CRED: Use RCU to access another task's creds and to release a task's own creds

[linux-2.6-block.git] / mm / migrate.c

diff --git a/mm/migrate.c b/mm/migrate.c
index 794443da1b4ffc336c14a5503640b3870c65b3e8..142284229ce20d3f4db8967795e32ab59ce40f35 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1045,7 +1045,7 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
                        const int __user *nodes,
                        int __user *status, int flags)
 {
-       struct cred *cred, *tcred;
+       const struct cred *cred = current_cred(), *tcred;
        struct task_struct *task;
        struct mm_struct *mm;
        int err;
@@ -1076,14 +1076,16 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
         * capabilities, superuser privileges or the same
         * userid as the target process.
         */
-       cred = current->cred;
-       tcred = task->cred;
+       rcu_read_lock();
+       tcred = __task_cred(task);
        if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
            cred->uid  != tcred->suid && cred->uid  != tcred->uid &&
            !capable(CAP_SYS_NICE)) {
+               rcu_read_unlock();
                err = -EPERM;
                goto out;
        }
+       rcu_read_unlock();
 
        err = security_task_movememory(task);
        if (err)