/* * libwebsockets - small server side websockets and web server implementation * * Copyright (C) 2010-2018 Andy Green * * 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 */ #include #define LWS_CPYAPP(ptr, str) { strcpy(ptr, str); ptr += strlen(str); } #if !defined(LWS_WITHOUT_EXTENSIONS) static int lws_extension_server_handshake(struct lws *wsi, char **p, int budget) { struct lws_context *context = wsi->context; struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi]; char ext_name[64], *args, *end = (*p) + budget - 1; const struct lws_ext_options *opts, *po; const struct lws_extension *ext; struct lws_ext_option_arg oa; int n, m, more = 1; int ext_count = 0; char ignore; char *c; /* * Figure out which extensions the client has that we want to * enable on this connection, and give him back the list */ if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) return 0; /* * break down the list of client extensions * and go through them */ if (lws_hdr_copy(wsi, (char *)pt->serv_buf, context->pt_serv_buf_size, WSI_TOKEN_EXTENSIONS) < 0) return 1; c = (char *)pt->serv_buf; lwsl_parser("WSI_TOKEN_EXTENSIONS = '%s'\n", c); wsi->ws->count_act_ext = 0; ignore = 0; n = 0; args = NULL; /* * We may get a simple request * * Sec-WebSocket-Extensions: permessage-deflate * * or an elaborated one with requested options * * Sec-WebSocket-Extensions: permessage-deflate; \ * server_no_context_takeover; \ * client_no_context_takeover */ while (more) { if (c >= (char *)pt->serv_buf + 255) return -1; if (*c && (*c != ',' && *c != '\t')) { if (*c == ';') { ignore = 1; if (!args) args = c + 1; } if (ignore || *c == ' ') { c++; continue; } ext_name[n] = *c++; if (n < (int)sizeof(ext_name) - 1) n++; continue; } ext_name[n] = '\0'; ignore = 0; if (!*c) more = 0; else { c++; if (!n) continue; } while (args && *args == ' ') args++; /* check a client's extension against our support */ ext = wsi->vhost->ws.extensions; while (ext && ext->callback) { if (strcmp(ext_name, ext->name)) { ext++; continue; } /* * oh, we do support this one he asked for... but let's * confirm he only gave it once */ for (m = 0; m < wsi->ws->count_act_ext; m++) if (wsi->ws->active_extensions[m] == ext) { lwsl_info("ext mentioned twice\n"); return 1; /* shenanigans */ } /* * ask user code if it's OK to apply it on this * particular connection + protocol */ m = (wsi->protocol->callback)(wsi, LWS_CALLBACK_CONFIRM_EXTENSION_OKAY, wsi->user_space, ext_name, 0); /* * zero return from callback means go ahead and allow * the extension, it's what we get if the callback is * unhandled */ if (m) { ext++; continue; } /* apply it */ ext_count++; /* instantiate the extension on this conn */ wsi->ws->active_extensions[wsi->ws->count_act_ext] = ext; /* allow him to construct his context */ if (ext->callback(lws_get_context(wsi), ext, wsi, LWS_EXT_CB_CONSTRUCT, (void *)&wsi->ws->act_ext_user[ wsi->ws->count_act_ext], (void *)&opts, 0)) { lwsl_info("ext %s failed construction\n", ext_name); ext_count--; ext++; continue; } if (ext_count > 1) *(*p)++ = ','; else LWS_CPYAPP(*p, "\x0d\x0aSec-WebSocket-Extensions: "); *p += lws_snprintf(*p, (end - *p), "%s", ext_name); /* * The client may send a bunch of different option * sets for the same extension, we are supposed to * pick one we like the look of. The option sets are * separated by comma. * * Actually we just either accept the first one or * nothing. * * Go through the options trying to apply the * recognized ones */ lwsl_info("ext args %s\n", args); while (args && *args && *args != ',') { while (*args == ' ') args++; po = opts; while (po->name) { /* only support arg-less options... */ if (po->type != EXTARG_NONE || strncmp(args, po->name, strlen(po->name))) { po++; continue; } oa.option_name = NULL; oa.option_index = (int)(po - opts); oa.start = NULL; oa.len = 0; lwsl_info("setting '%s'\n", po->name); if (!ext->callback(lws_get_context(wsi), ext, wsi, LWS_EXT_CB_OPTION_SET, wsi->ws->act_ext_user[ wsi->ws->count_act_ext], &oa, (end - *p))) { *p += lws_snprintf(*p, (end - *p), "; %s", po->name); lwsl_debug("adding option %s\n", po->name); } po++; } while (*args && *args != ',' && *args != ';') args++; if (*args == ';') args++; } wsi->ws->count_act_ext++; lwsl_parser("cnt_act_ext <- %d\n", wsi->ws->count_act_ext); if (args && *args == ',') more = 0; ext++; } n = 0; args = NULL; } return 0; } #endif int lws_process_ws_upgrade(struct lws *wsi) { struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi]; const struct lws_protocols *pcol = NULL; char buf[128], name[64]; struct lws_tokenize ts; lws_tokenize_elem e; if (!wsi->protocol) lwsl_err("NULL protocol at lws_read\n"); /* * We are upgrading to ws, so http/1.1 + h2 and keepalive + pipelined * header considerations about keeping the ah around no longer apply. * * However it's common for the first ws protocol data to have been * coalesced with the browser upgrade request and to already be in the * ah rx buffer. */ lws_pt_lock(pt, __func__); if (!wsi->h2_stream_carries_ws) lws_role_transition(wsi, LWSIFR_SERVER, LRS_ESTABLISHED, &role_ops_ws); lws_pt_unlock(pt); /* * It's either websocket or h2->websocket * * If we are on h1, confirm we got the required "connection: upgrade" * header. h2 / ws-over-h2 does not have this. */ #if defined(LWS_WITH_HTTP2) if (wsi->http2_substream) goto check_protocol; #endif lws_tokenize_init(&ts, buf, LWS_TOKENIZE_F_COMMA_SEP_LIST | LWS_TOKENIZE_F_MINUS_NONTERM); ts.len = lws_hdr_copy(wsi, buf, sizeof(buf) - 1, WSI_TOKEN_CONNECTION); if (ts.len <= 0) goto bad_conn_format; do { e = lws_tokenize(&ts); switch (e) { case LWS_TOKZE_TOKEN: if (!strcasecmp(ts.token, "upgrade")) e = LWS_TOKZE_ENDED; break; case LWS_TOKZE_DELIMITER: break; default: /* includes ENDED */ bad_conn_format: lwsl_err("%s: malformed or absent connection hdr\n", __func__); return 1; } } while (e > 0); #if defined(LWS_WITH_HTTP2) check_protocol: #endif /* * Select the first protocol we support from the list * the client sent us. */ lws_tokenize_init(&ts, buf, LWS_TOKENIZE_F_COMMA_SEP_LIST | LWS_TOKENIZE_F_MINUS_NONTERM | LWS_TOKENIZE_F_RFC7230_DELIMS); ts.len = lws_hdr_copy(wsi, buf, sizeof(buf) - 1, WSI_TOKEN_PROTOCOL); if (ts.len < 0) { lwsl_err("%s: protocol list too long\n", __func__); return 1; } if (!ts.len) { int n = wsi->vhost->default_protocol_index; /* * some clients only have one protocol and do not send the * protocol list header... allow it and match to the vhost's * default protocol (which itself defaults to zero) */ lwsl_info("%s: defaulting to prot handler %d\n", __func__, n); lws_bind_protocol(wsi, &wsi->vhost->protocols[n], "ws upgrade default pcol"); goto alloc_ws; } /* otherwise go through the user-provided protocol list */ do { e = lws_tokenize(&ts); switch (e) { case LWS_TOKZE_TOKEN: if (lws_tokenize_cstr(&ts, name, sizeof(name))) { lwsl_err("%s: pcol name too long\n", __func__); return 1; } lwsl_debug("checking %s\n", name); pcol = lws_vhost_name_to_protocol(wsi->vhost, name); if (pcol) { /* if we know it, bind to it and stop looking */ lws_bind_protocol(wsi, pcol, "ws upg pcol"); e = LWS_TOKZE_ENDED; } break; case LWS_TOKZE_DELIMITER: case LWS_TOKZE_ENDED: break; default: lwsl_err("%s: malformatted protocol list", __func__); return 1; } } while (e > 0); /* we didn't find a protocol he wanted? */ if (!pcol) { lwsl_notice("No supported protocol \"%s\"\n", buf); return 1; } alloc_ws: /* allocate the ws struct for the wsi */ wsi->ws = lws_zalloc(sizeof(*wsi->ws), "ws struct"); if (!wsi->ws) { lwsl_notice("OOM\n"); return 