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Thiébaud Weksteen 12ff111421 firmware_loader: use kernel credentials when reading firmware ... commit 581dd69830 upstream. 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). Previously, Android configurations were not setting up the firmware_class.path command line argument and were relying on the userspace fallback mechanism. In this case, the security context of the userspace daemon (i.e. ueventd) was consistently used to read firmware files. More Android devices are now found to set firmware_class.path which gives the kernel the opportunity to read the firmware directly (via kernel_read_file_from_path_initns). In this scenario, the current process credentials were used, even if unrelated to the loading of the firmware file. Signed-off-by: Thiébaud Weksteen <tweek@google.com> Cc: <stable@vger.kernel.org> # 5.10 Reviewed-by: Paul Moore <paul@paul-moore.com> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20220502004952.3970800-1-tweek@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2022-05-18 10:26:53 +02:00
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builtin	firmware_loader: remove unneeded 'comma' macro	2021-06-04 15:06:03 +02:00
fallback.c	firmware_loader: fix use-after-free in firmware_fallback_sysfs	2021-07-29 17:22:15 +02:00
fallback.h	firmware: Store opt_flags in fw_priv	2020-10-05 13:37:04 +02:00
fallback_platform.c	firmware: Store opt_flags in fw_priv	2020-10-05 13:37:04 +02:00
fallback_table.c	firmware_loader: move fw_fallback_config to a private kernel symbol namespace	2020-04-28 21:05:42 +02:00
firmware.h	firmware_loader: fix use-after-free in firmware_fallback_sysfs	2021-07-29 17:22:15 +02:00
Kconfig	drivers: base: Fix Kconfig indentation	2019-11-20 15:10:25 +01:00
main.c	firmware_loader: use kernel credentials when reading firmware	2022-05-18 10:26:53 +02:00
Makefile	firmware: Add new platform fallback mechanism and firmware_request_platform()	2020-03-20 14:54:04 +01:00