userns: Allow unprivileged use of setns.

- Push the permission check from the core setns syscall into
  the setns install methods where the user namespace of the
  target namespace can be determined, and used in a ns_capable
  call.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 0 insertions, 3 deletions

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index a214e0e9035f..4357a0a7d17d 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -242,9 +242,6 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype)
         struct file *file;
         int err;
 
-        if (!capable(CAP_SYS_ADMIN))
-                return -EPERM;
-
         file = proc_ns_fget(fd);
         if (IS_ERR(file))
                 return PTR_ERR(file);