1; } if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION)) wsi->ws->ietf_spec_revision = atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION)); /* allocate wsi->user storage */ if (lws_ensure_user_space(wsi)) { lwsl_notice("problem with user space\n"); return 1; } /* * Give the user code a chance to study the request and * have the opportunity to deny it */ if ((wsi->protocol->callback)(wsi, LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION, wsi->user_space, lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL), 0)) { lwsl_warn("User code denied connection\n"); return 1; } /* * Perform the handshake according to the protocol version the * client announced */ switch (wsi->ws->ietf_spec_revision) { default: lwsl_notice("Unknown client spec version %d\n", wsi->ws->ietf_spec_revision); wsi->ws->ietf_spec_revision = 13; //return 1; /* fallthru */ case 13: #if defined(LWS_WITH_HTTP2) if (wsi->h2_stream_carries_ws) { if (lws_h2_ws_handshake(wsi)) { lwsl_notice("h2 ws handshake failed\n"); return 1; } lws_role_transition(wsi, LWSIFR_SERVER | LWSIFR_P_ENCAP_H2, LRS_ESTABLISHED, &role_ops_ws); } else #endif { lwsl_parser("lws_parse calling handshake_04\n"); if (handshake_0405(wsi->context, wsi)) { lwsl_notice("hs0405 has failed the connection\n"); return 1; } } break; } lws_server_init_wsi_for_ws(wsi); lwsl_parser("accepted v%02d connection\n", wsi->ws->ietf_spec_revision); lwsl_info("%s: %p: dropping ah on ws upgrade\n", __func__, wsi); lws_header_table_detach(wsi, 1); return 0; } int handshake_0405(struct lws_context *context, struct lws *wsi) { struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi]; struct lws_process_html_args args; unsigned char hash[20]; int n, accept_len; char *response; char *p; if (!lws_hdr_total_length(wsi, WSI_TOKEN_HOST) || !lws_hdr_total_length(wsi, WSI_TOKEN_KEY)) { lwsl_info("handshake_04 missing pieces\n"); /* completed header processing, but missing some bits */ goto bail; } if (lws_hdr_total_length(wsi, WSI_TOKEN_KEY) >= MAX_WEBSOCKET_04_KEY_LEN) { lwsl_warn("Client key too long %d\n", MAX_WEBSOCKET_04_KEY_LEN); goto bail; } /* * since key length is restricted above (currently 128), cannot * overflow */ n = sprintf((char *)pt->serv_buf, "%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", lws_hdr_simple_ptr(wsi, WSI_TOKEN_KEY)); lws_SHA1(pt->serv_buf, n, hash); accept_len = lws_b64_encode_string((char *)hash, 20, (char *)pt->serv_buf, context->pt_serv_buf_size); if (accept_len < 0) { lwsl_warn("Base64 encoded hash too long\n"); goto bail; } /* allocate the per-connection user memory (if any) */ if (lws_ensure_user_space(wsi)) goto bail; /* create the response packet */ /* make a buffer big enough for everything */ response = (char *)pt->serv_buf + MAX_WEBSOCKET_04_KEY_LEN + 256 + LWS_PRE; p = response; LWS_CPYAPP(p, "HTTP/1.1 101 Switching Protocols\x0d\x0a" "Upgrade: WebSocket\x0d\x0a" "Connection: Upgrade\x0d\x0a" "Sec-WebSocket-Accept: "); strcpy(p, (char *)pt->serv_buf); p += accept_len; /* we can only return the protocol header if: * - one came in, and ... */ if (lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL) && /* - it is not an empty string */ wsi->protocol->name && wsi->protocol->name[0]) { LWS_CPYAPP(p, "\x0d\x0aSec-WebSocket-Protocol: "); p += lws_snprintf(p, 128, "%s", wsi->protocol->name); } #if !defined(LWS_WITHOUT_EXTENSIONS) /* * Figure out which extensions the client has that we want to * enable on this connection, and give him back the list. * * Give him a limited write bugdet */ if (lws_extension_server_handshake(wsi, &p, 192)) goto bail; #endif LWS_CPYAPP(p, "\x0d\x0a"); args.p = p; args.max_len = lws_ptr_diff((char *)pt->serv_buf + context->pt_serv_buf_size, p); if (user_callback_handle_rxflow(wsi->protocol->callback, wsi, LWS_CALLBACK_ADD_HEADERS, wsi->user_space, &args, 