Re: [PATCH net] sctp: add the missing sock_owned_by_user check in sctp_icmp_redirect
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: 2017-10-18 13:56:50
Also in:
linux-sctp
On Wed, Oct 18, 2017 at 09:37:49PM +0800, Xin Long wrote:
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>Nice catch, btw.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Thanks
quoted hunk ↗ jump to hunk
--- net/sctp/input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/net/sctp/input.c b/net/sctp/input.c index 92a0714..34f10e7 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c@@ -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)-- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html