diff options
Diffstat (limited to '')
| -rw-r--r-- | daemon/tls.c | 1214 |
1 files changed, 1214 insertions, 0 deletions
diff --git a/daemon/tls.c b/daemon/tls.c new file mode 100644 index 0000000..9637369 --- /dev/null +++ b/daemon/tls.c @@ -0,0 +1,1214 @@ +/* + * Copyright (C) 2016 American Civil Liberties Union (ACLU) + * Copyright (C) CZ.NIC, z.s.p.o + * + * Initial Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net> + * Ondřej Surý <ondrej@sury.org> + * + * SPDX-License-Identifier: GPL-3.0-or-later + */ + +#include <gnutls/abstract.h> +#include <gnutls/crypto.h> +#include <gnutls/gnutls.h> +#include <gnutls/x509.h> +#include <uv.h> + +#include <errno.h> +#include <stdlib.h> + +#include "contrib/ucw/lib.h" +#include "contrib/base64.h" +#include "daemon/tls.h" +#include "daemon/worker.h" +#include "daemon/session.h" + +#define EPHEMERAL_CERT_EXPIRATION_SECONDS_RENEW_BEFORE (60*60*24*7) +#define GNUTLS_PIN_MIN_VERSION 0x030400 + +#define VERBOSE_MSG(cl_side, ...)\ + if (cl_side) \ + kr_log_debug(TLSCLIENT, __VA_ARGS__); \ + else \ + kr_log_debug(TLS, __VA_ARGS__); + +/** @internal Debugging facility. */ +#ifdef DEBUG +#define DEBUG_MSG(...) kr_log_debug(TLS, __VA_ARGS__) +#else +#define DEBUG_MSG(...) +#endif + +struct async_write_ctx { + uv_write_t write_req; + struct tls_common_ctx *t; + char buf[]; +}; + +static int client_verify_certificate(gnutls_session_t tls_session); + +/** + * Set mandatory security settings from + * https://tools.ietf.org/html/draft-ietf-dprive-dtls-and-tls-profiles-11#section-9 + * Performance optimizations are not implemented at the moment. + */ +static int kres_gnutls_set_priority(gnutls_session_t session) { + static const char * const priorities = + "NORMAL:" /* GnuTLS defaults */ + "-VERS-TLS1.0:-VERS-TLS1.1:" /* TLS 1.2 and higher */ + /* Some distros by default allow features that are considered + * too insecure nowadays, so let's disable them explicitly. */ + "-VERS-SSL3.0:-ARCFOUR-128:-COMP-ALL:+COMP-NULL"; + const char *errpos = NULL; + int err = gnutls_priority_set_direct(session, priorities, &errpos); + if (err != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "setting priority '%s' failed at character %zd (...'%s') with %s (%d)\n", + priorities, errpos - priorities, errpos, gnutls_strerror_name(err), err); + } + return err; +} + +static ssize_t kres_gnutls_pull(gnutls_transport_ptr_t h, void *buf, size_t len) +{ + struct tls_common_ctx *t = (struct tls_common_ctx *)h; + if (kr_fails_assert(t)) { + errno = EFAULT; + return -1; + } + + ssize_t avail = t->nread - t->consumed; + DEBUG_MSG("[%s] pull wanted: %zu available: %zu\n", + t->client_side ? "tls_client" : "tls", len, avail); + if (t->nread <= t->consumed) { + errno = EAGAIN; + return -1; + } + + ssize_t transfer = MIN(avail, len); + memcpy(buf, t->buf + t->consumed, transfer); + t->consumed += transfer; + return transfer; +} + +static void on_write_complete(uv_write_t *req, int status) +{ + if (kr_fails_assert(req->data)) + return; + struct async_write_ctx *async_ctx = (struct async_write_ctx *)req->data; + struct tls_common_ctx *t = async_ctx->t; + if (t->write_queue_size) + t->write_queue_size -= 1; + else + kr_assert(false); + free(req->data); +} + +static bool stream_queue_is_empty(struct tls_common_ctx *t) +{ + return (t->write_queue_size == 0); +} + +static ssize_t kres_gnutls_vec_push(gnutls_transport_ptr_t h, const giovec_t * iov, int iovcnt) +{ + struct tls_common_ctx *t = (struct tls_common_ctx *)h; + if (kr_fails_assert(t)) { + errno = EFAULT; + return -1; + } + + if (iovcnt == 0) { + return 0; + } + + if (kr_fails_assert(t->session)) { + errno = EFAULT; + return -1; + } + uv_stream_t *handle = (uv_stream_t *)session_get_handle(t->session); + if (kr_fails_assert(handle && handle->type == UV_TCP)) { + errno = EFAULT; + return -1; + } + + /* + * This is a little bit complicated. There are two different writes: + * 1. Immediate, these don't need to own the buffered data and return immediately + * 2. Asynchronous, these need to own the buffers until the write completes + * In order to avoid copying the buffer, an immediate write is tried first if possible. + * If it isn't possible to write the data without queueing, an asynchronous write + * is created (with copied buffered data). + */ + + size_t total_len = 0; + uv_buf_t uv_buf[iovcnt]; + for (int i = 0; i < iovcnt; ++i) { + uv_buf[i].base = iov[i].iov_base; + uv_buf[i].len = iov[i].iov_len; + total_len += iov[i].iov_len; + } + + /* Try to perform the immediate write first to avoid copy */ + int ret = 0; + if (stream_queue_is_empty(t)) { + ret = uv_try_write(handle, uv_buf, iovcnt); + DEBUG_MSG("[%s] push %zu <%p> = %d\n", + t->client_side ? "tls_client" : "tls", total_len, h, ret); + /* from