Re: [PATCH v3 00/19] Introduce partial kernel_read_file() support

Scott Branden
2020-07-27T19:18:44Z

Hi Mimi/Kees,

On 2020-07-27 4:16 a.m., Mimi Zohar wrote:
> On Fri, 2020-07-24 at 14:36 -0700, Kees Cook wrote:
>> v3:
>> - add reviews/acks
>> - add "IMA: Add support for file reads without contents" patch
>> - trim CC list, in case that's why vger ignored v2
>> v2: [missing from lkml archives! (CC list too long?) repeating changes here]
>> - fix issues in firmware test suite
>> - add firmware partial read patches
>> - various bug fixes/cleanups
>> v1: https://lore.kernel.org/lkml/20200717174309.1164575-1-keescook@chromium.org/
>>
>> Hi,
>>
>> Here's my tree for adding partial read support in kernel_read_file(),
>> which fixes a number of issues along the way. It's got Scott's firmware
>> and IMA patches ported and everything tests cleanly for me (even with
>> CONFIG_IMA_APPRAISE=y).
> Thanks, Kees.  Other than my comments on the new
> security_kernel_post_load_data() hook, the patch set is really nice.
>
> In addition to compiling with CONFIG_IMA_APPRAISE enabled, have you
> booted the kernel with the ima_policy=tcb?  The tcb policy will add
> measurements to the IMA measurement list and extend the TPM with the
> file or buffer data digest.  Are you seeing the firmware measurements,
> in particular the partial read measurement?
I booted the kernel with ima_policy=tcb.

Unfortunately after enabling the following, fw_run_tests.sh does not run.

mkdir /sys/kernel/security
mount -t securityfs securityfs /sys/kernel/security
echo "measure func=FIRMWARE_CHECK" > /sys/kernel/security/ima/policy
echo "appraise func=FIRMWARE_CHECK appraise_type=imasig" > /sys/kernel/security/ima/policy
./fw_run_tests.sh

[ 1296.258052] test_firmware: loading 'test-firmware.bin'
[ 1296.263903] misc test_firmware: loading /lib/firmware/test-firmware.bin failed with error -13
[ 1296.263905] audit: type=1800 audit(1595905754.266:9): pid=5696 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=appraise_data cause=IMA-signature-required comm="fw_namespace" name="/lib/firmware/test-firmware.bin" dev="tmpfs" ino=4592 res=0
[ 1296.297085] misc test_firmware: Direct firmware load for test-firmware.bin failed with error -13
[ 1296.305947] test_firmware: load of 'test-firmware.bin' failed: -13

>
> thanks,
>
> Mimi