Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (105 commits)
  SELinux: don't check permissions for kernel mounts
  security: pass mount flags to security_sb_kern_mount()
  SELinux: correctly detect proc filesystems of the form "proc/foo"
  Audit: Log TIOCSTI
  user namespaces: document CFS behavior
  user namespaces: require cap_set{ug}id for CLONE_NEWUSER
  user namespaces: let user_ns be cloned with fairsched
  CRED: fix sparse warnings
  User namespaces: use the current_user_ns() macro
  User namespaces: set of cleanups (v2)
  nfsctl: add headers for credentials
  coda: fix creds reference
  capabilities: define get_vfs_caps_from_disk when file caps are not enabled
  CRED: Allow kernel services to override LSM settings for task actions
  CRED: Add a kernel_service object class to SELinux
  CRED: Differentiate objective and effective subjective credentials on a task
  CRED: Documentation
  CRED: Use creds in file structs
  CRED: Prettify commoncap.c
  CRED: Make execve() take advantage of copy-on-write credentials
  ...

1 files changed, 21 insertions, 5 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index e4bb1dd7b308..33cf4a1cbcd1 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -345,7 +345,9 @@ static inline struct task_group *task_group(struct task_struct *p)
 	struct task_group *tg;
 
 #ifdef CONFIG_USER_SCHED
-	tg = p->user->tg;
+	rcu_read_lock();
+	tg = __task_cred(p)->user->tg;
+	rcu_read_unlock();
 #elif defined(CONFIG_CGROUP_SCHED)
 	tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
 				struct task_group, css);
@@ -5134,6 +5136,22 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
 	set_load_weight(p);
 }
 
+/*
+ * check the target process has a UID that matches the current process's
+ */
+static bool check_same_owner(struct task_struct *p)
+{
+	const struct cred *cred = current_cred(), *pcred;
+	bool match;
+
+	rcu_read_lock();
+	pcred = __task_cred(p);
+	match = (cred->euid == pcred->euid ||
+		 cred->euid == pcred->uid);
+	rcu_read_unlock();
+	return match;
+}
+
 static int __sched_setscheduler(struct task_struct *p, int policy,
 				struct sched_param *param, bool user)
 {
@@ -5193,8 +5211,7 @@ recheck:
 			return -EPERM;
 
 		/* can't change other user's priorities */
-		if ((current->euid != p->euid) &&
-		    (current->euid != p->uid))
+		if (!check_same_owner(p))
 			return -EPERM;
 	}
 
@@ -5426,8 +5443,7 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
 	read_unlock(&tasklist_lock);
 
 	retval = -EPERM;
-	if ((current->euid != p->euid) && (current->euid != p->uid) &&
-			!capable(CAP_SYS_NICE))
+	if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
 		goto out_unlock;
 
 	retval = security_task_setscheduler(p, 0, NULL);