This is a note to let you know that I've just added the patch titled
netlink: don't send NETLINK_URELEASE for unbound sockets
to the 4.5-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:
netlink-don-t-send-netlink_urelease-for-unbound-sockets.patch
and it can be found in the queue-4.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e27260203912b40751fa353d009eaa5a642c739f Mon Sep 17 00:00:00 2001
From: Dmitry Ivanov <dmitrijs.ivanovs@xxxxxxxx>
Date: Thu, 7 Apr 2016 09:31:38 +0200
Subject: netlink: don't send NETLINK_URELEASE for unbound sockets
From: Dmitry Ivanov <dmitrijs.ivanovs@xxxxxxxx>
commit e27260203912b40751fa353d009eaa5a642c739f upstream.
All existing users of NETLINK_URELEASE use it to clean up resources that
were previously allocated to a socket via some command. As a result, no
users require getting this notification for unbound sockets.
Sending it for unbound sockets, however, is a problem because any user
(including unprivileged users) can create a socket that uses the same ID
as an existing socket. Binding this new socket will fail, but if the
NETLINK_URELEASE notification is generated for such sockets, the users
thereof will be tricked into thinking the socket that they allocated the
resources for is closed.
In the nl80211 case, this will cause destruction of virtual interfaces
that still belong to an existing hostapd process; this is the case that
Dmitry noticed. In the NFC case, it will cause a poll abort. In the case
of netlink log/queue it will cause them to stop reporting events, as if
NFULNL_CFG_CMD_UNBIND/NFQNL_CFG_CMD_UNBIND had been called.
Fix this problem by checking that the socket is bound before generating
the NETLINK_URELEASE notification.
Signed-off-by: Dmitry Ivanov <dima@xxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netlink/af_netlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1305,7 +1305,7 @@ static int netlink_release(struct socket
skb_queue_purge(&sk->sk_write_queue);
- if (nlk->portid) {
+ if (nlk->portid && nlk->bound) {
struct netlink_notify n = {
.net = sock_net(sk),
.protocol = sk->sk_protocol,
Patches currently in stable-queue which might be from dmitrijs.ivanovs@xxxxxxxx are
queue-4.5/nl80211-check-netlink-protocol-in-socket-release-notification.patch
queue-4.5/netlink-don-t-send-netlink_urelease-for-unbound-sockets.patch
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