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sctp: add the missing sock_owned_by_user check in sctp_icmp_redirect 

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 45caeaa5ac ("dccp/tcp: fix
routing redirect race") on sctp also needs this check.

Fixes: 55be7a9c60 ("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>
This commit is contained in:
Xin Long 2017-10-18 21:37:49 +08:00 committed by David S. Miller
parent df80cd9b28
commit 1cc276cec9
1 changed files with 1 additions and 1 deletions
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2
net/sctp/input.c
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@ -421,7 +421,7 @@ void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
{
struct dst_entry *dst;
if (!t)
if (sock_owned_by_user(sk) || !t)
return;
dst = sctp_transport_dst_check(t);
if (dst)