static int callback_acme_client(struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len) { struct per_vhost_data__lws_acme_client *vhd = (struct per_vhost_data__lws_acme_client *) lws_protocol_vh_priv_get(lws_get_vhost(wsi), lws_get_protocol(wsi)); char buf[LWS_PRE + 2536], *start = buf + LWS_PRE, *p = start, *end = buf + sizeof(buf) - 1, digest[32], *failreason = NULL; unsigned char **pp, *pend; const char *content_type; const struct lws_protocol_vhost_options *pvo; struct lws_acme_cert_aging_args *caa; struct acme_connection *ac = NULL; struct lws_genhash_ctx hctx; struct lws *cwsi; int n, m; if (vhd) ac = vhd->ac; switch ((int)reason) { case LWS_CALLBACK_PROTOCOL_INIT: vhd = lws_protocol_vh_priv_zalloc(lws_get_vhost(wsi), lws_get_protocol(wsi), sizeof(struct per_vhost_data__lws_acme_client)); vhd->context = lws_get_context(wsi); vhd->protocol = lws_get_protocol(wsi); vhd->vhost = lws_get_vhost(wsi); /* compute how much we need to hold all the pvo payloads */ m = 0; pvo = (const struct lws_protocol_vhost_options *)in; while (pvo) { m += strlen(pvo->value) + 1; pvo = pvo->next; } p = vhd->pvo_data = malloc(m); if (!p) return -1; pvo = (const struct lws_protocol_vhost_options *)in; while (pvo) { start = p; n = strlen(pvo->value) + 1; memcpy(start, pvo->value, n); p += n; for (m = 0; m < (int)LWS_ARRAY_SIZE(pvo_names); m++) if (!strcmp(pvo->name, pvo_names[m])) vhd->pvop[m] = start; pvo = pvo->next; } n = 0; for (m = 0; m < (int)LWS_ARRAY_SIZE(pvo_names); m++) if (!vhd->pvop[m] && m >= LWS_TLS_REQ_ELEMENT_COMMON_NAME) { lwsl_notice("%s: require pvo '%s'\n", __func__, pvo_names[m]); n |= 1; } else if (vhd->pvop[m]) lwsl_info(" %s: %s\n", pvo_names[m], vhd->pvop[m]); if (n) { free(vhd->pvo_data); vhd->pvo_data = NULL; return -1; } #if !defined(LWS_WITH_ESP32) /* * load (or create) the registration keypair while we * still have root */ if (lws_acme_load_create_auth_keys(vhd, 4096)) return 1; /* * in case we do an update, open the update files while we * still have root */ lws_snprintf(buf, sizeof(buf) - 1, "%s.upd", vhd->pvop[LWS_TLS_SET_CERT_PATH]); vhd->fd_updated_cert = lws_open(buf, LWS_O_WRONLY | LWS_O_CREAT | LWS_O_TRUNC, 0600); if (vhd->fd_updated_cert < 0) { lwsl_err("unable to create update cert file %s\n", buf); return -1; } lws_snprintf(buf, sizeof(buf) - 1, "%s.upd", vhd->pvop[LWS_TLS_SET_KEY_PATH]); vhd->fd_updated_key = lws_open(buf, LWS_O_WRONLY | LWS_O_CREAT | LWS_O_TRUNC, 0600); if (vhd->fd_updated_key < 0) { lwsl_err("unable to create update key file %s\n", buf); return -1; } #endif break; case LWS_CALLBACK_PROTOCOL_DESTROY: if (vhd && vhd->pvo_data) { free(vhd->pvo_data); vhd->pvo_data = NULL; } if (vhd) lws_acme_finished(vhd); break; case LWS_CALLBACK_VHOST_CERT_AGING: if (!vhd) break; caa = (struct lws_acme_cert_aging_args *)in; /* * Somebody is telling us about a cert some vhost is using. * * First see if the cert is getting close enough to expiry that * we *want* to do something about it. */ if ((int)(ssize_t)len > 14) break; /* * ...is this a vhost we were configured on? */ if (vhd->vhost != caa->vh) return 1; for (n = 0; n < (int)LWS_ARRAY_SIZE(vhd->pvop);n++) if (caa->element_overrides[n]) vhd->pvop_active[n] = caa->element_overrides[n]; else vhd->pvop_active[n] = vhd->pvop[n]; lwsl_notice("starting acme acquisition on %s: %s\n", lws_get_vhost_name(caa->vh), vhd->pvop_active[LWS_TLS_SET_DIR_URL]); lws_acme_start_acquisition(vhd, caa->vh); break; /* * Client */ case LWS_CALLBACK_CLIENT_ESTABLISHED: lwsl_notice("%s: CLIENT_ESTABLISHED\n", __func__); break; case LWS_CALLBACK_CLIENT_CONNECTION_ERROR: lwsl_notice("%s: CLIENT_CONNECTION_ERROR: %p\n", __func__, wsi); break; case LWS_CALLBACK_CLOSED_CLIENT_HTTP: lwsl_notice("%s: CLOSED_CLIENT_HTTP: %p\n", __func__, wsi); break; case LWS_CALLBACK_CLOSED: lwsl_notice("%s: CLOSED: %p\n", __func__, wsi); break; case LWS_CALLBACK_ESTABLISHED_CLIENT_HTTP: lwsl_notice("lws_http_client_http_response %d\n", lws_http_client_http_response(wsi)); if (!ac) break; ac->resp = lws_http_client_http_response(wsi); /* we get a new nonce each time */ if (lws_hdr_total_length(wsi, WSI_TOKEN_REPLAY_NONCE) && lws_hdr_copy(wsi, ac->replay_nonce, sizeof(ac->replay_nonce), WSI_TOKEN_REPLAY_NONCE) < 0) { lwsl_notice("%s: nonce too large\n", __func__); goto failed; } switch (ac->state) { case ACME_STATE_DIRECTORY: lejp_construct(&ac->jctx, cb_dir, vhd, jdir_tok, LWS_ARRAY_SIZE(jdir_tok)); break; case ACME_STATE_NEW_REG: break; case