netdev - [PATCH net-next v3 5/8] net-sysfs: require net admin in the init ns for setting tx

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Date:   Fri, 20 Jul 2018 21:56:51 +0000
From:   Tyler Hicks <tyhicks@...onical.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Tejun Heo <tj@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Stephen Hemminger <stephen@...workplumber.org>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        bridge@...ts.linux-foundation.org,
        Linux Containers <containers@...ts.linux-foundation.org>
Subject: [PATCH net-next v3 5/8] net-sysfs: require net admin in the init ns for setting tx_maxrate

An upcoming change will allow container root to open some /sys/class/net
files for writing. The tx_maxrate attribute can result in changes
to actual hardware devices so err on the side of caution by requiring
CAP_NET_ADMIN in the init namespace in the corresponding attribute store
operation.

Signed-off-by: Tyler Hicks <tyhicks@...onical.com>
---
 net/core/net-sysfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index ffa1d18f2c2c..405c41ecb20b 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1087,6 +1087,9 @@ static ssize_t tx_maxrate_store(struct netdev_queue *queue,
 	int err, index = get_netdev_queue_index(queue);
 	u32 rate = 0;
 
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
 	err = kstrtou32(buf, 10, &rate);
 	if (err < 0)
 		return err;
-- 
2.7.4