From: Mimi Zohar <zohar@kernel.org>
To: Scott Branden <scott.branden@broadcom.com>,
Luis Chamberlain <mcgrof@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
David Brown <david.brown@linaro.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Shuah Khan <shuah@kernel.org>,
bjorn.andersson@linaro.org,
Shuah Khan <skhan@linuxfoundation.org>,
Arnd Bergmann <arnd@arndb.de>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
Olof Johansson <olof@lixom.net>,
Andrew Morton <akpm@linux-foundation.org>,
Dan Carpenter <dan.carpenter@oracle.com>,
Colin Ian King <colin.king@canonical.com>,
Kees Cook <keescook@chromium.org>, Takashi Iwai <tiwai@suse.de>,
linux-kselftest@vger.kernel.org, Andy Gross <agross@kernel.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
linux-integrity <linux-integrity@vger.kernel.org>
Subject: Re: [PATCH v5 1/7] fs: introduce kernel_pread_file* support
Date: Wed, 13 May 2020 17:20:14 -0400 [thread overview]
Message-ID: <1589404814.5098.185.camel@kernel.org> (raw)
In-Reply-To: <a228ae0f-d551-e0e8-446e-5ae63462c520@broadcom.com>
On Wed, 2020-05-13 at 12:41 -0700, Scott Branden wrote:
>
> On 2020-05-13 12:39 p.m., Mimi Zohar wrote:
> > On Wed, 2020-05-13 at 12:18 -0700, Scott Branden wrote:
> >> On 2020-05-13 12:03 p.m., Mimi Zohar wrote:
> >>> On Wed, 2020-05-13 at 11:53 -0700, Scott Branden wrote:
> >> Even if the kernel successfully verified the firmware file signature it
> >> would just be wasting its time. The kernel in these use cases is not always
> >> trusted. The device needs to authenticate the firmware image itself.
> > There are also environments where the kernel is trusted and limits the
> > firmware being provided to the device to one which they signed.
> >
> >>> The device firmware is being downloaded piecemeal from somewhere and
> >>> won't be measured?
> >> It doesn't need to be measured for current driver needs.
> > Sure the device doesn't need the kernel measuring the firmware, but
> > hardened environments do measure firmware.
> >
> >> If someone has such need the infrastructure could be added to the kernel
> >> at a later date. Existing functionality is not broken in any way by
> >> this patch series.
> > Wow! You're saying that your patch set takes precedence over the
> > existing expectations and can break them.
> Huh? I said existing functionality is NOT broken by this patch series.
Assuming a system is configured to measure and appraise firmware
(rules below), with this change the firmware file will not be properly
measured and will fail signature verification.
Sample IMA policy rules:
measure func=FIRMWARE_CHECK
appraise func=FIRMWARE_CHECK appraise_type=imasig
Mimi
next prev parent reply other threads:[~2020-05-13 21:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200508002739.19360-1-scott.branden@broadcom.com>
[not found] ` <20200508002739.19360-2-scott.branden@broadcom.com>
2020-05-13 18:39 ` [PATCH v5 1/7] fs: introduce kernel_pread_file* support Mimi Zohar
2020-05-13 18:53 ` Scott Branden
2020-05-13 18:57 ` Scott Branden
2020-05-13 19:03 ` Mimi Zohar
2020-05-13 19:18 ` Scott Branden
2020-05-13 19:39 ` Mimi Zohar
2020-05-13 19:41 ` Scott Branden
2020-05-13 21:20 ` Mimi Zohar [this message]
2020-05-13 21:28 ` Luis Chamberlain
2020-05-13 22:12 ` Mimi Zohar
2020-05-13 22:48 ` Scott Branden
2020-05-13 23:00 ` Mimi Zohar
2020-05-13 23:34 ` Kees Cook
2020-05-13 23:58 ` Mimi Zohar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1589404814.5098.185.camel@kernel.org \
--to=zohar@kernel.org \
--cc=agross@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=bcm-kernel-feedback-list@broadcom.com \
--cc=bjorn.andersson@linaro.org \
--cc=colin.king@canonical.com \
--cc=dan.carpenter@oracle.com \
--cc=david.brown@linaro.org \
--cc=gregkh@linuxfoundation.org \
--cc=keescook@chromium.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=mcgrof@kernel.org \
--cc=olof@lixom.net \
--cc=rafael@kernel.org \
--cc=scott.branden@broadcom.com \
--cc=shuah@kernel.org \
--cc=skhan@linuxfoundation.org \
--cc=tiwai@suse.de \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).