ACME_STATE_NEW_AUTH: lejp_construct(&ac->jctx, cb_authz, ac, jauthz_tok, LWS_ARRAY_SIZE(jauthz_tok)); break; case ACME_STATE_POLLING: case ACME_STATE_ACCEPT_CHALL: lejp_construct(&ac->jctx, cb_chac, ac, jchac_tok, LWS_ARRAY_SIZE(jchac_tok)); break; case ACME_STATE_POLLING_CSR: ac->cpos = 0; if (ac->resp != 201) break; /* * He acknowledges he will create the cert... * get the URL to GET it from in the Location * header. */ if (lws_hdr_copy(wsi, ac->challenge_uri, sizeof(ac->challenge_uri), WSI_TOKEN_HTTP_LOCATION) < 0) { lwsl_notice("%s: missing cert location:\n", __func__); goto failed; } lwsl_notice("told to fetch cert from %s\n", ac->challenge_uri); break; default: break; } break; case LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER: if (!ac) break; switch (ac->state) { case ACME_STATE_DIRECTORY: break; case ACME_STATE_NEW_REG: p += lws_snprintf(p, end - p, "{" "\"resource\":\"new-reg\"," "\"contact\":[" "\"mailto:%s\"" "],\"agreement\":\"%s\"" "}", vhd->pvop_active[LWS_TLS_REQ_ELEMENT_EMAIL], ac->urls[JAD_TOS_URL]); puts(start); pkt_add_hdrs: ac->len = lws_jws_create_packet(&vhd->jwk, start, p - start, ac->replay_nonce, &ac->buf[LWS_PRE], sizeof(ac->buf) - LWS_PRE); if (ac->len < 0) { ac->len = 0; lwsl_notice("lws_jws_create_packet failed\n"); goto failed; } pp = (unsigned char **)in; pend = (*pp) + len; ac->pos = 0; content_type = "application/jose+json"; if (ac->state == ACME_STATE_POLLING_CSR) content_type = "application/pkix-cert"; if (lws_add_http_header_by_token(wsi, WSI_TOKEN_HTTP_CONTENT_TYPE, (uint8_t *)content_type, 21, pp, pend)) { lwsl_notice("could not add content type\n"); goto failed; } n = sprintf(buf, "%d", ac->len); if (lws_add_http_header_by_token(wsi, WSI_TOKEN_HTTP_CONTENT_LENGTH, (uint8_t *)buf, n, pp, pend)) { lwsl_notice("could not add content length\n"); goto failed; } lws_client_http_body_pending(wsi, 1); lws_callback_on_writable(wsi); lwsl_notice("prepare to send ACME_STATE_NEW_REG\n"); break; case ACME_STATE_NEW_AUTH: p += lws_snprintf(p, end - p, "{" "\"resource\":\"new-authz\"," "\"identifier\":{" "\"type\":\"http-01\"," "\"value\":\"%s\"" "}" "}", vhd->pvop_active[LWS_TLS_REQ_ELEMENT_COMMON_NAME]); goto pkt_add_hdrs; case ACME_STATE_ACCEPT_CHALL: /* * Several of the challenges in this document makes use * of a key authorization string. A key authorization * expresses a domain holder's authorization for a * specified key to satisfy a specified challenge, by * concatenating the token for the challenge with a key * fingerprint, separated by a "." character: * * key-authz = token || '.' || * base64(JWK_Thumbprint(accountKey)) * * The "JWK_Thumbprint" step indicates the computation * specified in [RFC7638], using the SHA-256 digest. As * specified in the individual challenges below, the * token for a challenge is a JSON string comprised * entirely of characters in the base64 alphabet. * The "||" operator indicates concatenation of strings. * * keyAuthorization (required, string): The key * authorization for this challenge. This value MUST * match the token from the challenge and the client's * account key. * * draft acme-01 tls-sni-01: * * { * "keyAuthorization": "evaGxfADs...62jcerQ", * } (Signed as JWS) * * draft acme-07 tls-sni-02: * * POST /acme/authz/1234/1 * Host: example.com * Content-Type: application/jose+json * * { * "protected": base64url({ * "alg": "ES256", * "kid": "https://example.com/acme/acct/1", * "nonce": "JHb54aT_KTXBWQOzGYkt9A", * "url": "https://example.com/acme/authz/1234/1" * }), * "payload": base64url({ * "keyAuthorization": "evaGxfADs...62jcerQ" * }), * "signature": "Q1bURgJoEslbD1c5...3pYdSMLio57mQNN4" * } * * On receiving a response, the server MUST verify that * the key authorization in the response matches the * "token" value in the challenge and the client's * account key. If they do not match, then the server * MUST return an HTTP error in response to the POST * request in which the client sent the challenge. */ lws_jwk_rfc7638_fingerprint(&vhd->jwk, digest); p = start; end = &buf[sizeof(buf) - 1]; p += lws_snprintf(p, end - p, "{\"resource\":\"challenge\"," "\"type\":\"tls-sni-0%d\"," "\"keyAuthorization\":\"%s.", 1 + ac->is_sni_02, ac->chall_token); n = lws_jws_base64_enc(digest, 32, p, end - p); if (n < 0) goto failed; p += n; p += lws_snprintf(p, end - p, "\"}"); puts(start); goto pkt_add_hdrs; case ACME_STATE_POLLING: break; case ACME_STATE_POLLING_CSR: /* * "To obtain a certificate for the domain, the agent * constructs a PKCS#10 Certificate Signing Request that * asks the Let’s Encrypt CA to issue a certificate for * example.com with a specified public key. As usual, * the CSR includes a signature by the private key * corresponding to the public key in the CSR. The agent * also signs the whole CSR with the authorized * key for example.com so that the Let’s Encrypt CA * knows it’s authorized." * * IOW we must create a new RSA keypair which will be * the cert public + private key, and put the public * key in the CSR. The CSR, just for transport, is also * signed with our JWK, showing that as the owner of the * authorized JWK, the request should be allowed. * * The cert comes back with our public key in it showing * that the owner of the matching private key (we * created that keypair) is the owner of the cert. * * We feed the CSR the elements we want in the cert, * like the CN etc, and it gives us the b64URL-encoded * CSR and the PEM-encoded (public +)private key in * memory buffers. */ if (ac->goes_around) break; p += lws_snprintf(p, end - p, "{\"resource\":\"new-cert\"," "\"csr\":\""); n = lws_tls_acme_sni_csr_create(vhd->context, &vhd->pvop_active[0], (uint8_t *)p, end - p, &ac->alloc_privkey_pem, &ac->len_privkey_pem); if (n < 0) { lwsl_notice("CSR generation failed\n"); goto failed; } p += n; p += lws_snprintf(p, end - p, "\"}"); puts(start); goto pkt_add_hdrs; default: break; } break; case LWS_CALLBACK_CLIENT_HTTP_WRITEABLE: lwsl_notice("LWS_CALLBACK_CLIENT_HTTP_WRITEABLE\n"); if (!ac) break; if (ac->pos == ac->len) break; ac->buf[LWS_PRE + ac->len] = '\0'; if (lws_write(wsi, (uint8_t *)ac->buf + LWS_PRE, ac->len, LWS_WRITE_HTTP_FINAL) < 0) return -1; lwsl_notice("wrote %d\n", ac->len); ac->pos = ac->len; lws_client_http_body_pending(wsi, 0); break; /* chunked content */ case LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ: if (!ac) return -1; switch (ac->state) { case ACME_STATE_POLLING: case ACME_STATE_ACCEPT_CHALL: case ACME_STATE_NEW_AUTH: case ACME_STATE_DIRECTORY: ((char *)in)[len] = '\0'; puts(in); m = (int)(signed char)lejp_parse(&ac->jctx, (uint8_t *)in, len); if (m < 0 && m != LEJP_CONTINUE) { lwsl_notice("lejp parse failed %d\n", m); goto failed; } break; case ACME_STATE_NEW_REG: ((char *)in)[len] = '\0'; puts(in); break; case ACME_STATE_POLLING_CSR: /* it should be the DER cert! */ if (ac->cpos + len > sizeof(ac->buf)) { lwsl_notice("Incoming cert is too large!\n"); goto failed; } memcpy(&ac->buf[ac->cpos], in, len); ac->cpos += len; break; default: break; } break; /* unchunked content */ case LWS_CALLBACK_RECEIVE_CLIENT_HTTP: lwsl_notice("%s: LWS_CALLBACK_RECEIVE_CLIENT_HTTP\n", __func__); { char buffer[2048 + LWS_PRE]; char *px = buffer + LWS_PRE; int lenx = sizeof(buffer) - LWS_PRE; if (lws_http_client_read(wsi, &px, &lenx) < 0) return -1; } break; case LWS_CALLBACK_COMPLETED_CLIENT_HTTP: lwsl_notice("%s: COMPLETED_CLIENT_HTTP\n", __func__); if (!ac) return -1; switch (ac->state) { case ACME_STATE_DIRECTORY: lejp_destruct(&ac->jctx); /* check dir validity */ for (n = 0; n < 6; n++) lwsl_notice(" %d: %s\n", n, ac->urls[n]); /* * So... having the directory now... we try to * register our keys next. It's OK if it ends up * they're already registered... this eliminates any * gaps where we stored the key but registration did * not complete for some reason... */ ac->state = ACME_STATE_NEW_REG; lws_acme_report_status(vhd->vhost, LWS_CUS_REG, NULL); strcpy(buf, ac->urls[JAD_NEW_REG_URL]); cwsi = lws_acme_client_connect(vhd->context, vhd->vhost, &ac->cwsi, &ac->i, buf, "POST"); if (!cwsi) { lwsl_notice("%s: failed to connect to acme\n", __func__); goto failed; } return -1; /* close the completed client connection */ case ACME_STATE_NEW_REG: if ((ac->resp >= 200 && ac->resp < 299) || ac->resp == 409) { /* * Our account already existed, or exists now. * * Move on to requesting a cert auth. */ ac->state = ACME_STATE_NEW_AUTH; lws_acme_report_status(vhd->vhost, LWS_CUS_AUTH, NULL); strcpy(buf, ac->urls[JAD_NEW_AUTHZ_URL]); cwsi = lws_acme_client_connect(vhd->context, vhd->vhost, &ac->cwsi, &ac->i, buf, "POST"); if (!cwsi) lwsl_notice("%s: failed to connect\n", __func__); return -1; /* close the completed client connection */ } else { lwsl_notice("new-reg replied %d\n", ac->resp); goto failed; } return -1; /* close the completed client connection */ case ACME_STATE_NEW_AUTH: lejp_destruct(&ac->jctx); if (ac->resp / 100 == 4) { lws_snprintf(buf, sizeof(buf), "Auth