Messages in this thread Patch in this message | | | Date | Mon, 25 Feb 2013 23:32:25 -0800 | From | Kees Cook <> | Subject | [PATCH] proc connector: reject unprivileged listener bumps |
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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> Cc: stable@vger.kernel.org --- drivers/connector/cn_proc.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index fce2000..1110478 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -313,6 +313,12 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, (task_active_pid_ns(current) != &init_pid_ns)) 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: @@ -325,6 +331,8 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, err = EINVAL; break; } + +out: cn_proc_ack(err, msg->seq, msg->ack); } -- 1.7.9.5
-- Kees Cook Chrome OS Security
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