diff options
Diffstat (limited to 'tools/plink/proxy.c')
| -rw-r--r-- | tools/plink/proxy.c | 3016 |
1 files changed, 1509 insertions, 1507 deletions
diff --git a/tools/plink/proxy.c b/tools/plink/proxy.c index fcc81475b..e2201c643 100644 --- a/tools/plink/proxy.c +++ b/tools/plink/proxy.c @@ -1,1507 +1,1509 @@ -/*
- * Network proxy abstraction in PuTTY
- *
- * A proxy layer, if necessary, wedges itself between the network
- * code and the higher level backend.
- */
-
-#include <assert.h>
-#include <ctype.h>
-#include <string.h>
-
-#define DEFINE_PLUG_METHOD_MACROS
-#include "putty.h"
-#include "network.h"
-#include "proxy.h"
-
-#define do_proxy_dns(conf) \
- (conf_get_int(conf, CONF_proxy_dns) == FORCE_ON || \
- (conf_get_int(conf, CONF_proxy_dns) == AUTO && \
- conf_get_int(conf, CONF_proxy_type) != PROXY_SOCKS4))
-
-/*
- * Call this when proxy negotiation is complete, so that this
- * socket can begin working normally.
- */
-void proxy_activate (Proxy_Socket p)
-{
- void *data;
- int len;
- long output_before, output_after;
-
- p->state = PROXY_STATE_ACTIVE;
-
- /* we want to ignore new receive events until we have sent
- * all of our buffered receive data.
- */
- sk_set_frozen(p->sub_socket, 1);
-
- /* how many bytes of output have we buffered? */
- output_before = bufchain_size(&p->pending_oob_output_data) +
- bufchain_size(&p->pending_output_data);
- /* and keep track of how many bytes do not get sent. */
- output_after = 0;
-
- /* send buffered OOB writes */
- while (bufchain_size(&p->pending_oob_output_data) > 0) {
- bufchain_prefix(&p->pending_oob_output_data, &data, &len);
- output_after += sk_write_oob(p->sub_socket, data, len);
- bufchain_consume(&p->pending_oob_output_data, len);
- }
-
- /* send buffered normal writes */
- while (bufchain_size(&p->pending_output_data) > 0) {
- bufchain_prefix(&p->pending_output_data, &data, &len);
- output_after += sk_write(p->sub_socket, data, len);
- bufchain_consume(&p->pending_output_data, len);
- }
-
- /* if we managed to send any data, let the higher levels know. */
- if (output_after < output_before)
- plug_sent(p->plug, output_after);
-
- /* if we were asked to flush the output during
- * the proxy negotiation process, do so now.
- */
- if (p->pending_flush) sk_flush(p->sub_socket);
-
- /* if we have a pending EOF to send, send it */
- if (p->pending_eof) sk_write_eof(p->sub_socket);
-
- /* if the backend wanted the socket unfrozen, try to unfreeze.
- * our set_frozen handler will flush buffered receive data before
- * unfreezing the actual underlying socket.
- */
- if (!p->freeze)
- sk_set_frozen((Socket)p, 0);
-}
-
-/* basic proxy socket functions */
-
-static Plug sk_proxy_plug (Socket s, Plug p)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
- Plug ret = ps->plug;
- if (p)
- ps->plug = p;
- return ret;
-}
-
-static void sk_proxy_close (Socket s)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
-
- sk_close(ps->sub_socket);
- sk_addr_free(ps->remote_addr);
- sfree(ps);
-}
-
-static int sk_proxy_write (Socket s, const char *data, int len)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- bufchain_add(&ps->pending_output_data, data, len);
- return bufchain_size(&ps->pending_output_data);
- }
- return sk_write(ps->sub_socket, data, len);
-}
-
-static int sk_proxy_write_oob (Socket s, const char *data, int len)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- bufchain_clear(&ps->pending_output_data);
- bufchain_clear(&ps->pending_oob_output_data);
- bufchain_add(&ps->pending_oob_output_data, data, len);
- return len;
- }
- return sk_write_oob(ps->sub_socket, data, len);
-}
-
-static void sk_proxy_write_eof (Socket s)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- ps->pending_eof = 1;
- return;
- }
- sk_write_eof(ps->sub_socket);
-}
-
-static void sk_proxy_flush (Socket s)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- ps->pending_flush = 1;
- return;
- }
- sk_flush(ps->sub_socket);
-}
-
-static void sk_proxy_set_private_ptr (Socket s, void *ptr)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
- sk_set_private_ptr(ps->sub_socket, ptr);
-}
-
-static void * sk_proxy_get_private_ptr (Socket s)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
- return sk_get_private_ptr(ps->sub_socket);
-}
-
-static void sk_proxy_set_frozen (Socket s, int is_frozen)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- ps->freeze = is_frozen;
- return;
- }
-
- /* handle any remaining buffered recv data first */
- if (bufchain_size(&ps->pending_input_data) > 0) {
- ps->freeze = is_frozen;
-
- /* loop while we still have buffered data, and while we are
- * unfrozen. the plug_receive call in the loop could result
- * in a call back into this function refreezing the socket,
- * so we have to check each time.
