/*
* libwebsockets ACME client protocol plugin
*
* Copyright (C) 2017 Andy Green <andy@warmcat.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation:
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*
*
* Acme is in a big messy transition at the moment from a homebrewed api
* to an IETF one. The old repo for the homebrew api (they currently
* implement) is marked up as deprecated and "not accurate[ly] reflect[ing]"
* what they implement, but the IETF standard, currently at v7 is not yet
* implemented at let's encrypt (ETA Jan 2018).
*
* This implementation follows draft 7 of the IETF standard, and falls back
* to whatever differences exist for Boulder's tls-sni-01 challenge. The
* tls-sni-02 support is there but nothing to test it against at the time of
* writing (Nov 1 2017).
*/
#if !defined (LWS_PLUGIN_STATIC)
#define LWS_DLL
#define LWS_INTERNAL
#include <libwebsockets.h>
#endif
#include <string.h>
#include <stdlib.h>
typedef enum {
ACME_STATE_DIRECTORY, /* get the directory JSON using GET + parse */
ACME_STATE_NEW_REG, /* register a new RSA key + email combo */
ACME_STATE_NEW_AUTH, /* start the process to request a cert */
ACME_STATE_ACCEPT_CHALL, /* notify server ready for one challenge */
ACME_STATE_POLLING, /* he should be trying our challenge */
ACME_STATE_POLLING_CSR, /* sent CSR, checking result */
ACME_STATE_FINISHED
} lws_acme_state;
struct acme_connection {
char buf[4096];
char replay_nonce[64];
char chall_token[64];
char challenge_uri[256];
char detail[64];
char status[16];
char san_a[100];
char san_b[100];
char urls[6][100]; /* directory contents */
lws_acme_state state;
struct lws_client_connect_info i;
struct lejp_ctx jctx;
struct lws_context_creation_info ci;
struct lws_vhost *vhost;
struct lws *cwsi;
const char *real_vh_name;
const char *real_vh_iface;
char *alloc_privkey_pem;
char *dest;
int pos;
int len;
int resp;
int cpos;
int real_vh_port;
int goes_around;
size_t len_privkey_pem;
unsigned int yes:2;
unsigned int use:1;
unsigned int is_sni_02:1;
};
struct per_vhost_data__lws_acme_client {
struct lws_context *context;
struct lws_vhost *vhost;
const struct lws_protocols *protocol;
/*
* the vhd is allocated for every vhost using the plugin.
* But ac is only allocated when we are doing the server auth.
*/
struct acme_connection *ac;
struct lws_jwk jwk;
struct lws_genrsa_ctx rsactx;
char *pvo_data;
char *pvop[LWS_TLS_TOTAL_COUNT];
const char *pvop_active[LWS_TLS_TOTAL_COUNT];
int count_live_pss;
char *dest;
int pos;
int len;
int fd_updated_cert; /* these are opened while we have root... */
int fd_updated_key; /* ...if nonempty next startup will replace old */
};
static int
callback_acme_client(struct lws *wsi, enum lws_callback_reasons reason,
void *user, void *in, size_t len);
#define LWS_PLUGIN_PROTOCOL_LWS_ACME_CLIENT \
{ \
"lws-acme-client", \
callback_acme_client, \
0, \
512, \
0, NULL, 0 \
}
static const struct lws_protocols acme_protocols[] = {
LWS_PLUGIN_PROTOCOL_LWS_ACME_CLIENT,
{ NULL, NULL, 0, 0, 0, NULL, 0 }
};
/* directory JSON parsing */
static const char * const jdir_tok[] = {
"key-change",
"meta.terms-of-service",
"new-authz",
"new-cert",
"new-reg",
"revoke-cert",
};
enum enum_jhdr_tok {
JAD_KEY_CHANGE_URL,
JAD_TOS_URL,
JAD_NEW_AUTHZ_URL,
