void
tls_crypt_v2_write_client_key_file(const char *filename,
const char *b64_metadata,
const char *server_key_file,
const char *server_key_inline)
{
struct gc_arena gc = gc_new();
struct key_ctx server_key = { 0 };
struct buffer client_key_pem = { 0 };
struct buffer dst = alloc_buf_gc(TLS_CRYPT_V2_CLIENT_KEY_LEN
+ TLS_CRYPT_V2_MAX_WKC_LEN, &gc);
struct key2 client_key = { 2 };
if (!rand_bytes((void *)client_key.keys, sizeof(client_key.keys)))
{
msg(M_FATAL, "ERROR: could not generate random key");
goto cleanup;
}
ASSERT(buf_write(&dst, client_key.keys, sizeof(client_key.keys)));
struct buffer metadata = alloc_buf_gc(TLS_CRYPT_V2_MAX_METADATA_LEN, &gc);
if (b64_metadata)
{
if (TLS_CRYPT_V2_MAX_B64_METADATA_LEN < strlen(b64_metadata))
{
msg(M_FATAL,
"ERROR: metadata too long (%d bytes, max %u bytes)",
(int)strlen(b64_metadata), TLS_CRYPT_V2_MAX_B64_METADATA_LEN);
}
ASSERT(buf_write(&metadata, &TLS_CRYPT_METADATA_TYPE_USER, 1));
int decoded_len = openvpn_base64_decode(b64_metadata, BPTR(&metadata),
BCAP(&metadata));
if (decoded_len < 0)
{
msg(M_FATAL, "ERROR: failed to base64 decode provided metadata");
goto cleanup;
}
ASSERT(buf_inc_len(&metadata, decoded_len));
}
else
{
int64_t timestamp = htonll((uint64_t)now);
ASSERT(buf_write(&metadata, &TLS_CRYPT_METADATA_TYPE_TIMESTAMP, 1));
ASSERT(buf_write(&metadata, ×tamp, sizeof(timestamp)));
}
tls_crypt_v2_init_server_key(&server_key, true, server_key_file,
server_key_inline);
if (!tls_crypt_v2_wrap_client_key(&dst, &client_key, &metadata, &server_key,
&gc))
{
msg(M_FATAL, "ERROR: could not wrap generated client key");
goto cleanup;
}
/* PEM-encode Kc || WKc */
if (!crypto_pem_encode(tls_crypt_v2_cli_pem_name, &client_key_pem, &dst,
&gc))
{
msg(M_FATAL, "ERROR: could not PEM-encode client key");
goto cleanup;
}
if (!buffer_write_file(filename, &client_key_pem))
{
msg(M_FATAL, "ERROR: could not write client key file");
goto cleanup;
}
/* Sanity check: load client key (as "client") */
struct key_ctx_bi test_client_key;
struct buffer test_wrapped_client_key;
msg(D_GENKEY, "Testing client-side key loading...");
tls_crypt_v2_init_client_key(&test_client_key, &test_wrapped_client_key,
filename, NULL);
free_key_ctx_bi(&test_client_key);
/* Sanity check: unwrap and load client key (as "server") */
struct buffer test_metadata = alloc_buf_gc(TLS_CRYPT_V2_MAX_METADATA_LEN,
&gc);
struct key2 test_client_key2 = { 0 };
free_key_ctx(&server_key);
tls_crypt_v2_init_server_key(&server_key, false, server_key_file,
server_key_inline);
msg(D_GENKEY, "Testing server-side key loading...");
ASSERT(tls_crypt_v2_unwrap_client_key(&test_client_key2, &test_metadata,
test_wrapped_client_key, &server_key));
secure_memzero(&test_client_key2, sizeof(test_client_key2));
free_buf(&test_wrapped_client_key);
cleanup:
secure_memzero(&client_key, sizeof(client_key));
free_key_ctx(&server_key);
buf_clear(&client_key_pem);
buf_clear(&dst);
gc_free(&gc);
}
void
free_key_ctx_bi (struct key_ctx_bi *ctx)
{
free_key_ctx(&ctx->encrypt);
free_key_ctx(&ctx->decrypt);
}