Commit 0c3e0e3b authored by Kirill Tkhai's avatar Kirill Tkhai Committed by David S. Miller
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tun: Add ioctl() TUNGETDEVNETNS cmd to allow obtaining real net ns of tun device

In commit f2780d6d

 "tun: Add ioctl() SIOCGSKNS cmd to allow
obtaining net ns of tun device" it was missed that tun may change
its net ns, while net ns of socket remains the same as it was
created initially. SIOCGSKNS returns net ns of socket, so it is
not suitable for obtaining net ns of device.

We may have two tun devices with the same names in two net ns,
and in this case it's not possible to determ, which of them
fd refers to (TUNGETIFF will return the same name).

This patch adds new ioctl() cmd for obtaining net ns of a device.

Reported-by: default avatarHarald Albrecht <>
Signed-off-by: default avatarKirill Tkhai <>
Signed-off-by: default avatarDavid S. Miller <>
parent 28b18b39
......@@ -3102,6 +3102,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
net = dev_net(tun->dev);
ret = 0;
switch (cmd) {
......@@ -3327,6 +3328,13 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
ret = tun_net_change_carrier(tun->dev, (bool)carrier);
ret = -EPERM;
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
goto unlock;
ret = open_related_ns(&net->ns, get_net_ns);
ret = -EINVAL;
......@@ -60,6 +60,7 @@
#define TUNSETSTEERINGEBPF _IOR('T', 224, int)
#define TUNSETFILTEREBPF _IOR('T', 225, int)
#define TUNSETCARRIER _IOW('T', 226, int)
#define TUNGETDEVNETNS _IO('T', 227)
/* TUNSETIFF ifr flags */
#define IFF_TUN 0x0001
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