failed: %s", ac->detail); failreason = buf; lwsl_notice("auth failed\n"); goto failed; } lwsl_notice("chall: %s (%d)\n", ac->chall_token, ac->resp); if (!ac->chall_token[0]) { lwsl_notice("no challenge\n"); goto failed; } ac->state = ACME_STATE_ACCEPT_CHALL; lws_acme_report_status(vhd->vhost, LWS_CUS_CHALLENGE, NULL); /* tls-sni-01 ... what a mess. * The stuff in * https://tools.ietf.org/html/ * draft-ietf-acme-acme-01#section-7.3 * "requires" n but it's missing from let's encrypt * tls-sni-01 challenge. The go docs say that they just * implement one hashing round regardless * https://godoc.org/golang.org/x/crypto/acme * * The go way is what is actually implemented today by * letsencrypt * * "A client responds to this challenge by constructing * a key authorization from the "token" value provided * in the challenge and the client's account key. The * client first computes the SHA-256 digest Z0 of the * UTF8-encoded key authorization, and encodes Z0 in * UTF-8 lower-case hexadecimal form." */ /* tls-sni-02 * * SAN A MUST be constructed as follows: compute the * SHA-256 digest of the UTF-8-encoded challenge token * and encode it in lowercase hexadecimal form. The * dNSName is "x.y.token.acme.invalid", where x * is the first half of the hexadecimal representation * and y is the second half. */ memset(&ac->ci, 0, sizeof(ac->ci)); /* first compute the key authorization */ lws_jwk_rfc7638_fingerprint(&vhd->jwk, digest); p = start; end = &buf[sizeof(buf) - 1]; p += lws_snprintf(p, end - p, "%s.", ac->chall_token); n = lws_jws_base64_enc(digest, 32, p, end - p); if (n < 0) goto failed; p += n; if (lws_genhash_init(&hctx, LWS_GENHASH_TYPE_SHA256)) return -1; if (lws_genhash_update(&hctx, (uint8_t *)start, lws_ptr_diff(p, start))) { lws_genhash_destroy(&hctx, NULL); return -1; } if (lws_genhash_destroy(&hctx, digest)) return -1; p = buf; for (n = 0; n < 32; n++) { p += lws_snprintf(p, end - p, "%02x", digest[n] & 0xff); if (n == (32 / 2) - 1) p = buf + 64; } p = ac->san_a; if (ac->is_sni_02) { lws_snprintf(p, sizeof(ac->san_a), "%s.%s.token.acme.invalid", buf, buf + 64); /* * SAN B MUST be constructed as follows: compute * the SHA-256 digest of the UTF-8 encoded key * authorization and encode it in lowercase * hexadecimal form. The dNSName is * "x.y.ka.acme.invalid" where x is the first * half of the hexadecimal representation and y * is the second half. */ lws_jwk_rfc7638_fingerprint(&vhd->jwk, (char *)digest); p = buf; for (n = 0; n < 32; n++) { p += lws_snprintf(p, end - p, "%02x", digest[n] & 0xff); if (n == (32 / 2) - 1) p = buf + 64; } p = ac->san_b; lws_snprintf(p, sizeof(ac->san_b), "%s.%s.ka.acme.invalid", buf, buf + 64); } else { lws_snprintf(p, sizeof(ac->san_a), "%s.%s.acme.invalid", buf, buf + 64); ac->san_b[0] = '\0'; } lwsl_notice("san_a: '%s'\n", ac->san_a); lwsl_notice("san_b: '%s'\n", ac->san_b); /* * tls-sni-01: * * The client then configures the TLS server at the * domain such that when a handshake is initiated with * the Server Name Indication extension set to * "<Zi[0:32]>.<Zi[32:64]>.acme.invalid", the * corresponding generated certificate is presented. * * tls-sni-02: * * The client MUST ensure that the certificate is * served to TLS connections specifying a Server Name * Indication (SNI) value of SAN A. */ ac->ci.vhost_name = ac->san_a; /* * we bind to exact iface of real vhost, so we can * share the listen socket by SNI */ ac->ci.iface = ac->real_vh_iface; /* listen on the same port as the vhost that triggered * us */ ac->ci.port = ac->real_vh_port; /* Skip filling in any x509 info into the ssl_ctx. * It will be done at the callback * LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS * in this callback handler (below) */ ac->ci.options = LWS_SERVER_OPTION_CREATE_VHOST_SSL_CTX | LWS_SERVER_OPTION_SKIP_PROTOCOL_INIT | LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT; /* make ourselves protocols[0] for the new vhost */ ac->ci.protocols = acme_protocols; /* * vhost .user points to the ac associated with the * temporary vhost */ ac->ci.user = ac; ac->vhost = lws_create_vhost(lws_get_context(wsi), &ac->ci); if (!ac->vhost) goto failed; /* * The challenge-specific vhost is up... let the ACME * server know we are ready to roll... */ ac->goes_around = 0; cwsi = lws_acme_client_connect(vhd->context, vhd->vhost, &ac->cwsi, &ac->i, ac->challenge_uri, "POST"); if (!cwsi) { lwsl_notice("%s: failed to connect\n", __func__); goto failed; } return -1; /* close the