[PATCH] selinux: fix tty locking

Take tty_mutex when accessing ->signal->tty in selinux code. Noted by Alan Cox. Longer term, we are looking at refactoring the code to provide better encapsulation of the tty layer, but this is a simple fix that addresses the immediate bug. Signed-off-by: Stephen Smalley <[email protected]> Acked-by: Alan Cox <[email protected]> Acked-by: James Morris <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
redpig · Sep 26, 2006 · b20c812 · b20c812
1 parent bc7e982
commit b20c812
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
@@ -1689,10 +1689,12 @@ static inline void flush_unauthorized_files(struct files_struct * files)
 {
 	struct avc_audit_data ad;
 	struct file *file, *devnull = NULL;
-	struct tty_struct *tty = current->signal->tty;
+	struct tty_struct *tty;
 	struct fdtable *fdt;
 	long j = -1;
 
+	mutex_lock(&tty_mutex);
+	tty = current->signal->tty;
 	if (tty) {
 		file_list_lock();
 		file = list_entry(tty->tty_files.next, typeof(*file), f_u.fu_list);
@@ -1712,6 +1714,7 @@ static inline void flush_unauthorized_files(struct files_struct * files)
 		}
 		file_list_unlock();
 	}
+	mutex_unlock(&tty_mutex);
 
 	/* Revalidate access to inherited open files. */