mirror of https://github.com/FreeRDP/FreeRDP
660 lines
15 KiB
C
660 lines
15 KiB
C
/**
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* FreeRDP: A Remote Desktop Protocol Implementation
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* HTTP Proxy support
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*
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* Copyright 2016 Christian Plattner <ccpp@gmx.at>
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <ctype.h>
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#include <errno.h>
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#include "proxy.h"
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#include "freerdp/settings.h"
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#include "tcp.h"
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#include "winpr/environment.h" /* For GetEnvironmentVariableA */
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#define CRLF "\r\n"
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#define TAG FREERDP_TAG("core.proxy")
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/* SOCKS Proxy auth methods by rfc1928 */
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enum
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{
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AUTH_M_NO_AUTH = 0,
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AUTH_M_GSSAPI = 1,
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AUTH_M_USR_PASS = 2
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};
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enum
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{
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SOCKS_CMD_CONNECT = 1,
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SOCKS_CMD_BIND = 2,
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SOCKS_CMD_UDP_ASSOCIATE = 3
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};
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enum
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{
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SOCKS_ADDR_IPV4 = 1,
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SOCKS_ADDR_FQDN = 3,
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SOCKS_ADDR_IPV6 = 4,
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};
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/* CONN REQ replies in enum. order */
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static const char* rplstat[] =
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{
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"succeeded",
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"general SOCKS server failure",
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"connection not allowed by ruleset",
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"Network unreachable",
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"Host unreachable",
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"Connection refused",
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"TTL expired",
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"Command not supported",
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"Address type not supported"
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};
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static BOOL http_proxy_connect(BIO* bufferedBio, const char* hostname, UINT16 port);
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static BOOL socks_proxy_connect(BIO* bufferedBio, const char* proxyUsername,
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const char* proxyPassword, const char* hostname, UINT16 port);
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void proxy_read_environment(rdpSettings* settings, char* envname);
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BOOL proxy_prepare(rdpSettings* settings, const char** lpPeerHostname, UINT16* lpPeerPort,
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const char** lpProxyUsername, const char** lpProxyPassword)
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{
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if (settings->ProxyType == PROXY_TYPE_IGNORE)
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return FALSE;
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/* For TSGateway, find the system HTTPS proxy automatically */
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if (settings->ProxyType == PROXY_TYPE_NONE)
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proxy_read_environment(settings, "https_proxy");
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if (settings->ProxyType == PROXY_TYPE_NONE)
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proxy_read_environment(settings, "HTTPS_PROXY");
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if (settings->ProxyType != PROXY_TYPE_NONE)
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proxy_read_environment(settings, "no_proxy");
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if (settings->ProxyType != PROXY_TYPE_NONE)
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proxy_read_environment(settings, "NO_PROXY");
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if (settings->ProxyType != PROXY_TYPE_NONE)
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{
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*lpPeerHostname = settings->ProxyHostname;
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*lpPeerPort = settings->ProxyPort;
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*lpProxyUsername = settings->ProxyUsername;
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*lpProxyPassword = settings->ProxyPassword;
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return TRUE;
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}
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return FALSE;
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}
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static BOOL cidr4_match(const struct in_addr* addr, const struct in_addr* net, BYTE bits)
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{
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uint32_t mask, amask, nmask;
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if (bits == 0)
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return TRUE;
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mask = htonl(0xFFFFFFFFu << (32 - bits));
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amask = addr->s_addr & mask;
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nmask = net->s_addr & mask;
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return amask == nmask;
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}
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static BOOL cidr6_match(const struct in6_addr* address, const struct in6_addr* network,
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uint8_t bits)
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{
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const uint32_t* a = (const uint32_t*)address;
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const uint32_t* n = (const uint32_t*)network;
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size_t bits_whole, bits_incomplete;
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bits_whole = bits >> 5;
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bits_incomplete = bits & 0x1F;
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if (bits_whole)
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{
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if (memcmp(a, n, bits_whole << 2) != 0)
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return FALSE;
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}
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if (bits_incomplete)
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{
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uint32_t mask = htonl((0xFFFFFFFFu) << (32 - bits_incomplete));
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if ((a[bits_whole] ^ n[bits_whole]) & mask)
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return FALSE;
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}
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return TRUE;
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}
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static BOOL check_no_proxy(rdpSettings* settings, const char* no_proxy)
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{
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const char* delimiter = ",";
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BOOL result = FALSE;
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char* current;
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char* copy;