completed client connection */ case ACME_STATE_ACCEPT_CHALL: /* * he returned something like this (which we parsed) * * { * "type": "tls-sni-01", * "status": "pending", * "uri": "https://acme-staging.api.letsencrypt.org/ * acme/challenge/xCt7bT3FaxoIQU3Qry87t5h * uKDcC-L-0ERcD5DLAZts/71100507", * "token": "j2Vs-vLI_dsza4A35SFHIU03aIe2PzFRijbqCY * dIVeE", * "keyAuthorization": "j2Vs-vLI_dsza4A35SFHIU03aIe2 * PzFRijbqCYdIVeE.nmOtdFd8Jikn6K8NnYYmT5 * vCM_PwSDT8nLdOYoFXhRU" * } * */ lwsl_notice("%s: COMPLETED accept chall: %s\n", __func__, ac->challenge_uri); poll_again: ac->state = ACME_STATE_POLLING; lws_acme_report_status(vhd->vhost, LWS_CUS_CHALLENGE, NULL); if (ac->goes_around++ == 20) { lwsl_notice("%s: too many chall retries\n", __func__); goto failed; } lws_timed_callback_vh_protocol(vhd->vhost, vhd->protocol, LWS_CALLBACK_USER + 0xac33, ac->goes_around == 1 ? 10 : 2); return -1; /* close the completed client connection */ case ACME_STATE_POLLING: if (ac->resp == 202 && strcmp(ac->status, "invalid") && strcmp(ac->status, "valid")) { lwsl_notice("status: %s\n", ac->status); goto poll_again; } if (!strcmp(ac->status, "invalid")) { lwsl_notice("%s: polling failed\n", __func__); lws_snprintf(buf, sizeof(buf), "Challenge Invalid: %s", ac->detail); failreason = buf; goto failed; } lwsl_notice("Challenge passed\n"); /* * The challenge was validated... so delete the * temp SNI vhost now its job is done */ if (ac->vhost) lws_vhost_destroy(ac->vhost); ac->vhost = NULL; /* * now our JWK is accepted as authorized to make * requests for the domain, next move is create the * CSR signed with the JWK, and send it to the ACME * server to request the actual certs. */ ac->state = ACME_STATE_POLLING_CSR; lws_acme_report_status(vhd->vhost, LWS_CUS_REQ, NULL); ac->goes_around = 0; strcpy(buf, ac->urls[JAD_NEW_CERT_URL]); cwsi = lws_acme_client_connect(vhd->context, vhd->vhost, &ac->cwsi, &ac->i, buf, "POST"); if (!cwsi) { lwsl_notice("%s: failed to connect to acme\n", __func__); goto failed; } return -1; /* close the completed client connection */ case ACME_STATE_POLLING_CSR: /* * (after POSTing the CSR)... * * If the CA decides to issue a certificate, then the * server creates a new certificate resource and * returns a URI for it in the Location header field * of a 201 (Created) response. * * HTTP/1.1 201 Created * Location: https://example.com/acme/cert/asdf * * If the certificate is available at the time of the * response, it is provided in the body of the response. * If the CA has not yet issued the certificate, the * body of this response will be empty. The client * should then send a GET request to the certificate URI * to poll for the certificate. As long as the * certificate is unavailable, the server MUST provide a * 202 (Accepted) response and include a Retry-After * header to indicate when the server believes the * certificate will be issued. */ if (ac->resp < 200 || ac->resp > 202) { lwsl_notice("CSR poll failed on resp %d\n", ac->resp); goto failed; } if (ac->resp == 200) { char *pp; int max; lwsl_notice("The cert was sent..\n"); lws_acme_report_status(vhd->vhost, LWS_CUS_ISSUE, NULL); /* * That means we have the issued cert DER in * ac->buf, length in ac->cpos; and the key in * ac->alloc_privkey_pem, length in * ac->len_privkey_pem. * * We write out a PEM copy of the cert, and a * PEM copy of the private key, using the * write-only fds we opened while we still * had root. * * Estimate the size of the PEM version of the * cert and allocate a temp buffer for it. * * This is a bit complicated because first we * drop the b64url version into the buffer at * +384, then we add the header at 0 and move * lines of it back + '\n' to make PEM. * * This avoids the need for two fullsize * allocations. */ max = (ac->cpos * 4) / 3 + 16 + 384; start = p = malloc(max); if (!p) goto failed; n = lws_b64_encode_string(ac->buf, ac->cpos, start + 384, max - 384); if (n < 0) { free(start); goto failed; } pp = start + 384; p += lws_snprintf(start, 64, "%s", "-----BEGIN CERTIFICATE-----\n"); while (n) { m = 65; if (n < m) m = n; memcpy(p, pp, m); n -= m; p += m; pp += m; if (n) *p++ = '\n'; } p += lws_snprintf(p, max - lws_ptr_diff(p, start), "%s", "\n-----END CERTIFICATE-----\n"); n = lws_plat_write_cert(vhd->vhost, 0, vhd->fd_updated_cert, start, lws_ptr_diff(p, start)); free(start); if (n) { lwsl_err("unable to write ACME cert! %d\n", n); goto failed; } /* * don't close it... we may update the certs * again */ if (lws_plat_write_cert(vhd->vhost, 1, vhd->fd_updated_key, ac->alloc_privkey_pem, ac->len_privkey_pem)) { lwsl_err("unable to write ACME key!