,8 +8557,10 @@ static int sctp_listen_start(struct sock *sk, int backlog)
*/
inet_sk_set_state(sk, SCTP_SS_LISTENING);
if (!ep->base.bind_addr.port) {
- if (sctp_autobind(sk))
+ if (sctp_autobind(sk)) {
+ inet_sk_set_state(sk, SCTP_SS_CLOSED);
return -EAGAIN;
+ }
} else {
if (sctp_get_port(sk, inet_sk(sk)->inet_num)) {
inet_sk_set_state(sk, SCTP_SS_CLOSED);
--
2.43.0
