/** * FreeRDP: A Remote Desktop Protocol Implementation * HTTP Proxy support * * Copyright 2016 Christian Plattner * * Licensed 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. */ #include #include #include #include "proxy.h" #include #include #include #include "tcp.h" #include #include /* For GetEnvironmentVariableA */ #define CRLF "\r\n" #include #define TAG FREERDP_TAG("core.proxy") /* SOCKS Proxy auth methods by rfc1928 */ enum { AUTH_M_NO_AUTH = 0, AUTH_M_GSSAPI = 1, AUTH_M_USR_PASS = 2 }; enum { SOCKS_CMD_CONNECT = 1, SOCKS_CMD_BIND = 2, SOCKS_CMD_UDP_ASSOCIATE = 3 }; enum { SOCKS_ADDR_IPV4 = 1, SOCKS_ADDR_FQDN = 3, SOCKS_ADDR_IPV6 = 4, }; /* CONN REQ replies in enum. order */ static const char* rplstat[] = { "succeeded", "general SOCKS server failure", "connection not allowed by ruleset", "Network unreachable", "Host unreachable", "Connection refused", "TTL expired", "Command not supported", "Address type not supported" }; static BOOL http_proxy_connect(BIO* bufferedBio, const char* proxyUsername, const char* proxyPassword, const char* hostname, UINT16 port); static BOOL socks_proxy_connect(BIO* bufferedBio, const char* proxyUsername, const char* proxyPassword, const char* hostname, UINT16 port); static void proxy_read_environment(rdpSettings* settings, char* envname); BOOL proxy_prepare(rdpSettings* settings, const char** lpPeerHostname, UINT16* lpPeerPort, const char** lpProxyUsername, const char** lpProxyPassword) { if (freerdp_settings_get_uint32(settings, FreeRDP_ProxyType) == PROXY_TYPE_IGNORE) return FALSE; /* For TSGateway, find the system HTTPS proxy automatically */ if (freerdp_settings_get_uint32(settings, FreeRDP_ProxyType) == PROXY_TYPE_NONE) proxy_read_environment(settings, "https_proxy"); if (freerdp_settings_get_uint32(settings, FreeRDP_ProxyType) == PROXY_TYPE_NONE) proxy_read_environment(settings, "HTTPS_PROXY"); if (freerdp_settings_get_uint32(settings, FreeRDP_ProxyType) != PROXY_TYPE_NONE) proxy_read_environment(settings, "no_proxy"); if (freerdp_settings_get_uint32(settings, FreeRDP_ProxyType) != PROXY_TYPE_NONE) proxy_read_environment(settings, "NO_PROXY"); if (freerdp_settings_get_uint32(settings, FreeRDP_ProxyType) != PROXY_TYPE_NONE) { *lpPeerHostname = freerdp_settings_get_string(settings, FreeRDP_ProxyHostname); *lpPeerPort = freerdp_settings_get_uint16(settings, FreeRDP_ProxyPort); *lpProxyUsername = freerdp_settings_get_string(settings, FreeRDP_ProxyUsername); *lpProxyPassword = freerdp_settings_get_string(settings, FreeRDP_ProxyPassword); return TRUE; } return FALSE; } static BOOL value_to_int(const char* value, LONGLONG* result, LONGLONG min, LONGLONG max) { long long rc; if (!value || !result) return FALSE; errno = 0; rc = _strtoi64(value, NULL, 0); if (errno != 0) return FALSE; if ((rc < min) || (rc > max)) return FALSE; *result = rc; return TRUE; } static BOOL cidr4_match(const struct in_addr* addr, const struct in_addr* net, BYTE bits) { uint32_t mask, amask, nmask; if (bits == 0) return TRUE; mask = htonl(0xFFFFFFFFu << (32 - bits)); amask = addr->s_addr & mask; nmask = net->s_addr & mask; return amask == nmask; } static BOOL cidr6_match(const struct in6_addr* address, const struct in6_addr* network, uint8_t bits) { const uint32_t* a = (const uint32_t*)address; const uint32_t* n = (const uint32_t*)network; size_t bits_whole, bits_incomplete; bits_whole = bits >> 5; bits_incomplete = bits & 0x1F; if (bits_whole) { if (memcmp(a, n, bits_whole << 2) != 0) return FALSE; } if (bits_incomplete) { uint32_t mask = htonl((0xFFFFFFFFu) << (32 - bits_incomplete)); if ((a[bits_whole] ^ n[bits_whole]) & mask) return FALSE; } return TRUE; } static BOOL check_no_proxy(rdpSettings* settings, const char* no_proxy) { const char* delimiter = ","; BOOL result = FALSE; char* current; char* copy; char* context = NULL; size_t host_len; struct sockaddr_in sa4; struct sockaddr_in6 sa6; BOOL is_ipv4 = FALSE; BOOL is_ipv6 = FALSE; if (!no_proxy || !settings) return FALSE; if (inet_pton(AF_INET, settings->ServerHostname, &sa4.sin_addr) == 1) is_ipv4 = TRUE; else if (inet_pton(AF_INET6, settings->ServerHostname, &sa6.sin6_addr) == 1) is_ipv6 = TRUE; host_len = strlen(settings->ServerHostname); copy = _strdup(no_proxy); if (!copy) return FALSE; current = strtok_s(copy, delimiter, &context); while (current && !result) { const size_t currentlen = strlen(current); if (currentlen > 0) { WLog_DBG(TAG, "%s => %s (%" PRIdz ")", settings->ServerHostname, current, currentlen); /* detect left and right "*" wildcard */ if (current[0] == '*') { if (host_len >= currentlen) { const size_t offset = host_len + 1 - currentlen; const char* name = settings->ServerHostname + offset; if (strncmp(current + 1, name, currentlen - 1) == 0) result = TRUE; } } else if (current[currentlen - 1] == '*') { if (strncmp(current, settings->ServerHostname, currentlen - 1) == 0) result = TRUE; } else if (current[0] == '.') /* Only compare if the no_proxy variable contains a whole domain. */ { if (host_len > currentlen) { const size_t offset = host_len - currentlen; const char* name = settings->ServerHostname + offset; if (strncmp(current, name, currentlen) == 0) result = TRUE; /* right-aligned match for host names */ } } else if (strcmp(current, settings->ServerHostname) == 0) result = TRUE; /* exact match */ else if (is_ipv4 || is_ipv6) { char* rangedelim = strchr(current, '/'); /* Check for IP ranges */ if (rangedelim != NULL) { const char* range = rangedelim + 1; int sub; int rc = sscanf(range, "%u", &sub); if ((rc == 1) && (rc >= 0)) { *rangedelim = '\0'; if (is_ipv4) { struct sockaddr_in mask; if (inet_pton(AF_INET, current, &mask.sin_addr)) result = cidr4_match(&sa4.sin_addr, &mask.sin_addr, sub); } else if (is_ipv6) { struct sockaddr_in6 mask; if (inet_pton(AF_INET6, current, &mask.sin6_addr)) result = cidr6_match(&sa6.sin6_addr, &mask.sin6_addr, sub); } } else WLog_WARN(TAG, "NO_PROXY invalid entry %s", current); } else if (strncmp(current, settings->ServerHostname, currentlen) == 0) result = TRUE; /* left-aligned match for IPs */ } } current = strtok_s(NULL, delimiter, &context); } free(copy); return result; } void proxy_read_environment(rdpSettings* settings, char* envname) { DWORD envlen; char* env; envlen = GetEnvironmentVariableA(envname, NULL, 0); if (!envlen) return; env = calloc(1, envlen); if (!env) { WLog_ERR(TAG, "Not enough memory"); return; } if (GetEnvironmentVariableA(envname, env, envlen) == envlen - 1) { if (_strnicmp("NO_PROXY", envname, 9) == 0) { if (check_no_proxy(settings, env)) { WLog_INFO(TAG, "deactivating proxy: %s [%s=%s]", freerdp_settings_get_string(settings, FreeRDP_ServerHostname), envname, env); freerdp_settings_set_uint32(settings, FreeRDP_ProxyType, PROXY_TYPE_NONE); } } else { if (!proxy_parse_uri(settings, env)) { WLog_WARN( TAG, "Error while parsing proxy URI from environment variable; ignoring proxy"); } } } free(env); } BOOL proxy_parse_uri(rdpSettings* settings, const char* uri_in) { BOOL rc = FALSE; const