/* Copyright 2018 Conor Patrick Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include #include "u2f.h" #include "ctap.h" #include "crypto.h" #include "log.h" #include "device.h" #include "wallet.h" #include APP_CONFIG // void u2f_response_writeback(uint8_t * buf, uint8_t len); static int16_t u2f_register(struct u2f_register_request * req); static int16_t u2f_authenticate(struct u2f_authenticate_request * req, uint8_t control); int8_t u2f_response_writeback(const uint8_t * buf, uint16_t len); void u2f_reset_response(); static CTAP_RESPONSE * _u2f_resp = NULL; void u2f_request(struct u2f_request_apdu* req, CTAP_RESPONSE * resp) { uint16_t rcode = 0; uint64_t t1,t2; uint32_t len = ((req->LC3) | ((uint32_t)req->LC2 << 8) | ((uint32_t)req->LC1 << 16)); uint8_t byte; _u2f_resp = resp; if (req->cla != 0) { printf1(TAG_U2F, "CLA not zero\n"); rcode = U2F_SW_CLASS_NOT_SUPPORTED; goto end; } #ifdef ENABLE_U2F_EXTENSIONS rcode = extend_u2f(req, len); #endif if (rcode != U2F_SW_NO_ERROR) // If the extension didn't do anything... { #ifdef ENABLE_U2F switch(req->ins) { case U2F_REGISTER: printf1(TAG_U2F, "U2F_REGISTER\n"); if (len != 64) { rcode = U2F_SW_WRONG_LENGTH; } else { t1 = millis(); rcode = u2f_register((struct u2f_register_request*)req->payload); t2 = millis(); printf1(TAG_TIME,"u2f_register time: %d ms\n", t2-t1); } break; case U2F_AUTHENTICATE: printf1(TAG_U2F, "U2F_AUTHENTICATE\n"); t1 = millis(); rcode = u2f_authenticate((struct u2f_authenticate_request*)req->payload, req->p1); t2 = millis(); printf1(TAG_TIME,"u2f_authenticate time: %d ms\n", t2-t1); break; case U2F_VERSION: printf1(TAG_U2F, "U2F_VERSION\n"); if (len) { rcode = U2F_SW_WRONG_LENGTH; } else { rcode = u2f_version(); } break; case U2F_VENDOR_FIRST: case U2F_VENDOR_LAST: printf1(TAG_U2F, "U2F_VENDOR\n"); rcode = U2F_SW_NO_ERROR; break; default: printf1(TAG_ERR, "Error, unknown U2F command\n"); rcode = U2F_SW_INS_NOT_SUPPORTED; break; } #endif } end: if (rcode != U2F_SW_NO_ERROR) { printf1(TAG_U2F,"U2F Error code %04x\n", rcode); ctap_response_init(_u2f_resp); } byte = (rcode & 0xff00)>>8; u2f_response_writeback(&byte,1); byte = rcode & 0xff; u2f_response_writeback(&byte,1); printf1(TAG_U2F,"u2f resp: "); dump_hex1(TAG_U2F, _u2f_resp->data, _u2f_resp->length); } int8_t u2f_response_writeback(const uint8_t * buf, uint16_t len) { if ((_u2f_resp->length + len) > _u2f_resp->data_size) { printf2(TAG_ERR, "Not enough space for U2F response, writeback\n"); exit(1); } memmove(_u2f_resp->data + _u2f_resp->length, buf, len); _u2f_resp->length += len; return 0; } void u2f_reset_response() { ctap_response_init(_u2f_resp); } static void dump_signature_der(uint8_t * sig) { uint8_t sigder[72]; int len; len = ctap_encode_der_sig(sig, sigder); u2f_response_writeback(sigder, len); } static int8_t u2f_load_key(struct u2f_key_handle * kh, uint8_t * appid) { crypto_ecc256_load_key((uint8_t*)kh, U2F_KEY_HANDLE_SIZE, NULL, 0); return 0; } static void u2f_make_auth_tag(struct u2f_key_handle * kh, uint8_t * appid, uint8_t * tag) { uint8_t hashbuf[32]; crypto_sha256_hmac_init(CRYPTO_MASTER_KEY, 0, hashbuf); crypto_sha256_update(kh->key, U2F_KEY_HANDLE_KEY_SIZE); crypto_sha256_update(appid, U2F_APPLICATION_SIZE); crypto_sha256_hmac_final(CRYPTO_MASTER_KEY, 