\n"); goto failed; } /* * we have written the persistent copies */ lwsl_notice("%s: Updated certs written for %s " "to %s.upd and %s.upd\n", __func__, vhd->pvop_active[LWS_TLS_REQ_ELEMENT_COMMON_NAME], vhd->pvop_active[LWS_TLS_SET_CERT_PATH], vhd->pvop_active[LWS_TLS_SET_KEY_PATH]); /* notify lws there was a cert update */ if (lws_tls_cert_updated(vhd->context, vhd->pvop_active[LWS_TLS_SET_CERT_PATH], vhd->pvop_active[LWS_TLS_SET_KEY_PATH], ac->buf, ac->cpos, ac->alloc_privkey_pem, ac->len_privkey_pem)) { lwsl_notice("problem setting certs\n"); } lws_acme_finished(vhd); lws_acme_report_status(vhd->vhost, LWS_CUS_SUCCESS, NULL); return 0; } lws_acme_report_status(vhd->vhost, LWS_CUS_CONFIRM, NULL); /* he is preparing the cert, go again with a GET */ if (ac->goes_around++ == 30) { lwsl_notice("%s: too many retries\n", __func__); goto failed; } strcpy(buf, ac->challenge_uri); cwsi = lws_acme_client_connect(vhd->context, vhd->vhost, &ac->cwsi, &ac->i, buf, "GET"); if (!cwsi) { lwsl_notice("%s: failed to connect to acme\n", __func__); goto failed; } return -1; /* close the completed client connection */ default: break; } break; case LWS_CALLBACK_USER + 0xac33: if (!vhd) break; cwsi = lws_acme_client_connect(vhd->context, vhd->vhost, &ac->cwsi, &ac->i, ac->challenge_uri, "GET"); if (!cwsi) { lwsl_notice("%s: failed to connect\n", __func__); goto failed; } break; case LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS: /* * This goes to vhost->protocols[0], but for our temp certs * vhost we created, we have arranged that to be our protocol, * so the callback will come here. * * When we created the temp vhost, we set its pvo to point * to the ac associated with the temp vhost. */ lwsl_debug("LWS_CALLBACK_OPENSSL_LOAD_EXTRA_SERVER_VERIFY_CERTS\n"); ac = (struct acme_connection *)lws_get_vhost_user( (struct lws_vhost *)in); lws_acme_report_status((struct lws_vhost *)in, LWS_CUS_CREATE_REQ, "creating challenge cert"); if (lws_tls_acme_sni_cert_create((struct lws_vhost *)in, ac->san_a, ac->san_b)) { lwsl_err("%s: creating the sni test cert failed\n", __func__); return -1; } break; default: break; } return 0; failed: lwsl_err("%s: failed out\n", __func__); lws_acme_report_status(vhd->vhost, LWS_CUS_FAILED, failreason); lws_acme_finished(vhd); return -1; }
int kex_ecdh(struct per_session_data__sshd *pss, uint8_t *reply, uint32_t *plen) { uint8_t pri_key[64], temp[64], payload_sig[64 + 32], a, *lp, kbi[64]; struct lws_kex *kex = pss->kex; struct lws_genhash_ctx ctx; unsigned long long smlen; uint8_t *p = reply + 5; uint32_t be, kbi_len; uint8_t servkey[256]; char keyt[33]; int r, c; r = get_gen_server_key_25519(pss, servkey, sizeof(servkey)); if (!r) { lwsl_err("%s: Failed to get or gen server key\n", __func__); return 1; } r = ed25519_key_parse(servkey, r, keyt, sizeof(keyt), pss->K_S /* public key */, pri_key); if (r) { lwsl_notice("%s: server key parse failed: %d\n", __func__, r); return 1; } keyt[32] = '\0'; lwsl_info("Server key type: %s\n", keyt); /* * 1) Generate ephemeral key pair [ eph_pri_key | kex->Q_S ] * 2) Compute shared secret. * 3) Generate and sign exchange hash. * * 1) A 32 bytes private key should be generated for each new * connection, using a secure PRNG. The following actions * must be done on the private key: * * mysecret[0] &= 248; * mysecret[31] &= 127; * mysecret[31] |= 64; */ lws_get_random(pss->vhd->context, kex->eph_pri_key, LWS_SIZE_EC25519); kex->eph_pri_key[0] &= 248; kex->eph_pri_key[31] &= 127; kex->eph_pri_key[31] |= 64; /* * 2) The public key is calculated using the cryptographic scalar * multiplication: * * const unsigned char privkey[32]; * unsigned char pubkey[32]; * * crypto_scalarmult (pubkey, privkey, basepoint); */ crypto_scalarmult_curve25519(kex->Q_S, kex->eph_pri_key, basepoint); a = 0; for (r = 0; r < sizeof(kex->Q_S); r++) a |= kex->Q_S[r]; if (!a) { lwsl_notice("all zero pubkey\n"); return SSH_DISCONNECT_KEY_EXCHANGE_FAILED; } /* * The shared secret, k, is defined in SSH specifications to be a big * integer. This number is calculated using the following procedure: * * X is the 32 bytes point obtained by the scalar multiplication of * the other side's public key and the local private key scalar. */ crypto_scalarmult_curve25519(pss->K, kex->eph_pri_key, kex->Q_C); /* * The whole 32 bytes of