ssize_t
ed25519_cert_extension_parse(ed25519_cert_extension_t **output, const uint8_t *input, const size_t len_in)
{
ssize_t result;
*output = ed25519_cert_extension_new();
if (NULL == *output)
return -1;
result = ed25519_cert_extension_parse_into(*output, input, len_in);
if (result < 0) {
ed25519_cert_extension_free(*output);
*output = NULL;
}
return result;
}
/** Helper for tor_cert_create(): signs any 32 bytes, not just an ed25519
* key.
*/
static tor_cert_t *
tor_cert_sign_impl(const ed25519_keypair_t *signing_key,
uint8_t cert_type,
uint8_t signed_key_type,
const uint8_t signed_key_info[32],
time_t now, time_t lifetime,
uint32_t flags)
{
tor_cert_t *torcert = NULL;
ed25519_cert_t *cert = ed25519_cert_new();
cert->cert_type = cert_type;
cert->exp_field = (uint32_t) CEIL_DIV(now + lifetime, 3600);
cert->cert_key_type = signed_key_type;
memcpy(cert->certified_key, signed_key_info, 32);
if (flags & CERT_FLAG_INCLUDE_SIGNING_KEY) {
ed25519_cert_extension_t *ext = ed25519_cert_extension_new();
ext->ext_type = CERTEXT_SIGNED_WITH_KEY;
memcpy(ext->un_signing_key, signing_key->pubkey.pubkey, 32);
ed25519_cert_add_ext(cert, ext);
++cert->n_extensions;
}
const ssize_t alloc_len = ed25519_cert_encoded_len(cert);
tor_assert(alloc_len > 0);
uint8_t *encoded = tor_malloc(alloc_len);
const ssize_t real_len = ed25519_cert_encode(encoded, alloc_len, cert);
if (real_len < 0)
goto err;
tor_assert(real_len == alloc_len);
tor_assert(real_len > ED25519_SIG_LEN);
uint8_t *sig = encoded + (real_len - ED25519_SIG_LEN);
tor_assert(tor_mem_is_zero((char*)sig, ED25519_SIG_LEN));
ed25519_signature_t signature;
if (ed25519_sign(&signature, encoded,
real_len-ED25519_SIG_LEN, signing_key)<0) {
log_warn(LD_BUG, "Can't sign certificate");
goto err;
}
memcpy(sig, signature.sig, ED25519_SIG_LEN);
torcert = tor_cert_parse(encoded, real_len);
if (! torcert) {
log_warn(LD_BUG, "Generated a certificate we cannot parse");
goto err;
}
if (tor_cert_checksig(torcert, &signing_key->pubkey, now) < 0) {
log_warn(LD_BUG, "Generated a certificate whose signature we can't check");
goto err;
}
tor_free(encoded);
goto done;
err:
tor_cert_free(torcert);
torcert = NULL;
done:
ed25519_cert_free(cert);
tor_free(encoded);
return torcert;
}
