userns: user namespaces: convert several capable() calls

CAP_IPC_OWNER and CAP_IPC_LOCK can be checked against current_user_ns(),
because the resource comes from current's own ipc namespace.

setuid/setgid are to uids in own namespace, so again checks can be against
current_user_ns().

Changelog:
	Jan 11: Use task_ns_capable() in place of sched_capable().
	Jan 11: Use nsown_capable() as suggested by Bastian Blank.
	Jan 11: Clarify (hopefully) some logic in futex and sched.c
	Feb 15: use ns_capable for ipc, not nsown_capable
	Feb 23: let copy_ipcs handle setting ipc_ns->user_ns
	Feb 23: pass ns down rather than taking it from current

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index 7d3bb22a9302..8644452f5c4c 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -623,7 +623,8 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
                         return -EFAULT;
         }
 
-        ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
+        ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
+                               &shmid64.shm_perm, 0);
         if (IS_ERR(ipcp))
                 return PTR_ERR(ipcp);
 
@@ -737,7 +738,7 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
                         result = 0;
                 }
                 err = -EACCES;
-                if (ipcperms (&shp->shm_perm, S_IRUGO))
+                if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
                         goto out_unlock;
                 err = security_shm_shmctl(shp, cmd);
                 if (err)
@@ -773,7 +774,7 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 
                 audit_ipc_obj(&(shp->shm_perm));
 
-                if (!capable(CAP_IPC_LOCK)) {
+                if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
                         uid_t euid = current_euid();
                         err = -EPERM;
                         if (euid != shp->shm_perm.uid &&
@@ -888,7 +889,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
         }
 
         err = -EACCES;
-        if (ipcperms(&shp->shm_perm, acc_mode))
+        if (ipcperms(ns, &shp->shm_perm, acc_mode))
                 goto out_unlock;
 
         err = security_shm_shmat(shp, shmaddr, shmflg);