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size_t host_len;
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struct sockaddr_in sa4;
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struct sockaddr_in6 sa6;
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BOOL is_ipv4 = FALSE;
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BOOL is_ipv6 = FALSE;
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if (!no_proxy || !settings)
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return FALSE;
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if (inet_pton(AF_INET, settings->ServerHostname, &sa4.sin_addr) == 1)
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is_ipv4 = TRUE;
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else if (inet_pton(AF_INET6, settings->ServerHostname, &sa6.sin6_addr) == 1)
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is_ipv6 = TRUE;
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host_len = strlen(settings->ServerHostname);
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copy = _strdup(no_proxy);
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if (!copy)
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return FALSE;
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current = strtok(copy, delimiter);
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while (current && !result)
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{
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const size_t currentlen = strlen(current);
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if (currentlen > 0)
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{
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WLog_DBG(TAG, "%s => %s (%"PRIdz")", settings->ServerHostname, current, currentlen);
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/* detect left and right "*" wildcard */
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if (current[0] == '*')
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{
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if (host_len >= currentlen)
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{
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const size_t offset = host_len + 1 - currentlen;
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const char* name = settings->ServerHostname + offset;
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if (strncmp(current + 1, name, currentlen - 1) == 0)
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result = TRUE;
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}
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}
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else if (current[currentlen - 1] == '*')
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{
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if (strncmp(current, settings->ServerHostname, currentlen - 1) == 0)
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result = TRUE;
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}
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else if (current[0] == '.') /* Only compare if the no_proxy variable contains a whole domain. */
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{
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if (host_len > currentlen)
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{
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const size_t offset = host_len - currentlen;
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const char* name = settings->ServerHostname + offset;
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if (strncmp(current, name, currentlen) == 0)
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result = TRUE; /* right-aligned match for host names */
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}
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}
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else if (strcmp(current, settings->ServerHostname) == 0)
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result = TRUE; /* exact match */
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else if (is_ipv4 || is_ipv6)
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{
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char* rangedelim = strchr(current, '/');
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/* Check for IP ranges */
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if (rangedelim != NULL)
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{
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const char* range = rangedelim + 1;
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int sub;
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int rc = sscanf(range, "%u", &sub);
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if ((rc == 1) && (rc >= 0))
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{
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*rangedelim = '\0';
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if (is_ipv4)
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{
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struct sockaddr_in mask;
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if (inet_pton(AF_INET, current, &mask.sin_addr))
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result = cidr4_match(&sa4.sin_addr, &mask.sin_addr, sub);
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}
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else if (is_ipv6)
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{
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struct sockaddr_in6 mask;
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if (inet_pton(AF_INET6, current, &mask.sin6_addr))
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result = cidr6_match(&sa6.sin6_addr, &mask.sin6_addr, sub);
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}
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}
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else
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WLog_WARN(TAG, "NO_PROXY invalid entry %s", current);
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}
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else if (strncmp(current, settings->ServerHostname, currentlen) == 0)
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result = TRUE; /* left-aligned match for IPs */
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}
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}
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current = strtok(NULL, delimiter);
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}
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free(copy);
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return result;
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}
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void proxy_read_environment(rdpSettings* settings, char* envname)
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{
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DWORD envlen;
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char* env;
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envlen = GetEnvironmentVariableA(envname, NULL, 0);
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if (!envlen)
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return;
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env = calloc(1, envlen);
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if (!env)
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{
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WLog_ERR(TAG, "Not enough memory");
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return;
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}
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if (GetEnvironmentVariableA(envname, env, envlen) == envlen - 1)
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{
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if (_strnicmp("NO_PROXY", envname, 9) == 0)
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{
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if (check_no_proxy(settings, env))
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{
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WLog_INFO(TAG, "deactivating proxy: %s [%s=%s]", settings->ServerHostname, envname, env);
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settings->ProxyType = PROXY_TYPE_NONE;
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}
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}
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else
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{
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proxy_parse_uri(settings, env);
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}
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}
