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-rw-r--r--proxy.c519
1 files changed, 519 insertions, 0 deletions
diff --git a/proxy.c b/proxy.c
new file mode 100644
index 0000000..5c8521a
--- /dev/null
+++ b/proxy.c
@@ -0,0 +1,519 @@
+/*
+ * 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 */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-10 23:25:14 +0000