From patchwork Mon Mar 7 22:35:35 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 593457 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 8BFE214017E; Tue, 8 Mar 2016 09:44:46 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ad3tL-00045c-IJ; Mon, 07 Mar 2016 22:44:43 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1ad3kZ-0007q2-Ds for kernel-team@lists.ubuntu.com; Mon, 07 Mar 2016 22:35:39 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ad3kY-0007bg-Vz; Mon, 07 Mar 2016 22:35:39 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1ad3kW-0000bS-9h; Mon, 07 Mar 2016 14:35:36 -0800 From: Kamal Mostafa To: Al Viro Subject: [4.2.y-ckt stable] Patch "should_follow_link(): validate ->d_seq after having decided to follow" has been added to the 4.2.y-ckt tree Date: Mon, 7 Mar 2016 14:35:35 -0800 Message-Id: <1457390135-2273-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 X-Extended-Stable: 4.2 Cc: Kamal Mostafa , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled should_follow_link(): validate ->d_seq after having decided to follow to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt5. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 06c2dfc05ebf63838350a7d2571a2cdf56fcd008 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 27 Feb 2016 19:31:01 -0500 Subject: should_follow_link(): validate ->d_seq after having decided to follow 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(+) -- 2.7.0 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); }