[PATCH net] ax25: use after free in ax25_connect
From: Hangyu Hua <hidden>
Date: 2022-01-11 04:21:30
Also in:
linux-hams, lkml
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
sk_to_ax25(sk) needs to be called after lock_sock(sk) to avoid UAF caused by a race condition. Signed-off-by: Hangyu Hua <redacted> --- net/ax25/af_ax25.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index cfca99e295b8..c5d62420a2a8 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c@@ -1127,7 +1127,7 @@ static int __must_check ax25_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags) { struct sock *sk = sock->sk; - ax25_cb *ax25 = sk_to_ax25(sk), *ax25t; + ax25_cb *ax25, *ax25t; struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)uaddr; ax25_digi *digi = NULL; int ct = 0, err = 0;
@@ -1155,6 +1155,8 @@ static int __must_check ax25_connect(struct socket *sock, lock_sock(sk); + ax25 = sk_to_ax25(sk); + /* deal with restarts */ if (sock->state == SS_CONNECTING) { switch (sk->sk_state) {
--
2.25.1