- */
- while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
- void *data;
- char databuf[512];
- int len;
- bufchain_prefix(&ps->pending_input_data, &data, &len);
- if (len > lenof(databuf))
- len = lenof(databuf);
- memcpy(databuf, data, len);
- bufchain_consume(&ps->pending_input_data, len);
- plug_receive(ps->plug, 0, databuf, len);
- }
-
- /* if we're still frozen, we'll have to wait for another
- * call from the backend to finish unbuffering the data.
- */
- if (ps->freeze) return;
- }
-
- sk_set_frozen(ps->sub_socket, is_frozen);
-}
-
-static const char * sk_proxy_socket_error (Socket s)
-{
- Proxy_Socket ps = (Proxy_Socket) s;
- if (ps->error != NULL || ps->sub_socket == NULL) {
- return ps->error;
- }
- return sk_socket_error(ps->sub_socket);
-}
-
-/* basic proxy plug functions */
-
-static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port,
- const char *error_msg, int error_code)
-{
- Proxy_Plug pp = (Proxy_Plug) plug;
- Proxy_Socket ps = pp->proxy_socket;
-
- plug_log(ps->plug, type, addr, port, error_msg, error_code);
-}
-
-static int plug_proxy_closing (Plug p, const char *error_msg,
- int error_code, int calling_back)
-{
- Proxy_Plug pp = (Proxy_Plug) p;
- Proxy_Socket ps = pp->proxy_socket;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- ps->closing_error_msg = error_msg;
- ps->closing_error_code = error_code;
- ps->closing_calling_back = calling_back;
- return ps->negotiate(ps, PROXY_CHANGE_CLOSING);
- }
- return plug_closing(ps->plug, error_msg,
- error_code, calling_back);
-}
-
-static int plug_proxy_receive (Plug p, int urgent, char *data, int len)
-{
- Proxy_Plug pp = (Proxy_Plug) p;
- Proxy_Socket ps = pp->proxy_socket;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- /* we will lose the urgentness of this data, but since most,
- * if not all, of this data will be consumed by the negotiation
- * process, hopefully it won't affect the protocol above us
- */
- bufchain_add(&ps->pending_input_data, data, len);
- ps->receive_urgent = urgent;
- ps->receive_data = data;
- ps->receive_len = len;
- return ps->negotiate(ps, PROXY_CHANGE_RECEIVE);
- }
- return plug_receive(ps->plug, urgent, data, len);
-}
-
-static void plug_proxy_sent (Plug p, int bufsize)
-{
- Proxy_Plug pp = (Proxy_Plug) p;
- Proxy_Socket ps = pp->proxy_socket;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- ps->sent_bufsize = bufsize;
- ps->negotiate(ps, PROXY_CHANGE_SENT);
- return;
- }
- plug_sent(ps->plug, bufsize);
-}
-
-static int plug_proxy_accepting (Plug p, OSSocket sock)
-{
- Proxy_Plug pp = (Proxy_Plug) p;
- Proxy_Socket ps = pp->proxy_socket;
-
- if (ps->state != PROXY_STATE_ACTIVE) {
- ps->accepting_sock = sock;
- return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING);
- }
- return plug_accepting(ps->plug, sock);
-}
-
-/*
- * This function can accept a NULL pointer as `addr', in which case
- * it will only check the host name.
- */
-static int proxy_for_destination (SockAddr addr, char *hostname, int port,
- Conf *conf)
-{
- int s = 0, e = 0;
- char hostip[64];
- int hostip_len, hostname_len;
- const char *exclude_list;
-
- /*
- * Check the host name and IP against the hard-coded
- * representations of `localhost'.
- */
- if (!conf_get_int(conf, CONF_even_proxy_localhost) &&
- (sk_hostname_is_local(hostname) ||
- (addr && sk_address_is_local(addr))))
- return 0; /* do not proxy */
-
- /* we want a string representation of the IP address for comparisons */
- if (addr) {
- sk_getaddr(addr, hostip, 64);
- hostip_len = strlen(hostip);
- } else
- hostip_len = 0; /* placate gcc; shouldn't be required */
-
- hostname_len = strlen(hostname);
-
- exclude_list = conf_get_str(conf, CONF_proxy_exclude_list);
-
- /* now parse the exclude list, and see if either our IP
- * or hostname matches anything in it.
