9p: do not crash on unknown lock status code

Current 9p implementation will crash whole system if sees unknown lock status code. It's trivial target for DOS: 9p server can produce such code easily. Let's fallback more gracefully: warning in dmesg + -ENOLCK. Signed-off-by: Kirill A. Shutemov <[email protected]> Signed-off-by: Dominique Martinet <[email protected]> Signed-off-by: Eric Van Hensbergen <[email protected]>
zuai · Mar 20, 2015 · b642f72 · b642f72
1 parent ad80492
commit b642f72
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
@@ -212,12 +212,13 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
 	case P9_LOCK_BLOCKED:
 		res = -EAGAIN;
 		break;
+	default:
+		WARN_ONCE(1, "unknown lock status code: %d\n", status);
+		/* fallthough */
 	case P9_LOCK_ERROR:
 	case P9_LOCK_GRACE:
 		res = -ENOLCK;
 		break;
-	default:
-		BUG();
 	}
 
 out_unlock: