/mod_proxy_connect.c
Last active Aug 4, 2019
Mod_proxy_connect.c modified such that the client IP address is forwarded to the backend in a 50 byte buffer
| /* Licensed to the Apache Software Foundation (ASF) under one or more | |
| * contributor license agreements. See the NOTICE file distributed with | |
| * this work for additional information regarding copyright ownership. | |
| * The ASF licenses this file to You under the Apache License, Version 2.0 | |
| * (the "License"); you may not use this file except in compliance with | |
| * the License. You may obtain a copy of the License at | |
| * | |
| * http://www.apache.org/licenses/LICENSE-2.0 | |
| * | |
| * Unless required by applicable law or agreed to in writing, software | |
| * distributed under the License is distributed on an "AS IS" BASIS, | |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| * See the License for the specific language governing permissions and | |
| * limitations under the License. | |
| */ | |
| /* CONNECT method for Apache proxy */ | |
| #include "mod_proxy.h" | |
| #include "apr_poll.h" | |
| #include <sys/param.h> | |
| #define CONN_BLKSZ AP_IOBUFSIZE | |
| module AP_MODULE_DECLARE_DATA proxy_connect_module; | |
| /* | |
| * This handles Netscape CONNECT method secure proxy requests. | |
| * A connection is opened to the specified host and data is | |
| * passed through between the WWW site and the browser. | |
| * | |
| * This code is based on the INTERNET-DRAFT document | |
| * "Tunneling SSL Through a WWW Proxy" currently at | |
| * http://www.mcom.com/newsref/std/tunneling_ssl.html. | |
| * | |
| * If proxyhost and proxyport are set, we send a CONNECT to | |
| * the specified proxy.. | |
| * | |
| * FIXME: this doesn't log the number of bytes sent, but | |
| * that may be okay, since the data is supposed to | |
| * be transparent. In fact, this doesn't log at all | |
| * yet. 8^) | |
| * FIXME: doesn't check any headers initally sent from the | |
| * client. | |
| * FIXME: should allow authentication, but hopefully the | |
| * generic proxy authentication is good enough. | |
| * FIXME: no check for r->assbackwards, whatever that is. | |
| */ | |
| typedef struct { | |
| apr_array_header_t *allowed_connect_ports; | |
| } connect_conf; | |
| typedef struct { | |
| int first; | |
| int last; | |
| } port_range; | |
| static void *create_config(apr_pool_t *p, server_rec *s) | |
| { | |
| connect_conf *c = apr_pcalloc(p, sizeof(connect_conf)); | |
| c->allowed_connect_ports = apr_array_make(p, 10, sizeof(port_range)); | |
| return c; | |
| } | |
| static void *merge_config(apr_pool_t *p, void *basev, void *overridesv) | |
| { | |
| connect_conf *c = apr_pcalloc(p, sizeof(connect_conf)); | |
| connect_conf *base = (connect_conf *) basev; | |
| connect_conf *overrides = (connect_conf *) overridesv; | |
| c->allowed_connect_ports = apr_array_append(p, | |
| base->allowed_connect_ports, | |
| overrides->allowed_connect_ports); | |
| return c; | |
| } | |
| /* | |
| * Set the ports CONNECT can use | |
| */ | |
| static const char * | |
| set_allowed_ports(cmd_parms *parms, void *dummy, const char *arg) | |
| { | |
| server_rec *s = parms->server; | |
| int first, last; | |
| connect_conf *conf = | |
| ap_get_module_config(s->module_config, &proxy_connect_module); | |
| port_range *New; | |
| char *endptr; | |
| const char *p = arg; | |
| if (!apr_isdigit(arg[0])) | |
| return "AllowCONNECT: port numbers must be numeric"; | |
| first = strtol(p, &endptr, 10); | |
| if (*endptr == '-') { | |
| p = endptr + 1; | |
| last = strtol(p, &endptr, 10); | |
| } | |
| else { | |
| last = first; | |
| } | |
| if (endptr == p || *endptr != '\0') { | |
| return apr_psprintf(parms->temp_pool, | |
| "Cannot parse '%s' as port number", p); | |
| } | |
| New = apr_array_push(conf->allowed_connect_ports); | |
| New->first = first; | |
| New->last = last; | |
| return NULL; | |
| } | |
| static int allowed_port(connect_conf *conf, int port) | |
| { | |
| int i; | |
