From: Gao Feng <f...@ikuai8.com>

Current tun driver permits the ifr_flags is set with IFF_TUN and
IFF_TAP at the same time. But actually there is only IFF_TUN flag
works. And it does not make sense these two flags are set, so add
this check.

Signed-off-by: Gao Feng <f...@ikuai8.com>
---
 drivers/net/tun.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8093e39..c1f89c1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1752,6 +1752,10 @@ static int tun_set_iff(struct net *net, struct file 
*file, struct ifreq *ifr)
                if (err < 0)
                        return err;
 
+               if ((ifr->ifr_flags & (IFF_TUN | IFF_TAP)) == (IFF_TUN | 
IFF_TAP)) {
+                       return -EINVAL;
+               }
+
                /* Set dev type */
                if (ifr->ifr_flags & IFF_TUN) {
                        /* TUN device */
-- 
1.9.1


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