Commit-ID: c2ceb5fd4e921506e86208b82fca716a2c3aad59 Gitweb: http://git.kernel.org/tip/c2ceb5fd4e921506e86208b82fca716a2c3aad59 Author: Ard Biesheuvel <ard.biesheu...@linaro.org> AuthorDate: Fri, 25 Aug 2017 16:50:16 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Sat, 26 Aug 2017 09:20:33 +0200
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.biesheu...@linaro.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Matt Fleming <m...@codeblueprint.co.uk> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: linux-...@vger.kernel.org Link: http://lkml.kernel.org/r/20170825155019.6740-3-ard.biesheu...@linaro.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- drivers/firmware/efi/efi.c | 3 ++- drivers/firmware/efi/libstub/random.c | 10 ++++------ include/linux/efi.h | 2 ++ 3 files changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index a32e146..c8a27a2 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 7e72954..e0e603a 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) diff --git a/include/linux/efi.h b/include/linux/efi.h index c241acc..33d41df 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1571,6 +1571,8 @@ efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table, void *priv, efi_exit_boot_map_processing priv_func); +#define EFI_RANDOM_SEED_SIZE 64U + struct linux_efi_random_seed { u32 size; u8 bits[];
