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 <[email protected]> --- drivers/firmware/efi/efi.c | 3 ++- drivers/firmware/efi/libstub/random.c | 2 -- include/linux/efi.h | 2 ++ 3 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 6519be44387c..9e822906adcb 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -522,6 +522,7 @@ 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"); } @@ -867,7 +868,7 @@ 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 fa10e14862b3..e460c59b448b 100644 --- a/drivers/firmware/efi/libstub/random.c +++ b/drivers/firmware/efi/libstub/random.c @@ -165,8 +165,6 @@ 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_table_guid = LINUX_EFI_RANDOM_SEED_TABLE_GUID; diff --git a/include/linux/efi.h b/include/linux/efi.h index 253749cd9b62..cd23e1c4803c 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1566,6 +1566,8 @@ 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[]; -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