| port_range *list = (port_range *) conf->allowed_connect_ports->elts; | |
| if (apr_is_empty_array(conf->allowed_connect_ports)) { | |
| return port == APR_URI_HTTPS_DEFAULT_PORT | |
| || port == APR_URI_SNEWS_DEFAULT_PORT; | |
| } | |
| for (i = 0; i < conf->allowed_connect_ports->nelts; i++) { | |
| if (port >= list[i].first && port <= list[i].last) | |
| return 1; | |
| } | |
| return 0; | |
| } | |
| /* canonicalise CONNECT URLs. */ | |
| static int proxy_connect_canon(request_rec *r, char *url) | |
| { | |
| if (r->method_number != M_CONNECT) { | |
| return DECLINED; | |
| } | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, "canonicalising URL %s", url); | |
| return OK; | |
| } | |
| /* CONNECT handler */ | |
| static int proxy_connect_handler(request_rec *r, proxy_worker *worker, | |
| proxy_server_conf *conf, | |
| char *url, const char *proxyname, | |
| apr_port_t proxyport) | |
| { | |
| connect_conf *c_conf = | |
| ap_get_module_config(r->server->module_config, &proxy_connect_module); | |
| apr_pool_t *p = r->pool; | |
| apr_socket_t *sock; | |
| conn_rec *c = r->connection; | |
| conn_rec *backconn; | |
| int done = 0; | |
| apr_bucket_brigade *bb_front; | |
| apr_bucket_brigade *bb_back; | |
| apr_status_t rv; | |
| apr_size_t nbytes; | |
| char buffer[HUGE_STRING_LEN]; | |
| apr_socket_t *client_socket = ap_get_conn_socket(c); | |
| int failed, rc; | |
| apr_pollset_t *pollset; | |
| apr_pollfd_t pollfd; | |
| const apr_pollfd_t *signalled; | |
| apr_int32_t pollcnt, pi; | |
| apr_int16_t pollevent; | |
| apr_sockaddr_t *nexthop; | |
| apr_uri_t uri; | |
| const char *connectname; | |
| apr_port_t connectport = 0; | |
| /* is this for us? */ | |
| if (r->method_number != M_CONNECT) { | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, "declining URL %s", url); | |
| return DECLINED; | |
| } | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, "serving URL %s", url); | |
| /* | |
| * Step One: Determine Who To Connect To | |
| * | |
| * Break up the URL to determine the host to connect to | |
| */ | |
| /* we break the URL into host, port, uri */ | |
| if (APR_SUCCESS != apr_uri_parse_hostinfo(p, url, &uri)) { | |
| return ap_proxyerror(r, HTTP_BAD_REQUEST, | |
| apr_pstrcat(p, "URI cannot be parsed: ", url, | |
| NULL)); | |
| } | |
| ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01019) | |
| "connecting %s to %s:%d", url, uri.hostname, uri.port); | |
| /* Determine host/port of next hop; from request URI or of a proxy. */ | |
| connectname = proxyname ? proxyname : uri.hostname; | |
| connectport = proxyname ? proxyport : uri.port; | |
| /* Do a DNS lookup for the next hop */ | |
| rv = apr_sockaddr_info_get(&nexthop, connectname, APR_UNSPEC, | |
| connectport, 0, p); | |
| if (rv != APR_SUCCESS) { | |
| ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(02327) | |
| "failed to resolve hostname '%s'", connectname); | |
| return ap_proxyerror(r, HTTP_BAD_GATEWAY, | |
| apr_pstrcat(p, "DNS lookup failure for: ", | |
| connectname, NULL)); | |
| } | |
| /* Check ProxyBlock directive on the hostname/address. */ | |
| if (ap_proxy_checkproxyblock2(r, conf, uri.hostname, | |
| proxyname ? NULL : nexthop) != OK) { | |
| return ap_proxyerror(r, HTTP_FORBIDDEN, | |
| "Connect to remote machine blocked"); | |
| } | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, | |
| "connecting to remote proxy %s on port %d", | |
| connectname, connectport); | |
| /* Check if it is an allowed port */ | |
| if (!allowed_port(c_conf, uri.port)) { | |
| return ap_proxyerror(r, HTTP_FORBIDDEN, | |
| "Connect to remote machine blocked"); | |
| } | |
| /* | |
| * Step Two: Make the Connection | |
| * | |
| * We have determined who to connect to. Now make the connection. | |
| */ | |
| /* | |
| * At this point we have a list of one or more IP addresses of | |
| * the machine to connect to. If configured, reorder this | |
| * list so that the "best candidate" is first try. "best | |
| * candidate" could mean the least loaded server, the fastest | |
