From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934551AbbLPRtK (ORCPT ); Wed, 16 Dec 2015 12:49:10 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:50129 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966612AbbLPRkw (ORCPT ); Wed, 16 Dec 2015 12:40:52 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Miklos Szeredi , Al Viro , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 110/128] ovl: fix permission checking for setattr Date: Wed, 16 Dec 2015 09:39:10 -0800 Message-Id: <1450287568-19808-111-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1450287568-19808-1-git-send-email-kamal@canonical.com> References: <1450287568-19808-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt12 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi commit acff81ec2c79492b180fade3c2894425cd35a545 upstream. [Al Viro] The bug is in being too enthusiastic about optimizing ->setattr() away - instead of "copy verbatim with metadata" + "chmod/chown/utimes" (with the former being always safe and the latter failing in case of insufficient permissions) it tries to combine these two. Note that copyup itself will have to do ->setattr() anyway; _that_ is where the elevated capabilities are right. Having these two ->setattr() (one to set verbatim copy of metadata, another to do what overlayfs ->setattr() had been asked to do in the first place) combined is where it breaks. Signed-off-by: Miklos Szeredi Signed-off-by: Al Viro Signed-off-by: Kamal Mostafa --- fs/overlayfs/inode.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 07d74b2..8525e67 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -49,13 +49,13 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) if (err) goto out; - upperdentry = ovl_dentry_upper(dentry); - if (upperdentry) { + err = ovl_copy_up(dentry); + if (!err) { + upperdentry = ovl_dentry_upper(dentry); + mutex_lock(&upperdentry->d_inode->i_mutex); err = notify_change(upperdentry, attr, NULL); mutex_unlock(&upperdentry->d_inode->i_mutex); - } else { - err = ovl_copy_up_last(dentry, attr, false); } ovl_drop_write(dentry); out: -- 1.9.1