/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef WIN32
#include "config-win32.h"
#else
#include "config.h"
#endif
#ifdef ENABLE_HTTP_PROXY
#include "syshead.h"
#include "common.h"
#include "misc.h"
#include "win32.h"
#include "socket.h"
#include "fdmisc.h"
#include "proxy.h"
#include "ntlm.h"
#include "memdbg.h"
/* cached proxy username/password */
static struct user_pass static_proxy_user_pass;
static bool
recv_line (socket_descriptor_t sd,
char *buf,
int len,
const int timeout_sec,
const bool verbose,
struct buffer *lookahead,
volatile int *signal_received)
{
struct buffer la;
int lastc = 0;
CLEAR (la);
if (lookahead)
la = *lookahead;
while (true)
{
int status;
ssize_t size;
fd_set reads;
struct timeval tv;
uint8_t c;
if (buf_defined (&la))
{
ASSERT (buf_init (&la, 0));
}
FD_ZERO (&reads);
FD_SET (sd, &reads);
tv.tv_sec = timeout_sec;
tv.tv_usec = 0;
status = select (sd + 1, &reads, NULL, NULL, &tv);
get_signal (signal_received);
if (*signal_received)
goto error;
/* timeout? */
if (status == 0)
{
if (verbose)
msg (D_LINK_ERRORS | M_ERRNO_SOCK, "recv_line: TCP port read timeout expired");
goto error;
}
/* error */
if (status < 0)
{
if (verbose)
msg (D_LINK_ERRORS | M_ERRNO_SOCK, "recv_line: TCP port read failed on select()");
goto error;
}
/* read single char */
size = recv (sd, &c, 1, MSG_NOSIGNAL);
/* error? */
if (size != 1)
{
if (verbose)
msg (D_LINK_ERRORS | M_ERRNO_SOCK, "recv_line: TCP port read failed on recv()");
goto error;
}
#if 0
if (isprint(c))
msg (M_INFO, "PROXY: read '%c' (%d)", c, (int)c);
else
msg (M_INFO, "PROXY: read (%d)", (int)c);
#endif
/* store char in buffer */
if (len > 1)
{
*buf++ = c;
--len;
}
/* also store char in lookahead buffer */
if (buf_defined (&la))
{
buf_write_u8 (&la, c);
if (!isprint(c) && !isspace(c)) /* not ascii? */
{
if (verbose)
msg (D_LINK_ERRORS | M_ERRNO_SOCK, "recv_line: Non-ASCII character (%d) read on recv()", (int)c);
*lookahead = la;
return false;
}
}
/* end of line? */
if (lastc == '\r' && c == '\n')
break;
lastc = c;
}
/* append trailing null */
if (len > 0)
*buf++ = '\0';
return true;
error:
return false;
}
static bool
send_line (socket_descriptor_t sd,
const char *buf)
{
const ssize_t size = send (sd, buf, strlen (buf), MSG_NOSIGNAL);
if (size != (ssize_t) strlen (buf))
{
msg (D_LINK_ERRORS | M_ERRNO_SOCK, "send_line: TCP port write failed on send()");
return false;
}
return true;
}
static bool
send_line_crlf (socket_descriptor_t sd,
const char *src)
{
bool ret;
struct buffer buf = alloc_buf (strlen (src) + 3);
ASSERT (buf_write (&buf, src, strlen (src)));
ASSERT (buf_write (&buf, "\r\n", 3));
ret = send_line (sd, BSTR (&buf));
free_buf (&buf);
return ret;
}
static bool
send_crlf (socket_descriptor_t sd)
{
return send_line_crlf (sd, "");
}
uint8_t *
make_base64_string2 (const uint8_t *str, int src_len, struct gc_arena *gc)
{
static const char base64_table[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
uint8_t *buf;
const uint8_t *src;
uint8_t *dst;
int bits, data, dst_len;
/* make base64 string */
dst_len = (src_len + 2) / 3 * 4;
buf = gc_malloc (dst_len + 1, false, gc);
bits = data = 0;
src = str;
dst = buf;
while (dst_len--)
{
if (bits < 6)
{
data = (data << 8) | *src;
bits += 8;
src++;
}
*dst++ = base64_table[0x3F & (data >> (bits - 6))];
bits -= 6;
}
*dst = '\0';
/* fix-up tail padding */
switch (src_len % 3)
{
case 1:
*--dst = '=';
case 2:
*--dst = '=';
}
return buf;
}
uint8_t *
make_base64_string (const uint8_t *str, struct gc_arena *gc)
{
