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efi/random: Treat EFI_RNG_PROTOCOL output as bootloader randomness 

Commit 428826f535 ("fdt: add support for rng-seed") introduced
add_bootloader_randomness(), permitting randomness provided by the
bootloader or firmware to be credited as entropy. However, the fact
that the UEFI support code was already wired into the RNG subsystem
via a call to add_device_randomness() was overlooked, and so it was
not converted at the same time.

Note that this UEFI (v2.4 or newer) feature is currently only
implemented for EFI stub booting on ARM, and further note that
CONFIG_RANDOM_TRUST_BOOTLOADER must be enabled, and this should be
done only if there indeed is sufficient trust in the bootloader
_and_ its source of randomness.

[ ardb: update commit log ]

Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-4-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
alistair/sunxi64-5.4-dsi
Dominik Brodowski 2019-10-29 18:37:52 +01:00 committed by Ingo Molnar
parent 2bb6a81633
commit 18b915ac6b
1 changed files with 1 additions and 1 deletions
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2
drivers/firmware/efi/efi.c
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@ -554,7 +554,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
sizeof(*seed) + size);
if (seed != NULL) {
pr_notice("seeding entropy pool\n");
add_device_randomness(seed->bits, seed->size);
add_bootloader_randomness(seed->bits, seed->size);
early_memunmap(seed, sizeof(*seed) + size);
} else {
pr_err("Could not map UEFI random seed!\n");