/* * WebSocket lib with support for "wss://" encryption. * Copyright 2010 Joel Martin * Licensed under LGPL version 3 (see docs/LICENSE.LGPL-3) * * You can make a cert/key with openssl using: * openssl req -new -x509 -days 365 -nodes -out self.pem -keyout self.pem * as taken from http://docs.python.org/dev/library/ssl.html#certificates */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // daemonizing #include #include #include /* base64 encode/decode */ #include /* md5 hash */ #include /* sha1 hash */ #include "websocket.h" #include "jsonescape.h" #include "kasmpasswd.h" #include /* * Global state * * Warning: not thread safe */ int ssl_initialized = 0; int pipe_error = 0; settings_t settings; void traffic(const char * token) { /*if ((settings.verbose) && (! settings.daemon)) { fprintf(stdout, "%s", token); fflush(stdout); }*/ } void error(char *msg) { perror(msg); } void fatal(char *msg) { perror(msg); exit(1); } /* resolve host with also IP address parsing */ int resolve_host(struct in_addr *sin_addr, const char *hostname) { if (!inet_aton(hostname, sin_addr)) { struct addrinfo *ai, *cur; struct addrinfo hints; memset(&hints, 0, sizeof(hints)); hints.ai_family = AF_INET; if (getaddrinfo(hostname, NULL, &hints, &ai)) return -1; for (cur = ai; cur; cur = cur->ai_next) { if (cur->ai_family == AF_INET) { *sin_addr = ((struct sockaddr_in *)cur->ai_addr)->sin_addr; freeaddrinfo(ai); return 0; } } freeaddrinfo(ai); return -1; } return 0; } static const char *parse_get(const char * const in, const char * const opt, unsigned *len) { const char *start = in; const char *end = strchrnul(start, '&'); const unsigned optlen = strlen(opt); *len = 0; while (1) { if (!strncmp(start, opt, optlen)) { const char *arg = strchr(start, '='); if (!arg) return ""; arg++; *len = end - arg; return arg; } if (!*end) break; end++; start = end; end = strchrnul(start, '&'); } return ""; } static void percent_decode(const char *src, char *dst, const uint8_t filter) { while (1) { if (!*src) break; if (*src != '%') { *dst++ = *src++; } else { src++; if (!src[0] || !src[1]) break; char hex[3]; hex[0] = src[0]; hex[1] = src[1]; hex[2] = '\0'; src += 2; *dst = strtol(hex, NULL, 16); if (filter) { // Avoid directory traversal if (*dst == '/') *dst = '_'; } dst++; } } *dst = '\0'; } static void percent_encode(const char *src, char *dst) { while (1) { if (!*src) break; if (isalnum(*src) || *src == '.' || *src == ',') { *dst++ = *src++; } else { *dst++ = '%'; sprintf(dst, "%02X", *src); dst += 2; src++; } } *dst = '\0'; } /* * SSL Wrapper Code */ ssize_t ws_recv(ws_ctx_t *ctx, void *buf, size_t len) { if (ctx->ssl) { //handler_msg("SSL recv\n"); return SSL_read(ctx->ssl, buf, len); } else { return recv(ctx->sockfd, buf, len, 0); } } ssize_t ws_send(ws_ctx_t *ctx, const void *buf, size_t len) { if (ctx->ssl) { //handler_msg("SSL send\n"); return SSL_write(ctx->ssl, buf, len); } else { return send(ctx->sockfd, buf, len, 0); } } ws_ctx_t *alloc_ws_ctx() { ws_ctx_t *ctx; if (! (ctx = calloc(sizeof(ws_ctx_t), 1)) ) { fatal("malloc()"); } if (! (ctx->cin_buf = malloc(BUFSIZE)) ) { fatal("malloc of cin_buf"); } if (! (ctx->cout_buf = malloc(BUFSIZE)) ) { fatal("malloc of cout_buf"); } if (! (ctx->tin_buf = malloc(BUFSIZE)) ) { fatal("malloc of tin_buf"); } if (! (ctx->tout_buf = malloc(BUFSIZE)) ) { fatal("malloc of tout_buf"); } ctx->headers = malloc(sizeof(headers_t)); ctx->ssl = NULL; ctx->ssl_ctx = NULL; return ctx; } void free_ws_ctx(ws_ctx_t *ctx) { free(ctx->cin_buf); free(ctx->cout_buf); free(ctx->tin_buf); free(ctx->tout_buf); free(ctx); } ws_ctx_t *ws_socket(ws_ctx_t *ctx, int socket) { ctx->sockfd = socket; return ctx; } ws_ctx_t *ws_socket_ssl(ws_ctx_t *ctx, int socket, char * certfile, char * keyfile) { int ret; char msg[1024]; char * use_keyfile; ws_socket(ctx, socket); if (keyfile && (keyfile[0] != '\0')) { // Separate key file use_keyfile = keyfile; } else { // Combined key and cert file use_keyfile = certfile; } // Initialize the library if (! ssl_initialized) { SSL_library_init(); OpenSSL_add_all_algorithms(); SSL_load_error_strings(); ssl_initialized = 1; } ctx->ssl_ctx = SSL_CTX_new(SSLv23_server_method()); if (ctx->ssl_ctx == NULL) { ERR_print_errors_fp(stderr); fatal("Failed to configure SSL context"); } SSL_CTX_set_options(ctx->ssl_ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); if (SSL_CTX_use_PrivateKey_file(ctx->ssl_ctx, use_keyfile, SSL_FILETYPE_PEM) <= 0) { sprintf(msg, "Unable to load private key file %s\n", use_keyfile); fatal(msg); } if (SSL_CTX_use_certificate_chain_file(ctx->ssl_ctx, certfile) <= 0) { sprintf(msg, "Unable to load certificate file %s\n", certfile); fatal(msg); } // if (SSL_CTX_set_cipher_list(ctx->ssl_ctx, "DEFAULT") != 1) { // sprintf(msg, "Unable to set cipher\n"); // fatal(msg); // } // Associate socket and ssl object ctx->ssl = SSL_new(ctx->ssl_ctx); SSL_set_fd(ctx->ssl, socket); ret = SSL_accept(ctx->ssl); if (ret < 0) { ERR_print_errors_fp(stderr); return NULL; } return ctx; } void ws_socket_free(ws_ctx_t *ctx) { if (ctx->ssl) { SSL_free(ctx->ssl); ctx->ssl = NULL; } if (ctx->ssl_ctx) { SSL_CTX_free(ctx->ssl_ctx); ctx->ssl_ctx = NULL; } if (ctx->sockfd) { shutdown(ctx->sockfd, SHUT_RDWR); close(ctx->sockfd); ctx->sockfd = 0; } } int ws_b64_ntop(const unsigned char const * src, size_t srclen, char * dst, size_t dstlen) { int len = 0; int total_len = 0; BIO *buff, *b64f; BUF_MEM *ptr; b64f = BIO_new(BIO_f_base64()); buff = BIO_new(BIO_s_mem()); buff = BIO_push(b64f, buff); BIO_set_flags(buff, BIO_FLAGS_BASE64_NO_NL); BIO_set_close(buff, BIO_CLOSE); do { len = BIO_write(buff, src + total_len, srclen - total_len); if (len > 0) total_len += len; } while (len && BIO_should_retry(buff)); BIO_flush(buff); BIO_get_mem_ptr(buff, &ptr); len = ptr->length; memcpy(dst, ptr->data, dstlen < len ? dstlen : len); dst[dstlen < len ? dstlen : len] = '\0'; BIO_free_all(buff); if (dstlen < len) return -1; return len; } int ws_b64_pton(const char const * src, unsigned char * dst, size_t dstlen) { int len = 0; int total_len = 0; int pending = 0; BIO *buff, *b64f; b64f = BIO_new(BIO_f_base64()); buff = BIO_new_mem_buf(src, -1); buff = BIO_push(b64f, buff); BIO_set_flags(buff, BIO_FLAGS_BASE64_NO_NL); BIO_set_close(buff, BIO_CLOSE); do { len = BIO_read(buff, dst + total_len, dstlen - total_len); if (len > 0) total_len += len; } while (len && BIO_should_retry(buff)); dst[total_len] = '\0'; pending = BIO_ctrl_pending(buff); BIO_free_all(buff); if (pending) return -1; return len; } /* ------------------------------------------------------- */ int encode_hixie(u_char const *src, size_t srclength, char *target, size_t targsize) { int sz = 0, len = 0; target[sz++] = '\x00'; len = ws_b64_ntop(src, srclength, target+sz, targsize-sz); if (len < 0) { return len; } sz += len; target[sz++] = '\xff'; return sz; } int decode_hixie(char *src, size_t srclength, u_char *target, size_t targsize, unsigned int *opcode, unsigned int *left) { char *start, *end, cntstr[4]; int len, framecount = 0, retlen = 0; if ((src[0] != '\x00') || (src[srclength-1] != '\xff')) { handler_emsg("WebSocket framing error\n"); return -1; } *left = srclength; if (srclength == 2 && (src[0] == '\xff') && (src[1] == '\x00')) { // client sent orderly close frame *opcode = 0x8; // Close frame return 0; } *opcode = 0x1; // Text frame start = src+1; // Skip '\x00' start do { /* We may have more than one frame */ end = (char *)memchr(start, '\xff', srclength); *end = '\x00'; len = ws_b64_pton(start, target+retlen, targsize-retlen); if (len < 0) { return len; } retlen += len; start = end + 2; // Skip '\xff' end and '\x00' start framecount++; } while (end < (src+srclength-1)); if (framecount > 1) { snprintf(cntstr, 3, "%d", framecount); traffic(cntstr); } *left = 0; return retlen; } int encode_hybi(u_char const *src, size_t srclength, char *target, size_t targsize, unsigned int opcode) { unsigned long long payload_offset = 2; int len = 0; if (opcode != OPCODE_TEXT && opcode != OPCODE_BINARY) { handler_emsg("Invalid opcode. Opcode must be 0x01 for text mode, or 0x02 for binary mode.\n"); return -1; } target[0] = (char)((opcode & 0x0F) | 0x80); if ((int)srclength <= 0) { return 0; } if (opcode & OPCODE_TEXT) { len = ((srclength - 1) / 3) * 4 + 4; } else { len = srclength; } if (len <= 125) { target[1] = (char) len; payload_offset = 2; } else if ((len > 125) && (len < 65536)) { target[1] = (char) 126; *(u_short*)&(target[2]) = htons(len); payload_offset = 4; } else { handler_emsg("Sending frames larger than 65535 bytes not supported\n"); return -1; //target[1] = (char) 127; // *(u_long*)&(target[2]) = htonl(b64_sz); //payload_offset = 10; } if (opcode & OPCODE_TEXT) { len = ws_b64_ntop(src, srclength, target+payload_offset, targsize-payload_offset); } else { memcpy(target+payload_offset, src, srclength); len = srclength; } if (len < 0) { return len; } return len + payload_offset; } int decode_hybi(unsigned char *src, size_t srclength, u_char *target, size_t targsize, unsigned int *opcode, unsigned