libuv documentation - + uv_try_write will return either: + > 0: number of bytes written (can be less than the supplied buffer size). + < 0: negative error code (UV_EAGAIN is returned if no data can be sent immediately). + */ + if (ret == total_len) { + /* All the data were buffered by libuv. + * Return. */ + return ret; + } + + if (ret < 0 && ret != UV_EAGAIN) { + /* uv_try_write() has returned error code other then UV_EAGAIN. + * Return. */ + VERBOSE_MSG(t->client_side, "uv_try_write error: %s\n", + uv_strerror(ret)); + ret = -1; + errno = EIO; + return ret; + } + /* Since we are here expression below is true + * (ret != total_len) && (ret >= 0 || ret == UV_EAGAIN) + * or the same + * (ret != total_len && ret >= 0) || (ret != total_len && ret == UV_EAGAIN) + * i.e. either occurs partial write or UV_EAGAIN. + * Proceed and copy data amount to owned memory and perform async write. + */ + if (ret == UV_EAGAIN) { + /* No data were buffered, so we must buffer all the data. */ + ret = 0; + } + } + + /* Fallback when the queue is full, and it's not possible to do an immediate write */ + char *p = malloc(sizeof(struct async_write_ctx) + total_len - ret); + if (p != NULL) { + struct async_write_ctx *async_ctx = (struct async_write_ctx *)p; + /* Save pointer to session tls context */ + async_ctx->t = t; + char *buf = async_ctx->buf; + /* Skip data written in the partial write */ + size_t to_skip = ret; + /* Copy the buffer into owned memory */ + size_t off = 0; + for (int i = 0; i < iovcnt; ++i) { + if (to_skip > 0) { + /* Ignore current buffer if it's all skipped */ + if (to_skip >= uv_buf[i].len) { + to_skip -= uv_buf[i].len; + continue; + } + /* Skip only part of the buffer */ + uv_buf[i].base += to_skip; + uv_buf[i].len -= to_skip; + to_skip = 0; + } + memcpy(buf + off, uv_buf[i].base, uv_buf[i].len); + off += uv_buf[i].len; + } + uv_buf[0].base = buf; + uv_buf[0].len = off; + + /* Create an asynchronous write request */ + uv_write_t *write_req = &async_ctx->write_req; + memset(write_req, 0, sizeof(uv_write_t)); + write_req->data = p; + + /* Perform an asynchronous write with a callback */ + if (uv_write(write_req, handle, uv_buf, 1, on_write_complete) == 0) { + ret = total_len; + t->write_queue_size += 1; + } else { + free(p); + VERBOSE_MSG(t->client_side, "uv_write error: %s\n", + uv_strerror(ret)); + errno = EIO; + ret = -1; + } + } else { + errno = ENOMEM; + ret = -1; + } + + DEBUG_MSG("[%s] queued %zu <%p> = %d\n", + t->client_side ? "tls_client" : "tls", total_len, h, ret); + + return ret; +} + +/** Perform TLS handshake and handle error codes according to the documentation. + * See See https://gnutls.org/manual/html_node/TLS-handshake.html#TLS-handshake + * The function returns kr_ok() or success or non fatal error, kr_error(EAGAIN) on blocking, or kr_error(EIO) on fatal error. + */ +static int tls_handshake(struct tls_common_ctx *ctx, tls_handshake_cb handshake_cb) { + struct session *session = ctx->session; + + int err = gnutls_handshake(ctx->tls_session); + if (err == GNUTLS_E_SUCCESS) { + /* Handshake finished, return success */ + ctx->handshake_state = TLS_HS_DONE; + struct sockaddr *peer = session_get_peer(session); + VERBOSE_MSG(ctx->client_side, "TLS handshake with %s has completed\n", + kr_straddr(peer)); + if (handshake_cb) { + if (handshake_cb(session, 0) != kr_ok()) { + return kr_error(EIO); + } + } + } else if (err == GNUTLS_E_AGAIN) { + return kr_error(EAGAIN); + } else if (gnutls_error_is_fatal(err)) { + /* Fatal errors, return error as it's not recoverable */ + VERBOSE_MSG(ctx->client_side, "gnutls_handshake failed: %s (%d)\n", + gnutls_strerror_name(err), err); + /* Notify the peer about handshake failure via an alert. */ + gnutls_alert_send_appropriate(ctx->tls_session, err); + if (handshake_cb) { + handshake_cb(session, -1); + } + return kr_error(EIO); + } else if (err == GNUTLS_E_WARNING_ALERT_RECEIVED) { + /* Handle warning when in verbose mode */ + const char *alert_name = gnutls_alert_get_name(gnutls_alert_get(ctx->tls_session)); + if (alert_name != NULL) { + struct sockaddr *peer = session_get_peer(session); + VERBOSE_MSG(ctx->client_side, "TLS alert from %s received: %s\n", + kr_straddr(peer), alert_name); + } + } + return kr_ok(); +} + + +struct tls_ctx *tls_new(struct worker_ctx *worker) +{ + if (kr_fails_assert(worker && worker->engine)) + return NULL; + + struct network *net = &worker->engine->net; + if (!net->tls_credentials) { + net->tls_credentials = tls_get_ephemeral_credentials(worker->engine); + if (!net->tls_credentials) { + kr_log_error(TLS, "X.509 credentials are missing, and ephemeral credentials failed; no TLS\n"); + return NULL; + } + kr_log_info(TLS, "Using ephemeral TLS credentials\n"); + tls_credentials_log_pins(net->tls_credentials); + } + + time_t