Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755497AbbLDTDA (ORCPT ); Fri, 4 Dec 2015 14:03:00 -0500 Received: from h2.hallyn.com ([78.46.35.8]:44201 "EHLO h2.hallyn.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753023AbbLDTC6 (ORCPT ); Fri, 4 Dec 2015 14:02:58 -0500 Date: Fri, 4 Dec 2015 13:02:57 -0600 From: "Serge E. Hallyn" To: Seth Forshee Cc: "Eric W. Biederman" , Alexander Viro , Serge Hallyn , 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 Subject: Re: [PATCH 13/19] fs: Allow superblock owner to access do_remount_sb() Message-ID: <20151204190257.GD3624@mail.hallyn.com> References: <1449070821-73820-1-git-send-email-seth.forshee@canonical.com> <1449070821-73820-14-git-send-email-seth.forshee@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1449070821-73820-14-git-send-email-seth.forshee@canonical.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1994 Lines: 51 Quoting Seth Forshee (seth.forshee@canonical.com): > 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 > > -- > 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/ -- 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/