int *left) { unsigned char *frame, *mask, *payload, save_char; char cntstr[4]; int masked = 0; int i = 0, len, framecount = 0; size_t remaining = 0; unsigned int target_offset = 0, hdr_length = 0, payload_length = 0; *left = srclength; frame = src; //printf("Deocde new frame\n"); while (1) { // Need at least two bytes of the header // Find beginning of next frame. First time hdr_length, masked and // payload_length are zero frame += hdr_length + 4*masked + payload_length; //printf("frame[0..3]: 0x%x 0x%x 0x%x 0x%x (tot: %d)\n", // (unsigned char) frame[0], // (unsigned char) frame[1], // (unsigned char) frame[2], // (unsigned char) frame[3], srclength); if (frame > src + srclength) { //printf("Truncated frame from client, need %d more bytes\n", frame - (src + srclength) ); break; } remaining = (src + srclength) - frame; if (remaining < 2) { //printf("Truncated frame header from client\n"); break; } framecount ++; *opcode = frame[0] & 0x0f; masked = (frame[1] & 0x80) >> 7; if (*opcode == 0x8) { // client sent orderly close frame break; } payload_length = frame[1] & 0x7f; if (payload_length < 126) { hdr_length = 2; //frame += 2 * sizeof(char); } else if (payload_length == 126) { payload_length = (frame[2] << 8) + frame[3]; hdr_length = 4; } else { handler_emsg("Receiving frames larger than 65535 bytes not supported\n"); return -1; } if ((hdr_length + 4*masked + payload_length) > remaining) { continue; } //printf(" payload_length: %u, raw remaining: %u\n", payload_length, remaining); payload = frame + hdr_length + 4*masked; if (*opcode != OPCODE_TEXT && *opcode != OPCODE_BINARY) { handler_msg("Ignoring non-data frame, opcode 0x%x\n", *opcode); continue; } if (payload_length == 0) { handler_msg("Ignoring empty frame\n"); continue; } if ((payload_length > 0) && (!masked)) { handler_emsg("Received unmasked payload from client\n"); return -1; } // Terminate with a null for base64 decode save_char = payload[payload_length]; payload[payload_length] = '\0'; // unmask the data mask = payload - 4; for (i = 0; i < payload_length; i++) { payload[i] ^= mask[i%4]; } if (*opcode & OPCODE_TEXT) { // base64 decode the data len = ws_b64_pton((const char*)payload, target+target_offset, targsize); } else { memcpy(target+target_offset, payload, payload_length); len = payload_length; } // Restore the first character of the next frame payload[payload_length] = save_char; if (len < 0) { handler_emsg("Base64 decode error code %d", len); return len; } target_offset += len; //printf(" len %d, raw %s\n", len, frame); } if (framecount > 1) { snprintf(cntstr, 3, "%d", framecount); traffic(cntstr); } *left = remaining; return target_offset; } int parse_handshake(ws_ctx_t *ws_ctx, char *handshake) { char *start, *end; headers_t *headers = ws_ctx->headers; headers->key1[0] = '\0'; headers->key2[0] = '\0'; headers->key3[0] = '\0'; if ((strlen(handshake) < 92) || (bcmp(handshake, "GET ", 4) != 0) || (!strcasestr(handshake, "Upgrade: websocket"))) { return 0; } start = handshake+4; end = strstr(start, " HTTP/1.1"); if (!end) { return 0; } strncpy(headers->path, start, end-start); headers->path[end-start] = '\0'; start = strstr(handshake, "\r\nHost: "); if (!start) { return 0; } start += 8; end = strstr(start, "\r\n"); strncpy(headers->host, start, end-start); headers->host[end-start] = '\0'; headers->origin[0] = '\0'; start = strcasestr(handshake, "\r\nOrigin: "); if (start) { start += 10; } else { start = strcasestr(handshake, "\r\nSec-WebSocket-Origin: "); if (!start) { return 0; } start += 24; } end = strstr(start, "\r\n"); strncpy(headers->origin, start, end-start); headers->origin[end-start] = '\0'; start = strcasestr(handshake, "\r\nSec-WebSocket-Version: "); if (start) { // HyBi/RFC 6455 start += 25; end = strstr(start, "\r\n"); strncpy(headers->version, start, end-start); headers->version[end-start] = '\0'; ws_ctx->hixie = 0; ws_ctx->hybi = strtol(headers->version, NULL, 10); start = strcasestr(handshake, "\r\nSec-WebSocket-Key: "); if (!start) { return 0; } start += 21; end = strstr(start, "\r\n"); strncpy(headers->key1, start, end-start); headers->key1[end-start] = '\0'; start = strstr(handshake, "\r\nConnection: "); if (!start) { return 0; } start += 14; end = strstr(start, "\r\n"); strncpy(headers->connection, start, end-start); headers->connection[end-start] = '\0'; start = strcasestr(handshake, "\r\nSec-WebSocket-Protocol: "); if (!start) { return 0; } start += 26; end = strstr(start, "\r\n"); strncpy(headers->protocols, start, end-start); headers->protocols[end-start] = '\0'; } else { // Hixie 75 or 76 ws_ctx->hybi = 0; start = strstr(handshake, "\r\n\r\n"); if (!start) { return 0; } start += 4; if (strlen(start) == 8) { ws_ctx->hixie = 76; strncpy(headers->key3, start, 8); headers->key3[8] = '\0'; start = strcasestr(handshake, "\r\nSec-WebSocket-Key1: "); if (!start) { return 0; } start += 22; end = strstr(start, "\r\n"); strncpy(headers->key1, start, end-start); headers->key1[end-start] = '\0'; start = strcasestr(handshake, "\r\nSec-WebSocket-Key2: "); if (!start) { return 0; } start += 22; end = strstr(start, "\r\n"); strncpy(headers->key2, start, end-start); headers->key2[end-start] = '\0'; } else { ws_ctx->hixie = 75; } } return 1; } int parse_hixie76_key(char * key) { unsigned long i, spaces = 0, num = 0; for (i=0; i < strlen(key); i++) { if (key[i] == ' ') { spaces += 1; } if ((key[i] >= 48) && (key[i] <= 57)) { num = num * 10 + (key[i] - 48); } } return num / spaces; } int gen_md5(headers_t *headers, char *target) { unsigned long key1 = parse_hixie76_key(headers->key1); unsigned long key2 = parse_hixie76_key(headers->key2); char *key3 = headers->key3; MD5_CTX c; char in[HIXIE_MD5_DIGEST_LENGTH] = { key1 >> 24, key1 >> 16, key1 >> 8, key1, key2 >> 24, key2 >> 16, key2 >> 8, key2, key3[0], key3[1], key3[2], key3[3], key3[4], key3[5], key3[6], key3[7] }; MD5_Init(&c); MD5_Update(&c, (void *)in, sizeof in); MD5_Final((void *)target, &c); target[HIXIE_MD5_DIGEST_LENGTH] = '\0'; return 1; } static void gen_sha1(headers_t *headers, char *target) { SHA_CTX c; unsigned char hash[SHA_DIGEST_LENGTH]; int r; SHA1_Init(&c); SHA1_Update(&c, headers->key1, strlen(headers->key1)); SHA1_Update(&c, HYBI_GUID, 36); SHA1_Final(hash, &c); r = ws_b64_ntop(hash, sizeof hash, target, HYBI10_ACCEPTHDRLEN); //assert(r == HYBI10_ACCEPTHDRLEN - 1); } static const char *name2mime(const char *name) { const char *end = strrchr(name, '.'); if (!end) goto def; end++; #define CMP(s) if (!strncmp(end, s, sizeof(s) - 1)) CMP("htm") return "text/html"; CMP("txt") return "text/plain"; CMP("css") return "text/css"; CMP("js") return "application/javascript"; CMP("gif") return "image/gif"; CMP("jpg") return "image/jpeg"; CMP("jpeg") return "image/jpeg"; CMP("png") return "image/png"; CMP("svg") return "image/svg+xml"; #undef CMP def: return "application/octet-stream"; } static void dirlisting(ws_ctx_t *ws_ctx, const char fullpath[], const char path[]) { char buf[4096]; char enc[PATH_MAX * 3 + 1]; unsigned i; // Redirect? const unsigned len = strlen(fullpath); if (fullpath[len - 1] != '/') { sprintf(buf, "HTTP/1.1 301 Moved Permanently\r\n" "Server: KasmVNC/4.0\r\n" "Location: %s/\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "\r\n", path); ws_send(ws_ctx, buf, strlen(buf)); return; } const char *start = memrchr(path, '/', len - 1); if (!start) start = path; // Directory listing sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/html\r\n" "\r\nDirectory Listing

%s


    ", path); ws_send(ws_ctx, buf, strlen(buf)); struct dirent **names; const unsigned num = scandir(fullpath, &names, NULL, alphasort); for (i = 0; i < num; i++) { if (!strcmp(names[i]->d_name, ".") || !strcmp(names[i]->d_name, "..")) continue; percent_encode(names[i]->d_name, enc); if (names[i]->d_type == DT_DIR) sprintf(buf, "
  • %s/
  • ", enc, names[i]->d_name); else sprintf(buf, "
  • %s
  • ", enc, names[i]->d_name); ws_send(ws_ctx, buf, strlen(buf)); } sprintf(buf, "
"); ws_send(ws_ctx, buf, strlen(buf)); } static void servefile(ws_ctx_t *ws_ctx, const char *in) { char buf[4096], path[4096], fullpath[4096]; //fprintf(stderr, "http servefile input '%s'\n", in); if (strncmp(in, "GET ", 4)) { wserr("non-GET request, rejecting\n"); goto nope; } in += 4; const char *end = strchr(in, ' '); unsigned len = end - in; if (len < 1 || len > 1024 || strstr(in, "../")) { wserr("Request too long (%u) or attempted dir traversal attack, rejecting\n", len); goto nope; } end = memchr(in, '?', len); if (end) len = end - in; memcpy(path, in, len); path[len] = '\0'; if (!strcmp(path, "/")) { strcpy(path, "/index.html"); len = strlen(path); } percent_decode(path, buf, 1); wserr("Requested file '%s'\n", buf); sprintf(fullpath, "%s/%s", settings.httpdir, buf); DIR *dir = opendir(fullpath); if (dir) { closedir(dir); dirlisting(ws_ctx, fullpath, buf); return; } FILE *f = fopen(fullpath, "r"); if (!f) { wserr("file not found or insufficient permissions\n"); goto nope; } fseek(f, 0, SEEK_END); const unsigned filesize = ftell(f); rewind(f); sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: %s\r\n" "Content-length: %u\r\n" "\r\n", name2mime(path), filesize); ws_send(ws_ctx, buf, strlen(buf)); //fprintf(stderr, "http servefile output '%s'\n", buf); unsigned count; while ((count = fread(buf, 1, 4096, f))) { ws_send(ws_ctx, buf, count); } fclose(f); return; nope: sprintf(buf, "HTTP/1.1 404 Not Found\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "\r\n" "404"); ws_send(ws_ctx, buf, strlen(buf)); } static uint8_t ownerapi_post(ws_ctx_t *ws_ctx, const char *in) { char buf[4096], path[4096]; uint8_t ret = 0; // 0 = continue checking in += 5; const char *end = strchr(in, ' '); unsigned len = end - in; if (len < 1 || len > 1024 || strstr(in, "../")) { wserr("Request too long (%u) or attempted dir traversal attack, rejecting\n", len); return 0; } end = memchr(in, '?', len); if (end) { wserr("Attempted GET params in a POST request, rejecting\n"); return 0; } memcpy(path, in, len); path[len] = '\0'; wserr("Requested owner POST api '%s'\n", path); in = strstr(in, "\r\n\r\n"); if (!in) { wserr("No content\n"); return 0; } in += 4; #define entry(x) if (!strcmp(path, x)) struct kasmpasswd_t *set = NULL; unsigned s; entry("/api/create_user") { set = parseJsonUsers(in); if (!set) { wserr("JSON parse error\n"); goto nope; } for (s = 0; s < set->num; s++) { if (!set->entries[s].user[0] || !set->entries[s].password[0]) { wserr("Username or password missing\n"); goto nope; } struct crypt_data cdata; cdata.initialized = 0; const char *encrypted = crypt_r(set->entries[s].password, "$5$kasm$", &cdata); strcpy(set->entries[s].password, encrypted); if (!settings.addOrUpdateUserCb(settings.messager, &set->entries[s])) { wserr("Couldn't add or update user\n"); goto nope; } } free(set->entries); free(set); sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: 6\r\n" "\r\n" "200 OK"); ws_send(ws_ctx, buf, strlen(buf)); ret = 1; } else entry("/api/remove_user") { set = parseJsonUsers(in); if (!set) { wserr("JSON parse error\n"); goto nope; } for (s = 0; s < set->num; s++) { if (!set->entries[s].user[0]) { wserr("Username missing\n"); goto nope; } if (!settings.removeCb(settings.messager, set->entries[s].user)) { wserr("Invalid params to remove_user\n"); goto nope; } } free(set->entries); free(set); sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: 6\r\n" "\r\n" "200 OK"); ws_send(ws_ctx, buf, strlen(buf)); ret = 1; } else entry("/api/update_user") { set = parseJsonUsers(in); if (!set) { wserr("JSON parse error\n"); goto nope; } for (s = 0; s < set->num; s++) { if (!set->entries[s].user[0]) { wserr("Username missing\n"); goto nope; } uint64_t mask = USER_UPDATE_WRITE_MASK | USER_UPDATE_OWNER_MASK; if (set->entries[s].password[0]) { struct crypt_data cdata; cdata.initialized = 0; const char *encrypted = crypt_r(set->entries[s].password, "$5$kasm$", &cdata); strcpy(set->entries[s].password, encrypted); mask |= USER_UPDATE_PASSWORD_MASK; } if (!settings.updateUserCb(settings.messager, set->entries[s].user, mask, set->entries[s].password, set->entries[s].write, set->entries[s].owner)) { wserr("Invalid params to update_user\n"); goto nope; } } free(set->entries); free(set); sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: 6\r\n" "\r\n" "200 OK"); ws_send(ws_ctx, buf, strlen(buf)); ret = 1; } #undef entry return ret; nope: sprintf(buf, "HTTP/1.1 400 Bad Request\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "\r\n" "400 Bad Request"); ws_send(ws_ctx, buf, strlen(buf)); return 1; } static uint8_t ownerapi(ws_ctx_t *ws_ctx, const char *in) { char buf[4096], path[4096], args[4096] = ""; uint8_t ret = 0; // 0 = continue checking if (strncmp(in, "GET ", 4)) { if (!strncmp(in, "POST ", 5)) return ownerapi_post(ws_ctx, in); wserr("non-GET, non-POST request, rejecting\n"); return 0; } in += 4; const char *end = strchr(in, ' '); unsigned len = end - in; if (len < 1 || len > 1024 || strstr(in, "../")) { wserr("Request too long (%u) or attempted dir traversal attack, rejecting\n", len); return 0; } end = memchr(in, '?', len); if (end) { len = end - in; end++; const char *argend = strchr(end, ' '); strncpy(args, end, argend - end); args[argend - end] = '\0'; } memcpy(path, in, len); path[len] = '\0'; if (strstr(args, "password=")) { wserr("Requested owner api '%s' with args (skipped, includes password)\n", path); } else { wserr("Requested owner api '%s' with args '%s'\n", path, args); } #define entry(x) if (!strcmp(path, x)) const char *param; entry("/api/get_screenshot") { uint8_t