| Message ID | 151852145162.22861.16732260881858951214.stgit@localhost.localdomain |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | Add ioctl() SIOCGSKNS cmd to allow obtaining net ns of tun device | expand |
Hi Kirill,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on net-next/master]
url: https://github.com/0day-ci/linux/commits/Kirill-Tkhai/net-Make-extern-and-export-get_net_ns/20180214-183342
config: x86_64-lkp (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All errors (new ones prefixed by >>):
>> ERROR: "open_related_ns" [drivers/net/tun.ko] undefined!
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
On 14.02.2018 15:27, kbuild test robot wrote: > Hi Kirill, > > Thank you for the patch! Yet something to improve: > > [auto build test ERROR on net-next/master] > > url: https://github.com/0day-ci/linux/commits/Kirill-Tkhai/net-Make-extern-and-export-get_net_ns/20180214-183342 > config: x86_64-lkp (attached as .config) > compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 > reproduce: > # save the attached .config to linux build tree > make ARCH=x86_64 > > All errors (new ones prefixed by >>): > >>> ERROR: "open_related_ns" [drivers/net/tun.ko] undefined! Thanks for reporting this. open_related_ns() also has to be exported. I'll send v2 of the patchset. Kirill
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 81e6cc951e7f..8e9a0ac644d2 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -78,6 +78,7 @@ #include <linux/mutex.h> #include <linux/uaccess.h> +#include <linux/proc_fs.h> /* Uncomment to enable debugging */ /* #define TUN_DEBUG 1 */ @@ -2793,6 +2794,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, struct tun_struct *tun; void __user* argp = (void __user*)arg; struct ifreq ifr; + struct net *net; kuid_t owner; kgid_t group; int sndbuf; @@ -2801,7 +2803,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, int le; int ret; - if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || _IOC_TYPE(cmd) == SOCK_IOC_TYPE) { + if (cmd == TUNSETIFF || cmd == TUNSETQUEUE || + (_IOC_TYPE(cmd) == SOCK_IOC_TYPE && cmd != SIOCGSKNS)) { if (copy_from_user(&ifr, argp, ifreq_len)) return -EFAULT; } else { @@ -2821,6 +2824,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, rtnl_lock(); tun = tun_get(tfile); + net = sock_net(&tfile->sk); if (cmd == TUNSETIFF) { ret = -EEXIST; if (tun) @@ -2828,7 +2832,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ifr.ifr_name[IFNAMSIZ-1] = '\0'; - ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr); + ret = tun_set_iff(net, file, &ifr); if (ret) goto unlock; @@ -2850,6 +2854,14 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, tfile->ifindex = ifindex; goto unlock; } + if (cmd == SIOCGSKNS) { + ret = -EPERM; + if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) + goto unlock; + + ret = open_related_ns(&net->ns, get_net_ns); + goto unlock; + } ret = -EBADFD; if (!tun)
This patch adds possibility to get tun device's net namespace fd in the same way we allow to do that for sockets. Socket ioctl numbers do not intersect with tun-specific, and there is already SIOCSIFHWADDR used in tun code. So, SIOCGSKNS number is choosen instead of custom-made for this functionality. Note, that open_related_ns() uses plain get_net_ns() and it's safe (net can't be already dead at this moment): tun socket is allocated via sk_alloc() with zero last arg (kern = 0). So, each alive socket increments net::count, and the socket is definitely alive during ioctl syscall. Also, common variable net is introduced, so small cleanup in TUNSETIFF is made. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> --- drivers/net/tun.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)