now = time(NULL); + if (net->tls_credentials->valid_until != GNUTLS_X509_NO_WELL_DEFINED_EXPIRATION) { + if (net->tls_credentials->ephemeral_servicename) { + /* ephemeral cert: refresh if due to expire within a week */ + if (now >= net->tls_credentials->valid_until - EPHEMERAL_CERT_EXPIRATION_SECONDS_RENEW_BEFORE) { + struct tls_credentials *newcreds = tls_get_ephemeral_credentials(worker->engine); + if (newcreds) { + tls_credentials_release(net->tls_credentials); + net->tls_credentials = newcreds; + kr_log_info(TLS, "Renewed expiring ephemeral X.509 cert\n"); + } else { + kr_log_error(TLS, "Failed to renew expiring ephemeral X.509 cert, using existing one\n"); + } + } + } else { + /* non-ephemeral cert: warn once when certificate expires */ + if (now >= net->tls_credentials->valid_until) { + kr_log_error(TLS, "X.509 certificate has expired!\n"); + net->tls_credentials->valid_until = GNUTLS_X509_NO_WELL_DEFINED_EXPIRATION; + } + } + } + + struct tls_ctx *tls = calloc(1, sizeof(struct tls_ctx)); + if (tls == NULL) { + kr_log_error(TLS, "failed to allocate TLS context\n"); + return NULL; + } + + int flags = GNUTLS_SERVER | GNUTLS_NONBLOCK; +#if GNUTLS_VERSION_NUMBER >= 0x030705 + if (gnutls_check_version("3.7.5")) + flags |= GNUTLS_NO_TICKETS_TLS12; +#endif + int err = gnutls_init(&tls->c.tls_session, flags); + if (err != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "gnutls_init(): %s (%d)\n", gnutls_strerror_name(err), err); + tls_free(tls); + return NULL; + } + tls->credentials = tls_credentials_reserve(net->tls_credentials); + err = gnutls_credentials_set(tls->c.tls_session, GNUTLS_CRD_CERTIFICATE, + tls->credentials->credentials); + if (err != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "gnutls_credentials_set(): %s (%d)\n", gnutls_strerror_name(err), err); + tls_free(tls); + return NULL; + } + if (kres_gnutls_set_priority(tls->c.tls_session) != GNUTLS_E_SUCCESS) { + tls_free(tls); + return NULL; + } + + tls->c.worker = worker; + tls->c.client_side = false; + + gnutls_transport_set_pull_function(tls->c.tls_session, kres_gnutls_pull); + gnutls_transport_set_vec_push_function(tls->c.tls_session, kres_gnutls_vec_push); + gnutls_transport_set_ptr(tls->c.tls_session, tls); + + if (net->tls_session_ticket_ctx) { + tls_session_ticket_enable(net->tls_session_ticket_ctx, + tls->c.tls_session); + } + + return tls; +} + +void tls_close(struct tls_common_ctx *ctx) +{ + if (ctx == NULL || ctx->tls_session == NULL || kr_fails_assert(ctx->session)) + return; + + if (ctx->handshake_state == TLS_HS_DONE) { + const struct sockaddr *peer = session_get_peer(ctx->session); + VERBOSE_MSG(ctx->client_side, "closing tls connection to `%s`\n", + kr_straddr(peer)); + ctx->handshake_state = TLS_HS_CLOSING; + gnutls_bye(ctx->tls_session, GNUTLS_SHUT_RDWR); + } +} + +void tls_client_close(struct tls_client_ctx *ctx) +{ + /* Store the current session data for potential resumption of this session */ + if (ctx->params) { + gnutls_free(ctx->params->session_data.data); + ctx->params->session_data.data = NULL; + ctx->params->session_data.size = 0; + gnutls_session_get_data2(ctx->c.tls_session, &ctx->params->session_data); + } + + tls_close(&ctx->c); +} + +void tls_free(struct tls_ctx *tls) +{ + if (!tls) { + return; + } + + if (tls->c.tls_session) { + /* Don't terminate TLS connection, just tear it down */ + gnutls_deinit(tls->c.tls_session); + tls->c.tls_session = NULL; + } + + tls_credentials_release(tls->credentials); + free(tls); +} + +int tls_write(uv_write_t *req, uv_handle_t *handle, knot_pkt_t *pkt, uv_write_cb cb) +{ + if (!pkt || !handle || !handle->data) { + return kr_error(EINVAL); + } + + struct session *s = handle->data; + struct tls_common_ctx *tls_ctx = session_tls_get_common_ctx(s); + + if (kr_fails_assert(tls_ctx && session_flags(s)->outgoing == tls_ctx->client_side)) + return kr_error(EINVAL); + + const uint16_t pkt_size = htons(pkt->size); + gnutls_session_t tls_session = tls_ctx->tls_session; + + gnutls_record_cork(tls_session); + ssize_t count = 0; + if ((count = gnutls_record_send(tls_session, &pkt_size, sizeof(pkt_size)) < 0) || + (count = gnutls_record_send(tls_session, pkt->wire, pkt->size) < 0)) { + VERBOSE_MSG(tls_ctx->client_side, "gnutls_record_send failed: %s (%zd)\n", + gnutls_strerror_name(count), count); + return kr_error(EIO); + } + + const ssize_t submitted = sizeof(pkt_size) + pkt->size; + + int ret = gnutls_record_uncork(tls_session, GNUTLS_RECORD_WAIT); + if (ret < 0) { + if (!gnutls_error_is_fatal(ret)) { + return kr_error(EAGAIN); + } else { + VERBOSE_MSG(tls_ctx->client_side, "gnutls_record_uncork failed: %s (%d)\n", + gnutls_strerror_name(ret), ret); + return kr_error(EIO); + } + } + + if (ret != submitted) { + kr_log_error(TLS, "gnutls_record_uncork didn't send all data (%d of %zd)\n", ret, submitted); + return kr_error(EIO); + } + + /* The data is now accepted in gnutls internal buffers, the message can be treated as sent */ + req->handle = (uv_stream_t *)handle; + cb(req, 0); + + return kr_ok(); +} + +ssize_t tls_process_input_data(struct session *s, const uint8_t *buf, ssize_t nread) +{ + struct tls_common_ctx *tls_p = session_tls_get_common_ctx(s); + if (!tls_p) { + return kr_error(ENOSYS); + } + + if (kr_fails_assert(tls_p->session == s)) + return kr_error(EINVAL); + const bool ok = tls_p->recv_buf == buf && nread <= sizeof(tls_p->recv_buf); + if (kr_fails_assert(ok)) /* don't risk overflowing the buffer if we have a mistake somewhere */ + return kr_error(EINVAL); + + tls_p->buf = buf; + tls_p->nread = nread >= 0 ? nread : 0; + tls_p->consumed = 0; + + /* Ensure TLS handshake is performed before receiving data. + * See https://www.gnutls.org/manual/html_node/TLS-handshake.html */ + while (tls_p->handshake_state <= TLS_HS_IN_PROGRESS) { + int err = tls_handshake(tls_p, tls_p->handshake_cb); + if (err == kr_error(EAGAIN)) { + return 0; /* Wait for more data */ + } else if (err != kr_ok()) { + return err; + } + } + + /* See https://gnutls.org/manual/html_node/Data-transfer-and-termination.html#Data-transfer-and-termination */ + ssize_t submitted = 0; + uint8_t *wire_buf = session_wirebuf_get_free_start(s); + size_t wire_buf_size = session_wirebuf_get_free_size(s); + while (true) { + ssize_t count = gnutls_record_recv(tls_p->tls_session, wire_buf, wire_buf_size); + if (count == GNUTLS_E_AGAIN) { + if (tls_p->consumed == tls_p->nread) { + /* See https://www.gnutls.org/manual/html_node/Asynchronous-operation.html */ + break; /* No more data available in this libuv buffer */ + } + continue; + } else if (count == GNUTLS_E_INTERRUPTED) { + continue; + } else if (count == GNUTLS_E_REHANDSHAKE) { + /* See https://www.gnutls.org/manual/html_node/Re_002dauthentication.html */ + struct sockaddr *peer = session_get_peer(s); + VERBOSE_MSG(tls_p->client_side, "TLS rehandshake with %s has started\n", + kr_straddr(peer)); + tls_set_hs_state(tls_p, TLS_HS_IN_PROGRESS); + int err = kr_ok(); + while (tls_p->handshake_state <= TLS_HS_IN_PROGRESS) { + err = tls_handshake(tls_p, tls_p->handshake_cb); + if (err == kr_error(EAGAIN)) { + break; + } else if (err != kr_ok()) { + return err; + } + } + if (err == kr_error(EAGAIN)) { + /* pull function is out of data */ + break; + } + /* There are can be data available, check it. */ + continue; + } else if (count < 0) { + VERBOSE_MSG(tls_p->client_side, "gnutls_record_recv failed: %s (%zd)\n", + gnutls_strerror_name(count), count); + return kr_error(EIO); + } else if (count == 0) { + break; + } + DEBUG_MSG("[%s] received %zd data\n", tls_p->client_side ? "tls_client" : "tls", count); + wire_buf += count; + wire_buf_size -= count; + submitted += count; + if (wire_buf_size == 0 && tls_p->consumed != tls_p->nread) { + /* session buffer is full + * whereas not all the data were consumed */ + return kr_error(ENOSPC); + } + } + /* Here all data must be consumed. */ + if (tls_p->consumed != tls_p->nread) { + /* Something went wrong, better return error. + * This is most probably due to gnutls_record_recv() did not + * consume all available network data by calling kres_gnutls_pull(). + * TODO assess the need for buffering of data amount. + */ + return kr_error(ENOSPC); + } + return submitted; +} + +#if TLS_CAN_USE_PINS +/* + DNS-over-TLS Out of band key-pinned authentication profile uses the + same form of pins as HPKP: + + e.g. pin-sha256="FHkyLhvI0n70E47cJlRTamTrnYVcsYdjUGbr79CfAVI=" + + DNS-over-TLS OOB key-pins: https://tools.ietf.org/html/rfc7858#appendix-A + HPKP pin reference: https://tools.ietf.org/html/rfc7469#appendix-A +*/ +#define PINLEN ((((32) * 8 + 4)/6) + 3 + 1) + +/* Compute pin_sha256 for the certificate. + * It may be in raw format - just TLS_SHA256_RAW_LEN bytes without termination, + * or it may be a base64 0-terminated string requiring up to + * TLS_SHA256_BASE64_BUFLEN bytes. + * \return error code */ +static int get_oob_key_pin(gnutls_x509_crt_t crt, char *outchar, ssize_t outchar_len, bool raw) +{ + if (kr_fails_assert(!raw || outchar_len >= TLS_SHA256_RAW_LEN)) { + return kr_error(ENOSPC); + /* With !raw we have check inside kr_base64_encode. */ + } + gnutls_pubkey_t key; + int err = gnutls_pubkey_init(&key); + if (err != GNUTLS_E_SUCCESS) return err; + + gnutls_datum_t datum = { .data = NULL, .size = 0 }; + err = gnutls_pubkey_import_x509(key, crt, 0); + if (err != GNUTLS_E_SUCCESS) goto leave; + + err = gnutls_pubkey_export2(key, GNUTLS_X509_FMT_DER, &datum); + if (err != GNUTLS_E_SUCCESS) goto leave; + + char