q = 7, dedup = 0; uint16_t w = 4096, h = 4096; param = parse_get(args, "width", &len); if (len && isdigit(param[0])) w = atoi(param); param = parse_get(args, "height", &len); if (len && isdigit(param[0])) h = atoi(param); param = parse_get(args, "quality", &len); if (len && isdigit(param[0])) q = atoi(param); param = parse_get(args, "deduplicate", &len); if (len && isalpha(param[0])) { if (!strncmp(param, "true", len)) dedup = 1; } uint8_t *staging = malloc(1024 * 1024 * 8); settings.screenshotCb(settings.messager, w, h, q, dedup, &len, staging); if (len == 16) { sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: %u\r\n" "\r\n", len); ws_send(ws_ctx, buf, strlen(buf)); ws_send(ws_ctx, staging, len); wserr("Screenshot hadn't changed and dedup was requested, sent hash\n"); ret = 1; } else if (len) { sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: image/jpeg\r\n" "Content-length: %u\r\n" "\r\n", len); ws_send(ws_ctx, buf, strlen(buf)); ws_send(ws_ctx, staging, len); wserr("Sent screenshot %u bytes\n", len); ret = 1; } free(staging); if (!len) { wserr("Invalid params to screenshot\n"); goto nope; } } else entry("/api/create_user") { char decname[1024] = "", decpw[1024] = ""; uint8_t write = 0, owner = 0; param = parse_get(args, "name", &len); if (len) { memcpy(buf, param, len); buf[len] = '\0'; percent_decode(buf, decname, 0); } param = parse_get(args, "password", &len); if (len) { memcpy(buf, param, len); buf[len] = '\0'; percent_decode(buf, decpw, 0); struct crypt_data cdata; cdata.initialized = 0; const char *encrypted = crypt_r(decpw, "$5$kasm$", &cdata); strcpy(decpw, encrypted); } param = parse_get(args, "write", &len); if (len && isalpha(param[0])) { if (!strncmp(param, "true", len)) write = 1; } param = parse_get(args, "owner", &len); if (len && isalpha(param[0])) { if (!strncmp(param, "true", len)) owner = 1; } if (!decname[0] || !decpw[0]) goto nope; if (!settings.adduserCb(settings.messager, decname, decpw, write, owner)) { wserr("Invalid params to create_user\n"); goto nope; } sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: 6\r\n" "\r\n" "200 OK"); ws_send(ws_ctx, buf, strlen(buf)); ret = 1; } else entry("/api/remove_user") { char decname[1024] = ""; param = parse_get(args, "name", &len); if (len) { memcpy(buf, param, len); buf[len] = '\0'; percent_decode(buf, decname, 0); } if (!decname[0]) goto nope; if (!settings.removeCb(settings.messager, decname)) { wserr("Invalid params to remove_user\n"); goto nope; } sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: 6\r\n" "\r\n" "200 OK"); ws_send(ws_ctx, buf, strlen(buf)); ret = 1; } else entry("/api/update_user") { char decname[1024] = ""; param = parse_get(args, "name", &len); if (len) { memcpy(buf, param, len); buf[len] = '\0'; percent_decode(buf, decname, 0); } if (!decname[0]) goto nope; uint64_t mask = 0; uint8_t mywrite = 0; param = parse_get(args, "write", &len); if (len && isalpha(param[0])) { mask |= USER_UPDATE_WRITE_MASK; if (!strncmp(param, "true", len)) mywrite = 1; } uint8_t myowner = 0; param = parse_get(args, "owner", &len); if (len && isalpha(param[0])) { mask |= USER_UPDATE_OWNER_MASK; if (!strncmp(param, "true", len)) myowner = 1; } if (!settings.updateUserCb(settings.messager, decname, mask, "", mywrite, myowner)) { wserr("Invalid params to update_user\n"); goto nope; } sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: 6\r\n" "\r\n" "200 OK"); ws_send(ws_ctx, buf, strlen(buf)); ret = 1; } else entry("/api/get_bottleneck_stats") { char statbuf[4096]; settings.bottleneckStatsCb(settings.messager, statbuf, 4096); sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: %lu\r\n" "\r\n", strlen(statbuf)); ws_send(ws_ctx, buf, strlen(buf)); ws_send(ws_ctx, statbuf, strlen(statbuf)); wserr("Sent bottleneck stats to API caller\n"); ret = 1; } else entry("/api/get_users") { const char *ptr; settings.getUsersCb(settings.messager, &ptr); sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: %lu\r\n" "\r\n", strlen(ptr)); ws_send(ws_ctx, buf, strlen(buf)); ws_send(ws_ctx, ptr, strlen(ptr)); free((char *) ptr); wserr("Sent user list to API caller\n"); ret = 1; } else entry("/api/get_frame_stats") { char statbuf[4096], decname[1024]; unsigned waitfor; param = parse_get(args, "client", &len); if (len) { memcpy(buf, param, len); buf[len] = '\0'; percent_decode(buf, decname, 0); } else { wserr("client param required\n"); goto nope; } if (!decname[0]) goto nope; if (!strcmp(decname, "none")) { waitfor = 0; if (!settings.requestFrameStatsNoneCb(settings.messager)) goto nope; } else if (!strcmp(decname, "auto")) { waitfor = settings.ownerConnectedCb(settings.messager); if (!waitfor) { if (!settings.requestFrameStatsNoneCb(settings.messager)) goto nope; } else { if (!settings.requestFrameStatsOwnerCb(settings.messager)) goto nope; } } else if (!strcmp(decname, "all")) { waitfor = settings.numActiveUsersCb(settings.messager); if (!settings.requestFrameStatsAllCb(settings.messager)) goto nope; } else { waitfor = 1; if (!settings.requestFrameStatsOneCb(settings.messager, decname)) goto nope; } while (1) { usleep(10 * 1000); if (settings.serverFrameStatsReadyCb(settings.messager)) break; } if (waitfor) { unsigned waits; for (waits = 0; waits < 20; waits++) { // wait up to 2s if (settings.getClientFrameStatsNumCb(settings.messager) >= waitfor) break; usleep(100 * 1000); } } settings.frameStatsCb(settings.messager, statbuf, 4096); sprintf(buf, "HTTP/1.1 200 OK\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "Content-length: %lu\r\n" "\r\n", strlen(statbuf)); ws_send(ws_ctx, buf, strlen(buf)); ws_send(ws_ctx, statbuf, strlen(statbuf)); wserr("Sent frame stats to API caller\n"); ret = 1; } #undef entry return ret; nope: sprintf(buf, "HTTP/1.1 400 Bad Request\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "\r\n" "400 Bad Request"); ws_send(ws_ctx, buf, strlen(buf)); return 1; } ws_ctx_t *do_handshake(int sock, const char *ip) { char handshake[4096], response[4096], sha1[29], trailer[17]; char *scheme, *pre; headers_t *headers; int len, i, offset; ws_ctx_t * ws_ctx; char *response_protocol; // Peek, but don't read the data len = recv(sock, handshake, 1024, MSG_PEEK); handshake[len] = 0; if (len == 0) { handler_msg("ignoring empty handshake\n"); return NULL; } else if ((bcmp(handshake, "\x16", 1) == 0) || (bcmp(handshake, "\x80", 1) == 0)) { // SSL if (!settings.cert) { handler_msg("SSL connection but no cert specified\n"); return NULL; } else if (access(settings.cert, R_OK) != 0) { handler_msg("SSL connection but '%s' not found\n", settings.cert); return NULL; } ws_ctx = alloc_ws_ctx(); ws_socket_ssl(ws_ctx, sock, settings.cert, settings.key); if (! ws_ctx) { return NULL; } scheme = "wss"; handler_msg("using SSL socket\n"); } else if (settings.ssl_only) { handler_msg("non-SSL connection disallowed\n"); return NULL; } else { ws_ctx = alloc_ws_ctx(); ws_socket(ws_ctx, sock); if (! ws_ctx) { return NULL; } scheme = "ws"; handler_msg("using plain (not SSL) socket\n"); } offset = 0; for (i = 0; i < 10; i++) { /* (offset + 1): reserve one byte for the trailing '\0' */ if (0 > (len = ws_recv(ws_ctx, handshake + offset, sizeof(handshake) - (offset + 1)))) { handler_emsg("Read error during handshake: %m\n"); free_ws_ctx(ws_ctx); return NULL; } else if (0 == len) { handler_emsg("Client closed during handshake\n"); free_ws_ctx(ws_ctx); return NULL; } offset += len; handshake[offset] = 0; if (strstr(handshake, "\r\n\r\n")) { break; } else if (sizeof(handshake) <= (size_t)(offset + 1)) { handler_emsg("Oversized handshake\n"); free_ws_ctx(ws_ctx); return NULL; } else if (9 == i) { handler_emsg("Incomplete handshake\n"); free_ws_ctx(ws_ctx); return NULL; } usleep(10); } if (bl_isBlacklisted(ip)) { wserr("IP %s is blacklisted, dropping\n", ip); sprintf(response, "HTTP/1.1 401 Forbidden\r\n" "\r\n"); ws_send(ws_ctx, response, strlen(response)); free_ws_ctx(ws_ctx); return NULL; } unsigned char owner = 0; if (!settings.disablebasicauth) { const char *hdr = strstr(handshake, "Authorization: Basic "); if (!hdr) { bl_addFailure(ip); handler_emsg("BasicAuth required, but client didn't send any. 401 Unauth\n"); sprintf(response, "HTTP/1.1 401 Unauthorized\r\n" "WWW-Authenticate: Basic realm=\"Websockify\"\r\n" "\r\n"); ws_send(ws_ctx, response, strlen(response)); free_ws_ctx(ws_ctx); return NULL; } hdr += sizeof("Authorization: Basic ") - 1; const char *end = strchr(hdr, '\r'); if (!end || end - hdr > 256) { handler_emsg("Client sent invalid BasicAuth, dropping connection\n"); bl_addFailure(ip); free_ws_ctx(ws_ctx); return NULL; } len = end - hdr; char tmp[257]; memcpy(tmp, hdr, len); tmp[len] = '\0'; len = ws_b64_pton(tmp, response, 256); char authbuf[4096] = ""; // Do we need to read it from the file? char *resppw = strchr(response, ':'); if (resppw && *resppw) resppw++; if (settings.passwdfile) { if (resppw && *resppw && resppw - response < 32) { char pwbuf[4096]; struct kasmpasswd_t *set = readkasmpasswd(settings.passwdfile); if (!set->num) { fprintf(stderr, " websocket %d: Error: BasicAuth configured to read password from file %s, but the file doesn't exist or has no valid users\n", wsthread_handler_id, settings.passwdfile); } else { unsigned i; char inuser[32]; unsigned char found = 0; memcpy(inuser, response, resppw - response - 1); inuser[resppw - response - 1] = '\0'; for (i = 0; i < set->num; i++) { if (!strcmp(set->entries[i].user, inuser)) { found = 1; strcpy(ws_ctx->user, inuser); snprintf(authbuf, 4096, "%s:%s", set->entries[i].user, set->entries[i].password); authbuf[4095] = '\0'; if (set->entries[i].owner) owner = 1; break; } } if (!found) handler_emsg("BasicAuth user %s not found\n", inuser); } free(set->entries); free(set); struct crypt_data cdata; cdata.initialized = 0; const char *encrypted = crypt_r(resppw, "$5$kasm$", &cdata); *resppw = '\0'; snprintf(pwbuf, 4096, "%s%s", response, encrypted); pwbuf[4095] = '\0'; strcpy(response, pwbuf); } else { // Client tried an empty password, just fail them response[0] = '\0'; authbuf[0] = 'a'; authbuf[1] = '\0'; } } if (len <= 0 || strcmp(authbuf, response)) { handler_emsg("BasicAuth user/pw did not match\n"); bl_addFailure(ip); sprintf(response, "HTTP/1.1 401 Forbidden\r\n" "\r\n"); ws_send(ws_ctx, response, strlen(response)); free_ws_ctx(ws_ctx); return NULL; } handler_emsg("BasicAuth matched\n"); } //handler_msg("handshake: %s\n", handshake); if (!parse_handshake(ws_ctx, handshake)) { handler_emsg("Invalid WS request, maybe a HTTP one\n"); if (strstr(handshake, "/api/")) { handler_emsg("HTTP request under /api/\n"); if (owner) { if (ownerapi(ws_ctx, handshake)) goto done; } else { sprintf(response, "HTTP/1.1 401 Unauthorized\r\n" "Server: KasmVNC/4.0\r\n" "Connection: close\r\n" "Content-type: text/plain\r\n" "\r\n" "401 Unauthorized"); ws_send(ws_ctx, response, strlen(response)); goto done; } } if (settings.httpdir && settings.httpdir[0]) servefile(ws_ctx, handshake); done: free_ws_ctx(ws_ctx); return NULL; } headers = ws_ctx->headers; response_protocol = strtok(headers->protocols, ","); if (!response_protocol || !strlen(response_protocol)) { ws_ctx->opcode = OPCODE_BINARY; response_protocol = "null"; } else if (!strcmp(response_protocol, "base64")) { ws_ctx->opcode = OPCODE_TEXT; } else { ws_ctx->opcode = OPCODE_BINARY; } if (ws_ctx->hybi > 0) { handler_msg("using protocol HyBi/IETF 6455 %d\n", ws_ctx->hybi); gen_sha1(headers, sha1); snprintf(response, sizeof(response), SERVER_HANDSHAKE_HYBI, sha1, response_protocol); } else { if (ws_ctx->hixie == 76) { handler_msg("using protocol Hixie 76\n"); gen_md5(headers, trailer); pre = "Sec-"; } else { handler_msg("using protocol Hixie 75\n"); trailer[0] = '\0'; pre = ""; } snprintf(response, sizeof(response), SERVER_HANDSHAKE_HIXIE, pre, headers->origin, pre, scheme, headers->host, headers->path, pre, "base64", trailer); } //handler_msg("response: %s\n", response); ws_send(ws_ctx, response, strlen(response)); return ws_ctx; } void proxy_handler(ws_ctx_t *ws_ctx); __thread unsigned wsthread_handler_id; void *subthread(void *ptr) { const struct wspass_t * const pass = ptr; const int csock = pass->csock; wsthread_handler_id = pass->id; ws_ctx_t *ws_ctx; ws_ctx = do_handshake(csock, pass->ip); if (ws_ctx == NULL) { handler_msg("No connection after handshake\n"); goto out; // Child process exits } memcpy(ws_ctx->ip, pass->ip, sizeof(pass->ip)); proxy_handler(ws_ctx); if (pipe_error) { handler_emsg("Closing due to SIGPIPE\n"); } out: free((void *) pass); if (ws_ctx) { ws_socket_free(ws_ctx); free_ws_ctx(ws_ctx); } else { shutdown(csock, SHUT_RDWR); close(csock); } handler_msg("handler exit\n"); return NULL; } void *start_server(void *unused) { int csock, pid; struct sockaddr_in cli_addr; socklen_t clilen; // printf("Waiting for connections on %s:%d\n", // settings.listen_host, settings.listen_port); while (1) { clilen = sizeof(cli_addr); pipe_error = 0; pid = 0; do { csock = accept(settings.listen_sock, (struct sockaddr *) &cli_addr, &clilen); } while (csock == -1 && errno == EINTR); if (csock < 0) { error("ERROR on accept"); continue; } struct wspass_t *pass = calloc(1, sizeof(struct wspass_t)); inet_ntop(cli_addr.sin_family, &cli_addr.sin_addr, pass->ip, sizeof(pass->ip)); fprintf(stderr, " websocket %d: got client connection from %s\n", settings.handler_id, pass->ip); pthread_t tid; pass->id = settings.handler_id; pass->csock = csock; pthread_create(&tid, NULL, subthread, pass); settings.handler_id += 1; } handler_msg("websockify exit\n"); return NULL; }