tun: Add ioctl() TUNGETDEVNETNS cmd to allow obtaining real net ns of tun device (0c3e0e3b) · Commits · 戴 / test

In commit "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:

Harald Albrecht <harald.albrecht@gmx.net> Signed-off-by:

Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/tun.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -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) {
		case TUNGETIFF:
		@@ -3327,6 +3328,13 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
		ret = tun_net_change_carrier(tun->dev, (bool)carrier);
		break;

		case TUNGETDEVNETNS:
		ret = -EPERM;
		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
		goto unlock;
		ret = open_related_ns(&net->ns, get_net_ns);
		break;

		default:
		ret = -EINVAL;
		break;

include/uapi/linux/if_tun.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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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