JAD_NEW_CERT_URL,
JAD_NEW_REG_URL,
JAD_REVOKE_CERT_URL,
};
static signed char
cb_dir(struct lejp_ctx *ctx, char reason)
{
struct per_vhost_data__lws_acme_client *s =
(struct per_vhost_data__lws_acme_client *)ctx->user;
if (reason == LEJPCB_VAL_STR_START && ctx->path_match) {
s->pos = 0;
s->len = sizeof(s->ac->urls[0]) - 1;
s->dest = s->ac->urls[ctx->path_match - 1];
return 0;
}
if (!(reason & LEJP_FLAG_CB_IS_VALUE) || !ctx->path_match)
return 0;
if (s->pos + ctx->npos > s->len) {
lwsl_notice("url too long\n");
return -1;
}
memcpy(s->dest + s->pos, ctx->buf, ctx->npos);
s->pos += ctx->npos;
s->dest[s->pos] = '\0';
return 0;
}
/* authz JSON parsing */
static const char * const jauthz_tok[] = {
"identifier.type",
"identifier.value",
"status",
"expires",
"challenges[].type",
"challenges[].status",
"challenges[].uri",
"challenges[].token",
"detail"
};
enum enum_jauthz_tok {
JAAZ_ID_TYPE,
JAAZ_ID_VALUE,
JAAZ_STATUS,
JAAZ_EXPIRES,
JAAZ_CHALLENGES_TYPE,
JAAZ_CHALLENGES_STATUS,
JAAZ_CHALLENGES_URI,
JAAZ_CHALLENGES_TOKEN,
JAAZ_DETAIL,
};
static signed char
cb_authz(struct lejp_ctx *ctx, char reason)
{
struct acme_connection *s = (struct acme_connection *)ctx->user;
if (reason == LEJPCB_CONSTRUCTED) {
s->yes = 0;
s->use = 0;
s->chall_token[0] = '\0';
s->is_sni_02 = 0;
}
if (!(reason & LEJP_FLAG_CB_IS_VALUE) || !ctx->path_match)
return 0;
switch (ctx->path_match - 1) {
case JAAZ_ID_TYPE:
break;
case JAAZ_ID_VALUE:
break;
case JAAZ_STATUS:
break;
case JAAZ_EXPIRES:
break;
case JAAZ_DETAIL:
lws_snprintf(s->detail, sizeof(s->detail), "%s", ctx->buf);
break;
case JAAZ_CHALLENGES_TYPE:
if (s->is_sni_02)
break;
s->use = !strcmp(ctx->buf, "tls-sni-01") ||
!strcmp(ctx->buf, "tls-sni-02");
s->is_sni_02 = !strcmp(ctx->buf, "tls-sni-02");
break;
case JAAZ_CHALLENGES_STATUS:
lws_strncpy(s->status, ctx->buf, sizeof(s->status));
break;
case JAAZ_CHALLENGES_URI:
if (s->use) {
lws_strncpy(s->challenge_uri, ctx->buf,
sizeof(s->challenge_uri));
s->yes |= 2;
}
break;
case JAAZ_CHALLENGES_TOKEN:
lwsl_notice("JAAZ_CHALLENGES_TOKEN: %s %d\n", ctx->buf, s->use);
if (s->use) {
lws_strncpy(s->chall_token, ctx->buf,
sizeof(s->chall_token));
s->yes |= 1;
}
break;
}
return 0;
}
/* challenge accepted JSON parsing */
static const char * const jchac_tok[] = {
"type",
"status",
"uri",
"token",
"error.detail"
};
enum enum_jchac_tok {
JCAC_TYPE,
JCAC_STATUS,
JCAC_URI,
JCAC_TOKEN,
JCAC_DETAIL,
};
static signed char
cb_chac(struct lejp_ctx *ctx, char reason)
{
struct acme_connection *s = (struct acme_connection *)ctx->user;
if (reason == LEJPCB_CONSTRUCTED) {
s->yes = 0;
s->use = 0;
}
if (!(reason & LEJP_FLAG_CB_IS_VALUE) || !ctx->path_match)
return 0;
switch (ctx->path_match - 1) {
case JCAC_TYPE:
if (strcmp(ctx->buf, "tls-sni-01") &&
strcmp(ctx->buf, "tls-sni-02"))
return 1;
break;
case JCAC_STATUS:
lws_strncpy(s->status, ctx->buf, sizeof(s->status));
break;
case JCAC_URI:
s->yes |= 2;
break;
case JCAC_TOKEN:
lws_strncpy(s->chall_token, ctx->buf,
sizeof(s->chall_token));
s->yes |= 1;
break;
case JCAC_DETAIL:
lws_snprintf(s->detail, sizeof(s->detail), "%s", ctx->buf);
break;
}
return 0;
}
/* https://github.com/letsencrypt/boulder/blob/release/docs/acme-divergences.md
*
* 7.1:
*
* Boulder does not implement the new-order resource.
