Messages in this thread Patch in this message | | | From | Hangyu Hua <> | Subject | [PATCH net] ax25: use after free in ax25_connect | Date | Tue, 11 Jan 2022 12:20:48 +0800 |
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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 <hbh25y@gmail.com> --- 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
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