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;
}