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free(env);
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}
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BOOL proxy_parse_uri(rdpSettings* settings, const char* uri)
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{
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const char* hostname, *pport;
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const char* protocol;
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const char* p;
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UINT16 port;
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int hostnamelen;
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p = strstr(uri, "://");
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if (p)
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{
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if (p == uri + 4 && !strncmp("http", uri, 4))
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{
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settings->ProxyType = PROXY_TYPE_HTTP;
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protocol = "http";
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}
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else if (p == uri + 6 && !strncmp("socks5", uri, 6))
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{
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settings->ProxyType = PROXY_TYPE_SOCKS;
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protocol = "socks5";
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}
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else
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{
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WLog_ERR(TAG, "Only HTTP and SOCKS5 proxies supported by now");
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return FALSE;
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}
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uri = p + 3;
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}
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else
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{
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WLog_ERR(TAG, "No scheme in proxy URI");
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return FALSE;
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}
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hostname = uri;
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pport = strchr(hostname, ':');
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if (pport)
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{
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long val;
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errno = 0;
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val = strtol(pport + 1, NULL, 0);
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if ((errno != 0) || (val <= 0) || (val > UINT16_MAX))
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return FALSE;
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port = val;
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}
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else
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{
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/* The default is 80. Also for Proxys. */
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port = 80;
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pport = strchr(hostname, '/');
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}
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if (pport)
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{
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hostnamelen = pport - hostname;
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}
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else
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{
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hostnamelen = strlen(hostname);
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}
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settings->ProxyHostname = calloc(hostnamelen + 1, 1);
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if (!settings->ProxyHostname)
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{
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WLog_ERR(TAG, "Not enough memory");
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return FALSE;
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}
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memcpy(settings->ProxyHostname, hostname, hostnamelen);
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settings->ProxyPort = port;
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WLog_INFO(TAG, "Parsed proxy configuration: %s://%s:%d", protocol, settings->ProxyHostname,
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settings->ProxyPort);
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return TRUE;
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}
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BOOL proxy_connect(rdpSettings* settings, BIO* bufferedBio, const char* proxyUsername,
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const char* proxyPassword,
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const char* hostname, UINT16 port)
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{
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switch (settings->ProxyType)
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{
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case PROXY_TYPE_NONE:
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case PROXY_TYPE_IGNORE:
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return TRUE;
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case PROXY_TYPE_HTTP:
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return http_proxy_connect(bufferedBio, hostname, port);
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case PROXY_TYPE_SOCKS:
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return socks_proxy_connect(bufferedBio, proxyUsername, proxyPassword, hostname, port);
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default:
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WLog_ERR(TAG, "Invalid internal proxy configuration");
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return FALSE;
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}
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}
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static BOOL http_proxy_connect(BIO* bufferedBio, const char* hostname, UINT16 port)
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{
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int status;
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wStream* s;
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char port_str[10], recv_buf[256], *eol;
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size_t resultsize;
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_itoa_s(port, port_str, sizeof(port_str), 10);
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s = Stream_New(NULL, 200);
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Stream_Write(s, "CONNECT ", 8);
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Stream_Write(s, hostname, strlen(hostname));
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Stream_Write_UINT8(s, ':');
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Stream_Write(s, port_str, strlen(port_str));
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Stream_Write(s, " HTTP/1.1" CRLF "Host: ", 17);
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Stream_Write(s, hostname, strlen(hostname));
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Stream_Write_UINT8(s, ':');
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Stream_Write(s, port_str, strnlen(port_str, sizeof (port_str)));
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Stream_Write(s, CRLF CRLF, 4);
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status = BIO_write(bufferedBio, Stream_Buffer(s), Stream_GetPosition(s));
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if ((status < 0) || ((size_t)status != Stream_GetPosition(s)))
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{
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Stream_Free(s, TRUE);
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WLog_ERR(TAG, "HTTP proxy: failed to write CONNECT request");
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return FALSE;
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}
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Stream_Free(s, TRUE);
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s = NULL;
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/* Read result until CR-LF-CR-LF.