- */
-
- while (exclude_list[s]) {
- while (exclude_list[s] &&
- (isspace((unsigned char)exclude_list[s]) ||
- exclude_list[s] == ',')) s++;
-
- if (!exclude_list[s]) break;
-
- e = s;
-
- while (exclude_list[e] &&
- (isalnum((unsigned char)exclude_list[e]) ||
- exclude_list[e] == '-' ||
- exclude_list[e] == '.' ||
- exclude_list[e] == '*')) e++;
-
- if (exclude_list[s] == '*') {
- /* wildcard at beginning of entry */
-
- if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
- exclude_list + s + 1, e - s - 1) == 0) ||
- strnicmp(hostname + hostname_len - (e - s - 1),
- exclude_list + s + 1, e - s - 1) == 0)
- return 0; /* IP/hostname range excluded. do not use proxy. */
-
- } else if (exclude_list[e-1] == '*') {
- /* wildcard at end of entry */
-
- if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
- strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
- return 0; /* IP/hostname range excluded. do not use proxy. */
-
- } else {
- /* no wildcard at either end, so let's try an absolute
- * match (ie. a specific IP)
- */
-
- if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
- return 0; /* IP/hostname excluded. do not use proxy. */
- if (strnicmp(hostname, exclude_list + s, e - s) == 0)
- return 0; /* IP/hostname excluded. do not use proxy. */
- }
-
- s = e;
-
- /* Make sure we really have reached the next comma or end-of-string */
- while (exclude_list[s] &&
- !isspace((unsigned char)exclude_list[s]) &&
- exclude_list[s] != ',') s++;
- }
-
- /* no matches in the exclude list, so use the proxy */
- return 1;
-}
-
-SockAddr name_lookup(char *host, int port, char **canonicalname,
- Conf *conf, int addressfamily)
-{
- if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
- do_proxy_dns(conf) &&
- proxy_for_destination(NULL, host, port, conf)) {
- *canonicalname = dupstr(host);
- return sk_nonamelookup(host);
- }
-
- return sk_namelookup(host, canonicalname, addressfamily);
-}
-
-Socket new_connection(SockAddr addr, char *hostname,
- int port, int privport,
- int oobinline, int nodelay, int keepalive,
- Plug plug, Conf *conf)
-{
- static const struct socket_function_table socket_fn_table = {
- sk_proxy_plug,
- sk_proxy_close,
- sk_proxy_write,
- sk_proxy_write_oob,
- sk_proxy_write_eof,
- sk_proxy_flush,
- sk_proxy_set_private_ptr,
- sk_proxy_get_private_ptr,
- sk_proxy_set_frozen,
- sk_proxy_socket_error
- };
-
- static const struct plug_function_table plug_fn_table = {
- plug_proxy_log,
- plug_proxy_closing,
- plug_proxy_receive,
- plug_proxy_sent,
- plug_proxy_accepting
- };
-
- if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
- proxy_for_destination(addr, hostname, port, conf))
- {
- Proxy_Socket ret;
- Proxy_Plug pplug;
- SockAddr proxy_addr;
- char *proxy_canonical_name;
- Socket sret;
- int type;
-
- if ((sret = platform_new_connection(addr, hostname, port, privport,
- oobinline, nodelay, keepalive,
- plug, conf)) !=
- NULL)
- return sret;
-
- ret = snew(struct Socket_proxy_tag);
- ret->fn = &socket_fn_table;
- ret->conf = conf_copy(conf);
- ret->plug = plug;
- ret->remote_addr = addr; /* will need to be freed on close */
- ret->remote_port = port;
-
- ret->error = NULL;
- ret->pending_flush = 0;
- ret->pending_eof = 0;
- ret->freeze = 0;
-
- bufchain_init(&ret->pending_input_data);
- bufchain_init(&ret->pending_output_data);
- bufchain_init(&ret->pending_oob_output_data);
-
- ret->sub_socket = NULL;
- ret->state = PROXY_STATE_NEW;
- ret->negotiate = NULL;
-
- type = conf_get_int(conf, CONF_proxy_type);
- if (type == PROXY_HTTP) {
- ret->negotiate = proxy_http_negotiate;
- } else if (type == PROXY_SOCKS4) {
- ret->negotiate = proxy_socks4_negotiate;
- } else if (type == PROXY_SOCKS5) {
- ret->negotiate = proxy_socks5_negotiate;
- } else if (type == PROXY_TELNET) {
- ret->negotiate = proxy_telnet_negotiate;
- } else {
- ret->error = "Proxy error: Unknown proxy method";
- return (Socket) ret;
- }
-
- /* create the proxy plug to map calls from the actual
- * socket into our proxy socket layer */
- pplug = snew(struct Plug_proxy_tag);
- pplug->fn = &plug_fn_table;
- pplug->proxy_socket = ret;
-
- /* look-up proxy */
- proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
- &proxy_canonical_name,
- conf_get_int(conf, CONF_addressfamily));
- if (sk_addr_error(proxy_addr) != NULL) {
- ret->error = "Proxy error: Unable to resolve proxy host name";
- return (Socket)ret;
- }
- sfree(proxy_canonical_name);
-
- /* create the actual socket we will be using,
- * connected to our proxy server and port.
- */
- ret->sub_socket = sk_new(proxy_addr,
- conf_get_int(conf, CONF_proxy_port),
- privport, oobinline,
- nodelay, keepalive, (Plug) pplug);
- if (sk_socket_error(ret->sub_socket) != NULL)
- return (Socket) ret;
-
- /* start the proxy negotiation process... */
- sk_set_frozen(ret->sub_socket, 0);
- ret->negotiate(ret, PROXY_CHANGE_NEW);
-
- return (Socket) ret;
- }
-
- /* no proxy, so just return the direct socket */
- return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
-}
-
-Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
- Conf *conf, int addressfamily)
-{
- /* TODO: SOCKS (and potentially others) support inbound
- * TODO: connections via the proxy. support them.
