dnsjit/src/output/dnssim/tls.c

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/*
* Copyright (c) 2020, CZ.NIC, z.s.p.o.
* All rights reserved.
*
* This file is part of dnsjit.
*
* dnsjit is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* dnsjit 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with dnsjit. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "output/dnssim.h"
#include "output/dnssim/internal.h"
#include "output/dnssim/ll.h"
#include "core/assert.h"
#include <gnutls/gnutls.h>
#include <string.h>
#if GNUTLS_VERSION_NUMBER >= DNSSIM_MIN_GNUTLS_VERSION
#ifndef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b)) /** Minimum of two numbers **/
#endif
static core_log_t _log = LOG_T_INIT("output.dnssim");
struct async_write_ctx {
uv_write_t write_req;
_output_dnssim_connection_t* conn;
char buf[];
};
static int _tls_handshake(_output_dnssim_connection_t* conn)
{
mlassert(conn, "conn is nil");
mlassert(conn->tls, "conn must have tls context");
mlassert(conn->client, "conn must belong to a client");
mlassert(conn->state <= _OUTPUT_DNSSIM_CONN_TLS_HANDSHAKE, "conn in invalid state");
/* Set TLS session resumption ticket if available. */
if (conn->state < _OUTPUT_DNSSIM_CONN_TLS_HANDSHAKE && conn->client->tls_ticket.size != 0) {
gnutls_datum_t* ticket = &conn->client->tls_ticket;
gnutls_session_set_data(conn->tls->session, ticket->data, ticket->size);
}
conn->state = _OUTPUT_DNSSIM_CONN_TLS_HANDSHAKE;
return gnutls_handshake(conn->tls->session);
}
void _output_dnssim_tls_process_input_data(_output_dnssim_connection_t* conn)
{
mlassert(conn, "conn is nil");
mlassert(conn->client, "conn must have client");
mlassert(conn->client->dnssim, "client must have dnssim");
mlassert(conn->tls, "conn must have tls ctx");
if (conn->state >= _OUTPUT_DNSSIM_CONN_CLOSING)
return;
output_dnssim_t* self = conn->client->dnssim;
/* Ensure TLS handshake is performed before receiving data.
* See https://www.gnutls.org/manual/html_node/TLS-handshake.html */
while (conn->state <= _OUTPUT_DNSSIM_CONN_TLS_HANDSHAKE) {
int err = _tls_handshake(conn);
mldebug("tls handshake returned: %s", gnutls_strerror(err));
if (err == GNUTLS_E_SUCCESS) {
if (gnutls_session_is_resumed(conn->tls->session))
conn->stats->conn_resumed++;
if (_self->transport == OUTPUT_DNSSIM_TRANSPORT_HTTPS2) {
if (_output_dnssim_https2_setup(conn) < 0) {
_output_dnssim_conn_close(conn);
return;
}
}
_output_dnssim_conn_activate(conn);
break;
} else if (err == GNUTLS_E_AGAIN) {
return; /* Wait for more data */
} else if (err == GNUTLS_E_FATAL_ALERT_RECEIVED) {
gnutls_alert_description_t alert = gnutls_alert_get(conn->tls->session);
mlwarning("gnutls_handshake failed: %s", gnutls_alert_get_name(alert));
_output_dnssim_conn_close(conn);
return;
} else if (gnutls_error_is_fatal(err)) {
mlwarning("gnutls_handshake failed: %s", gnutls_strerror_name(err));
_output_dnssim_conn_close(conn);
return;
}
}
/* See https://gnutls.org/manual/html_node/Data-transfer-and-termination.html#Data-transfer-and-termination */
while (true) {
/* Connection might have been closed due to an error, don't try to use it. */
if (conn->state < _OUTPUT_DNSSIM_CONN_ACTIVE || conn->state >= _OUTPUT_DNSSIM_CONN_CLOSING)
return;
ssize_t count = gnutls_record_recv(conn->tls->session, _self->wire_buf, WIRE_BUF_SIZE);
if (count > 0) {
switch (_self->transport) {
case OUTPUT_DNSSIM_TRANSPORT_TLS:
_output_dnssim_read_dns_stream(conn, count, _self->wire_buf);
break;
case OUTPUT_DNSSIM_TRANSPORT_HTTPS2:
_output_dnssim_https2_process_input_data(conn, count, _self->wire_buf);
break;
default:
lfatal("unsupported transport layer");
break;
}
} else if (count == GNUTLS_E_AGAIN) {
if (conn->tls->buf_pos == conn->tls->buf_len) {
/* 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) {
continue; /* Ignore rehandshake request. */
} else if (count < 0) {
mlwarning("gnutls_record_recv failed: %s", gnutls_strerror_name(count));
_output_dnssim_conn_close(conn);
return;
