1 files changed, 475 insertions, 0 deletions

diff --git a/src/output/dnssim/tls.c b/src/output/dnssim/tls.c
new file mode 100644
index 0000000..e87ca47
--- /dev/null
+++ b/src/output/dnssim/tls.c
@@ -0,0 +1,475 @@
+/*
+ * 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