raw_pin[TLS_SHA256_RAW_LEN]; /* TMP buffer if raw == false */ + err = gnutls_hash_fast(GNUTLS_DIG_SHA256, datum.data, datum.size, + (raw ? outchar : raw_pin)); + if (err != GNUTLS_E_SUCCESS || raw/*success*/) + goto leave; + /* Convert to non-raw. */ + err = kr_base64_encode((uint8_t *)raw_pin, sizeof(raw_pin), + (uint8_t *)outchar, outchar_len); + if (err >= 0 && err < outchar_len) { + err = GNUTLS_E_SUCCESS; + outchar[err] = '\0'; /* kr_base64_encode() doesn't do it */ + } else if (kr_fails_assert(err < 0)) { + err = kr_error(ENOSPC); /* base64 fits but '\0' doesn't */ + outchar[outchar_len - 1] = '\0'; + } +leave: + gnutls_free(datum.data); + gnutls_pubkey_deinit(key); + return err; +} + +void tls_credentials_log_pins(struct tls_credentials *tls_credentials) +{ + for (int index = 0;; index++) { + gnutls_x509_crt_t *certs = NULL; + unsigned int cert_count = 0; + int err = gnutls_certificate_get_x509_crt(tls_credentials->credentials, + index, &certs, &cert_count); + if (err != GNUTLS_E_SUCCESS) { + if (err != GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) { + kr_log_error(TLS, "could not get X.509 certificates (%d) %s\n", + err, gnutls_strerror_name(err)); + } + return; + } + + for (int i = 0; i < cert_count; i++) { + char pin[TLS_SHA256_BASE64_BUFLEN] = { 0 }; + err = get_oob_key_pin(certs[i], pin, sizeof(pin), false); + if (err != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "could not calculate RFC 7858 OOB key-pin from cert %d (%d) %s\n", + i, err, gnutls_strerror_name(err)); + } else { + kr_log_info(TLS, "RFC 7858 OOB key-pin (%d): pin-sha256=\"%s\"\n", + i, pin); + } + gnutls_x509_crt_deinit(certs[i]); + } + gnutls_free(certs); + } +} +#else +void tls_credentials_log_pins(struct tls_credentials *tls_credentials) +{ + kr_log_debug(TLS, "could not calculate RFC 7858 OOB key-pin; GnuTLS 3.4.0+ required\n"); +} +#endif + +static int str_replace(char **where_ptr, const char *with) +{ + char *copy = with ? strdup(with) : NULL; + if (with && !copy) { + return kr_error(ENOMEM); + } + + free(*where_ptr); + *where_ptr = copy; + return kr_ok(); +} + +static time_t _get_end_entity_expiration(gnutls_certificate_credentials_t creds) +{ + gnutls_datum_t data; + gnutls_x509_crt_t cert = NULL; + int err; + time_t ret = GNUTLS_X509_NO_WELL_DEFINED_EXPIRATION; + + if ((err = gnutls_certificate_get_crt_raw(creds, 0, 0, &data)) != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "failed to get cert to check expiration: (%d) %s\n", + err, gnutls_strerror_name(err)); + goto done; + } + if ((err = gnutls_x509_crt_init(&cert)) != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "failed to initialize cert: (%d) %s\n", + err, gnutls_strerror_name(err)); + goto done; + } + if ((err = gnutls_x509_crt_import(cert, &data, GNUTLS_X509_FMT_DER)) != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "failed to construct cert while checking expiration: (%d) %s\n", + err, gnutls_strerror_name(err)); + goto done; + } + + ret = gnutls_x509_crt_get_expiration_time (cert); + done: + /* do not free data; g_c_get_crt_raw() says to treat it as + * constant. */ + gnutls_x509_crt_deinit(cert); + return ret; +} + +int tls_certificate_set(struct network *net, const char *tls_cert, const char *tls_key) +{ + if (!net) { + return kr_error(EINVAL); + } + + struct tls_credentials *tls_credentials = calloc(1, sizeof(*tls_credentials)); + if (tls_credentials == NULL) { + return kr_error(ENOMEM); + } + + int err = 0; + if ((err = gnutls_certificate_allocate_credentials(&tls_credentials->credentials)) != GNUTLS_E_SUCCESS) { + kr_log_error(TLS, "gnutls_certificate_allocate_credentials() failed: (%d) %s\n", + err, gnutls_strerror_name(err)); + tls_credentials_free(tls_credentials); + return kr_error(ENOMEM); + } + if ((err = gnutls_certificate_set_x509_system_trust(tls_credentials->credentials)) < 0) { + if (err != GNUTLS_E_UNIMPLEMENTED_FEATURE) { + kr_log_warning(TLS, "warning: gnutls_certificate_set_x509_system_trust() failed: (%d) %s\n", + err, gnutls_strerror_name(err)); + tls_credentials_free(tls_credentials); + return err; + } + } + + if ((str_replace(&tls_credentials->tls_cert, tls_cert) != 0) || + (str_replace(&tls_credentials->tls_key, tls_key) != 0)) { + tls_credentials_free(tls_credentials); + return kr_error(ENOMEM); + } + + if ((err = gnutls_certificate_set_x509_key_file(tls_credentials->credentials, + tls_cert, tls_key, GNUTLS_X509_FMT_PEM)) != GNUTLS_E_SUCCESS) { + tls_credentials_free(tls_credentials); + kr_log_error(TLS, "gnutls_certificate_set_x509_key_file(%s,%s) failed: %d (%s)\n", + tls_cert, tls_key, err, gnutls_strerror_name(err)); + return kr_error(EINVAL); + } + /* record the expiration date: */ + tls_credentials->valid_until = _get_end_entity_expiration(tls_credentials->credentials); + + /* Exchange the x509 credentials */ + struct tls_credentials *old_credentials = net->tls_credentials; + + /* Start using the new x509_credentials */ + net->tls_credentials = tls_credentials; + tls_credentials_log_pins(net->tls_credentials); + + if (old_credentials) { + err = tls_credentials_release(old_credentials); + if (err != kr_error(EBUSY)) { + return err; + } + } + + return kr_ok(); +} + +struct tls_credentials *tls_credentials_reserve(struct tls_credentials *tls_credentials) { + if (!tls_credentials) { + return NULL; + } + tls_credentials->count++; + return tls_credentials; +} + +int tls_credentials_release(struct tls_credentials *tls_credentials) { + if (!tls_credentials) { + return kr_error(EINVAL); + } + if (--tls_credentials->count < 0) { + tls_credentials_free(tls_credentials); + } else { + return kr_error(EBUSY); + } + return kr_ok(); +} + +void tls_credentials_free(struct tls_credentials *tls_credentials) { + if (!tls_credentials) { + return; + } + + if (tls_credentials->credentials) { + gnutls_certificate_free_credentials(tls_credentials->credentials); + } + if (tls_credentials->tls_cert) { + free(tls_credentials->tls_cert); + } + if (tls_credentials->tls_key) { + free(tls_credentials->tls_key); + } + if (tls_credentials->ephemeral_servicename) { + free(tls_credentials->ephemeral_servicename); + } + free(tls_credentials); +} + +void tls_client_param_unref(tls_client_param_t *entry) +{ + if (!entry || kr_fails_assert(entry->refs)) return; + --(entry->refs); + if (entry->refs) return; + + DEBUG_MSG("freeing TLS parameters %p\n", (void *)entry); + + for (int i = 0; i < entry->ca_files.len; ++i) { + free_const(entry->ca_files.at[i]); + } + array_clear(entry->ca_files); + + free_const(entry->hostname); + + for (int i = 0; i < entry->pins.len; ++i) { + free_const(entry->pins.at[i]); + } + array_clear(entry->pins); + + if (entry->credentials) { + gnutls_certificate_free_credentials(entry->credentials); + } + + if (entry->session_data.data) { + gnutls_free(entry->session_data.data); + } + + free(entry); +} +static int param_free(void **param, void *null) +{ + if (kr_fails_assert(param && *param)) + return -1; + tls_client_param_unref(*param); + return 0; +} +void tls_client_params_free(tls_client_params_t *params) +{ + if (!params) return; + trie_apply(params, param_free, NULL); + trie_free(params); +} + +tls_client_param_t * tls_client_param_new() +{ + tls_client_param_t *e = calloc(1, sizeof(*e)); + if (kr_fails_assert(e)) + return NULL; + /* Note: those array_t don't need further initialization. */ + e->refs = 1; + int ret = gnutls_certificate_allocate_credentials(&e->credentials); + if (ret != GNUTLS_E_SUCCESS) { + kr_log_error(TLSCLIENT, "error: gnutls_certificate_allocate_credentials() fails (%s)\n", + gnutls_strerror_name(ret)); + free(e); + return NULL; + } + gnutls_certificate_set_verify_function(e->credentials, client_verify_certificate); + return e; +} + +/** + * Convert an IP address and port number to binary key. + * + * \precond buffer \param key must have sufficient size + * \param addr[in] + * \param len[out] output length + * \param key[out] output buffer + */ +static bool construct_key(const union kr_sockaddr *addr, uint32_t *len, char *key) +{ + switch (addr->ip.sa_family) { + case AF_INET: + memcpy(key, &addr->ip4.sin_port, sizeof(addr->ip4.sin_port)); + memcpy(key + sizeof(addr->ip4.sin_port), &addr->ip4.sin_addr, + sizeof(addr->ip4.sin_addr)); + *len = sizeof(addr->ip4.sin_port) + sizeof(addr->ip4.sin_addr); + return true; + case AF_INET6: + memcpy(key, &addr->ip6.sin6_port, sizeof(addr->ip6.sin6_port)); + memcpy(key + sizeof(addr->ip6.sin6_port), &addr->ip6.sin6_addr, + sizeof(addr->ip6.sin6_addr)); + *len = sizeof(addr->ip6.sin6_port) + sizeof(addr->ip6.sin6_addr); + return true; + default: + kr_assert(!EINVAL); + return false; + } +} +tls_client_param_t ** tls_client_param_getptr(tls_client_params_t **params, + const struct sockaddr *addr, bool do_insert) +{ + if (kr_fails_assert(params && addr)) + return NULL; + /* We accept NULL for empty map; ensure the map exists if needed. */ + if (!