} else if (count == 0) {
break;
}
}
mlassert(conn->tls->buf_len == conn->tls->buf_pos, "tls didn't read the entire buffer");
}
static ssize_t _tls_pull(gnutls_transport_ptr_t ptr, void* buf, size_t len)
{
_output_dnssim_connection_t* conn = (_output_dnssim_connection_t*)ptr;
mlassert(conn != NULL, "conn is null");
mlassert(conn->tls != NULL, "conn must have tls ctx");
ssize_t avail = conn->tls->buf_len - conn->tls->buf_pos;
if (avail <= 0) {
mldebug("tls pull: no more data");
errno = EAGAIN;
return -1;
}
ssize_t transfer = MIN(avail, len);
memcpy(buf, conn->tls->buf + conn->tls->buf_pos, transfer);
conn->tls->buf_pos += transfer;
return transfer;
}
static void _tls_on_write_complete(uv_write_t* req, int status)
{
mlassert(req->data != NULL, "uv_write req has no data pointer");
struct async_write_ctx* async_ctx = (struct async_write_ctx*)req->data;
_output_dnssim_connection_t* conn = async_ctx->conn;
mlassert(conn, "conn is nil");
mlassert(conn->tls, "conn must have tls ctx");
mlassert(conn->tls->write_queue_size > 0, "invalid write_queue_size: %d", conn->tls->write_queue_size);
conn->tls->write_queue_size -= 1;
free(req->data);
if (status < 0)
_output_dnssim_conn_close(conn);
}
static ssize_t _tls_vec_push(gnutls_transport_ptr_t ptr, const giovec_t* iov, int iovcnt)
{
_output_dnssim_connection_t* conn = (_output_dnssim_connection_t*)ptr;
mlassert(conn != NULL, "conn is null");
mlassert(conn->tls != NULL, "conn must have tls ctx");
if (iovcnt == 0)
return 0;
/*
* 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];
int i;
for (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 (conn->tls->write_queue_size == 0) {
ret = uv_try_write((uv_stream_t*)conn->handle, uv_buf, iovcnt);
/* 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. */
errno = EIO;
return -1;
}
/* 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;
async_ctx->conn = conn;
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;
int i;
for (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, (uv_stream_t*)conn->handle, uv_buf, 1, _tls_on_write_complete) == 0) {
ret = total_len;
conn->tls->write_queue_size += 1;
} else {
free(p);
errno = EIO;
ret = -1;
}
} else {
errno = ENOMEM;
ret = -1;
}
return ret;
}
int _tls_pull_timeout(gnutls_transport_ptr_t ptr, unsigned int ms)
{
_output_dnssim_connection_t* conn = (_output_dnssim_connection_t*)ptr;
mlassert(conn != NULL, "conn is null");
mlassert(conn->tls != NULL, "conn must have tls ctx");
ssize_t avail = conn->tls->buf_len - conn->tls->buf_pos;
if (avail <= 0) {
errno = EAGAIN;
return -1;
}
return avail;
}
int _output_dnssim_tls_init(_output_dnssim_connection_t* conn)
{
mlassert(conn, "conn is nil");
mlassert(conn->tls == NULL, "conn already has tls context");
int ret;
mlfatal_oom(conn->tls = malloc(sizeof(_output_dnssim_tls_ctx_t)));
conn->tls->buf = NULL;
conn->tls->buf_len = 0;
conn->tls->buf_pos = 0;
conn->tls->write_queue_size = 0;
ret = gnutls_init(&conn->tls->session, GNUTLS_CLIENT | GNUTLS_NONBLOCK);
if (ret < 0) {
mldebug("failed gnutls_init() (%s)", gnutls_strerror(ret));
free(conn->tls);
conn->tls = 0;
return ret;
}
output_dnssim_t* self = conn->client->dnssim;
if (_self->tls_priority == NULL) {
ret = gnutls_set_default_priority(conn->tls->session);
if (ret < 0) {
mldebug("failed gnutls_set_default_priority() (%s)", gnutls_strerror(ret));
gnutls_deinit(conn->tls->session);
free(conn->tls);
conn->tls = 0;
return ret;
}
} else {
ret = gnutls_priority_set(conn->tls->session, *_self->tls_priority);
if (ret < 0) {
mldebug("failed gnutls_priority_set() (%s)", gnutls_strerror(ret));
gnutls_deinit(conn->tls->session);
free(conn->tls);
conn->tls = 0;
return ret;
}
}
ret = gnutls_credentials_set(conn->tls->session, GNUTLS_CRD_CERTIFICATE, _self->tls_cred);
if (ret < 0) {
mldebug("failed gnutls_credentials_set() (%s)", gnutls_strerror(ret));
gnutls_deinit(conn->tls->session);
free(conn->tls);
conn->tls = 0;
return ret;
}
gnutls_transport_set_pull_function(conn->tls->session, _tls_pull);
