From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf1-x444.google.com ([2607:f8b0:4864:20::444]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jyggO-0004d2-Pd for kexec@lists.infradead.org; Thu, 23 Jul 2020 19:15:10 +0000 Received: by mail-pf1-x444.google.com with SMTP id t11so3491829pfq.11 for ; Thu, 23 Jul 2020 12:15:07 -0700 (PDT) Date: Thu, 23 Jul 2020 12:15:03 -0700 From: Kees Cook Subject: Re: [PATCH v2 15/18] fs/kernel_file_read: Add "offset" arg for partial reads Message-ID: <202007231131.9704A8B330@keescook> References: <20200722193020.2676422-1-keescook@chromium.org> <20200722193020.2676422-16-keescook@chromium.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Scott Branden Cc: linux-efi@vger.kernel.org, "Rafael J. Wysocki" , Peter Zijlstra , linux-fsdevel@vger.kernel.org, Stephen Boyd , SeongJae Park , Mimi Zohar , David Howells , Tushar Sugandhi , Peter Jones , linux-kselftest@vger.kernel.org, "Joel Fernandes (Google)" , Shuah Khan , Ard Biesheuvel , Thomas Cedeno , linux-security-module@vger.kernel.org, Anders Roxell , Paul Moore , Mauro Carvalho Chehab , Michael Ellerman , Nayna Jain , Matthew Garrett , James Morris , Lakshmi Ramasubramanian , Aaron Goidel , "Serge E. Hallyn" , Wenwen Wang , selinux@vger.kernel.org, Jessica Yu , Hans de Goede , Alexander Viro , Matthieu Baerts , KP Singh , Eric Paris , linux-integrity@vger.kernel.org, Florent Revest , Andrea Righi , Greg Kroah-Hartman , Stephen Smalley , Randy Dunlap , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Luis Chamberlain , Eric Biederman , Dave Olsthoorn , Dmitry Kasatkin , Casey Schaufler , Joe Perches , Andrew Morton , Thiago Jung Bauermann On Wed, Jul 22, 2020 at 03:29:26PM -0700, Scott Branden wrote: > These changes don't pass the kernel-selftest for partial reads I added > (which are at the end of this patch v2 series). Oh, interesting. Is there any feedback in dmesg? I wonder if I have the LSMs configured differently than you? > See change below added for temp workaround for issue. > > [...] > > + > > + whole_file = (offset == 0 && i_size <= buf_size); > A hack to get this passing I added which probably breaks some security? > if (whole_file) { > > + ret = security_kernel_read_file(file, id, whole_file); > > + if (ret) > > + goto out; > > + > } This would imply I did something wrong in the LSM hook refactoring (i.e. some LSM is rejecting the !whole_file case, but if the entire call to the hooks are skipped, it's okay). What does this return on your test system: echo $(cat /sys/kernel/security/lsm) (I wonder if I have IMA configured differently...) Mimi, have you had a chance to test these changes? -- Kees Cook _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec