diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/random.c')
-rw-r--r-- | drivers/firmware/efi/libstub/random.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c index f8e2e5ae6872..3a3feacc329f 100644 --- a/drivers/firmware/efi/libstub/random.c +++ b/drivers/firmware/efi/libstub/random.c @@ -143,3 +143,51 @@ 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; + efi_guid_t rng_algo_raw = EFI_RNG_ALGORITHM_RAW; + efi_guid_t rng_table_guid = LINUX_EFI_RANDOM_SEED_TABLE_GUID; + struct efi_rng_protocol *rng; + struct linux_efi_random_seed *seed; + efi_status_t status; + + status = efi_call_early(locate_protocol, &rng_proto, NULL, + (void **)&rng); + if (status != EFI_SUCCESS) + return status; + + status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA, + sizeof(*seed) + RANDOM_SEED_SIZE, + (void **)&seed); + if (status != EFI_SUCCESS) + return status; + + status = rng->get_rng(rng, &rng_algo_raw, 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, + seed->bits); + + if (status != EFI_SUCCESS) + goto err_freepool; + + seed->size = RANDOM_SEED_SIZE; + status = efi_call_early(install_configuration_table, &rng_table_guid, + seed); + if (status != EFI_SUCCESS) + goto err_freepool; + + return EFI_SUCCESS; + +err_freepool: + efi_call_early(free_pool, seed); + return status; +} |