- */
-
- return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
-}
-
-/* ----------------------------------------------------------------------
- * HTTP CONNECT proxy type.
- */
-
-static int get_line_end (char * data, int len)
-{
- int off = 0;
-
- while (off < len)
- {
- if (data[off] == '\n') {
- /* we have a newline */
- off++;
-
- /* is that the only thing on this line? */
- if (off <= 2) return off;
-
- /* if not, then there is the possibility that this header
- * continues onto the next line, if it starts with a space
- * or a tab.
- */
-
- if (off + 1 < len &&
- data[off+1] != ' ' &&
- data[off+1] != '\t') return off;
-
- /* the line does continue, so we have to keep going
- * until we see an the header's "real" end of line.
- */
- off++;
- }
-
- off++;
- }
-
- return -1;
-}
-
-int proxy_http_negotiate (Proxy_Socket p, int change)
-{
- if (p->state == PROXY_STATE_NEW) {
- /* we are just beginning the proxy negotiate process,
- * so we'll send off the initial bits of the request.
- * for this proxy method, it's just a simple HTTP
- * request
- */
- char *buf, dest[512];
- char *username, *password;
-
- sk_getaddr(p->remote_addr, dest, lenof(dest));
-
- buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
- dest, p->remote_port, dest, p->remote_port);
- sk_write(p->sub_socket, buf, strlen(buf));
- sfree(buf);
-
- username = conf_get_str(p->conf, CONF_proxy_username);
- password = conf_get_str(p->conf, CONF_proxy_password);
- if (username[0] || password[0]) {
- char *buf, *buf2;
- int i, j, len;
- buf = dupprintf("%s:%s", username, password);
- len = strlen(buf);
- buf2 = snewn(len * 4 / 3 + 100, char);
- sprintf(buf2, "Proxy-Authorization: Basic ");
- for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
- base64_encode_atom((unsigned char *)(buf+i),
- (len-i > 3 ? 3 : len-i), buf2+j);
- strcpy(buf2+j, "\r\n");
- sk_write(p->sub_socket, buf2, strlen(buf2));
- sfree(buf);
- sfree(buf2);
- }
-
- sk_write(p->sub_socket, "\r\n", 2);
-
- p->state = 1;
- return 0;
- }
-
- if (change == PROXY_CHANGE_CLOSING) {
- /* if our proxy negotiation process involves closing and opening
- * new sockets, then we would want to intercept this closing
- * callback when we were expecting it. if we aren't anticipating
- * a socket close, then some error must have occurred. we'll
- * just pass those errors up to the backend.
- */
- return plug_closing(p->plug, p->closing_error_msg,
- p->closing_error_code,
- p->closing_calling_back);
- }
-
- if (change == PROXY_CHANGE_SENT) {
- /* some (or all) of what we wrote to the proxy was sent.
- * we don't do anything new, however, until we receive the
- * proxy's response. we might want to set a timer so we can
- * timeout the proxy negotiation after a while...
- */
- return 0;
- }
-
- if (change == PROXY_CHANGE_ACCEPTING) {
- /* we should _never_ see this, as we are using our socket to
- * connect to a proxy, not accepting inbound connections.
- * what should we do? close the socket with an appropriate
- * error message?
- */
- return plug_accepting(p->plug, p->accepting_sock);
- }
-
- if (change == PROXY_CHANGE_RECEIVE) {
- /* we have received data from the underlying socket, which
- * we'll need to parse, process, and respond to appropriately.
- */
-
- char *data, *datap;
- int len;
- int eol;
-
- if (p->state == 1) {
-
- int min_ver, maj_ver, status;
-
- /* get the status line */
- len = bufchain_size(&p->pending_input_data);
- assert(len > 0); /* or we wouldn't be here */
- data = snewn(len+1, char);
- bufchain_fetch(&p->pending_input_data, data, len);
- /*
- * We must NUL-terminate this data, because Windows
- * sscanf appears to require a NUL at the end of the
- * string because it strlens it _first_. Sigh.
