From patchwork Wed Jul 6 18:12:01 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 9216827 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A1A6160752 for ; Wed, 6 Jul 2016 18:25:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 971BE28335 for ; Wed, 6 Jul 2016 18:25:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8BCB42833F; Wed, 6 Jul 2016 18:25:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4EC1428335 for ; Wed, 6 Jul 2016 18:25:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755452AbcGFSZA (ORCPT ); Wed, 6 Jul 2016 14:25:00 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:33491 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751171AbcGFSY7 (ORCPT ); Wed, 6 Jul 2016 14:24:59 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out01.mta.xmission.com with esmtps (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1bKrVF-0000CM-Ky; Wed, 06 Jul 2016 12:24:53 -0600 Received: from 67-3-204-119.omah.qwest.net ([67.3.204.119] helo=x220.int.ebiederm.org) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1bKrVE-00055P-QR; Wed, 06 Jul 2016 12:24:53 -0600 From: "Eric W. Biederman" To: Linux Containers Cc: Seth Forshee , linux-fsdevel@vger.kernel.org, Linux API , James Bottomley , Djalal Harouni , "Serge E. Hallyn" , Andy Lutomirski , Jan Kara , Jann Horn , Michael Kerrisk Date: Wed, 6 Jul 2016 13:12:01 -0500 Message-Id: <20160706181212.16267-1-ebiederm@xmission.com> X-Mailer: git-send-email 2.8.3 In-Reply-To: <874m82bptc.fsf@x220.int.ebiederm.org> References: <874m82bptc.fsf@x220.int.ebiederm.org> X-XM-SPF: eid=1bKrVE-00055P-QR; ; ; mid=<20160706181212.16267-1-ebiederm@xmission.com>; ; ; hst=in01.mta.xmission.com; ; ; ip=67.3.204.119; ; ; frm=ebiederm@xmission.com; ; ; spf=neutral X-XM-AID: U2FsdGVkX18Axl6x1duWcJ+HfWr8I8TXtSlxG0kKdRQ= X-SA-Exim-Connect-IP: 67.3.204.119 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH review 01/12] fs: Refuse uid/gid changes which don't map into s_user_ns X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Seth Forshee Add checks to notify_change to verify that uid and gid changes will map into the superblock's user namespace. If they do not fail with -EOVERFLOW. This is mandatory so that fileystems don't have to even think of dealing with ia_uid and ia_gid that --EWB Moved the test from inode_change_ok to notify_change Signed-off-by: Seth Forshee Acked-by: Serge Hallyn Signed-off-by: Eric W. Biederman --- fs/attr.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/attr.c b/fs/attr.c index 25b24d0f6c88..dd723578ddce 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -255,6 +255,17 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID))) return 0; + /* + * Verify that uid/gid changes are valid in the target + * namespace of the superblock. + */ + if (ia_valid & ATTR_UID && + !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid)) + return -EOVERFLOW; + if (ia_valid & ATTR_GID && + !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid)) + return -EOVERFLOW; + error = security_inode_setattr(dentry, attr); if (error) return error;