Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933330AbbLGV3P (ORCPT ); Mon, 7 Dec 2015 16:29:15 -0500 Received: from mail-ig0-f174.google.com ([209.85.213.174]:36745 "EHLO mail-ig0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933075AbbLGVXf (ORCPT ); Mon, 7 Dec 2015 16:23:35 -0500 From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro , Serge Hallyn Cc: Richard Weinberger , Austin S Hemmelgarn , Miklos Szeredi , linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, fuse-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, Seth Forshee Subject: [PATCH v2 11/18] fs: Ensure the mounter of a filesystem is privileged towards its inodes Date: Mon, 7 Dec 2015 15:21:20 -0600 Message-Id: <1449523289-144238-12-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1449523289-144238-1-git-send-email-seth.forshee@canonical.com> References: <1449523289-144238-1-git-send-email-seth.forshee@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2224 Lines: 62 The mounter of a filesystem should be privileged towards the inodes of that filesystem. Extend the checks in inode_owner_or_capable() and capable_wrt_inode_uidgid() to permit access by users priviliged in the user namespace of the inode's superblock. Signed-off-by: Seth Forshee Acked-by: Serge Hallyn --- fs/inode.c | 3 +++ kernel/capability.c | 13 +++++++++---- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 1be5f9003eb3..01c036fe1950 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1962,6 +1962,9 @@ bool inode_owner_or_capable(const struct inode *inode) ns = current_user_ns(); if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) return true; + + if (ns_capable(inode->i_sb->s_user_ns, CAP_FOWNER)) + return true; return false; } EXPORT_SYMBOL(inode_owner_or_capable); diff --git a/kernel/capability.c b/kernel/capability.c index 45432b54d5c6..5137a38a5670 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -437,13 +437,18 @@ EXPORT_SYMBOL(file_ns_capable); * * Return true if the current task has the given capability targeted at * its own user namespace and that the given inode's uid and gid are - * mapped into the current user namespace. + * mapped into the current user namespace, or if the current task has + * the capability towards the user namespace of the inode's superblock. */ bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) { - struct user_namespace *ns = current_user_ns(); + struct user_namespace *ns; - return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && - kgid_has_mapping(ns, inode->i_gid); + ns = current_user_ns(); + if (ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && + kgid_has_mapping(ns, inode->i_gid)) + return true; + + return ns_capable(inode->i_sb->s_user_ns, cap); } EXPORT_SYMBOL(capable_wrt_inode_uidgid); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/