* Instead of new-order Boulder implements the new-cert resource that is
* defined in draft-ietf-acme-02 Section 6.5.
*
* Boulder also doesn't implement the new-nonce endpoint.
*
* Boulder implements the new-account resource only under the new-reg key.
*
* Boulder implements Link: rel="next" headers from new-reg to new-authz, and
* new-authz to new-cert, as specified in draft-02, but these links are not
* provided in the latest draft, and clients should use URLs from the directory
* instead.
*
* Boulder does not provide the "index" link relation pointing at the
* directory URL.
*
* (ie, just use new-cert instead of new-order, use the directory for links)
*/
static int
lws_acme_report_status(struct lws_vhost *v, int state, const char *json)
{
lws_callback_vhost_protocols_vhost(v, LWS_CALLBACK_VHOST_CERT_UPDATE,
(void *)json, state);
return 0;
}
/*
* Notice: trashes i and url
*/
static struct lws *
lws_acme_client_connect(struct lws_context *context, struct lws_vhost *vh,
struct lws **pwsi, struct lws_client_connect_info *i,
char *url, const char *method)
{
const char *prot, *p;
char path[200], _url[256];
struct lws *wsi;
memset(i, 0, sizeof(*i));
i->port = 443;
lws_strncpy(_url, url, sizeof(_url));
if (lws_parse_uri(_url, &prot, &i->address, &i->port, &p)) {
lwsl_err("unable to parse uri %s\n", url);
return NULL;
}
/* add back the leading / on path */
path[0] = '/';
lws_strncpy(path + 1, p, sizeof(path) - 1);
i->path = path;
i->context = context;
i->vhost = vh;
i->ssl_connection = 1;
i->host = i->address;
i->origin = i->address;
i->method = method;
i->pwsi = pwsi;
i->protocol = "lws-acme-client";
wsi = lws_client_connect_via_info(i);
if (!wsi) {
lws_snprintf(path, sizeof(path) - 1,
"Unable to connect to %s", url);
lwsl_notice("%s: %s\n", __func__, path);
lws_acme_report_status(vh, LWS_CUS_FAILED, path);
}
return wsi;
}
static void
lws_acme_finished(struct per_vhost_data__lws_acme_client *vhd)
{
lwsl_debug("%s\n", __func__);
if (vhd->ac) {
if (vhd->ac->vhost)
lws_vhost_destroy(vhd->ac->vhost);
if (vhd->ac->alloc_privkey_pem)
free(vhd->ac->alloc_privkey_pem);
free(vhd->ac);
}
lws_genrsa_destroy(&vhd->rsactx);
lws_jwk_destroy(&vhd->jwk);
vhd->ac = NULL;
#if defined(LWS_WITH_ESP32)
lws_esp32.acme = 0; /* enable scanning */
#endif
}
static const char * const pvo_names[] = {
"country",
"state",
"locality",
"organization",
"common-name",
"email",
"directory-url",
"auth-path",
"cert-path",
"key-path",
};
static int
lws_acme_load_create_auth_keys(struct per_vhost_data__lws_acme_client *vhd,
int bits)
{
int n;
if (!lws_jwk_load(&vhd->jwk, vhd->pvop[LWS_TLS_SET_AUTH_PATH],
NULL, NULL))
return 0;
vhd->jwk.kty = LWS_GENCRYPTO_KTY_RSA;
lwsl_notice("Generating ACME %d-bit keypair... "
"will take a little while\n", bits);
n = lws_genrsa_new_keypair(vhd->context, &vhd->rsactx, LGRSAM_PKCS1_1_5,
vhd->jwk.e, bits);
if (n) {
lwsl_notice("failed to create keypair\n");
return 1;
}
lwsl_notice("...keypair generated\n");
if (lws_jwk_save(&vhd->jwk,
vhd->pvop[LWS_TLS_SET_AUTH_PATH])) {
lwsl_notice("unable to save %s\n",
vhd->pvop[LWS_TLS_SET_AUTH_PATH]);
return 1;
}
return 0;
}
static int
lws_acme_start_acquisition(struct per_vhost_data__lws_acme_client *vhd,
struct lws_vhost *v)
{
char buf[128];
/* ...and we were given enough info to do the update? */
if (!vhd->pvop[LWS_TLS_REQ_ELEMENT_COMMON_NAME])
return -1;
/*
* ...well... we should try to do something about it then...
