On Mon, Apr 04, 2022 at 03:46:42PM +1000, Thiébaud Weksteen wrote: > Device drivers may decide to not load firmware when probed to avoid > slowing down the boot process should the firmware filesystem not be > available yet. In this case, the firmware loading request may be done > when a device file associated with the driver is first accessed. The > credentials of the userspace process accessing the device file may be > used to validate access to the firmware files requested by the driver. > Ensure that the kernel assumes the responsibility of reading the > firmware. > > This was observed on Android for a graphic driver loading their firmware > when the device file (e.g. /dev/mali0) was first opened by userspace > (i.e. surfaceflinger). The security context of surfaceflinger was used > to validate the access to the firmware file (e.g. > /vendor/firmware/mali.bin). > > Because previous configurations were relying on the userspace fallback > mechanism, the security context of the userspace daemon (i.e. ueventd) > was consistently used to read firmware files. More devices are found to > use the command line argument firmware_class.path which gives the kernel > the opportunity to read the firmware directly, hence surfacing this > misattribution. > > Signed-off-by: Thiébaud Weksteen <tweek@xxxxxxxxxx> > --- > drivers/base/firmware_loader/main.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) Is this a bugfix? if so, what commit does this fix? If not, how has this never been a problem in the past (i.e. what changed to cause problems?) thanks, greg k-h
