From mboxrd@z Thu Jan 1 00:00:00 1970 From: Seth Forshee Subject: [PATCH RESEND v2 13/18] fs: Allow superblock owner to access do_remount_sb() Date: Mon, 4 Jan 2016 12:03:52 -0600 Message-ID: <1451930639-94331-14-git-send-email-seth.forshee@canonical.com> References: <1451930639-94331-1-git-send-email-seth.forshee@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1451930639-94331-1-git-send-email-seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: fuse-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Seth Forshee , dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Miklos Szeredi , linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, fuse-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Austin S Hemmelgarn , linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, selinux-+05T5uksL2qpZYMLLGbcSA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-raid.ids Superblock level remounts are currently restricted to global CAP_SYS_ADMIN, as is the path for changing the root mount to read only on umount. Loosen both of these permission checks to also allow CAP_SYS_ADMIN in any namespace which is privileged towards the userns which originally mounted the filesystem. Signed-off-by: Seth Forshee Acked-by: "Eric W. Biederman" Acked-by: Serge Hallyn --- fs/namespace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 18fc58760aec..b00a765895e7 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1510,7 +1510,7 @@ static int do_umount(struct mount *mnt, int flags) * Special case for "unmounting" root ... * we just try to remount it readonly. */ - if (!capable(CAP_SYS_ADMIN)) + if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) return -EPERM; down_write(&sb->s_umount); if (!(sb->s_flags & MS_RDONLY)) @@ -2199,7 +2199,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags, down_write(&sb->s_umount); if (flags & MS_BIND) err = change_mount_flags(path->mnt, flags); - else if (!capable(CAP_SYS_ADMIN)) + else if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) err = -EPERM; else err = do_remount_sb(sb, flags, data, 0); -- 1.9.1 ------------------------------------------------------------------------------ From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753000AbcADSJ7 (ORCPT ); Mon, 4 Jan 2016 13:09:59 -0500 Received: from mail-ig0-f175.google.com ([209.85.213.175]:34450 "EHLO mail-ig0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752486AbcADSEk (ORCPT ); Mon, 4 Jan 2016 13:04:40 -0500 From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Richard Weinberger , Austin S Hemmelgarn , Miklos Szeredi , linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@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 RESEND v2 13/18] fs: Allow superblock owner to access do_remount_sb() Date: Mon, 4 Jan 2016 12:03:52 -0600 Message-Id: <1451930639-94331-14-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1451930639-94331-1-git-send-email-seth.forshee@canonical.com> References: <1451930639-94331-1-git-send-email-seth.forshee@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Superblock level remounts are currently restricted to global CAP_SYS_ADMIN, as is the path for changing the root mount to read only on umount. Loosen both of these permission checks to also allow CAP_SYS_ADMIN in any namespace which is privileged towards the userns which originally mounted the filesystem. Signed-off-by: Seth Forshee Acked-by: "Eric W. Biederman" Acked-by: Serge Hallyn --- fs/namespace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 18fc58760aec..b00a765895e7 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1510,7 +1510,7 @@ static int do_umount(struct mount *mnt, int flags) * Special case for "unmounting" root ... * we just try to remount it readonly. */ - if (!capable(CAP_SYS_ADMIN)) + if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) return -EPERM; down_write(&sb->s_umount); if (!(sb->s_flags & MS_RDONLY)) @@ -2199,7 +2199,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags, down_write(&sb->s_umount); if (flags & MS_BIND) err = change_mount_flags(path->mnt, flags); - else if (!capable(CAP_SYS_ADMIN)) + else if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) err = -EPERM; else err = do_remount_sb(sb, flags, data, 0); -- 1.9.1