Re: [PATCH v2 15/18] fs/kernel_file_read: Add "offset" arg for partial reads

Scott Branden
2020-07-24T05:46:39Z

On 2020-07-23 12:17 p.m., Kees Cook wrote:
> On Wed, Jul 22, 2020 at 11:23:43PM -0700, Scott Branden wrote:
>> I made an adjustment in the logic of the driver with use of
>> request_partial_firmware_into_buf and now everything is working.
> Excellent! Was there something wrong with how I ported the
> request_partial_firmware_into_buf() changes? (Should the behavior be
> changed in some way? I didn't change the self-tests, so I thought the
> behavior matched your original series.)
The change in behaviour is fw->fw_size used to indicate the position in
the file after the partial read completes.
Your version has fw->fw_size indicate the amount of data read.
No need for you to change anything.  I just need a local variable now to
keep track of where I left off in the file.
>
>> So only issue I find with this entire patch series is the problem
>> of security failing without the workaround below.
> Yup; I'm trying to reproduce this now too...
I replied in the other email with details and the dmesg log.
>