From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1C54CA9ED3 for ; Mon, 4 Nov 2019 21:53:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78A8321D7F for ; Mon, 4 Nov 2019 21:53:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=android.com header.i=@android.com header.b="YGooEbC/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387490AbfKDVxN (ORCPT ); Mon, 4 Nov 2019 16:53:13 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:40054 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730919AbfKDVxK (ORCPT ); Mon, 4 Nov 2019 16:53:10 -0500 Received: by mail-pl1-f194.google.com with SMTP id e3so6168419plt.7 for ; Mon, 04 Nov 2019 13:53:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8J8d9IDvRoUC4AVADMVMFKu1u3aWQelO26+oyWH8/ZU=; b=YGooEbC/FZt/rx/Q4C8AAxDrLoXSJS2L5JXBZYa+3jbO6XTOXiHGSgdAyUPSKCYK3t xKs+nz4eCsQxb3xFGOr3uyiHgaAdHoo7xAybFQLZBN0AfDW7AxTng6VRUJnfBwjuurGq 5QlYGyEizmKZkHB91EwRE9mg/r/1x65V8IESorxsBxD/VNtXAugORC3+G6tHh6tc0/b1 VsmlzpRd5j2F0FaU2WCkP5QVzIcPAAQtOPVyOICXzrOJ9L/oca3jwahTPdaMXrcob09P JAK5Ny9etwU4yLbLBNTICIRVIzEi6KCnKk0rTZS6hdYmGNPzLwWknlk2oKc+yM7v6ifB FWrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8J8d9IDvRoUC4AVADMVMFKu1u3aWQelO26+oyWH8/ZU=; b=eSSZu9suj/v0vJoBgM7jI7quWxukT1yob7Qn/QztrZ2kWdUO4E2qwyYiXdhmkOhG70 9heE5i6gv/LUYJZUjhNZdMgGBP2c45cwNmJqRNobfxj4HJggA//OGb2za2xBVeq75TQc BgoODS9KJw2P7wXo0ojEBrw3Nj37xZM2x00rxaS+9gET6Z3FLWgkdO/eJtM/i3sDoZ1R FHxYjzSjyqpB9aUdNcjgBRHHuH4n5WDkXLls3xBf7lp7x7pPj+le61F5Z3bzsTGRyOmJ HxGkjtuIxR6us1u4FuiVzyZJy4PLI8rXihoVptLFALtjfylQqJQ6wqnPgc2cL7zneuRv bovg== X-Gm-Message-State: APjAAAVb3rwv1d3egkr2keor7qOaMyolhi6Qqj2f2A20wDWkFm0u3R20 RBWoQPnQA8xOaCUjrDCPyKQWR2YAQ/V9iw== X-Google-Smtp-Source: APXvYqxX9UqKrw8lrRrBt5lN1xyC9Rblbt8uiPQ5DQtjXLaEKb4PPpnhQUllos59EPtfA5JhrETjgw== X-Received: by 2002:a17:902:521:: with SMTP id 30mr29357684plf.37.1572904389349; Mon, 04 Nov 2019 13:53:09 -0800 (PST) Received: from nebulus.mtv.corp.google.com ([2620:15c:211:200:5404:91ba:59dc:9400]) by smtp.gmail.com with ESMTPSA id e198sm19231350pfh.83.2019.11.04.13.53.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Nov 2019 13:53:08 -0800 (PST) From: Mark Salyzyn To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, Mark Salyzyn , Miklos Szeredi , Jonathan Corbet , Vivek Goyal , "Eric W . Biederman" , Amir Goldstein , Randy Dunlap , Stephen Smalley , linux-unionfs@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v15 0/4] overlayfs override_creds=off & nested get xattr fix Date: Mon, 4 Nov 2019 13:52:45 -0800 Message-Id: <20191104215253.141818-1-salyzyn@android.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Patch series: Mark Salyzyn (4): Add flags option to get xattr method paired to __vfs_getxattr overlayfs: handle XATTR_NOSECURITY flag for get xattr method overlayfs: internal getxattr operations without sepolicy checking overlayfs: override_creds=off option bypass creator_cred The first three patches address fundamental security issues that should be solved regardless of the override_creds=off feature. The fourth adds the feature depends on these other fixes. By default, all access to the upper, lower and work directories is the recorded mounter's MAC and DAC credentials. The incoming accesses are checked against the caller's credentials. If the principles of least privilege are applied for sepolicy, the mounter's credentials might not overlap the credentials of the caller's when accessing the overlayfs filesystem. For example, a file that a lower DAC privileged caller can execute, is MAC denied to the generally higher DAC privileged mounter, to prevent an attack vector. We add the option to turn off override_creds in the mount options; all subsequent operations after mount on the filesystem will be only the caller's credentials. The module boolean parameter and mount option override_creds is also added as a presence check for this "feature", existence of /sys/module/overlay/parameters/overlay_creds Signed-off-by: Mark Salyzyn Cc: Miklos Szeredi Cc: Jonathan Corbet