From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933053AbcCGXVy (ORCPT ); Mon, 7 Mar 2016 18:21:54 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:39618 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754002AbcCGWzZ (ORCPT ); Mon, 7 Mar 2016 17:55:25 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Al Viro , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 217/273] should_follow_link(): validate ->d_seq after having decided to follow Date: Mon, 7 Mar 2016 14:50:08 -0800 Message-Id: <1457391064-6660-218-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457391064-6660-1-git-send-email-kamal@canonical.com> References: <1457391064-6660-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Al Viro commit a7f775428b8f5808815c0e3004020cedb94cbe3b upstream. ... otherwise d_is_symlink() above might have nothing to do with the inode value we've got. Signed-off-by: Al Viro Signed-off-by: Kamal Mostafa --- fs/namei.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index 1047096..414561f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1714,6 +1714,11 @@ static inline int should_follow_link(struct nameidata *nd, struct path *link, return 0; if (!follow) return 0; + /* make sure that d_is_symlink above matches inode */ + if (nd->flags & LOOKUP_RCU) { + if (read_seqcount_retry(&link->dentry->d_seq, seq)) + return -ECHILD; + } return pick_link(nd, link, inode, seq); } -- 2.7.0