tree 93aa0f83a70f704e33ed378b2ad4636533bd7bde
parent 74a3e5a71c9b54c63bff978e9cafbcef67600f0b
author Eric W. Biederman <ebiederm@xmission.com> 1232449068 +0000
committer David S. Miller <davem@davemloft.net> 1232582443 -0800

tun: Fix races in tun_set_iff

It is possible for two different tasks with access to the same file
descriptor to call tun_set_iff on it at the same time and race to
attach to a tap device.  Prevent this by placing all of the logic to
attach to a file descriptor in one function and testing the file
descriptor to be certain it is not already attached to another tun
device.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>