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, 6 insertions, 4 deletions

diff --git a/ipc/sem.c b/ipc/sem.c
index 0e0d49bbb867..ae040a0727c2 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -817,7 +817,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid,
                 }
 
                 err = -EACCES;
-                if (ipcperms (&sma->sem_perm, S_IRUGO))
+                if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
                         goto out_unlock;
 
                 err = security_sem_semctl(sma, cmd);
@@ -862,7 +862,8 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
         nsems = sma->sem_nsems;
 
         err = -EACCES;
-        if (ipcperms (&sma->sem_perm, (cmd==SETVAL||cmd==SETALL)?S_IWUGO:S_IRUGO))
+        if (ipcperms(ns, &sma->sem_perm,
+                        (cmd == SETVAL || cmd == SETALL) ? S_IWUGO : S_IRUGO))
                 goto out_unlock;
 
         err = security_sem_semctl(sma, cmd);
@@ -1047,7 +1048,8 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
                         return -EFAULT;
         }
 
-        ipcp = ipcctl_pre_down(&sem_ids(ns), semid, cmd, &semid64.sem_perm, 0);
+        ipcp = ipcctl_pre_down(ns, &sem_ids(ns), semid, cmd,
+                               &semid64.sem_perm, 0);
         if (IS_ERR(ipcp))
                 return PTR_ERR(ipcp);
 
@@ -1386,7 +1388,7 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
                 goto out_unlock_free;
 
         error = -EACCES;
-        if (ipcperms(&sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
+        if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
                 goto out_unlock_free;
 
         error = security_sem_semop(sma, sops, nsops, alter);