Merge branch 'stable-4.11' of git://git.infradead.org/users/pcmoore/selinux into next

1 files changed, 9 insertions, 4 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 8e7e61b..988c5a7 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2488,6 +2488,12 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
 	length = -ESRCH;
 	if (!task)
 		goto out_no_task;
+
+	/* A task may only write its own attributes. */
+	length = -EACCES;
+	if (current != task)
+		goto out;
+
 	if (count > PAGE_SIZE)
 		count = PAGE_SIZE;
 
@@ -2503,14 +2509,13 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
 	}
 
 	/* Guard against adverse ptrace interaction */
-	length = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
+	length = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
 	if (length < 0)
 		goto out_free;
 
-	length = security_setprocattr(task,
-				      (char*)file->f_path.dentry->d_name.name,
+	length = security_setprocattr(file->f_path.dentry->d_name.name,
 				      page, count);
-	mutex_unlock(&task->signal->cred_guard_mutex);
+	mutex_unlock(&current->signal->cred_guard_mutex);
 out_free:
 	kfree(page);
 out: