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[NET]: Allow group ownership of TUN/TAP devices. 

Introduce a new syscall TUNSETGROUP for group ownership setting of tap
devices. The user now is allowed to send packages if either his euid or
his egid matches the one specified via tunctl (via -u or -g
respecitvely). If both, gid and uid, are set via tunctl, both have to
match.

Signed-off-by: Guido Guenther <agx@sigxcpu.org>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Guido Guenther 2007-07-02 22:50:25 -07:00 committed by David S. Miller
parent 0ba4805383
commit 8c644623fe
2 changed files with 15 additions and 2 deletions
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15
drivers/net/tun.c
View File

@ -432,6 +432,7 @@ static void tun_setup(struct net_device *dev)
init_waitqueue_head(&tun->read_wait);
tun->owner = -1;
tun->group = -1;
SET_MODULE_OWNER(dev);
dev->open = tun_net_open;
@ -467,8 +468,11 @@ static int tun_set_iff(struct file *file, struct ifreq *ifr)
return -EBUSY;
/* Check permissions */
if (tun->owner != -1 &&
current->euid != tun->owner && !capable(CAP_NET_ADMIN))
if (((tun->owner != -1 &&
current->euid != tun->owner) ||
(tun->group != -1 &&
current->egid != tun->group)) &&
!capable(CAP_NET_ADMIN))
return -EPERM;
}
else if (__dev_get_by_name(ifr->ifr_name))
@ -610,6 +614,13 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
break;
case TUNSETGROUP:
/* Set group of the device */
tun->group= (gid_t) arg;
DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
break;
case TUNSETLINK:
/* Only allow setting the type when the interface is down */
if (tun->dev->flags & IFF_UP) {

2
include/linux/if_tun.h
View File

@ -36,6 +36,7 @@ struct tun_struct {
unsigned long flags;
int attached;
uid_t owner;
gid_t group;
wait_queue_head_t read_wait;
struct sk_buff_head readq;
@ -78,6 +79,7 @@ struct tun_struct {
#define TUNSETPERSIST _IOW('T', 203, int)
#define TUNSETOWNER _IOW('T', 204, int)
#define TUNSETLINK _IOW('T', 205, int)
#define TUNSETGROUP _IOW('T', 206, int)
/* TUNSETIFF ifr flags */
#define IFF_TUN 0x0001