return make_base64_string2 (str, strlen ((const char *)str), gc);
}
static const char *
username_password_as_base64 (const struct http_proxy_info *p,
struct gc_arena *gc)
{
struct buffer out = alloc_buf_gc (strlen (p->up.username) + strlen (p->up.password) + 2, gc);
ASSERT (strlen (p->up.username) > 0);
buf_printf (&out, "%s:%s", p->up.username, p->up.password);
return (const char *)make_base64_string ((const uint8_t*)BSTR (&out), gc);
}
struct http_proxy_info *
new_http_proxy (const struct http_proxy_options *o,
struct gc_arena *gc)
{
struct http_proxy_info *p;
ALLOC_OBJ_CLEAR_GC (p, struct http_proxy_info, gc);
if (!o->server)
msg (M_FATAL, "HTTP_PROXY: server not specified");
ASSERT (legal_ipv4_port (o->port));
p->options = *o;
/* parse authentication method */
p->auth_method = HTTP_AUTH_NONE;
if (o->auth_method_string)
{
if (!strcmp (o->auth_method_string, "none"))
p->auth_method = HTTP_AUTH_NONE;
else if (!strcmp (o->auth_method_string, "basic"))
p->auth_method = HTTP_AUTH_BASIC;
else if (!strcmp (o->auth_method_string, "ntlm"))
p->auth_method = HTTP_AUTH_NTLM;
else
msg (M_FATAL, "ERROR: unknown HTTP authentication method: '%s' -- only the 'none', 'basic', or 'ntlm' methods are currently supported",
o->auth_method_string);
}
/* only basic and NTLM authentication supported so far */
if (p->auth_method == HTTP_AUTH_BASIC || p->auth_method == HTTP_AUTH_NTLM)
{
get_user_pass (&static_proxy_user_pass,
o->auth_file,
false,
"HTTP Proxy",
GET_USER_PASS_MANAGEMENT);
p->up = static_proxy_user_pass;
}
#if !NTLM
if (p->auth_method == HTTP_AUTH_NTLM)
msg (M_FATAL, "Sorry, this version of " PACKAGE_NAME " was built without NTLM Proxy support.");
#endif
p->defined = true;
return p;
}
void
establish_http_proxy_passthru (struct http_proxy_info *p,
socket_descriptor_t sd, /* already open to proxy */
const char *host, /* openvpn server remote */
const int port, /* openvpn server port */
struct buffer *lookahead,
volatile int *signal_received)
{
struct gc_arena gc = gc_new ();
char buf[256];
char buf2[128];
char get[80];
int status;
int nparms;
/* format HTTP CONNECT message */
openvpn_snprintf (buf, sizeof(buf), "CONNECT %s:%d HTTP/%s",
host,
port,
p->options.http_version);
msg (D_PROXY, "Send to HTTP proxy: '%s'", buf);
/* send HTTP CONNECT message to proxy */
if (!send_line_crlf (sd, buf))
goto error;
/* send User-Agent string if provided */
if (p->options.user_agent)
{
openvpn_snprintf (buf, sizeof(buf), "User-Agent: %s",
p->options.user_agent);
if (!send_line_crlf (sd, buf))
goto error;
}
/* auth specified? */
switch (p->auth_method)
{
case HTTP_AUTH_NONE:
break;
case HTTP_AUTH_BASIC:
openvpn_snprintf (buf, sizeof(buf), "Proxy-Authorization: Basic %s",
username_password_as_base64 (p, &gc));
msg (D_PROXY, "Attempting Basic Proxy-Authorization");
dmsg (D_SHOW_KEYS, "Send to HTTP proxy: '%s'", buf);
openvpn_sleep (1);
if (!send_line_crlf (sd, buf))
goto error;
break;
#if NTLM
case HTTP_AUTH_NTLM:
openvpn_snprintf (buf, sizeof(buf), "Proxy-Authorization: NTLM %s",
ntlm_phase_1 (p, &gc));
msg (D_PROXY, "Attempting NTLM Proxy-Authorization phase 1");
dmsg (D_SHOW_KEYS, "Send to HTTP proxy: '%s'", buf);
openvpn_sleep (1);
if (!send_line_crlf (sd, buf))
goto error;
break;
#endif
default:
ASSERT (0);
}
/* send empty CR, LF */
openvpn_sleep (1);
if (!send_crlf (sd))
goto error;
/* receive reply from proxy */
if (!recv_line (sd, buf, sizeof(buf), p->options.timeout, true, NULL, signal_received))
goto error;
/* remove trailing CR, LF */
