[ 3.5.y.z extended stable ] Patch "proc connector: reject unprivileged listener bumps" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Wed Mar 20 10:43:45 UTC 2013

This is a note to let you know that I have just added a patch titled

    proc connector: reject unprivileged listener bumps

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see



>From 5c337ad4940ae60287ea29d7c91de5b2b8436876 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook at chromium.org>
Date: Mon, 25 Feb 2013 21:32:25 +0000
Subject: [PATCH] proc connector: reject unprivileged listener bumps

commit e70ab977991964a5a7ad1182799451d067e62669 upstream.

While PROC_CN_MCAST_LISTEN/IGNORE is entirely advisory, it was possible
for an unprivileged user to turn off notifications for all listeners by
sending PROC_CN_MCAST_IGNORE. Instead, require the same privileges as
required for a multicast bind.

Signed-off-by: Kees Cook <keescook at chromium.org>
Cc: Evgeniy Polyakov <zbr at ioremap.net>
Cc: Matt Helsley <matthltc at us.ibm.com>
Acked-by: Evgeniy Polyakov <zbr at ioremap.net>
Acked-by: Matt Helsley <matthltc at us.ibm.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backported to 3.5 ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 drivers/connector/cn_proc.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 77e1e6c..9d90e8c 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -303,7 +303,13 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg,
 	if (msg->len != sizeof(*mc_op))

-	mc_op = (enum proc_cn_mcast_op*)msg->data;
+	/* Can only change if privileged. */
+	if (!capable(CAP_NET_ADMIN)) {
+		err = EPERM;
+		goto out;
+	}
+	mc_op = (enum proc_cn_mcast_op *)msg->data;
 	switch (*mc_op) {
@@ -315,6 +321,8 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg,
 		err = EINVAL;
 	cn_proc_ack(err, msg->seq, msg->ack);


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