char* protocol = ""; UINT16 port; char* p; char* atPtr; char* uri_copy = _strdup(uri_in); char* uri = uri_copy; if (!uri) goto fail; p = strstr(uri, "://"); if (p) { *p = '\0'; if (_stricmp("no_proxy", uri) == 0) { if (!freerdp_settings_set_uint32(settings, FreeRDP_ProxyType, PROXY_TYPE_IGNORE)) goto fail; } if (_stricmp("http", uri) == 0) { if (!freerdp_settings_set_uint32(settings, FreeRDP_ProxyType, PROXY_TYPE_HTTP)) goto fail; protocol = "http"; } else if (_stricmp("socks5", uri) == 0) { if (!freerdp_settings_set_uint32(settings, FreeRDP_ProxyType, PROXY_TYPE_SOCKS)) goto fail; protocol = "socks5"; } else { WLog_ERR(TAG, "Only HTTP and SOCKS5 proxies supported by now"); goto fail; } uri = p + 3; } else { /* default proxy protocol is http */ if (!freerdp_settings_set_uint32(settings, FreeRDP_ProxyType, PROXY_TYPE_HTTP)) goto fail; protocol = "http"; } /* uri is now [user:password@]hostname:port */ atPtr = strrchr(uri, '@'); if (atPtr) { /* got a login / password, * atPtr * v * [user:password@]hostname:port * ^ * colonPtr */ char* colonPtr = strchr(uri, ':'); if (!colonPtr || (colonPtr > atPtr)) { WLog_ERR(TAG, "invalid syntax for proxy (contains no password)"); goto fail; } *colonPtr = '\0'; if (!freerdp_settings_set_string(settings, FreeRDP_ProxyUsername, uri)) { WLog_ERR(TAG, "unable to allocate proxy username"); goto fail; } *atPtr = '\0'; if (!freerdp_settings_set_string(settings, FreeRDP_ProxyPassword, colonPtr + 1)) { WLog_ERR(TAG, "unable to allocate proxy password"); goto fail; } uri = atPtr + 1; } p = strchr(uri, ':'); if (p) { LONGLONG val; if (!value_to_int(&p[1], &val, 0, UINT16_MAX)) { WLog_ERR(TAG, "invalid syntax for proxy (invalid port)"); goto fail; } if (val == 0) { WLog_ERR(TAG, "invalid syntax for proxy (port missing)"); goto fail; } port = (UINT16)val; *p = '\0'; } else { if (_stricmp("http", protocol) == 0) { /* The default is 80. Also for Proxys. */ port = 80; } else { port = 1080; } WLog_DBG(TAG, "setting default proxy port: %" PRIu16, port); } if (!freerdp_settings_set_uint16(settings, FreeRDP_ProxyPort, port)) goto fail; p = strchr(uri, '/'); if (p) *p = '\0'; if (!freerdp_settings_set_string(settings, FreeRDP_ProxyHostname, uri)) goto fail; if (_stricmp("", uri) == 0) { WLog_ERR(TAG, "invalid syntax for proxy (hostname missing)"); goto fail; } if (freerdp_settings_get_string(settings, FreeRDP_ProxyUsername)) { WLog_INFO(TAG, "Parsed proxy configuration: %s://%s:%s@%s:%" PRIu16, protocol, freerdp_settings_get_string(settings, FreeRDP_ProxyUsername), "******", freerdp_settings_get_string(settings, FreeRDP_ProxyHostname), freerdp_settings_get_uint16(settings, FreeRDP_ProxyPort)); } else { WLog_INFO(TAG, "Parsed proxy configuration: %s://%s:%" PRIu16, protocol, freerdp_settings_get_string(settings, FreeRDP_ProxyHostname), freerdp_settings_get_uint16(settings, FreeRDP_ProxyPort)); } rc = TRUE; fail: free(uri_copy); return rc; } BOOL proxy_connect(rdpSettings* settings, BIO* bufferedBio, const char* proxyUsername, const char* proxyPassword, const char* hostname, UINT16 port) { switch (freerdp_settings_get_uint32(settings, FreeRDP_ProxyType)) { case PROXY_TYPE_NONE: case PROXY_TYPE_IGNORE: return TRUE; case PROXY_TYPE_HTTP: return http_proxy_connect(bufferedBio, proxyUsername, proxyPassword, hostname, port); case PROXY_TYPE_SOCKS: return socks_proxy_connect(bufferedBio, proxyUsername, proxyPassword, hostname, port); default: WLog_ERR(TAG, "Invalid internal proxy configuration"); return