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From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/6] efi/random: treat EFI_RNG_PROTOCOL output as bootloader randomness
Date: Tue, 29 Oct 2019 18:37:52 +0100
Message-ID: <20191029173755.27149-4-ardb@kernel.org> (raw)
In-Reply-To: <20191029173755.27149-1-ardb@kernel.org>

From: Dominik Brodowski <linux@dominikbrodowski.net>

Commit 428826f5358c ("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.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
[ardb: update commit log]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/efi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 69f00f7453a3..e98bbf8e56d9 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -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");
-- 
2.17.1


  parent reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-29 17:37 [GIT PULL v2 0/6] EFI fixes for v5.4 Ard Biesheuvel
2019-10-29 17:37 ` [PATCH v2 1/6] efi: Make CONFIG_EFI_RCI2_TABLE selectable on x86 only Ard Biesheuvel
2019-10-31 11:55   ` [tip: efi/urgent] " tip-bot2 for Narendra K
2019-10-29 17:37 ` [PATCH v2 2/6] efi/tpm: return -EINVAL when determining tpm final events log size fails Ard Biesheuvel
2019-10-31 11:55   ` [tip: efi/urgent] efi/tpm: Return " tip-bot2 for Jerry Snitselaar
2019-10-29 17:37 ` Ard Biesheuvel [this message]
2019-10-29 19:14   ` [PATCH v2 3/6] efi/random: treat EFI_RNG_PROTOCOL output as bootloader randomness Bhupesh Sharma
2019-10-31  8:24     ` Ard Biesheuvel
2019-10-31  8:41       ` Ingo Molnar
2019-10-31 13:47         ` Ard Biesheuvel
2019-10-31 11:55   ` [tip: efi/urgent] efi/random: Treat " tip-bot2 for Dominik Brodowski
2019-10-29 17:37 ` [PATCH v2 4/6] efi: libstub/arm: account for firmware reserved memory at the base of RAM Ard Biesheuvel
2019-10-31 11:55   ` [tip: efi/urgent] efi: libstub/arm: Account " tip-bot2 for Ard Biesheuvel
2019-10-29 17:37 ` [PATCH v2 5/6] x86, efi: never relocate kernel below lowest acceptable address Ard Biesheuvel
2019-10-31 11:55   ` [tip: efi/urgent] x86, efi: Never " tip-bot2 for Kairui Song
2019-10-29 17:37 ` [PATCH v2 6/6] efi/efi_test: lock down /dev/efi_test and require CAP_SYS_ADMIN Ard Biesheuvel
2019-10-31 11:55   ` [tip: efi/urgent] efi/efi_test: Lock " tip-bot2 for Javier Martinez Canillas

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