0)) goto bail; p = args.p; /* end of response packet */ LWS_CPYAPP(p, "\x0d\x0a"); /* okay send the handshake response accepting the connection */ lwsl_parser("issuing resp pkt %d len\n", lws_ptr_diff(p, response)); #if defined(DEBUG) fwrite(response, 1, p - response, stderr); #endif n = lws_write(wsi, (unsigned char *)response, p - response, LWS_WRITE_HTTP_HEADERS); if (n != (p - response)) { lwsl_info("%s: ERROR writing to socket %d\n", __func__, n); goto bail; } /* alright clean up and set ourselves into established state */ lwsi_set_state(wsi, LRS_ESTABLISHED); wsi->lws_rx_parse_state = LWS_RXPS_NEW; { const char * uri_ptr = lws_hdr_simple_ptr(wsi, WSI_TOKEN_GET_URI); int uri_len = lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI); const struct lws_http_mount *hit = lws_find_mount(wsi, uri_ptr, uri_len); if (hit && hit->cgienv && wsi->protocol->callback(wsi, LWS_CALLBACK_HTTP_PMO, wsi->user_space, (void *)hit->cgienv, 0)) return 1; } return 0; bail: /* caller will free up his parsing allocations */ return -1; } /* * Once we reach LWS_RXPS_WS_FRAME_PAYLOAD, we know how much * to expect in that state and can deal with it in bulk more efficiently. */ static int lws_ws_frame_rest_is_payload(struct lws *wsi, uint8_t **buf, size_t len) { unsigned int avail = (unsigned int)len; uint8_t *buffer = *buf, mask[4]; struct lws_tokens ebuf; #if !defined(LWS_WITHOUT_EXTENSIONS) unsigned int old_packet_length = (int)wsi->ws->rx_packet_length; #endif int n = 0; /* * With zlib, we can give it as much input as we like. The pmd * extension will draw it down in chunks (default 1024). * * If we try to restrict how much we give it, because we must go * back to the event loop each time, we will drop the remainder... */ #if !defined(LWS_WITHOUT_EXTENSIONS) if (!wsi->ws->count_act_ext) #endif { if (wsi->protocol->rx_buffer_size) avail = (int)wsi->protocol->rx_buffer_size; else avail = wsi->context->pt_serv_buf_size; } /* do not consume more than we should */ if (avail > wsi->ws->rx_packet_length) avail = (unsigned int)wsi->ws->rx_packet_length; /* do not consume more than what is in the buffer */ if (avail > len) avail = (unsigned int)len; if (!avail) return 0; ebuf.token = (char *)buffer; ebuf.len = avail; //lwsl_hexdump_notice(ebuf.token, ebuf.len); if (!wsi->ws->all_zero_nonce) { for (n = 0; n < 4; n++) mask[n] = wsi->ws->mask[(wsi->ws->mask_idx + n) & 3]; /* deal with 4-byte chunks using unwrapped loop */ n = avail >> 2; while (n--) { *(buffer) = *(buffer) ^ mask[0]; buffer++; *(buffer) = *(buffer) ^ mask[1]; buffer++; *(buffer) = *(buffer) ^ mask[2]; buffer++; *(buffer) = *(buffer) ^ mask[3]; buffer++; } /* and the remaining bytes bytewise */ for (n = 0; n < (int)(avail & 3); n++) { *(buffer) = *(buffer) ^ mask[n]; buffer++; } wsi->ws->mask_idx = (wsi->ws->mask_idx + avail) & 3; } lwsl_info("%s: using %d of raw input (total %d on offer)\n", __func__, avail, (int)len); (*buf) += avail; len -= avail; #if !defined(LWS_WITHOUT_EXTENSIONS) n = lws_ext_cb_active(wsi, LWS_EXT_CB_PAYLOAD_RX, &ebuf, 0); lwsl_info("%s: ext says %d / ebuf.len %d\n", __func__, n, ebuf.len); #endif /* * ebuf may be pointing somewhere completely different now, * it's the output */ #if !defined(LWS_WITHOUT_EXTENSIONS) if (n < 0) { /* * we may rely on this to get RX, just drop connection */ lwsl_notice("%s: LWS_EXT_CB_PAYLOAD_RX blew out\n", __func__); wsi->socket_is_permanently_unusable = 1; return -1; } #endif wsi->ws->rx_packet_length -= avail; #if !defined(LWS_WITHOUT_EXTENSIONS) /* * if we had an rx fragment right at the last compressed byte of the * message, we can get a zero length inflated output, where no prior * rx inflated output marked themselves with FIN, since there was * raw ws payload still to drain at that time. * * Then