FALSE; } } static const char* get_response_header(char* response) { char* current_pos = strchr(response, '\r'); if (!current_pos) current_pos = strchr(response, '\n'); if (current_pos) *current_pos = '\0'; return response; } static BOOL http_proxy_connect(BIO* bufferedBio, const char* proxyUsername, const char* proxyPassword, const char* hostname, UINT16 port) { BOOL rc = FALSE; int status; wStream* s; char port_str[10] = { 0 }; char recv_buf[256] = { 0 }; char* eol = NULL; size_t resultsize = 0; size_t reserveSize; size_t portLen; size_t hostLen; const char connect[] = "CONNECT "; const char httpheader[] = " HTTP/1.1" CRLF "Host: "; WINPR_ASSERT(bufferedBio); WINPR_ASSERT(hostname); _itoa_s(port, port_str, sizeof(port_str), 10); hostLen = strlen(hostname); portLen = strnlen(port_str, sizeof(port_str)); reserveSize = strlen(connect) + (hostLen + 1 + portLen) * 2 + strlen(httpheader); s = Stream_New(NULL, reserveSize); if (!s) goto fail; Stream_Write(s, connect, strlen(connect)); Stream_Write(s, hostname, hostLen); Stream_Write_UINT8(s, ':'); Stream_Write(s, port_str, portLen); Stream_Write(s, httpheader, strlen(httpheader)); Stream_Write(s, hostname, hostLen); Stream_Write_UINT8(s, ':'); Stream_Write(s, port_str, portLen); if (proxyUsername && proxyPassword) { const int length = _scprintf("%s:%s", proxyUsername, proxyPassword); if (length > 0) { const size_t size = (size_t)length + 1ull; char* creds = (char*)malloc(size); if (!creds) goto fail; else { const char basic[] = CRLF "Proxy-Authorization: Basic "; char* base64; sprintf_s(creds, size, "%s:%s", proxyUsername, proxyPassword); base64 = crypto_base64_encode((const BYTE*)creds, size - 1); if (!base64 || !Stream_EnsureRemainingCapacity(s, strlen(basic) + strlen(base64))) { free(base64); free(creds); goto fail; } Stream_Write(s, basic, strlen(basic)); Stream_Write(s, base64, strlen(base64)); free(base64); } free(creds); } } if (!Stream_EnsureRemainingCapacity(s, 4)) goto fail; Stream_Write(s, CRLF CRLF, 4); ERR_clear_error(); status = BIO_write(bufferedBio, Stream_Buffer(s), Stream_GetPosition(s)); if ((status < 0) || ((size_t)status != Stream_GetPosition(s))) { WLog_ERR(TAG, "HTTP proxy: failed to write CONNECT request"); goto fail; } /* Read result until CR-LF-CR-LF. * Keep recv_buf a null-terminated string. */ while (strstr(recv_buf, CRLF CRLF) == NULL) { if (resultsize >= sizeof(recv_buf) - 1) { WLog_ERR(TAG, "HTTP Reply headers too long: %s", get_response_header(recv_buf)); goto fail; } ERR_clear_error(); status = BIO_read(bufferedBio, (BYTE*)recv_buf + resultsize, sizeof(recv_buf) - resultsize - 1); if (status < 0) { /* Error? */ if (BIO_should_retry(bufferedBio)) { USleep(100); continue; } WLog_ERR(TAG, "Failed reading reply from HTTP proxy (Status %d)", status); goto fail; } else if (status == 0) { /* Error? */ WLog_ERR(TAG, "Failed reading reply from HTTP proxy (BIO_read returned zero)"); goto fail; } resultsize += status; } /* Extract HTTP status line */ eol = strchr(recv_buf, '\r'); if (!eol) { /* should never happen */ goto fail; } *eol = '\0'; WLog_INFO(TAG, "HTTP Proxy: %s", recv_buf); if (strnlen(recv_buf, sizeof(recv_buf)) < 12) goto fail; recv_buf[7] = 'X'; if (strncmp(recv_buf, "HTTP/1.X 200", 12)) goto fail; rc = TRUE; fail: Stream_Free(s, TRUE); return rc; } static int recv_socks_reply(BIO* bufferedBio, BYTE* buf, int len, char* reason, BYTE checkVer) { int status; for (;;) { ERR_clear_error(); status = BIO_read(bufferedBio, buf, len); if (status > 