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>
diff --git a/kernel/futex.c b/kernel/futex.c
index 8af1002..e069621 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -439,10 +439,11 @@
static struct task_struct * futex_find_get_task(pid_t pid)
{
struct task_struct *p;
+ uid_t euid = current_euid();
rcu_read_lock();
p = find_task_by_vpid(pid);
- if (!p || ((current->euid != p->euid) && (current->euid != p->uid)))
+ if (!p || (euid != p->euid && euid != p->uid))
p = ERR_PTR(-ESRCH);
else
get_task_struct(p);
@@ -1829,6 +1830,7 @@
{
struct robust_list_head __user *head;
unsigned long ret;
+ uid_t euid = current_euid();
if (!futex_cmpxchg_enabled)
return -ENOSYS;
@@ -1844,8 +1846,8 @@
if (!p)
goto err_unlock;
ret = -EPERM;
- if ((current->euid != p->euid) && (current->euid != p->uid) &&
- !capable(CAP_SYS_PTRACE))
+ if (euid != p->euid && euid != p->uid &&
+ !capable(CAP_SYS_PTRACE))
goto err_unlock;
head = p->robust_list;
rcu_read_unlock();