- */
- data[len] = '\0';
-
- eol = get_line_end(data, len);
- if (eol < 0) {
- sfree(data);
- return 1;
- }
-
- status = -1;
- /* We can't rely on whether the %n incremented the sscanf return */
- if (sscanf((char *)data, "HTTP/%i.%i %n",
- &maj_ver, &min_ver, &status) < 2 || status == -1) {
- plug_closing(p->plug, "Proxy error: HTTP response was absent",
- PROXY_ERROR_GENERAL, 0);
- sfree(data);
- return 1;
- }
-
- /* remove the status line from the input buffer. */
- bufchain_consume(&p->pending_input_data, eol);
- if (data[status] != '2') {
- /* error */
- char *buf;
- data[eol] = '\0';
- while (eol > status &&
- (data[eol-1] == '\r' || data[eol-1] == '\n'))
- data[--eol] = '\0';
- buf = dupprintf("Proxy error: %s", data+status);
- plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
- sfree(buf);
- sfree(data);
- return 1;
- }
-
- sfree(data);
-
- p->state = 2;
- }
-
- if (p->state == 2) {
-
- /* get headers. we're done when we get a
- * header of length 2, (ie. just "\r\n")
- */
-
- len = bufchain_size(&p->pending_input_data);
- assert(len > 0); /* or we wouldn't be here */
- data = snewn(len, char);
- datap = data;
- bufchain_fetch(&p->pending_input_data, data, len);
-
- eol = get_line_end(datap, len);
- if (eol < 0) {
- sfree(data);
- return 1;
- }
- while (eol > 2)
- {
- bufchain_consume(&p->pending_input_data, eol);
- datap += eol;
- len -= eol;
- eol = get_line_end(datap, len);
- }
-
- if (eol == 2) {
- /* we're done */
- bufchain_consume(&p->pending_input_data, 2);
- proxy_activate(p);
- /* proxy activate will have dealt with
- * whatever is left of the buffer */
- sfree(data);
- return 1;
- }
-
- sfree(data);
- return 1;
- }
- }
-
- plug_closing(p->plug, "Proxy error: unexpected proxy error",
- PROXY_ERROR_UNEXPECTED, 0);
- return 1;
-}
-
-/* ----------------------------------------------------------------------
- * SOCKS proxy type.
- */
-
-/* SOCKS version 4 */
-int proxy_socks4_negotiate (Proxy_Socket p, int change)
-{
- if (p->state == PROXY_CHANGE_NEW) {
-
- /* request format:
- * version number (1 byte) = 4
- * command code (1 byte)
- * 1 = CONNECT
- * 2 = BIND
- * dest. port (2 bytes) [network order]
- * dest. address (4 bytes)
- * user ID (variable length, null terminated string)
- */
-
- int length, type, namelen;
- char *command, addr[4], hostname[512];
- char *username;
-
- type = sk_addrtype(p->remote_addr);
- if (type == ADDRTYPE_IPV6) {
- plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
- " not support IPv6", PROXY_ERROR_GENERAL, 0);
- return 1;
- } else if (type == ADDRTYPE_IPV4) {
- namelen = 0;
- sk_addrcopy(p->remote_addr, addr);
- } else { /* type == ADDRTYPE_NAME */
- assert(type == ADDRTYPE_NAME);
- sk_getaddr(p->remote_addr, hostname, lenof(hostname));
- namelen = strlen(hostname) + 1; /* include the NUL */
- addr[0] = addr[1] = addr[2] = 0;
- addr[3] = 1;
- }
-
- username = conf_get_str(p->conf, CONF_proxy_username);
- length = strlen(username) + namelen + 9;
- command = snewn(length, char);
- strcpy(command + 8, username);
-
- command[0] = 4; /* version 4 */
- command[1] = 1; /* CONNECT command */
-
- /* port */
- command[2] = (char) (p->remote_port >> 8) & 0xff;
- command[3] = (char) p->remote_port & 0xff;
-
- /* address */
- memcpy(command + 4, addr, 4);
-
- /* hostname */
- memcpy(command + 8 + strlen(username) + 1,
- hostname, namelen);
-
- sk_write(p->sub_socket, command, length);
- sfree(username);
- sfree(command);
-
- p->state = 1;
- return 0;
- }
-
- if (change == PROXY_CHANGE_CLOSING) {
- /* if our proxy negotiation process involves closing and opening
- * new sockets, then we would want to intercept this closing
- * callback when we were expecting it. if we aren't anticipating
- * a socket close, then some error must have occurred. we'll
- * just pass those errors up to the backend.
- */
- return plug_closing(p->plug, p->closing_error_msg,
- p->closing_error_code,
- p->closing_calling_back);
- }
-
- if (change == PROXY_CHANGE_SENT) {
- /* some (or all) of what we wrote to the proxy was sent.
- * we don't do anything new, however, until we receive the
- * proxy's response. we might want to set a timer so we can
- * timeout the proxy negotiation after a while...
- */
- return 0;
- }
-
- if (change == PROXY_CHANGE_ACCEPTING) {
- /* we should _never_ see this, as we are using our socket to
- * connect to a proxy, not accepting inbound connections.
- * what should we do? close the socket with an appropriate
- * error message?
- */
- return plug_accepting(p->plug, p->accepting_sock);
- }
-
- if (change == PROXY_CHANGE_RECEIVE) {
- /* we have received data from the underlying socket, which
- * we'll need to parse, process, and respond to appropriately.
