Re: [PATCH v2] firmware_loader: use kernel credentials when reading firmware

From: Thiébaud Weksteen
Date: Tue Apr 26 2022 - 00:19:20 EST

> Can you elaborate on the last sentence? It's unclear how what you
> describe is used exactly to allow driver to use direct filesystem
> firmware loading.

I realize my use of the word "device" here was unfortunate. I meant devices as
Android devices/systems. This may have contributed to the confusion.

Previously, Android systems were not setting up the firmware_class.path
command line argument. It means that the userspace fallback was always
kicking-in when a driver called request_firmware. This was handled by the
ueventd process on Android, which is generally given access to all firmware

Now that more devices are setting up firmware_class.path, the call to
request_firmware will end up using kernel_read_file_from_path_initns, which
would have used the current process credentials.

> And, given the feedback from Android it would seem this is a fix
> which likely may be desirable to backport to some stable kernels?

Yes, that's right.