From 1bd4978a88ac2589f3105f599b1d404a312fb7f6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 16 Dec 2015 08:57:37 -0800 Subject: tun: honor IFF_UP in tun_get_user() If a tun interface is turned down, we should not allow packet injection into the kernel. Kernel does not send packets to the tun already. TUNATTACHFILTER can not be used as only tun_net_xmit() is taking care of it. Reported-by: Curt Wohlgemuth Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- drivers/net/tun.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index f0db770e8b2f..88bb8cc3555b 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1095,6 +1095,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, u32 rxhash; ssize_t n; + if (!(tun->dev->flags & IFF_UP)) + return -EIO; + if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) return -EINVAL; -- cgit v1.2.3-59-g8ed1b