| * responding server, whatever. | |
| * | |
| * For now we do nothing, ie we get DNS round robin. | |
| * XXX FIXME | |
| */ | |
| failed = ap_proxy_connect_to_backend(&sock, "CONNECT", nexthop, | |
| connectname, conf, r); | |
| /* handle a permanent error from the above loop */ | |
| if (failed) { | |
| if (proxyname) { | |
| return DECLINED; | |
| } | |
| else { | |
| return HTTP_SERVICE_UNAVAILABLE; | |
| } | |
| } | |
| /* setup polling for connection */ | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r, "setting up poll()"); | |
| if ((rv = apr_pollset_create(&pollset, 2, r->pool, 0)) != APR_SUCCESS) { | |
| apr_socket_close(sock); | |
| ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01020) | |
| "error apr_pollset_create()"); | |
| return HTTP_INTERNAL_SERVER_ERROR; | |
| } | |
| /* Add client side to the poll */ | |
| pollfd.p = r->pool; | |
| pollfd.desc_type = APR_POLL_SOCKET; | |
| pollfd.reqevents = APR_POLLIN | APR_POLLHUP; | |
| pollfd.desc.s = client_socket; | |
| pollfd.client_data = NULL; | |
| apr_pollset_add(pollset, &pollfd); | |
| /* Add the server side to the poll */ | |
| pollfd.desc.s = sock; | |
| apr_pollset_add(pollset, &pollfd); | |
| /* | |
| * Step Three: Send the Request | |
| * | |
| * Send the HTTP/1.1 CONNECT request to the remote server | |
| */ | |
| backconn = ap_run_create_connection(c->pool, r->server, sock, | |
| c->id, c->sbh, c->bucket_alloc); | |
| if (!backconn) { | |
| /* peer reset */ | |
| ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(01021) | |
| "an error occurred creating a new connection " | |
| "to %pI (%s)", nexthop, connectname); | |
| apr_socket_close(sock); | |
| return HTTP_INTERNAL_SERVER_ERROR; | |
| } | |
| ap_proxy_ssl_engine(backconn, r->per_dir_config, 0); | |
| rc = ap_run_pre_connection(backconn, sock); | |
| if (rc != OK && rc != DONE) { | |
| backconn->aborted = 1; | |
| ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01022) | |
| "pre_connection setup failed (%d)", rc); | |
| return HTTP_INTERNAL_SERVER_ERROR; | |
| } | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r, | |
| "connection complete to %pI (%s)", | |
| nexthop, connectname); | |
| apr_table_setn(r->notes, "proxy-source-port", apr_psprintf(r->pool, "%hu", | |
| backconn->local_addr->port)); | |
| bb_front = apr_brigade_create(p, c->bucket_alloc); | |
| bb_back = apr_brigade_create(p, backconn->bucket_alloc); | |
| /* If we are connecting through a remote proxy, we need to pass | |
| * the CONNECT request on to it. | |
| */ | |
| if (proxyport) { | |
| /* FIXME: Error checking ignored. | |
| */ | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r, | |
| "sending the CONNECT request to the remote proxy"); | |
| ap_fprintf(backconn->output_filters, bb_back, | |
| "CONNECT %s HTTP/1.0" CRLF, r->uri); | |
| ap_fprintf(backconn->output_filters, bb_back, | |
| "Proxy-agent: %s" CRLF CRLF, ap_get_server_banner()); | |
| ap_fflush(backconn->output_filters, bb_back); | |
| } | |
| else { | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, "Returning 200 OK"); | |
| nbytes = apr_snprintf(buffer, sizeof(buffer), | |
| "HTTP/1.0 200 Connection Established" CRLF); | |
| ap_xlate_proto_to_ascii(buffer, nbytes); | |
| ap_fwrite(c->output_filters, bb_front, buffer, nbytes); | |
| nbytes = apr_snprintf(buffer, sizeof(buffer), | |
| "Proxy-agent: %s" CRLF CRLF, | |
| ap_get_server_banner()); | |
| ap_xlate_proto_to_ascii(buffer, nbytes); | |
| ap_fwrite(c->output_filters, bb_front, buffer, nbytes); | |
| ap_fflush(c->output_filters, bb_front); | |
| #if 0 | |
| /* This is safer code, but it doesn't work yet. I'm leaving it | |
| * here so that I can fix it later. | |
| */ | |
| r->status = HTTP_OK; | |
| r->header_only = 1; | |
| apr_table_set(r->headers_out, "Proxy-agent: %s", ap_get_server_banner()); | |
| ap_rflush(r); | |
| #endif | |
| memset(buffer, 0, MIN(50, sizeof(buffer))); | |
| nbytes = apr_snprintf(buffer, sizeof(buffer), | |
| "%s", r->useragent_ip); | |
| ap_fwrite(backconn->output_filters, bb_back, buffer, MIN(50, sizeof(buffer)) ); | |