*params) { + if (!do_insert) return NULL; + *params = trie_create(NULL); + if (kr_fails_assert(*params)) + return NULL; + } + /* Construct the key. */ + const union kr_sockaddr *ia = (const union kr_sockaddr *)addr; + char key[sizeof(ia->ip6.sin6_port) + sizeof(ia->ip6.sin6_addr)]; + uint32_t len; + if (!construct_key(ia, &len, key)) + return NULL; + /* Get the entry. */ + return (tls_client_param_t **) + (do_insert ? trie_get_ins : trie_get_try)(*params, key, len); +} + +int tls_client_param_remove(tls_client_params_t *params, const struct sockaddr *addr) +{ + const union kr_sockaddr *ia = (const union kr_sockaddr *)addr; + char key[sizeof(ia->ip6.sin6_port) + sizeof(ia->ip6.sin6_addr)]; + uint32_t len; + if (!construct_key(ia, &len, key)) + return kr_error(EINVAL); + trie_val_t param_ptr; + int ret = trie_del(params, key, len, ¶m_ptr); + if (ret != KNOT_EOK) + return kr_error(ret); + tls_client_param_unref(param_ptr); + return kr_ok(); +} + +/** + * Verify that at least one certificate in the certificate chain matches + * at least one certificate pin in the non-empty params->pins array. + * \returns GNUTLS_E_SUCCESS if pin matches, any other value is an error + */ +static int client_verify_pin(const unsigned int cert_list_size, + const gnutls_datum_t *cert_list, + tls_client_param_t *params) +{ + if (kr_fails_assert(params->pins.len > 0)) + return GNUTLS_E_CERTIFICATE_ERROR; +#if TLS_CAN_USE_PINS + for (int i = 0; i < cert_list_size; i++) { + gnutls_x509_crt_t cert; + int ret = gnutls_x509_crt_init(&cert); + if (ret != GNUTLS_E_SUCCESS) { + return ret; + } + + ret = gnutls_x509_crt_import(cert, &cert_list[i], GNUTLS_X509_FMT_DER); + if (ret != GNUTLS_E_SUCCESS) { + gnutls_x509_crt_deinit(cert); + return ret; + } + + #ifdef DEBUG + if (kr_log_is_debug(TLS, NULL)) { + char pin_base64[TLS_SHA256_BASE64_BUFLEN]; + /* DEBUG: additionally compute and print the base64 pin. + * Not very efficient, but that's OK for DEBUG. */ + ret = get_oob_key_pin(cert, pin_base64, sizeof(pin_base64), false); + if (ret == GNUTLS_E_SUCCESS) { + DEBUG_MSG("[tls_client] received pin: %s\n", pin_base64); + } else { + DEBUG_MSG("[tls_client] failed to convert received pin\n"); + /* Now we hope that `ret` below can't differ. */ + } + } + #endif + char cert_pin[TLS_SHA256_RAW_LEN]; + /* Get raw pin and compare. */ + ret = get_oob_key_pin(cert, cert_pin, sizeof(cert_pin), true); + gnutls_x509_crt_deinit(cert); + if (ret != GNUTLS_E_SUCCESS) { + return ret; + } + for (size_t j = 0; j < params->pins.len; ++j) { + const uint8_t *pin = params->pins.at[j]; + if (memcmp(cert_pin, pin, TLS_SHA256_RAW_LEN) != 0) + continue; /* mismatch */ + DEBUG_MSG("[tls_client] matched a configured pin no. %zd\n", j); + return GNUTLS_E_SUCCESS; + } + DEBUG_MSG("[tls_client] none of %zd configured pin(s) matched\n", + params->pins.len); + } + + kr_log_error(TLSCLIENT, "no pin matched: %zu pins * %d certificates\n", + params->pins.len, cert_list_size); + return GNUTLS_E_CERTIFICATE_ERROR; + +#else /* TLS_CAN_USE_PINS */ + kr_log_error(TLSCLIENT, "internal inconsistency: TLS_CAN_USE_PINS\n"); + kr_assert(false); + return GNUTLS_E_CERTIFICATE_ERROR; +#endif +} + +/** + * Verify that \param tls_session contains a valid X.509 certificate chain + * with given hostname. + * + * \returns GNUTLS_E_SUCCESS if certificate chain is valid, any other value is an error + */ +static int client_verify_certchain(gnutls_session_t tls_session, const char *hostname) +{ + if (kr_fails_assert(hostname)) { + kr_log_error(TLSCLIENT, "internal config inconsistency: no hostname set\n"); + return GNUTLS_E_CERTIFICATE_ERROR; + } + + unsigned int status; + int ret = gnutls_certificate_verify_peers3(tls_session, hostname, &status); + if ((ret == GNUTLS_E_SUCCESS) && (status == 0)) { + return GNUTLS_E_SUCCESS; + } + + if (ret == GNUTLS_E_SUCCESS) { + gnutls_datum_t msg; + ret = gnutls_certificate_verification_status_print( + status, gnutls_certificate_type_get(tls_session), &msg, 0); + if (ret == GNUTLS_E_SUCCESS) { + kr_log_error(TLSCLIENT, "failed to verify peer certificate: " + "%s\n", msg.data); + gnutls_free(msg.data); + } else { + kr_log_error(TLSCLIENT, "failed to verify peer certificate: " + "unable to print reason: %s (%s)\n", + gnutls_strerror(ret), gnutls_strerror_name(ret)); + } /* gnutls_certificate_verification_status_print end */ + } else { + kr_log_error(TLSCLIENT, "failed to verify peer certificate: " + "gnutls_certificate_verify_peers3 error: %s (%s)\n", + gnutls_strerror(ret), gnutls_strerror_name(ret)); + } /* gnutls_certificate_verify_peers3 end */ + return GNUTLS_E_CERTIFICATE_ERROR; +} + +/** + * Verify that actual TLS security parameters of \param tls_session + * match requirements provided by user in tls_session->params. + * \returns GNUTLS_E_SUCCESS if requirements were met, any other value is an error + */ +static int client_verify_certificate(gnutls_session_t tls_session) +{ + struct tls_client_ctx *ctx = gnutls_session_get_ptr(tls_session); + if (kr_fails_assert(ctx->params)) + return GNUTLS_E_CERTIFICATE_ERROR; + + if (ctx->params->insecure) { + return GNUTLS_E_SUCCESS; + } + + gnutls_certificate_type_t cert_type = gnutls_certificate_type_get(tls_session); + if (cert_type != GNUTLS_CRT_X509) { + kr_log_error(TLSCLIENT, "invalid certificate type %i has been received\n", + cert_type); + return