CRED: Wrap task credential accesses in the core kernel

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-audit@redhat.com
Cc: containers@lists.linux-foundation.org
Cc: linux-mm@kvack.org
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index 04ac3a9e42cf..3254d4e41e88 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -135,6 +135,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
 {
         struct compat_robust_list_head __user *head;
         unsigned long ret;
+        uid_t euid = current_euid();
 
         if (!futex_cmpxchg_enabled)
                 return -ENOSYS;
@@ -150,7 +151,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
                 if (!p)
                         goto err_unlock;
                 ret = -EPERM;
-                if ((current->euid != p->euid) && (current->euid != p->uid) &&
+                if (euid != p->euid && euid != p->uid &&
                                 !capable(CAP_SYS_PTRACE))
                         goto err_unlock;
                 head = p->compat_robust_list;