diff options
Diffstat (limited to 'ks_volatile.c')
| -rw-r--r-- | ks_volatile.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/ks_volatile.c b/ks_volatile.c index 2381f4c..b71e27e 100644 --- a/ks_volatile.c +++ b/ks_volatile.c @@ -55,6 +55,17 @@ static hal_ks_keydb_t db[1]; +/* + * There's no good place to store the master key (KEK) in this volatile memory implementation. + * We might be able to add a bit of protection doing things like using locked physical memory, + * as gpg does, or obfuscating the KEK a bit to make it harder to pull out of a crash dump, + * but, really, there's not a lot we can do against a determined opponant in this case. + * + * For now, we just go through the motions. + */ + +static uint8_t kekbuf[bitsToBytes(256)]; + const hal_ks_keydb_t *hal_ks_get_keydb(void) { return db; @@ -99,6 +110,31 @@ hal_error_t hal_ks_set_pin(const hal_user_t user, return HAL_OK; } +hal_error_t hal_ks_get_kek(uint8_t *kek, + size_t *kek_len, + const size_t kek_max) +{ + if (kek == NULL || kek_len == NULL || kek_max < bitsToBytes(128)) + return HAL_ERROR_BAD_ARGUMENTS; + + hal_error_t err; + + const size_t len = ((kek_max < bitsToBytes(192)) ? bitsToBytes(128) : + (kek_max < bitsToBytes(256)) ? bitsToBytes(192) : + bitsToBytes(256)); + + uint8_t t = 0; + + for (int i = 0; i < sizeof(kekbuf); i++) + t |= kekbuf[i]; + + if (t == 0 && (err = hal_rpc_get_random(kekbuf, sizeof(kekbuf))) != HAL_OK) + return err; + + memcpy(kek, kekbuf, len); + return HAL_OK; +} + /* * Local variables: * indent-tabs-mode: nil |