| ap_fflush(backconn->output_filters, bb_back); | |
| } | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r, "setting up poll()"); | |
| /* | |
| * Step Four: Handle Data Transfer | |
| * | |
| * Handle two way transfer of data over the socket (this is a tunnel). | |
| */ | |
| /* we are now acting as a tunnel - the input/output filter stacks should | |
| * not contain any non-connection filters. | |
| */ | |
| r->output_filters = c->output_filters; | |
| r->proto_output_filters = c->output_filters; | |
| r->input_filters = c->input_filters; | |
| r->proto_input_filters = c->input_filters; | |
| /* r->sent_bodyct = 1;*/ | |
| do { /* Loop until done (one side closes the connection, or an error) */ | |
| rv = apr_pollset_poll(pollset, -1, &pollcnt, &signalled); | |
| if (rv != APR_SUCCESS) { | |
| if (APR_STATUS_IS_EINTR(rv)) { | |
| continue; | |
| } | |
| apr_socket_close(sock); | |
| ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01023) "error apr_poll()"); | |
| return HTTP_INTERNAL_SERVER_ERROR; | |
| } | |
| #ifdef DEBUGGING | |
| ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01024) | |
| "woke from poll(), i=%d", pollcnt); | |
| #endif | |
| for (pi = 0; pi < pollcnt; pi++) { | |
| const apr_pollfd_t *cur = &signalled[pi]; | |
| if (cur->desc.s == sock) { | |
| pollevent = cur->rtnevents; | |
| if (pollevent & (APR_POLLIN | APR_POLLHUP)) { | |
| #ifdef DEBUGGING | |
| ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01025) | |
| "sock was readable"); | |
| #endif | |
| done |= ap_proxy_transfer_between_connections(r, backconn, | |
| c, bb_back, | |
| bb_front, | |
| "sock", NULL, | |
| CONN_BLKSZ, 1) | |
| != APR_SUCCESS; | |
| } | |
| else if (pollevent & APR_POLLERR) { | |
| ap_log_rerror(APLOG_MARK, APLOG_NOTICE, 0, r, APLOGNO(01026) | |
| "err on backconn"); | |
| backconn->aborted = 1; | |
| done = 1; | |
| } | |
| } | |
| else if (cur->desc.s == client_socket) { | |
| pollevent = cur->rtnevents; | |
| if (pollevent & (APR_POLLIN | APR_POLLHUP)) { | |
| #ifdef DEBUGGING | |
| ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01027) | |
| "client was readable"); | |
| #endif | |
| done |= ap_proxy_transfer_between_connections(r, c, | |
| backconn, | |
| bb_front, | |
| bb_back, | |
| "client", | |
| NULL, | |
| CONN_BLKSZ, 1) | |
| != APR_SUCCESS; | |
| } | |
| else if (pollevent & APR_POLLERR) { | |
| ap_log_rerror(APLOG_MARK, APLOG_NOTICE, 0, r, APLOGNO(02827) | |
| "err on client"); | |
| c->aborted = 1; | |
| done = 1; | |
| } | |
| } | |
| else { | |
| ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(01028) | |
| "unknown socket in pollset"); | |
| done = 1; | |
| } | |
| } | |
| } while (!done); | |
| ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r, | |
| "finished with poll() - cleaning up"); | |
| /* | |
| * Step Five: Clean Up | |
| * | |
| * Close the socket and clean up | |
| */ | |
| if (backconn->aborted) | |
| apr_socket_close(sock); | |
| else | |
| ap_lingering_close(backconn); | |
| c->keepalive = AP_CONN_CLOSE; | |
| return OK; | |
| } | |
| static void ap_proxy_connect_register_hook(apr_pool_t *p) | |
| { | |
| proxy_hook_scheme_handler(proxy_connect_handler, NULL, NULL, APR_HOOK_MIDDLE); | |
| proxy_hook_canon_handler(proxy_connect_canon, NULL, NULL, APR_HOOK_MIDDLE); | |
| } | |
| static const command_rec cmds[] = | |
| { | |
| AP_INIT_ITERATE("AllowCONNECT", set_allowed_ports, NULL, RSRC_CONF, | |
| "A list of ports or port ranges which CONNECT may connect to"), | |
| {NULL} | |
| }; | |
| AP_DECLARE_MODULE(proxy_connect) = { | |
| STANDARD20_MODULE_STUFF, | |
| NULL, /* create per-directory config structure */ | |
| NULL, /* merge per-directory config structures */ | |
| create_config, /* create per-server config structure */ | |
| merge_config, /* merge per-server config structures */ | |
| cmds, /* command apr_table_t */ | |
| ap_proxy_connect_register_hook /* register hooks */ | |
| }; |
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