the number X are then converted into a big * integer k. This conversion follows the network byte order. This * step differs from RFC5656. */ kbi_len = lws_mpint_rfc4251(kbi, pss->K, LWS_SIZE_EC25519, 1); /* * The exchange hash H is computed as the hash of the concatenation of * the following: * * string V_C, the client's identification string (CR and LF * excluded) * string V_S, the server's identification string (CR and LF * excluded) * string I_C, the payload of the client's SSH_MSG_KEXINIT * string I_S, the payload of the server's SSH_MSG_KEXINIT * string K_S, the host key * mpint Q_C, exchange value sent by the client * mpint Q_S, exchange value sent by the server * mpint K, the shared secret * * However there are a lot of unwritten details in the hash * definition... */ if (lws_genhash_init(&ctx, LWS_GENHASH_TYPE_SHA256)) { lwsl_notice("genhash init failed\n"); return 1; } if (_genhash_update_len(&ctx, pss->V_C, strlen(pss->V_C))) goto hash_probs; if (_genhash_update_len(&ctx, pss->vhd->ops->server_string, /* aka V_S */ strlen(pss->vhd->ops->server_string))) goto hash_probs; if (_genhash_update_len(&ctx, kex->I_C, kex->I_C_payload_len)) goto hash_probs; if (_genhash_update_len(&ctx, kex->I_S, kex->I_S_payload_len)) goto hash_probs; /* * K_S (host public key) * * sum of name + key lengths and headers * name length: name * key length: key * ---> */ lws_p32((uint8_t *)&be, 8 + strlen(keyt) + LWS_SIZE_EC25519); if (lws_genhash_update(&ctx, (void *)&be, 4)) goto hash_probs; if (_genhash_update_len(&ctx, keyt, strlen(keyt))) goto hash_probs; if (_genhash_update_len(&ctx, pss->K_S, LWS_SIZE_EC25519)) goto hash_probs; /* <---- */ if (_genhash_update_len(&ctx, kex->Q_C, LWS_SIZE_EC25519)) goto hash_probs; if (_genhash_update_len(&ctx, kex->Q_S, LWS_SIZE_EC25519)) goto hash_probs; if (lws_genhash_update(&ctx, kbi, kbi_len)) goto hash_probs; if (lws_genhash_destroy(&ctx, temp)) goto hash_probs; /* * Sign the 32-byte SHA256 "exchange hash" in temp * The signature is itself 64 bytes */ smlen = LWS_SIZE_EC25519 + 64; if (crypto_sign_ed25519(payload_sig, &smlen, temp, LWS_SIZE_EC25519, pri_key)) return 1; #if 0 l = LWS_SIZE_EC25519; n = crypto_sign_ed25519_open(temp, &l, payload_sig, smlen, pss->K_S); lwsl_notice("own sig sanity check says %d\n", n); #endif /* sig [64] and payload [32] concatenated in payload_sig * * The server then responds with the following * * uint32 packet length (exl self + mac) * byte padding len * byte SSH_MSG_KEX_ECDH_REPLY * string server public host key and certificates (K_S) * string Q_S (exchange value sent by the server) * string signature of H * padding */ *p++ = SSH_MSG_KEX_ECDH_REPLY; /* server public host key and certificates (K_S) */ lp = p; p +=4; lws_sized_blob(&p, keyt, strlen(keyt)); lws_sized_blob(&p, pss->K_S, LWS_SIZE_EC25519); lws_p32(lp, p - lp - 4); /* Q_S (exchange value sent by the server) */ lws_sized_blob(&p, kex->Q_S, LWS_SIZE_EC25519); /* signature of H */ lp = p; p +=4; lws_sized_blob(&p, keyt, strlen(keyt)); lws_sized_blob(&p, payload_sig, 64); lws_p32(lp, p - lp - 4); /* end of message */ lws_pad_set_length(pss, reply, &p, &pss->active_keys_stc); *plen = p - reply; if (!pss->active_keys_stc.valid) memcpy(pss->session_id, temp, LWS_SIZE_EC25519); /* RFC4253 7.2: * * The key exchange produces two values: a shared secret K, * and an exchange hash H. Encryption and authentication * keys are derived from these. The exchange hash H from the * first key exchange is additionally used as the session * identifier, which is a unique identifier for this connection. * It is used by authentication methods as a part of the data * that is signed as a proof of possession of a private key. * Once computed, the session identifier is not changed, * even if keys are later re-exchanged. * * The hash alg used in the KEX must be used for key derivation. * * 1) Initial IV client to server: * * HASH(K || H || "A" || session_id) * * (Here K is encoded as mpint and "A" as byte and session_id * as raw data. "A" means the single character A, ASCII 65). * * */ for (c = 0; c < 3; c++) { kex_ecdh_dv(kex->keys_next_cts.key[c], LWS_SIZE_CHACHA256_KEY, kbi, kbi_len, temp, 'A' + (c * 2), pss->session_id); kex_ecdh_dv(kex->keys_next_stc.key[c], LWS_SIZE_CHACHA256_KEY, kbi, kbi_len, temp, 'B' + (c * 2), pss->session_id); } explicit_bzero(temp, sizeof(temp)); return 0; hash_probs: lws_genhash_destroy(&ctx, NULL); return 1; }