GNUTLS_E_CERTIFICATE_ERROR; + } + unsigned int cert_list_size = 0; + const gnutls_datum_t *cert_list = + gnutls_certificate_get_peers(tls_session, &cert_list_size); + if (cert_list == NULL || cert_list_size == 0) { + kr_log_error(TLSCLIENT, "empty certificate list\n"); + return GNUTLS_E_CERTIFICATE_ERROR; + } + + if (ctx->params->pins.len > 0) + /* check hash of the certificate but ignore everything else */ + return client_verify_pin(cert_list_size, cert_list, ctx->params); + else + return client_verify_certchain(ctx->c.tls_session, ctx->params->hostname); +} + +struct tls_client_ctx *tls_client_ctx_new(tls_client_param_t *entry, + struct worker_ctx *worker) +{ + struct tls_client_ctx *ctx = calloc(1, sizeof (struct tls_client_ctx)); + if (!ctx) { + return NULL; + } + unsigned int flags = GNUTLS_CLIENT | GNUTLS_NONBLOCK +#ifdef GNUTLS_ENABLE_FALSE_START + | GNUTLS_ENABLE_FALSE_START +#endif + ; +#if GNUTLS_VERSION_NUMBER >= 0x030705 + if (gnutls_check_version("3.7.5")) + flags |= GNUTLS_NO_TICKETS_TLS12; +#endif + int ret = gnutls_init(&ctx->c.tls_session, flags); + if (ret != GNUTLS_E_SUCCESS) { + tls_client_ctx_free(ctx); + return NULL; + } + + ret = kres_gnutls_set_priority(ctx->c.tls_session); + if (ret != GNUTLS_E_SUCCESS) { + tls_client_ctx_free(ctx); + return NULL; + } + + /* Must take a reference on parameters as the credentials are owned by it + * and must not be freed while the session is active. */ + ++(entry->refs); + ctx->params = entry; + + ret = gnutls_credentials_set(ctx->c.tls_session, GNUTLS_CRD_CERTIFICATE, + entry->credentials); + if (ret == GNUTLS_E_SUCCESS && entry->hostname) { + ret = gnutls_server_name_set(ctx->c.tls_session, GNUTLS_NAME_DNS, + entry->hostname, strlen(entry->hostname)); + kr_log_debug(TLSCLIENT, "set hostname, ret = %d\n", ret); + } else if (!entry->hostname) { + kr_log_debug(TLSCLIENT, "no hostname\n"); + } + if (ret != GNUTLS_E_SUCCESS) { + tls_client_ctx_free(ctx); + return NULL; + } + + ctx->c.worker = worker; + ctx->c.client_side = true; + + gnutls_transport_set_pull_function(ctx->c.tls_session, kres_gnutls_pull); + gnutls_transport_set_vec_push_function(ctx->c.tls_session, kres_gnutls_vec_push); + gnutls_transport_set_ptr(ctx->c.tls_session, ctx); + return ctx; +} + +void tls_client_ctx_free(struct tls_client_ctx *ctx) +{ + if (ctx == NULL) { + return; + } + + if (ctx->c.tls_session != NULL) { + gnutls_deinit(ctx->c.tls_session); + ctx->c.tls_session = NULL; + } + + /* Must decrease the refcount for referenced parameters */ + tls_client_param_unref(ctx->params); + + free (ctx); +} + +int tls_pull_timeout_func(gnutls_transport_ptr_t h, unsigned int ms) +{ + struct tls_common_ctx *t = (struct tls_common_ctx *)h; + if (kr_fails_assert(t)) { + errno = EFAULT; + return -1; + } + ssize_t avail = t->nread - t->consumed; + DEBUG_MSG("[%s] timeout check: available: %zu\n", + t->client_side ? "tls_client" : "tls", avail); + if (avail <= 0) { + errno = EAGAIN; + return -1; + } + return avail; +} + +int tls_client_connect_start(struct tls_client_ctx *client_ctx, + struct session *session, + tls_handshake_cb handshake_cb) +{ + if (session == NULL || client_ctx == NULL) + return kr_error(EINVAL); + + if (kr_fails_assert(session_flags(session)->outgoing && session_get_handle(session)->type == UV_TCP)) + return kr_error(EINVAL); + + struct tls_common_ctx *ctx = &client_ctx->c; + + gnutls_session_set_ptr(ctx->tls_session, client_ctx); + gnutls_handshake_set_timeout(ctx->tls_session, ctx->worker->engine->net.tcp.tls_handshake_timeout); + gnutls_transport_set_pull_timeout_function(ctx->tls_session, tls_pull_timeout_func); + session_tls_set_client_ctx(session, client_ctx); + ctx->handshake_cb = handshake_cb; + ctx->handshake_state = TLS_HS_IN_PROGRESS; + ctx->session = session; + + tls_client_param_t *tls_params = client_ctx->params; + if (tls_params->session_data.data != NULL) { + gnutls_session_set_data(ctx->tls_session, tls_params->session_data.data, + tls_params->session_data.size); + } + + /* See https://www.gnutls.org/manual/html_node/Asynchronous-operation.html */ + while (ctx->handshake_state <= TLS_HS_IN_PROGRESS) { + int ret = tls_handshake(ctx, handshake_cb); + if (ret != kr_ok()) { + return ret; + } + } + return kr_ok(); +} + +tls_hs_state_t tls_get_hs_state(const struct tls_common_ctx *ctx) +{ + return ctx->handshake_state; +} + +int tls_set_hs_state(struct tls_common_ctx *ctx, tls_hs_state_t state) +{ + if (state >= TLS_HS_LAST) { + return kr_error(EINVAL); + } + ctx->handshake_state = state; + return kr_ok(); +} + +int tls_client_ctx_set_session(struct tls_client_ctx *ctx, struct session *session) +{ + if (!ctx) { + return kr_error(EINVAL); + } + ctx->c.session = session; + return kr_ok(); +} + +#undef DEBUG_MSG +#undef VERBOSE_MSG |