- */
-
- if (p->state == 1) {
- /* response format:
- * version number (1 byte) = 4
- * reply code (1 byte)
- * 90 = request granted
- * 91 = request rejected or failed
- * 92 = request rejected due to lack of IDENTD on client
- * 93 = request rejected due to difference in user ID
- * (what we sent vs. what IDENTD said)
- * dest. port (2 bytes)
- * dest. address (4 bytes)
- */
-
- char data[8];
-
- if (bufchain_size(&p->pending_input_data) < 8)
- return 1; /* not got anything yet */
-
- /* get the response */
- bufchain_fetch(&p->pending_input_data, data, 8);
-
- if (data[0] != 0) {
- plug_closing(p->plug, "Proxy error: SOCKS proxy responded with "
- "unexpected reply code version",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
-
- if (data[1] != 90) {
-
- switch (data[1]) {
- case 92:
- plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client",
- PROXY_ERROR_GENERAL, 0);
- break;
- case 93:
- plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree",
- PROXY_ERROR_GENERAL, 0);
- break;
- case 91:
- default:
- plug_closing(p->plug, "Proxy error: Error while communicating with proxy",
- PROXY_ERROR_GENERAL, 0);
- break;
- }
-
- return 1;
- }
- bufchain_consume(&p->pending_input_data, 8);
-
- /* we're done */
- proxy_activate(p);
- /* proxy activate will have dealt with
- * whatever is left of the buffer */
- return 1;
- }
- }
-
- plug_closing(p->plug, "Proxy error: unexpected proxy error",
- PROXY_ERROR_UNEXPECTED, 0);
- return 1;
-}
-
-/* SOCKS version 5 */
-int proxy_socks5_negotiate (Proxy_Socket p, int change)
-{
- if (p->state == PROXY_CHANGE_NEW) {
-
- /* initial command:
- * version number (1 byte) = 5
- * number of available authentication methods (1 byte)
- * available authentication methods (1 byte * previous value)
- * authentication methods:
- * 0x00 = no authentication
- * 0x01 = GSSAPI
- * 0x02 = username/password
- * 0x03 = CHAP
- */
-
- char command[5];
- char *username, *password;
- int len;
-
- command[0] = 5; /* version 5 */
- username = conf_get_str(p->conf, CONF_proxy_username);
- password = conf_get_str(p->conf, CONF_proxy_password);
- if (username[0] || password[0]) {
- command[2] = 0x00; /* no authentication */
- len = 3;
- proxy_socks5_offerencryptedauth (command, &len);
- command[len++] = 0x02; /* username/password */
- command[1] = len - 2; /* Number of methods supported */
- } else {
- command[1] = 1; /* one methods supported: */
- command[2] = 0x00; /* no authentication */
- len = 3;
- }
-
- sk_write(p->sub_socket, command, len);
-
- p->state = 1;
- return 0;
- }
-
- if (change == PROXY_CHANGE_CLOSING) {
- /* if our proxy negotiation process involves closing and opening
- * new sockets, then we would want to intercept this closing
- * callback when we were expecting it. if we aren't anticipating
- * a socket close, then some error must have occurred. we'll
- * just pass those errors up to the backend.
- */
- return plug_closing(p->plug, p->closing_error_msg,
- p->closing_error_code,
- p->closing_calling_back);
- }
-
- if (change == PROXY_CHANGE_SENT) {
- /* some (or all) of what we wrote to the proxy was sent.
- * we don't do anything new, however, until we receive the
- * proxy's response. we might want to set a timer so we can
- * timeout the proxy negotiation after a while...
- */
- return 0;
- }
-
- if (change == PROXY_CHANGE_ACCEPTING) {
- /* we should _never_ see this, as we are using our socket to
- * connect to a proxy, not accepting inbound connections.
- * what should we do? close the socket with an appropriate
- * error message?
- */
- return plug_accepting(p->plug, p->accepting_sock);
- }
-
- if (change == PROXY_CHANGE_RECEIVE) {
- /* we have received data from the underlying socket, which
- * we'll need to parse, process, and respond to appropriately.
