From: Nathaniel Filardo Date: Tue, 5 Feb 2008 11:05:07 +0000 (-0800) Subject: tun: impossible to deassert IFF_ONE_QUEUE or IFF_NO_PI X-Git-Tag: v2.6.25-rc1~787^2~12 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a26af1e08a3a1e0f88e6f2685ac2313d713a59c9;p=pandora-kernel.git tun: impossible to deassert IFF_ONE_QUEUE or IFF_NO_PI From: "Nathaniel Filardo" 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 Signed-off-by: Andrew Morton Signed-off-by: David S. Miller --- Reading git-diff-tree failed