diff options
| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2017-08-25 17:50:16 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-26 09:20:33 +0200 |
| commit | c2ceb5fd4e921506e86208b82fca716a2c3aad59 (patch) | |
| tree | 960b9e5412ea59b8326b83939104f1c1ada0cab1 /drivers/firmware | |
| parent | efi/libstub: Enable reset attack mitigation (diff) | |
| download | linux-c2ceb5fd4e921506e86208b82fca716a2c3aad59.tar.xz linux-c2ceb5fd4e921506e86208b82fca716a2c3aad59.zip | |
efi/random: Increase size of firmware supplied randomness
The crng code requires at least 64 bytes (2 * CHACHA20_BLOCK_SIZE)
to complete the fast boot-time init, so provide that many bytes
when invoking UEFI protocols to seed the entropy pool. Also, add
a notice so we can tell from the boot log when the seeding actually
took place.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170825155019.6740-3-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efi/efi.c | 3 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/random.c | 10 |
2 files changed, 6 insertions, 7 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index a32e1460ade8..c8a27a2c30c1 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -541,6 +541,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, if (seed != NULL) { add_device_randomness(seed->bits, seed->size); early_memunmap(seed, sizeof(*seed) + size); + pr_notice("seeding entropy pool\n"); } else { pr_err("Could not map UEFI random seed!\n"); } @@ -900,7 +901,7 @@ static int update_efi_random_seed(struct notifier_block *nb, seed = memremap(efi.rng_seed, sizeof(*seed), MEMREMAP_WB); if (seed != NULL) { - size = min(seed->size, 32U); + size = min(seed->size, EFI_RANDOM_SEED_SIZE); memunmap(seed); } else { pr_err("Could not map UEFI random seed!\n"); diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c index 7e72954d5860..e0e603a89aa9 100644 --- a/drivers/firmware/efi/libstub/random.c +++ b/drivers/firmware/efi/libstub/random.c @@ -145,8 +145,6 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg, return status; } -#define RANDOM_SEED_SIZE 32 - efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg) { efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID; @@ -162,25 +160,25 @@ efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg) return status; status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA, - sizeof(*seed) + RANDOM_SEED_SIZE, + sizeof(*seed) + EFI_RANDOM_SEED_SIZE, (void **)&seed); if (status != EFI_SUCCESS) return status; - status = rng->get_rng(rng, &rng_algo_raw, RANDOM_SEED_SIZE, + status = rng->get_rng(rng, &rng_algo_raw, EFI_RANDOM_SEED_SIZE, seed->bits); if (status == EFI_UNSUPPORTED) /* * Use whatever algorithm we have available if the raw algorithm * is not implemented. */ - status = rng->get_rng(rng, NULL, RANDOM_SEED_SIZE, + status = rng->get_rng(rng, NULL, EFI_RANDOM_SEED_SIZE, seed->bits); if (status != EFI_SUCCESS) goto err_freepool; - seed->size = RANDOM_SEED_SIZE; + seed->size = EFI_RANDOM_SEED_SIZE; status = efi_call_early(install_configuration_table, &rng_table_guid, seed); if (status != EFI_SUCCESS) |