- */
-
- if (p->state == 1) {
-
- /* initial response:
- * version number (1 byte) = 5
- * authentication method (1 byte)
- * authentication methods:
- * 0x00 = no authentication
- * 0x01 = GSSAPI
- * 0x02 = username/password
- * 0x03 = CHAP
- * 0xff = no acceptable methods
- */
- char data[2];
-
- if (bufchain_size(&p->pending_input_data) < 2)
- return 1; /* not got anything yet */
-
- /* get the response */
- bufchain_fetch(&p->pending_input_data, data, 2);
-
- if (data[0] != 5) {
- plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
-
- if (data[1] == 0x00) p->state = 2; /* no authentication needed */
- else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */
- else if (data[1] == 0x02) p->state = 5; /* username/password authentication */
- else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */
- else {
- plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
- bufchain_consume(&p->pending_input_data, 2);
- }
-
- if (p->state == 7) {
-
- /* password authentication reply format:
- * version number (1 bytes) = 1
- * reply code (1 byte)
- * 0 = succeeded
- * >0 = failed
- */
- char data[2];
-
- if (bufchain_size(&p->pending_input_data) < 2)
- return 1; /* not got anything yet */
-
- /* get the response */
- bufchain_fetch(&p->pending_input_data, data, 2);
-
- if (data[0] != 1) {
- plug_closing(p->plug, "Proxy error: SOCKS password "
- "subnegotiation contained wrong version number",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
-
- if (data[1] != 0) {
-
- plug_closing(p->plug, "Proxy error: SOCKS proxy refused"
- " password authentication",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
-
- bufchain_consume(&p->pending_input_data, 2);
- p->state = 2; /* now proceed as authenticated */
- }
-
- if (p->state == 8) {
- int ret;
- ret = proxy_socks5_handlechap(p);
- if (ret) return ret;
- }
-
- if (p->state == 2) {
-
- /* request format:
- * version number (1 byte) = 5
- * command code (1 byte)
- * 1 = CONNECT
- * 2 = BIND
- * 3 = UDP ASSOCIATE
- * reserved (1 byte) = 0x00
- * address type (1 byte)
- * 1 = IPv4
- * 3 = domainname (first byte has length, no terminating null)
- * 4 = IPv6
- * dest. address (variable)
- * dest. port (2 bytes) [network order]
- */
-
- char command[512];
- int len;
- int type;
-
- type = sk_addrtype(p->remote_addr);
- if (type == ADDRTYPE_IPV4) {
- len = 10; /* 4 hdr + 4 addr + 2 trailer */
- command[3] = 1; /* IPv4 */
- sk_addrcopy(p->remote_addr, command+4);
- } else if (type == ADDRTYPE_IPV6) {
- len = 22; /* 4 hdr + 16 addr + 2 trailer */
- command[3] = 4; /* IPv6 */
- sk_addrcopy(p->remote_addr, command+4);
- } else {
- assert(type == ADDRTYPE_NAME);
- command[3] = 3;
- sk_getaddr(p->remote_addr, command+5, 256);
- command[4] = strlen(command+5);
- len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */
- }
-
- command[0] = 5; /* version 5 */
- command[1] = 1; /* CONNECT command */
- command[2] = 0x00;
-
- /* port */
- command[len-2] = (char) (p->remote_port >> 8) & 0xff;
- command[len-1] = (char) p->remote_port & 0xff;
-
- sk_write(p->sub_socket, command, len);
-
- p->state = 3;
- return 1;
- }
-
- if (p->state == 3) {
-
- /* reply format:
- * version number (1 bytes) = 5
- * reply code (1 byte)
- * 0 = succeeded
- * 1 = general SOCKS server failure
- * 2 = connection not allowed by ruleset
- * 3 = network unreachable
- * 4 = host unreachable
- * 5 = connection refused
- * 6 = TTL expired
- * 7 = command not supported
- * 8 = address type not supported
- * reserved (1 byte) = x00
- * address type (1 byte)
- * 1 = IPv4
- * 3 = domainname (first byte has length, no terminating null)
- * 4 = IPv6
- * server bound address (variable)
- * server bound port (2 bytes) [network order]
- */
- char data[5];
- int len;
-
- /* First 5 bytes of packet are enough to tell its length. */
- if (bufchain_size(&p->pending_input_data) < 5)
- return 1; /* not got anything yet */
-
- /* get the response */
- bufchain_fetch(&p->pending_input_data, data, 5);
-
- if (data[0] != 5) {
- plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
-
- if (data[1] != 0) {
- char buf[256];
-
- strcpy(buf, "Proxy error: ");
-
- switch (data[1]) {
- case 1: strcat(buf, "General SOCKS server failure"); break;
- case 2: strcat(buf, "Connection not allowed by ruleset"); break;
- case 3: strcat(buf, "Network unreachable"); break;
- case 4: strcat(buf, "Host unreachable"); break;
- case 5: strcat(buf, "Connection refused"); break;
- case 6: strcat(buf, "TTL expired"); break;
- case 7: strcat(buf, "Command not supported"); break;
- case 8: strcat(buf, "Address type not supported"); break;
- default: sprintf(buf+strlen(buf),
- "Unrecognised SOCKS error code %d",
- data[1]);
- break;
- }
- plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0);
-
- return 1;
- }
-
- /*
- * Eat the rest of the reply packet.
- */
- len = 6; /* first 4 bytes, last 2 */
- switch (data[3]) {
- case 1: len += 4; break; /* IPv4 address */
- case 4: len += 16; break;/* IPv6 address */
- case 3: len += (unsigned char)data[4]; break; /* domain name */
- default:
- plug_closing(p->plug, "Proxy error: SOCKS proxy returned "
- "unrecognised address format",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
- if (bufchain_size(&p->pending_input_data) < len)
- return 1; /* not got whole reply yet */
- bufchain_consume(&p->pending_input_data, len);
-
- /* we're done */
- proxy_activate(p);
- return 1;
- }
-
- if (p->state == 4) {
- /* TODO: Handle GSSAPI authentication */
- plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
-
- if (p->state == 5) {
- char *username = conf_get_str(p->conf, CONF_proxy_username);
- char *password = conf_get_str(p->conf, CONF_proxy_password);
- if (username[0] || password[0]) {
- char userpwbuf[255 + 255 + 3];
- int ulen, plen;
- ulen = strlen(username);
- if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
- plen = strlen(password);
- if (plen > 255) plen = 255; if (plen < 1) plen = 1;
- userpwbuf[0] = 1; /* version number of subnegotiation */
- userpwbuf[1] = ulen;
- memcpy(userpwbuf+2, username, ulen);
- userpwbuf[ulen+2] = plen;
- memcpy(userpwbuf+ulen+3, password, plen);
- sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
- p->state = 7;
- } else
- plug_closing(p->plug, "Proxy error: Server chose "
- "username/password authentication but we "
- "didn't offer it!",
- PROXY_ERROR_GENERAL, 0);
- return 1;
- }
-
- if (p->state == 6) {
- int ret;
- ret = proxy_socks5_selectchap(p);
- if (ret) return ret;
- }
-
- }
-
- plug_closing(p->plug, "Proxy error: Unexpected proxy error",
- PROXY_ERROR_UNEXPECTED, 0);
- return 1;
-}
-
-/* ----------------------------------------------------------------------
- * `Telnet' proxy type.