gnutls_transport_set_pull_timeout_function(conn->tls->session, _tls_pull_timeout);
gnutls_transport_set_vec_push_function(conn->tls->session, _tls_vec_push);
gnutls_transport_set_ptr(conn->tls->session, conn);
return 0;
}
int _output_dnssim_create_query_tls(output_dnssim_t* self, _output_dnssim_request_t* req)
{
mlassert_self();
lassert(req, "req is nil");
lassert(req->client, "request must have a client associated with it");
_output_dnssim_query_tcp_t* qry;
lfatal_oom(qry = calloc(1, sizeof(_output_dnssim_query_tcp_t)));
qry->qry.transport = OUTPUT_DNSSIM_TRANSPORT_TLS;
qry->qry.req = req;
qry->qry.state = _OUTPUT_DNSSIM_QUERY_PENDING_WRITE;
req->qry = &qry->qry; // TODO change when adding support for multiple Qs for req
_ll_append(req->client->pending, &qry->qry);
return _output_dnssim_handle_pending_queries(req->client);
}
void _output_dnssim_close_query_tls(_output_dnssim_query_tcp_t* qry)
{
mlassert(qry, "qry can't be null");
mlassert(qry->qry.req, "query must be part of a request");
_output_dnssim_request_t* req = qry->qry.req;
mlassert(req->client, "request must belong to a client");
_ll_try_remove(req->client->pending, &qry->qry);
if (qry->conn) {
_output_dnssim_connection_t* conn = qry->conn;
_ll_try_remove(conn->sent, &qry->qry);
qry->conn = NULL;
_output_dnssim_conn_idle(conn);
}
_ll_remove(req->qry, &qry->qry);
free(qry);
}
void _output_dnssim_tls_close(_output_dnssim_connection_t* conn)
{
mlassert(conn, "conn can't be nil");
mlassert(conn->tls, "conn must have tls ctx");
mlassert(conn->client, "conn must belong to a client");
/* Try and get a TLS session ticket for potential resumption. */
int ret;
if (gnutls_session_get_flags(conn->tls->session) & GNUTLS_SFLAGS_SESSION_TICKET) {
if (conn->client->tls_ticket.size != 0) {
gnutls_free(conn->client->tls_ticket.data);
}
ret = gnutls_session_get_data2(conn->tls->session, &conn->client->tls_ticket);
if (ret < 0) {
mldebug("gnutls_session_get_data2 failed: %s", gnutls_strerror(ret));
conn->client->tls_ticket.size = 0;
}
}
gnutls_deinit(conn->tls->session);
_output_dnssim_tcp_close(conn);
}
void _output_dnssim_tls_write_query(_output_dnssim_connection_t* conn, _output_dnssim_query_tcp_t* qry)
{
mlassert(qry, "qry can't be null");
mlassert(qry->qry.state == _OUTPUT_DNSSIM_QUERY_PENDING_WRITE, "qry must be pending write");
mlassert(qry->qry.req, "req can't be null");
mlassert(qry->qry.req->dns_q, "dns_q can't be null");
mlassert(qry->qry.req->dns_q->obj_prev, "payload can't be null");
mlassert(conn, "conn can't be null");
mlassert(conn->state == _OUTPUT_DNSSIM_CONN_ACTIVE, "connection state != ACTIVE");
mlassert(conn->tls, "conn must have tls ctx");
mlassert(conn->client, "conn must be associated with client");
mlassert(conn->client->pending, "conn has no pending queries");
core_object_payload_t* payload = (core_object_payload_t*)qry->qry.req->dns_q->obj_prev;
uint16_t len = htons(payload->len);
gnutls_record_cork(conn->tls->session);
ssize_t count = 0;
if ((count = gnutls_record_send(conn->tls->session, &len, sizeof(len)) < 0) || (count = gnutls_record_send(conn->tls->session, payload->payload, payload->len) < 0)) {
mlwarning("gnutls_record_send failed: %s", gnutls_strerror_name(count));
_output_dnssim_conn_close(conn);
return;
}
const ssize_t submitted = sizeof(len) + payload->len;
int ret = gnutls_record_uncork(conn->tls->session, GNUTLS_RECORD_WAIT);
if (gnutls_error_is_fatal(ret)) {
mlinfo("gnutls_record_uncorck failed: %s", gnutls_strerror_name(ret));
_output_dnssim_conn_close(conn);
return;
}
if (ret != submitted) {
mlwarning("gnutls_record_uncork didn't send all data");
_output_dnssim_conn_close(conn);
return;
}
qry->conn = conn;
_ll_remove(conn->client->pending, &qry->qry);
_ll_append(conn->sent, &qry->qry);
/* Stop idle timer, since there are queries to answer now. */
if (conn->idle_timer != NULL) {
conn->is_idle = false;
uv_timer_stop(conn->idle_timer);
}
qry->qry.state = _OUTPUT_DNSSIM_QUERY_SENT;
}
#endif