| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 24/92] tcp: release sk_frag.page in tcp_disconnect | Date | Fri, 9 Feb 2018 14:38:53 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Li RongQing <lirongqing@baidu.com>
[ 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@baidu.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ipv4/tcp.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2316,6 +2316,12 @@ 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; }
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