Re: [PATCH v2 39/39] tests: add vfs/idmapped mounts test suite

From: Kees Cook <keescook@chromium.org>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: "Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Christoph Hellwig" <hch@infradead.org>,
	linux-fsdevel@vger.kernel.org,
	"John Johansen" <john.johansen@canonical.com>,
	"James Morris" <jmorris@namei.org>,
	"Mimi Zohar" <zohar@linux.ibm.com>,
	"Dmitry Kasatkin" <dmitry.kasatkin@gmail.com>,
	"Stephen Smalley" <stephen.smalley.work@gmail.com>,
	"Casey Schaufler" <casey@schaufler-ca.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Andreas Dilger" <adilger.kernel@dilger.ca>,
	"OGAWA Hirofumi" <hirofumi@mail.parknet.co.jp>,
	"Geoffrey Thomas" <geofft@ldpreload.com>,
	"Mrunal Patel" <mpatel@redhat.com>,
	"Josh Triplett" <josh@joshtriplett.org>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Theodore Tso" <tytso@mit.edu>, "Alban Crequy" <alban@kinvolk.io>,
	"Tycho Andersen" <tycho@tycho.ws>,
	"David Howells" <dhowells@redhat.com>,
	"James Bottomley" <James.Bottomley@hansenpartnership.com>,
	"Jann Horn" <jannh@google.com>,
	"Seth Forshee" <seth.forshee@canonical.com>,
	"Stéphane Graber" <stgraber@ubuntu.com>,
	"Aleksa Sarai" <cyphar@cyphar.com>,
	"Lennart Poettering" <lennart@poettering.net>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	smbarber@chromium.org, "Phil Estes" <estesp@gmail.com>,
	"Serge Hallyn" <serge@hallyn.com>, "Todd Kjos" <tkjos@google.com>,
	"Jonathan Corbet" <corbet@lwn.net>,
	containers@lists.linux-foundation.org,
	linux-security-module@vger.kernel.org, linux-api@vger.kernel.org,
	linux-ext4@vger.kernel.org, linux-audit@redhat.com,
	linux-integrity@vger.kernel.org, selinux@vger.kernel.org,
	"Christoph Hellwig" <hch@lst.de>
Subject: Re: [PATCH v2 39/39] tests: add vfs/idmapped mounts test suite
Date: Fri, 20 Nov 2020 13:15:57 -0800	[thread overview]
Message-ID: <202011201300.B158F1E4B@keescook> (raw)
In-Reply-To: <20201115103718.298186-40-christian.brauner@ubuntu.com>

On Sun, Nov 15, 2020 at 11:37:18AM +0100, Christian Brauner wrote:
> This adds a whole test suite for idmapped mounts but in order to ensure that
> there are no regression for the vfs itself it also includes tests for correct
> functionality on non-idmapped mounts. The following tests are currently
> available with more to come in the future:

Awesome! :)

Some glitches in the build, though... something about the ordering or
the Make rules produces odd results on a failure:

$ make
gcc -g -I../../../../usr/include/ -Wall -O2 -pthread    xattr.c internal.h utils.c utils.h -lcap -o /home/kees/src/linux-build/seccomp/tools/testing/selftests/idmap_mounts/xattr
gcc -g -I../../../../usr/include/ -Wall -O2 -pthread    core.c internal.h utils.c utils.h -lcap -o /home/kees/src/linux-build/seccomp/tools/testing/selftests/idmap_mounts/core
core.c:19:10: fatal error: sys/acl.h: No such file or directory
   19 | #include <sys/acl.h>
      |          ^~~~~~~~~~~
compilation terminated.
make: *** [../lib.mk:139: /home/kees/src/linux-build/seccomp/tools/testing/selftests/idmap_mounts/core]
Error 1
$ make
make: Nothing to be done for 'all'.
$ file xattr core
xattr: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=7a3c1951e54f20e657b4181c1be77c7183a54f81, for GNU/Linux 3.2.0, with debug_info, not stripped
core:  GCC precompiled header (version 014) for C

Even after I install libacl1-dev, I still get a "core" file output which
breaks attempts to build again. :)

Is there any way to have the test suite not depend on
__NR_mount_setattr? Running this test on older kernels fails everything.

-- 
Kees Cook