tree 02153d39ee525edaee35953c663926cb57075757
parent 1a5645bc901aea6f3f446888061b2b084bbf1ba6
author Michael Tokarev <mjt@tls.msk.ru> 1233646496 -0800
committer David S. Miller <davem@davemloft.net> 1233646496 -0800

tun: Check supplemental groups in TUN/TAP driver.

Michael Tokarev wrote:
[]
> 2, and this is the main one: How about supplementary groups?
>
> Here I have a valid usage case: a group of testers running various
> versions of windows using KVM (kernel virtual machine), 1 at a time,
> to test some software.  kvm is set up to use bridge with a tap device
> (there should be a way to connect to the machine).  Anyone on that group
> has to be able to start/stop the virtual machines.
>
> My first attempt - pretty obvious when I saw -g option of tunctl - is
> to add group ownership for the tun device and add a supplementary group
> to each user (their primary group should be different).  But that fails,
> since kernel only checks for egid, not any other group ids.
>
> What's the reasoning to not allow supplementary groups and to only check
> for egid?

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>