chomp (buf);
msg (D_PROXY, "HTTP proxy returned: '%s'", buf);
/* parse return string */
nparms = sscanf (buf, "%*s %d", &status);
/* check for a "407 Proxy Authentication Required" response */
if (nparms >= 1 && status == 407)
{
msg (D_PROXY, "Proxy requires authentication");
/* check for NTLM */
if (p->auth_method == HTTP_AUTH_NTLM)
{
#if NTLM
/* look for the phase 2 response */
while (true)
{
if (!recv_line (sd, buf, sizeof(buf), p->options.timeout, true, NULL, signal_received))
goto error;
chomp (buf);
msg (D_PROXY, "HTTP proxy returned: '%s'", buf);
openvpn_snprintf (get, sizeof get, "%%*s NTLM %%%ds", (int) sizeof (buf2) - 1);
nparms = sscanf (buf, get, buf2);
buf2[127] = 0; /* we only need the beginning - ensure it's null terminated. */
/* check for "Proxy-Authenticate: NTLM TlRM..." */
if (nparms == 1)
{
/* parse buf2 */
msg (D_PROXY, "auth string: '%s'", buf2);
break;
}
}
/* if we are here then auth string was got */
msg (D_PROXY, "Received NTLM Proxy-Authorization phase 2 response");
/* receive and discard everything else */
while (recv_line (sd, NULL, 0, p->options.timeout, true, NULL, signal_received))
;
/* now send the phase 3 reply */
/* format HTTP CONNECT message */
openvpn_snprintf (buf, sizeof(buf), "CONNECT %s:%d HTTP/%s",
host,
port,
p->options.http_version);
msg (D_PROXY, "Send to HTTP proxy: '%s'", buf);
/* send HTTP CONNECT message to proxy */
if (!send_line_crlf (sd, buf))
goto error;
/* send HOST etc, */
openvpn_sleep (1);
openvpn_snprintf (buf, sizeof(buf), "Host: %s", host);
msg (D_PROXY, "Send to HTTP proxy: '%s'", buf);
if (!send_line_crlf (sd, buf))
goto error;
openvpn_snprintf (buf, sizeof(buf), "Proxy-Authorization: NTLM %s",
ntlm_phase_3 (p, buf2, &gc));
msg (D_PROXY, "Attempting NTLM Proxy-Authorization phase 3");
msg (D_PROXY, "Send to HTTP proxy: '%s'", buf);
openvpn_sleep (1);
if (!send_line_crlf (sd, buf))
goto error;
/* ok so far... */
/* send empty CR, LF */
openvpn_sleep (1);
if (!send_crlf (sd))
goto error;
/* receive reply from proxy */
if (!recv_line (sd, buf, sizeof(buf), p->options.timeout, true, NULL, signal_received))
goto error;
/* remove trailing CR, LF */
chomp (buf);
msg (D_PROXY, "HTTP proxy returned: '%s'", buf);
/* parse return string */
nparms = sscanf (buf, "%*s %d", &status);
#else
ASSERT (0); /* No NTLM support */
#endif
}
else goto error;
}
/* check return code, success = 200 */
if (nparms < 1 || status != 200)
{
msg (D_LINK_ERRORS, "HTTP proxy returned bad status");
#if 0
/* DEBUGGING -- show a multi-line HTTP error response */
while (true)
{
if (!recv_line (sd, buf, sizeof (buf), p->options.timeout, true, NULL, signal_received))
goto error;
chomp (buf);
msg (D_PROXY, "HTTP proxy returned: '%s'", buf);
}
#endif
goto error;
}
/* receive line from proxy and discard */
if (!recv_line (sd, NULL, 0, p->options.timeout, true, NULL, signal_received))
goto error;
/*
* Toss out any extraneous chars, but don't throw away the
* start of the OpenVPN data stream (put it in lookahead).
*/
while (recv_line (sd, NULL, 0, 2, false, lookahead, signal_received))
;
#if 0
if (lookahead && BLEN (lookahead))
msg (M_INFO, "HTTP PROXY: lookahead: %s", format_hex (BPTR (lookahead), BLEN (lookahead), 0));
#endif
gc_free (&gc);
return;
error:
/* on error, should we exit or restart? */
if (!*signal_received)
*signal_received = (p->options.retry ? SIGUSR1 : SIGTERM); /* SOFT-SIGUSR1 -- HTTP proxy error */
gc_free (&gc);
return;
}
#else
static void dummy(void) {}
#endif /* ENABLE_HTTP_PROXY */
