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| author | Michael Tokarev <mjt@tls.msk.ru> | 2009-02-02 23:34:56 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-02-02 23:34:56 -0800 |
| commit | 1bded710a574f20d41bc9e7fb531301db282d623 (patch) | |
| tree | 02153d39ee525edaee35953c663926cb57075757 /drivers/net/tun.c | |
| parent | 1a5645bc901aea6f3f446888061b2b084bbf1ba6 (diff) | |
| download | linux-1bded710a574f20d41bc9e7fb531301db282d623.tar.gz linux-1bded710a574f20d41bc9e7fb531301db282d623.tar.bz2 linux-1bded710a574f20d41bc9e7fb531301db282d623.zip | |
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>
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 457f2d7430cf..15d67635bb10 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -123,7 +123,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file) /* Check permissions */ if (((tun->owner != -1 && cred->euid != tun->owner) || - (tun->group != -1 && cred->egid != tun->group)) && + (tun->group != -1 && !in_egroup_p(tun->group))) && !capable(CAP_NET_ADMIN)) return -EPERM; |