From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752129AbaILOm0 (ORCPT ); Fri, 12 Sep 2014 10:42:26 -0400 Received: from mail-oi0-f47.google.com ([209.85.218.47]:43278 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751242AbaILOmV (ORCPT ); Fri, 12 Sep 2014 10:42:21 -0400 From: Seth Forshee To: Miklos Szeredi , Alexander Viro , "Eric W. Biederman" Cc: Serge Hallyn , fuse-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Seth Forshee Subject: [PATCH v3 2/4] vfs,userns: Ensure real root is always capable towards inodes Date: Fri, 12 Sep 2014 09:41:43 -0500 Message-Id: <1410532905-114262-3-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1410532905-114262-1-git-send-email-seth.forshee@canonical.com> References: <1410532905-114262-1-git-send-email-seth.forshee@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently root is restricted from performing some modifications to inodes whose owner is INVALID_UID or group is INVALID_GID because this id doesn't map into any user namespace. Add a special case to the relevant checks to make sure root is always capable of performing these operations. Signed-off-by: Seth Forshee --- fs/inode.c | 3 +++ kernel/capability.c | 6 +++++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/inode.c b/fs/inode.c index 26753ba7b6d6..1029320ff029 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1840,6 +1840,9 @@ bool inode_owner_or_capable(const struct inode *inode) { struct user_namespace *ns; + if (capable(CAP_SYS_ADMIN)) + return true; + if (uid_eq(current_fsuid(), inode->i_uid)) return true; diff --git a/kernel/capability.c b/kernel/capability.c index 989f5bfc57dc..a472eaa52b6a 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -438,8 +438,12 @@ EXPORT_SYMBOL(capable); */ bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) { - struct user_namespace *ns = current_user_ns(); + struct user_namespace *ns; + if (capable(CAP_SYS_ADMIN)) + return true; + + ns = current_user_ns(); return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && kgid_has_mapping(ns, inode->i_gid); } -- 1.9.1