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* Keep recv_buf a null-terminated string. */
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memset(recv_buf, '\0', sizeof(recv_buf));
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resultsize = 0;
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while (strstr(recv_buf, CRLF CRLF) == NULL)
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{
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if (resultsize >= sizeof(recv_buf) - 1)
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{
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WLog_ERR(TAG, "HTTP Reply headers too long.");
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return FALSE;
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}
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status = BIO_read(bufferedBio, (BYTE*)recv_buf + resultsize, sizeof(recv_buf) - resultsize - 1);
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if (status < 0)
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{
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/* Error? */
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if (BIO_should_retry(bufferedBio))
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{
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USleep(100);
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continue;
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}
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WLog_ERR(TAG, "Failed reading reply from HTTP proxy (Status %d)", status);
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return FALSE;
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}
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else if (status == 0)
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{
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/* Error? */
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WLog_ERR(TAG, "Failed reading reply from HTTP proxy (BIO_read returned zero)");
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return FALSE;
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}
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resultsize += status;
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}
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/* Extract HTTP status line */
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eol = strchr(recv_buf, '\r');
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if (!eol)
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{
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/* should never happen */
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return FALSE;
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}
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*eol = '\0';
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WLog_INFO(TAG, "HTTP Proxy: %s", recv_buf);
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if (strnlen(recv_buf, sizeof(recv_buf)) < 12)
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{
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return FALSE;
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}
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recv_buf[7] = 'X';
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if (strncmp(recv_buf, "HTTP/1.X 200", 12))
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return FALSE;
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return TRUE;
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}
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static int recv_socks_reply(BIO* bufferedBio, BYTE* buf, int len, char* reason, BYTE checkVer)
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{
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int status;
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for (;;)
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{
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status = BIO_read(bufferedBio, buf, len);
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if (status > 0)
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{
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break;
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}
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else if (status < 0)
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{
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/* Error? */
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if (BIO_should_retry(bufferedBio))
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{
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USleep(100);
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continue;
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}
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WLog_ERR(TAG, "Failed reading %s reply from SOCKS proxy (Status %d)", reason, status);
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return -1;
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}
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else // if (status == 0)
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{
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/* Error? */
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WLog_ERR(TAG, "Failed reading %s reply from SOCKS proxy (BIO_read returned zero)", reason);
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return -1;
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}
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}
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if (status < 2)
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{
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WLog_ERR(TAG, "SOCKS Proxy reply packet too short (%s)", reason);
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return -1;
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}
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if (buf[0] != checkVer)
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{
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WLog_ERR(TAG, "SOCKS Proxy version is not 5 (%s)", reason);
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return -1;
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}
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return status;
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}
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static BOOL socks_proxy_connect(BIO* bufferedBio, const char* proxyUsername,
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const char* proxyPassword,
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const char* hostname, UINT16 port)
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{
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int status;
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int nauthMethods = 1, writeLen = 3;
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BYTE buf[3 + 255 + 255]; /* biggest packet is user/pass auth */
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size_t hostnlen = strnlen(hostname, 255);
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if (proxyUsername && proxyPassword)
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{
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nauthMethods++;
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writeLen++;
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}
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/* select auth. method */
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buf[0] = 5; /* SOCKS version */
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buf[1] = nauthMethods; /* #of methods offered */
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buf[2] = AUTH_M_NO_AUTH;
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if (nauthMethods > 1)
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buf[3] = AUTH_M_USR_PASS;
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status = BIO_write(bufferedBio, buf, writeLen);
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if (status != writeLen)
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{
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WLog_ERR(TAG, "SOCKS proxy: failed to write AUTH METHOD request");
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return FALSE;
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}
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status = recv_socks_reply(bufferedBio, buf, 2, "AUTH REQ", 5);
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if (status <= 0)
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return FALSE;
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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);
|
|
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;
|
|
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:%d", 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: %d status not listed in rfc1928", buf[1]);
|
|
|
|
return FALSE;
|
|
}
|