0,hashbuf); memmove(tag, hashbuf, CREDENTIAL_TAG_SIZE); } static int8_t u2f_new_keypair(struct u2f_key_handle * kh, uint8_t * appid, uint8_t * pubkey) { ctap_generate_rng(kh->key, U2F_KEY_HANDLE_KEY_SIZE); u2f_make_auth_tag(kh, appid, kh->tag); crypto_ecc256_derive_public_key((uint8_t*)kh, U2F_KEY_HANDLE_SIZE, pubkey, pubkey+32); return 0; } static int8_t u2f_appid_eq(struct u2f_key_handle * kh, uint8_t * appid) { uint8_t tag[U2F_KEY_HANDLE_TAG_SIZE]; u2f_make_auth_tag(kh, appid, tag); if (memcmp(kh->tag, tag, U2F_KEY_HANDLE_TAG_SIZE) == 0) { return 0; } else { printf1(TAG_U2F, "key handle + appid not authentic\n"); printf1(TAG_U2F, "calc tag: \n"); dump_hex1(TAG_U2F,tag, U2F_KEY_HANDLE_TAG_SIZE); printf1(TAG_U2F, "inp tag: \n"); dump_hex1(TAG_U2F,kh->tag, U2F_KEY_HANDLE_TAG_SIZE); return -1; } } static int16_t u2f_authenticate(struct u2f_authenticate_request * req, uint8_t control) { uint8_t up = 1; uint32_t count; uint8_t hash[32]; uint8_t * sig = (uint8_t*)req; if (control == U2F_AUTHENTICATE_CHECK) { if (u2f_appid_eq(&req->kh, req->app) == 0) { return U2F_SW_CONDITIONS_NOT_SATISFIED; } else { return U2F_SW_WRONG_DATA; } } if ( control != U2F_AUTHENTICATE_SIGN || req->khl != U2F_KEY_HANDLE_SIZE || u2f_appid_eq(&req->kh, req->app) != 0 || // Order of checks is important u2f_load_key(&req->kh, req->app) != 0 ) { return U2F_SW_WRONG_PAYLOAD; } if (ctap_user_presence_test() == 0) { return U2F_SW_CONDITIONS_NOT_SATISFIED; } count = ctap_atomic_count(0); crypto_sha256_init(); crypto_sha256_update(req->app,32); crypto_sha256_update(&up,1); crypto_sha256_update((uint8_t *)&count,4); crypto_sha256_update(req->chal,32); crypto_sha256_final(hash); printf1(TAG_U2F, "sha256: "); dump_hex1(TAG_U2F,hash,32); crypto_ecc256_sign(hash, 32, sig); u2f_response_writeback(&up,1); u2f_response_writeback((uint8_t *)&count,4); dump_signature_der(sig); return U2F_SW_NO_ERROR; } static int16_t u2f_register(struct u2f_register_request * req) { uint8_t i[] = {0x0,U2F_EC_FMT_UNCOMPRESSED}; struct u2f_key_handle key_handle; uint8_t pubkey[64]; uint8_t hash[32]; uint8_t * sig = (uint8_t*)req; const uint16_t attest_size = attestation_cert_der_size; if ( ! ctap_user_presence_test()) { return U2F_SW_CONDITIONS_NOT_SATISFIED; } if ( u2f_new_keypair(&key_handle, req->app, pubkey) == -1) { return U2F_SW_INSUFFICIENT_MEMORY; } crypto_sha256_init(); crypto_sha256_update(i,1); crypto_sha256_update(req->app,32); crypto_sha256_update(req->chal,32); crypto_sha256_update((uint8_t*)&key_handle,U2F_KEY_HANDLE_SIZE); crypto_sha256_update(i+1,1); crypto_sha256_update(pubkey,64); crypto_sha256_final(hash); crypto_ecc256_load_attestation_key(); printf1(TAG_U2F, "sha256: "); dump_hex1(TAG_U2F,hash,32); crypto_ecc256_sign(hash, 32, sig); i[0] = 0x5; u2f_response_writeback(i,2); u2f_response_writeback(pubkey,64); i[0] = U2F_KEY_HANDLE_SIZE; u2f_response_writeback(i,1); u2f_response_writeback((uint8_t*)&key_handle,U2F_KEY_HANDLE_SIZE); u2f_response_writeback(attestation_cert_der,attest_size); dump_signature_der(sig); /*printf1(TAG_U2F, "dersig: "); dump_hex1(TAG_U2F,sig,74);*/ return U2F_SW_NO_ERROR; } int16_t u2f_version() { const char version[] = "U2F_V2"; u2f_response_writeback((uint8_t*)version, sizeof(version)-1); return U2F_SW_NO_ERROR; }