0) { break; } else if (status < 0) { /* Error? */ if (BIO_should_retry(bufferedBio)) { USleep(100); continue; } WLog_ERR(TAG, "Failed reading %s reply from SOCKS proxy (Status %d)", reason, status); return -1; } else // if (status == 0) { /* Error? */ WLog_ERR(TAG, "Failed reading %s reply from SOCKS proxy (BIO_read returned zero)", reason); return -1; } } if (status < 2) { WLog_ERR(TAG, "SOCKS Proxy reply packet too short (%s)", reason); return -1; } if (buf[0] != checkVer) { WLog_ERR(TAG, "SOCKS Proxy version is not 5 (%s)", reason); return -1; } return status; } static BOOL socks_proxy_connect(BIO* bufferedBio, const char* proxyUsername, const char* proxyPassword, const char* hostname, UINT16 port) { int status; int nauthMethods = 1, writeLen = 3; BYTE buf[3 + 255 + 255]; /* biggest packet is user/pass auth */ size_t hostnlen = strnlen(hostname, 255); if (proxyUsername && proxyPassword) { nauthMethods++; writeLen++; } /* select auth. method */ buf[0] = 5; /* SOCKS version */ buf[1] = nauthMethods; /* #of methods offered */ buf[2] = AUTH_M_NO_AUTH; if (nauthMethods > 1) buf[3] = AUTH_M_USR_PASS; ERR_clear_error(); status = BIO_write(bufferedBio, buf, writeLen); if (status != writeLen) { WLog_ERR(TAG, "SOCKS proxy: failed to write AUTH METHOD request"); return FALSE; } status = recv_socks_reply(bufferedBio, buf, 2, "AUTH REQ", 5); if (status <= 0) return FALSE; switch (buf[1]) { case AUTH_M_NO_AUTH: WLog_DBG(TAG, "SOCKS Proxy: (NO AUTH) method was selected"); break; case AUTH_M_USR_PASS: if (!proxyUsername || !proxyPassword) return FALSE; else { int usernameLen = strnlen(proxyUsername, 255); int userpassLen = strnlen(proxyPassword, 255); BYTE* ptr; if (nauthMethods < 2) { WLog_ERR(TAG, "SOCKS Proxy: USER/PASS method was not proposed to server"); return FALSE; } /* user/password v1 method */ ptr = buf + 2; buf[0] = 1; buf[1] = usernameLen; memcpy(ptr, proxyUsername, usernameLen); ptr += usernameLen; *ptr = userpassLen; ptr++; memcpy(ptr, proxyPassword, userpassLen); ERR_clear_error(); status = BIO_write(bufferedBio, buf, 3 + usernameLen + userpassLen); if (status != 3 + usernameLen + userpassLen) { WLog_ERR(TAG, "SOCKS Proxy: error writing user/password request"); return FALSE; } status = recv_socks_reply(bufferedBio, buf, 2, "AUTH REQ", 1); if (status < 2) return FALSE; if (buf[1] != 0x00) { WLog_ERR(TAG, "SOCKS Proxy: invalid user/password"); return FALSE; } } break; default: WLog_ERR(TAG, "SOCKS Proxy: unknown method 0x%x was selected by proxy", buf[1]); return FALSE; } /* CONN request */ buf[0] = 5; /* SOCKS version */ buf[1] = SOCKS_CMD_CONNECT; /* command */ buf[2] = 0; /* 3rd octet is reserved x00 */ buf[3] = SOCKS_ADDR_FQDN; /* addr.type */ buf[4] = hostnlen; /* DST.ADDR */ memcpy(buf + 5, hostname, hostnlen); /* follows DST.PORT in netw. format */ buf[hostnlen + 5] = (port >> 8) & 0xff; buf[hostnlen + 6] = port & 0xff; ERR_clear_error(); status = BIO_write(bufferedBio, buf, hostnlen + 7U); if ((status < 0) || ((size_t)status != (hostnlen + 7U))) { WLog_ERR(TAG, "SOCKS proxy: failed to write CONN REQ"); return FALSE; } status = recv_socks_reply(bufferedBio, buf, sizeof(buf), "CONN REQ", 5); if (status < 4) return FALSE; if (buf[1] == 0) { WLog_INFO(TAG, "Successfully connected to %s:%" PRIu16, hostname, port); return TRUE; } if (buf[1] > 0 && buf[1] < 9) WLog_INFO(TAG, "SOCKS Proxy replied: %s", rplstat[buf[1]]); else WLog_INFO(TAG, "SOCKS Proxy replied: %" PRIu8 " status not listed in rfc1928", buf[1]); return FALSE; }