This is a note to let you know that I've just added the patch titled

sctp: add the missing sock_owned_by_user check in sctp_icmp_redirect

to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: sctp-add-the-missing-sock_owned_by_user-check-in-sctp_icmp_redirect.patch and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Wed Nov 15 17:25:34 CET 2017

From: Xin Long lucien.xin@gmail.com Date: Wed, 18 Oct 2017 21:37:49 +0800 Subject: sctp: add the missing sock_owned_by_user check in sctp_icmp_redirect

From: Xin Long lucien.xin@gmail.com

[ Upstream commit 1cc276cec9ec574d41cf47dfc0f51406b6f26ab4 ]

Now sctp processes icmp redirect packet in sctp_icmp_redirect where it calls sctp_transport_dst_check in which tp->dst can be released.

The problem is before calling sctp_transport_dst_check, it doesn't check sock_owned_by_user, which means tp->dst could be freed while a process is accessing it with owning the socket.

An use-after-free issue could be triggered by this.

This patch is to fix it by checking sock_owned_by_user before calling sctp_transport_dst_check in sctp_icmp_redirect, so that it would not release tp->dst if users still hold sock lock.

Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix routing redirect race") on sctp also needs this check.

Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers") Reported-by: Eric Dumazet edumazet@google.com Signed-off-by: Xin Long lucien.xin@gmail.com Acked-by: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Acked-by: Neil Horman nhorman@tuxdriver.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sctp/input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -421,7 +421,7 @@ void sctp_icmp_redirect(struct sock *sk, { struct dst_entry *dst;

- if (!t) + if (sock_owned_by_user(sk) || !t) return; dst = sctp_transport_dst_check(t); if (dst)

Patches currently in stable-queue which might be from lucien.xin@gmail.com are

queue-4.13/sctp-reset-owner-sk-for-data-chunks-on-out-queues-when-migrating-a-sock.patch queue-4.13/ipip-only-increase-err_count-for-some-certain-type-icmp-in-ipip_err.patch queue-4.13/sctp-full-support-for-ipv6-ip_nonlocal_bind-ip_freebind.patch queue-4.13/sctp-add-the-missing-sock_owned_by_user-check-in-sctp_icmp_redirect.patch queue-4.13/ip6_gre-only-increase-err_count-for-some-certain-type-icmpv6-in-ip6gre_err.patch queue-4.13/ip6_gre-update-dst-pmtu-if-dev-mtu-has-been-updated-by-toobig-in-__gre6_xmit.patch