4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Li RongQing <lirongqing@xxxxxxxxx>
[ Upstream commit 9b42d55a66d388e4dd5550107df051a9637564fc ]
socket can be disconnected and gets transformed back to a listening
socket, if sk_frag.page is not released, which will be cloned into
a new socket by sk_clone_lock, but the reference count of this page
is increased, lead to a use after free or double free issue
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2276,6 +2276,12 @@ int tcp_disconnect(struct sock *sk, int
WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
+ if (sk->sk_frag.page) {
+ put_page(sk->sk_frag.page);
+ sk->sk_frag.page = NULL;
+ sk->sk_frag.offset = 0;
+ }
+
sk->sk_error_report(sk);
return err;
}