This is a note to let you know that I've just added the patch titled
l2tp: ensure session can't get removed during pppol2tp_session_ioctl()
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
l2tp-ensure-session-can-t-get-removed-during-pppol2tp_session_ioctl.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 57377d63547861919ee634b845c7caa38de4a452 Mon Sep 17 00:00:00 2001
From: Guillaume Nault <g.nault@xxxxxxxxxxxx>
Date: Fri, 31 Mar 2017 13:02:26 +0200
Subject: l2tp: ensure session can't get removed during pppol2tp_session_ioctl()
From: Guillaume Nault <g.nault@xxxxxxxxxxxx>
commit 57377d63547861919ee634b845c7caa38de4a452 upstream.
Holding a reference on session is required before calling
pppol2tp_session_ioctl(). The session could get freed while processing the
ioctl otherwise. Since pppol2tp_session_ioctl() uses the session's socket,
we also need to take a reference on it in l2tp_session_get().
Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault <g.nault@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/l2tp/l2tp_ppp.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1141,11 +1141,18 @@ static int pppol2tp_tunnel_ioctl(struct
if (stats.session_id != 0) {
/* resend to session ioctl handler */
struct l2tp_session *session =
- l2tp_session_find(sock_net(sk), tunnel, stats.session_id);
- if (session != NULL)
- err = pppol2tp_session_ioctl(session, cmd, arg);
- else
+ l2tp_session_get(sock_net(sk), tunnel,
+ stats.session_id, true);
+
+ if (session) {
+ err = pppol2tp_session_ioctl(session, cmd,
+ arg);
+ if (session->deref)
+ session->deref(session);
+ l2tp_session_dec_refcount(session);
+ } else {
err = -EBADR;
+ }
break;
}
#ifdef CONFIG_XFRM
Patches currently in stable-queue which might be from g.nault@xxxxxxxxxxxx are
queue-4.9/l2tp-take-a-reference-on-sessions-used-in-genetlink-handlers.patch
queue-4.9/l2tp-ensure-session-can-t-get-removed-during-pppol2tp_session_ioctl.patch
queue-4.9/l2tp-fix-race-in-l2tp_recv_common.patch
queue-4.9/l2tp-hold-session-while-sending-creation-notifications.patch
queue-4.9/l2tp-fix-duplicate-session-creation.patch