we need to generate a zero length ws rx that can be understood * as the message completion. */ if (!ebuf.len && /* zero-length inflation output */ !n && /* nothing left to drain from the inflator */ wsi->ws->count_act_ext && /* we are using pmd */ old_packet_length && /* we gave the inflator new input */ !wsi->ws->rx_packet_length && /* raw ws packet payload all gone */ wsi->ws->final && /* the raw ws packet is a FIN guy */ wsi->protocol->callback && !wsi->wsistate_pre_close) { if (user_callback_handle_rxflow(wsi->protocol->callback, wsi, LWS_CALLBACK_RECEIVE, wsi->user_space, NULL, 0)) return -1; return avail; } #endif if (!ebuf.len) return avail; if ( #if !defined(LWS_WITHOUT_EXTENSIONS) n && #endif ebuf.len) /* extension had more... main loop will come back */ lws_add_wsi_to_draining_ext_list(wsi); else lws_remove_wsi_from_draining_ext_list(wsi); if (wsi->ws->check_utf8 && !wsi->ws->defeat_check_utf8) { if (lws_check_utf8(&wsi->ws->utf8, (unsigned char *)ebuf.token, ebuf.len)) { lws_close_reason(wsi, LWS_CLOSE_STATUS_INVALID_PAYLOAD, (uint8_t *)"bad utf8", 8); goto utf8_fail; } /* we are ending partway through utf-8 character? */ if (!wsi->ws->rx_packet_length && wsi->ws->final && wsi->ws->utf8 && !n) { lwsl_info("FINAL utf8 error\n"); lws_close_reason(wsi, LWS_CLOSE_STATUS_INVALID_PAYLOAD, (uint8_t *)"partial utf8", 12); utf8_fail: lwsl_info("utf8 error\n"); lwsl_hexdump_info(ebuf.token, ebuf.len); return -1; } } if (wsi->protocol->callback && !wsi->wsistate_pre_close) if (user_callback_handle_rxflow(wsi->protocol->callback, wsi, LWS_CALLBACK_RECEIVE, wsi->user_space, ebuf.token, ebuf.len)) return -1; wsi->ws->first_fragment = 0; #if !defined(LWS_WITHOUT_EXTENSIONS) lwsl_info("%s: input used %d, output %d, rem len %d, rx_draining_ext %d\n", __func__, avail, ebuf.len, (int)len, wsi->ws->rx_draining_ext); #endif return avail; /* how much we used from the input */ } int lws_parse_ws(struct lws *wsi, unsigned char **buf, size_t len) { int m, bulk = 0; lwsl_debug("%s: received %d byte packet\n", __func__, (int)len); //lwsl_hexdump_notice(*buf, len); /* let the rx protocol state machine have as much as it needs */ while (len) { /* * we were accepting input but now we stopped doing so */ if (wsi->rxflow_bitmap) { lwsl_info("%s: doing rxflow\n", __func__); lws_rxflow_cache(wsi, *buf, 0, (int)len); lwsl_parser("%s: cached %ld\n", __func__, (long)len); *buf += len; /* stashing it is taking care of it */ return 1; } #if !defined(LWS_WITHOUT_EXTENSIONS) if (wsi->ws->rx_draining_ext) { lwsl_debug("%s: draining rx ext\n", __func__); m = lws_ws_rx_sm(wsi, ALREADY_PROCESSED_IGNORE_CHAR, 0); if (m < 0) return -1; continue; } #endif /* consume payload bytes efficiently */ while (wsi->lws_rx_parse_state == LWS_RXPS_WS_FRAME_PAYLOAD && (wsi->ws->opcode == LWSWSOPC_TEXT_FRAME || wsi->ws->opcode == LWSWSOPC_BINARY_FRAME || wsi->ws->opcode == LWSWSOPC_CONTINUATION) && len) { uint8_t *bin = *buf; bulk = 1; m = lws_ws_frame_rest_is_payload(wsi, buf, len); assert((int)lws_ptr_diff(*buf, bin) <= (int)len); len -= lws_ptr_diff(*buf, bin); if (!m) { break; } if (m < 0) { lwsl_info("%s: rest_is_payload bailed\n", __func__); return -1; } } if (!bulk) { /* process the byte */ m = lws_ws_rx_sm(wsi, 0, *(*buf)++); len--; } else { /* * We already handled this byte in bulk, just deal * with the ramifications */ #if !defined(LWS_WITHOUT_EXTENSIONS) lwsl_debug("%s: coming out of bulk with len %d, " "wsi->ws->rx_draining_ext %d\n", __func__, (int)len, wsi->ws->rx_draining_ext); #endif m = lws_ws_rx_sm(wsi, ALREADY_PROCESSED_IGNORE_CHAR | ALREADY_PROCESSED_NO_CB, 0); } if (m < 0) { lwsl_info("%s: lws_ws_rx_sm bailed %d\n", __func__, bulk); return -1; } bulk = 0; } lwsl_debug("%s: exit with %d unused\n", __func__, (int)len); return 0; }