Cc: Vivek Goyal Cc: Eric W. Biederman Cc: Amir Goldstein Cc: Randy Dunlap Cc: Stephen Smalley Cc: linux-unionfs@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- v15 - Revert back to v4 with fixes from on the way from v5-v14. The single structure argument passing to address the complaints about too many arguments was rejected by the community. - Drop the udner discussion fix for an additional CAP_DAC_READ_SEARCH check. Can address that independently. - ToDo: upstream test frame for thes security fixes (currently testing is all in Android). v14: - Rejoin, rebase and a few adjustments. v13: - Pull out first patch and try to get it in alone feedback, some Acks, and then because people forgot why we were doing i. v12: - Restore squished out patch 2 and 3 in the series, then change algorithm to add flags argument. Per-thread flag is a large security surface. v11: - Squish out v10 introduced patch 2 and 3 in the series, then and use per-thread flag instead for nesting. - Switch name to ovl_do_vds_getxattr for __vds_getxattr wrapper. - Add sb argument to ovl_revert_creds to match future work. v10: - Return NULL on CAP_DAC_READ_SEARCH - Add __get xattr method to solve sepolicy logging issue - Drop unnecessary sys_admin sepolicy checking for administrative driver internal xattr functions. v6: - Drop CONFIG_OVERLAY_FS_OVERRIDE_CREDS. - Do better with the documentation, drop rationalizations. - pr_warn message adjusted to report consequences. v5: - beefed up the caveats in the Documentation - Is dependent on "overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh" "overlayfs: check CAP_MKNOD before issuing vfs_whiteout" - Added prwarn when override_creds=off v4: - spelling and grammar errors in text v3: - Change name from caller_credentials / creator_credentials to the boolean override_creds. - Changed from creator to mounter credentials. - Updated and fortified the documentation. - Added CONFIG_OVERLAY_FS_OVERRIDE_CREDS v2: - Forward port changed attr to stat, resulting in a build error. - altered commit message. Documentation/filesystems/locking.rst | 2 +- Documentation/filesystems/overlayfs.txt | 23 ++++++++++++++++ fs/9p/acl.c | 3 ++- fs/9p/xattr.c | 3 ++- fs/afs/xattr.c | 26 +++++++++--------- fs/btrfs/xattr.c | 3 ++- fs/ceph/xattr.c | 3 ++- fs/cifs/xattr.c | 2 +- fs/ecryptfs/inode.c | 6 +++-- fs/ecryptfs/mmap.c | 2 +- fs/erofs/xattr.c | 3 ++- fs/ext2/xattr_security.c | 2 +- fs/ext2/xattr_trusted.c | 2 +- fs/ext2/xattr_user.c | 2 +- fs/ext4/xattr_security.c | 2 +- fs/ext4/xattr_trusted.c | 2 +- fs/ext4/xattr_user.c | 2 +- fs/f2fs/xattr.c | 4 +-- fs/fuse/xattr.c | 4 +-- fs/gfs2/xattr.c | 3 ++- fs/hfs/attr.c | 2 +- fs/hfsplus/xattr.c | 3 ++- fs/hfsplus/xattr_security.c | 3 ++- fs/hfsplus/xattr_trusted.c | 3 ++- fs/hfsplus/xattr_user.c | 3 ++- fs/jffs2/security.c | 3 ++- fs/jffs2/xattr_trusted.c | 3 ++- fs/jffs2/xattr_user.c | 3 ++- fs/jfs/xattr.c | 5 ++-- fs/kernfs/inode.c | 3 ++- fs/nfs/nfs4proc.c | 6 +++-- fs/ocfs2/xattr.c | 9 ++++--- fs/orangefs/xattr.c | 3 ++- fs/overlayfs/copy_up.c | 2 +- fs/overlayfs/dir.c | 17 +++++++----- fs/overlayfs/file.c | 20 +++++++------- fs/overlayfs/inode.c | 23 ++++++++-------- fs/overlayfs/namei.c | 18 +++++++------ fs/overlayfs/overlayfs.h | 11 +++++++- fs/overlayfs/ovl_entry.h | 1 + fs/overlayfs/readdir.c | 4 +-- fs/overlayfs/super.c | 34 ++++++++++++++++++----- fs/overlayfs/util.c | 30 +++++++++++++-------- fs/posix_acl.c | 2 +- fs/reiserfs/xattr_security.c | 3 ++- fs/reiserfs/xattr_trusted.c | 3 ++- fs/reiserfs/xattr_user.c | 3 ++- fs/squashfs/xattr.c | 2 +- fs/ubifs/xattr.c | 3 ++- fs/xattr.c | 36 ++++++++++++------------- fs/xfs/xfs_xattr.c | 3 ++- include/linux/xattr.h | 9 ++++--- include/uapi/linux/xattr.h | 7 +++-- mm/shmem.c | 3 ++- net/socket.c | 3 ++- security/commoncap.c | 6 +++-- security/integrity/evm/evm_main.c | 3 ++- security/selinux/hooks.c | 11 +++++--- security/smack/smack_lsm.c | 5 ++-- 59 files changed, 261 insertions(+), 149 deletions(-) -- 2.24.0.rc1.363.gb1bccd3e3d-goog