*/
lwsl_notice("%s: ACME cert needs creating / updating: "
"vhost %s\n", __func__, lws_get_vhost_name(vhd->vhost));
vhd->ac = malloc(sizeof(*vhd->ac));
memset(vhd->ac, 0, sizeof(*vhd->ac));
/*
* So if we don't have it, the first job is get the directory.
*
* If we already have the directory, jump straight into trying
* to register our key.
*
* We always try to register the keys... if it's not the first
* time, we will get a JSON body in the (legal, nonfatal)
* response like this
*
* {
* "type": "urn:acme:error:malformed",
* "detail": "Registration key is already in use",
* "status": 409
* }
*/
if (!vhd->ac->urls[0][0]) {
vhd->ac->state = ACME_STATE_DIRECTORY;
lws_snprintf(buf, sizeof(buf) - 1, "%s",
vhd->pvop_active[LWS_TLS_SET_DIR_URL]);
} else {
vhd->ac->state = ACME_STATE_NEW_REG;
lws_snprintf(buf, sizeof(buf) - 1, "%s",
vhd->ac->urls[JAD_NEW_REG_URL]);
}
vhd->ac->real_vh_port = lws_get_vhost_port(vhd->vhost);
vhd->ac->real_vh_name = lws_get_vhost_name(vhd->vhost);
vhd->ac->real_vh_iface = lws_get_vhost_iface(vhd->vhost);
lws_acme_report_status(vhd->vhost, LWS_CUS_STARTING, NULL);
#if defined(LWS_WITH_ESP32)
lws_acme_report_status(vhd->vhost, LWS_CUS_CREATE_KEYS,
"Generating keys, please wait");
if (lws_acme_load_create_auth_keys(vhd, 2048))
goto bail;
lws_acme_report_status(vhd->vhost, LWS_CUS_CREATE_KEYS,
"Auth keys created");
#endif
if (lws_acme_client_connect(vhd->context, vhd->vhost,
&vhd->ac->cwsi, &vhd->ac->i, buf, "GET"))
return 0;
#if defined(LWS_WITH_ESP32)
bail:
#endif
free(vhd->ac);
vhd->ac = NULL;
return 1;
}
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;
const struct lws_protocol_vhost_options *pvo;
struct lws_acme_cert_aging_args *caa;
struct acme_connection *ac = NULL;
struct lws_genhash_ctx hctx;
unsigned char **pp, *pend;
const char *content_type;
struct lws_jwe jwe;
struct lws *cwsi;
int n, m;
if (vhd)
ac = vhd->ac;
lws_jwe_init(&jwe, lws_get_context(wsi));
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:
if (lws_gencrypto_jwe_alg_to_definition("RSA1_5", &jwe.jose.alg)) {
ac->len = 0;
lwsl_notice("%s: no RSA1_5\n", __func__);
goto failed;
}
jwe.jws.jwk = &vhd->jwk;
ac->len = lws_jwe_create_packet(&jwe,
start, p - start,
ac->replay_nonce,
&ac->buf[LWS_PRE],
sizeof(ac->buf) -
LWS_PRE,
lws_get_context(wsi));
if (ac->len < 0) {
ac->len = 0;
lwsl_notice("lws_jwe_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;
}
#if !defined (LWS_PLUGIN_STATIC)
static const struct lws_protocols protocols[] = {
LWS_PLUGIN_PROTOCOL_LWS_ACME_CLIENT
};
LWS_EXTERN LWS_VISIBLE int
init_protocol_lws_acme_client(struct lws_context *context,
struct lws_plugin_capability *c)
{
if (c->api_magic != LWS_PLUGIN_API_MAGIC) {
lwsl_err("Plugin API %d, library API %d", LWS_PLUGIN_API_MAGIC,
c->api_magic);
return 1;
}
c->protocols = protocols;
c->count_protocols = LWS_ARRAY_SIZE(protocols);
c->extensions = NULL;
c->count_extensions = 0;
return 0;
}
LWS_EXTERN LWS_VISIBLE int
destroy_protocol_lws_acme_client(struct lws_context *context)
{
return 0;
}
#endif