LWS_VISIBLE int lws_tls_acme_sni_cert_create(struct lws_vhost *vhost, const char *san_a, const char *san_b) { int buflen = 0x560; uint8_t *buf = lws_malloc(buflen, "tmp cert buf"), *p = buf, *pkey_asn1; struct lws_genrsa_ctx ctx; struct lws_genrsa_elements el; uint8_t digest[32]; struct lws_genhash_ctx hash_ctx; int pkey_asn1_len = 3 * 1024; int n, keybits = lws_plat_recommended_rsa_bits(), adj; if (!buf) return 1; n = lws_genrsa_new_keypair(vhost->context, &ctx, &el, keybits); if (n < 0) { lws_jwk_destroy_genrsa_elements(&el); goto bail1; } n = sizeof(ss_cert_leadin); memcpy(p, ss_cert_leadin, n); p += n; adj = (0x0556 - 0x401) + (keybits / 4) + 1; buf[2] = adj >> 8; buf[3] = adj & 0xff; adj = (0x033e - 0x201) + (keybits / 8) + 1; buf[6] = adj >> 8; buf[7] = adj & 0xff; adj = (0x0222 - 0x201) + (keybits / 8) + 1; buf[0xc3] = adj >> 8; buf[0xc4] = adj & 0xff; adj = (0x020f - 0x201) + (keybits / 8) + 1; buf[0xd6] = adj >> 8; buf[0xd7] = adj & 0xff; adj = (0x020a - 0x201) + (keybits / 8) + 1; buf[0xdb] = adj >> 8; buf[0xdc] = adj & 0xff; *p++ = ((keybits / 8) + 1) >> 8; *p++ = ((keybits / 8) + 1) & 0xff; /* we need to drop 1 + (keybits / 8) bytes of n in here, 00 + key */ *p++ = 0x00; memcpy(p, el.e[JWK_KEY_N].buf, el.e[JWK_KEY_N].len); p += el.e[JWK_KEY_N].len; memcpy(p, ss_cert_san_leadin, sizeof(ss_cert_san_leadin)); p += sizeof(ss_cert_san_leadin); /* drop in 78 bytes of san_a */ memcpy(p, san_a, SAN_A_LENGTH); p += SAN_A_LENGTH; memcpy(p, ss_cert_sig_leadin, sizeof(ss_cert_sig_leadin)); p[17] = ((keybits / 8) + 1) >> 8; p[18] = ((keybits / 8) + 1) & 0xff; p += sizeof(ss_cert_sig_leadin); /* hash the cert plaintext */ if (lws_genhash_init(&hash_ctx, LWS_GENHASH_TYPE_SHA256)) goto bail2; if (lws_genhash_update(&hash_ctx, buf, lws_ptr_diff(p, buf))) { lws_genhash_destroy(&hash_ctx, NULL); goto bail2; } if (lws_genhash_destroy(&hash_ctx, digest)) goto bail2; /* sign the hash */ n = lws_genrsa_public_sign(&ctx, digest, LWS_GENHASH_TYPE_SHA256, p, buflen - lws_ptr_diff(p, buf)); if (n < 0) goto bail2; p += n; pkey_asn1 = lws_malloc(pkey_asn1_len, "mbed crt tmp"); if (!pkey_asn1) goto bail2; n = lws_genrsa_render_pkey_asn1(&ctx, 1, pkey_asn1, pkey_asn1_len); if (n < 0) { lws_free(pkey_asn1); goto bail2; } lwsl_debug("private key\n"); lwsl_hexdump_level(LLL_DEBUG, pkey_asn1, n); /* and to use our generated private key */ n = SSL_CTX_use_PrivateKey_ASN1(0, vhost->ssl_ctx, pkey_asn1, n); lws_free(pkey_asn1); if (n != 1) { lwsl_notice("%s: SSL_CTX_use_PrivateKey_ASN1 failed\n", __func__); } lws_genrsa_destroy(&ctx); lws_jwk_destroy_genrsa_elements(&el); if (n == 1) { lwsl_hexdump_level(LLL_DEBUG, buf, lws_ptr_diff(p, buf)); n = SSL_CTX_use_certificate_ASN1(vhost->ssl_ctx, lws_ptr_diff(p, buf), buf); if (n != 1) lwsl_notice("%s: generated cert failed to load 0x%x\n", __func__, -n); } lws_free(buf); return n != 1; bail2: lws_genrsa_destroy(&ctx); lws_jwk_destroy_genrsa_elements(&el); bail1: lws_free(buf); return -1; }
static int kex_ecdh_dv(uint8_t *dest, int dest_len, const uint8_t *kbi, int kbi_len, const uint8_t *H, char c, const uint8_t *session_id) { uint8_t pool[LWS_SIZE_SHA256]; struct lws_genhash_ctx ctx; int n = 0, m; /* * Key data MUST be taken from the beginning of the hash output. * As many bytes as needed are taken from the beginning of the hash * value. * * If the key length needed is longer than the output of the HASH, * the key is extended by computing HASH of the concatenation of K * and H and the entire key so far, and appending the resulting * bytes (as many as HASH generates) to the key. This process is * repeated until enough key material is available; the key is taken * from the beginning of this value. In other words: * * K1 = HASH(K || H || X || session_id) (X is e.g., "A") * K2 = HASH(K || H || K1) * K3 = HASH(K || H || K1 || K2) * ... * key = K1 || K2 || K3 || ... */ while (n < dest_len) { if (lws_genhash_init(&ctx, LWS_GENHASH_TYPE_SHA256)) return 1; if (lws_genhash_update(&ctx, kbi, kbi_len)) goto hash_failed; if (lws_genhash_update(&ctx, H, LWS_SIZE_SHA256)) goto hash_failed; if (!n) { if (lws_genhash_update(&ctx, (void *)&c, 1)) goto hash_failed; if (lws_genhash_update(&ctx, session_id, LWS_SIZE_EC25519)) goto hash_failed; } else if (lws_genhash_update(&ctx, pool, LWS_SIZE_EC25519)) goto hash_failed; lws_genhash_destroy(&ctx, pool); m = LWS_SIZE_EC25519; if (m > (dest_len - n)) m = dest_len - n; memcpy(dest, pool, m); n += m; dest += m; } return 0; hash_failed: lws_genhash_destroy(&ctx, NULL); return 1; }