From 117991ed14861122ea87133d0ea5881e6e3403ed Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Fri, 26 Jan 2018 16:40:41 +0800 Subject: [PATCH] tcp: release sk_frag.page in tcp_disconnect [ 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 Cc: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 37e8966a457b..23d77ff1da59 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2276,6 +2276,12 @@ int tcp_disconnect(struct sock *sk, int flags) 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; }