proc connector: reject unprivileged listener bumps

commit e70ab97799 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@chromium.org>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kees Cook 2013-02-25 21:32:25 +00:00 committed by Greg Kroah-Hartman
parent f7741e3b3f
commit 2f590c4701

View file

@ -331,6 +331,12 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg,
if (msg->len != sizeof(*mc_op))
return;
/* 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) {
case PROC_CN_MCAST_LISTEN:
@ -343,6 +349,8 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg,
err = EINVAL;
break;
}
out:
cn_proc_ack(err, msg->seq, msg->ack);
}