Re: [PATCH 1/7] fs: introduce kernel_pread_file* support

From: Scott Branden
Date: Fri Aug 23 2019 - 15:55:36 EST


Hi Takashi

On 2019-08-23 5:29 a.m., Takashi Iwai wrote:
On Thu, 22 Aug 2019 21:24:45 +0200,
Scott Branden wrote:
Add kernel_pread_file* support to kernel to allow for partial read
of files with an offset into the file. Existing kernel_read_file
functions call new kernel_pread_file functions with offset=0 and
flags=KERNEL_PREAD_FLAG_WHOLE.
Would this change passes the security check like ima?
I thought security_kernel_post_read_file() checks the whole content
for calculating the hash...

It passes the fw_run_tests.sh. How do you test the firmware loader passes this security check?


What exactly does this ima do? How do you enable/disable using it?

Any reasonable device would check the integrity of the firmware image being loaded to it.

And, if part of a security model, authenticate the image.

Whatever security check you are referring to is not needed by request_firmware_into_buf when loading

a partial file into a buffer.




thanks,

Takashi