From 8c644623fe7e41f59fe97cdf666cba3cb7ced7d8 Mon Sep 17 00:00:00 2001 From: Guido Guenther Date: Mon, 2 Jul 2007 22:50:25 -0700 Subject: [PATCH] [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 Signed-off-by: Jeff Dike Signed-off-by: David S. Miller --- drivers/net/tun.c | 15 +++++++++++++-- include/linux/if_tun.h | 2 ++ 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index a2c6caaaae93..62b2b3005019 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -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) { diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h index 88aef7b86ef4..42eb6945b93e 100644 --- a/include/linux/if_tun.h +++ b/include/linux/if_tun.h @@ -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 -- GitLab