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| author |   Nathaniel Filardo <nwfilardo@gmail.com> | 2008-02-05 03:05:07 -0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2008-02-05 03:05:07 -0800 |
| commit | a26af1e08a3a1e0f88e6f2685ac2313d713a59c9 (patch) | |
| tree | c4b9cdf04305c094e88e2446ec25f7823d38158e /drivers/net/tun.c | |
| parent | hamradio: fix dmascc section mismatch (diff) | |
| download | linux-dev-a26af1e08a3a1e0f88e6f2685ac2313d713a59c9.tar.xz linux-dev-a26af1e08a3a1e0f88e6f2685ac2313d713a59c9.zip | |
tun: impossible to deassert IFF_ONE_QUEUE or IFF_NO_PI
From: "Nathaniel Filardo" <nwfilardo@gmail.com>
Taken from http://bugzilla.kernel.org/show_bug.cgi?id=9806
The TUN/TAP driver only permits one-way transitions of IFF_NO_PI or
IFF_ONE_QUEUE during the lifetime of a tap/tun interface. Note that
tun_set_iff contains
541 if (ifr->ifr_flags & IFF_NO_PI)
542 tun->flags |= TUN_NO_PI;
543
544 if (ifr->ifr_flags & IFF_ONE_QUEUE)
545 tun->flags |= TUN_ONE_QUEUE;
This is easily fixed by adding else branches which clear these bits.
Steps to reproduce:
This is easily reproduced by setting an interface persistant using tunctl then
attempting to open it as IFF_TAP or IFF_TUN, without asserting the IFF_NO_PI
flag. The ioctl() will succeed and the ifr.flags word is not modified, but the
interface remains in IFF_NO_PI mode (as it was set by tunctl).
Acked-by: Maxim Krasnyansky <maxk@qualcomm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 46339f6bcd00..038c1ef94d2e 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -529,9 +529,13 @@ static int tun_set_iff(struct file *file, struct ifreq *ifr) if (ifr->ifr_flags & IFF_NO_PI) tun->flags |= TUN_NO_PI; + else + tun->flags &= ~TUN_NO_PI; if (ifr->ifr_flags & IFF_ONE_QUEUE) tun->flags |= TUN_ONE_QUEUE; + else + tun->flags &= ~TUN_ONE_QUEUE; file->private_data = tun; tun->attached = 1; |