- *
- * (This is for ad-hoc proxies where you connect to the proxy's
- * telnet port and send a command such as `connect host port'. The
- * command is configurable, since this proxy type is typically not
- * standardised or at all well-defined.)
- */
-
-char *format_telnet_command(SockAddr addr, int port, Conf *conf)
-{
- char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
- char *ret = NULL;
- int retlen = 0, retsize = 0;
- int so = 0, eo = 0;
-#define ENSURE(n) do { \
- if (retsize < retlen + n) { \
- retsize = retlen + n + 512; \
- ret = sresize(ret, retsize, char); \
- } \
-} while (0)
-
- /* we need to escape \\, \%, \r, \n, \t, \x??, \0???,
- * %%, %host, %port, %user, and %pass
- */
-
- while (fmt[eo] != 0) {
-
- /* scan forward until we hit end-of-line,
- * or an escape character (\ or %) */
- while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
- eo++;
-
- /* if we hit eol, break out of our escaping loop */
- if (fmt[eo] == 0) break;
-
- /* if there was any unescaped text before the escape
- * character, send that now */
- if (eo != so) {
- ENSURE(eo - so);
- memcpy(ret + retlen, fmt + so, eo - so);
- retlen += eo - so;
- }
-
- so = eo++;
-
- /* if the escape character was the last character of
- * the line, we'll just stop and send it. */
- if (fmt[eo] == 0) break;
-
- if (fmt[so] == '\\') {
-
- /* we recognize \\, \%, \r, \n, \t, \x??.
- * anything else, we just send unescaped (including the \).
- */
-
- switch (fmt[eo]) {
-
- case '\\':
- ENSURE(1);
- ret[retlen++] = '\\';
- eo++;
- break;
-
- case '%':
- ENSURE(1);
- ret[retlen++] = '%';
- eo++;
- break;
-
- case 'r':
- ENSURE(1);
- ret[retlen++] = '\r';
- eo++;
- break;
-
- case 'n':
- ENSURE(1);
- ret[retlen++] = '\n';
- eo++;
- break;
-
- case 't':
- ENSURE(1);
- ret[retlen++] = '\t';
- eo++;
- break;
-
- case 'x':
- case 'X':
- {
- /* escaped hexadecimal value (ie. \xff) */
- unsigned char v = 0;
- int i = 0;
-
- for (;;) {
- eo++;
- if (fmt[eo] >= '0' && fmt[eo] <= '9')
- v += fmt[eo] - '0';
- else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
- v += fmt[eo] - 'a' + 10;
- else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
- v += fmt[eo] - 'A' + 10;
- else {
- /* non hex character, so we abort and just
- * send the whole thing unescaped (including \x)
- */
- ENSURE(1);
- ret[retlen++] = '\\';
- eo = so + 1;
- break;
- }
-
- /* we only extract two hex characters */
- if (i == 1) {
- ENSURE(1);
- ret[retlen++] = v;
- eo++;
- break;
- }
-
- i++;
- v <<= 4;
- }
- }
- break;
-
- default:
- ENSURE(2);
- memcpy(ret+retlen, fmt + so, 2);
- retlen += 2;
- eo++;
- break;
- }
- } else {
-
- /* % escape. we recognize %%, %host, %port, %user, %pass.
- * %proxyhost, %proxyport. Anything else we just send
- * unescaped (including the %).
- */
-
- if (fmt[eo] == '%') {
- ENSURE(1);
- ret[retlen++] = '%';
- eo++;
- }
- else if (strnicmp(fmt + eo, "host", 4) == 0) {
- char dest[512];
- int destlen;
- sk_getaddr(addr, dest, lenof(dest));
- destlen = strlen(dest);
- ENSURE(destlen);
- memcpy(ret+retlen, dest, destlen);
- retlen += destlen;
- eo += 4;
- }
- else if (strnicmp(fmt + eo, "port", 4) == 0) {
- char portstr[8], portlen;
- portlen = sprintf(portstr, "%i", port);
- ENSURE(portlen);
- memcpy(ret + retlen, portstr, portlen);
- retlen += portlen;
- eo += 4;
- }
- else if (strnicmp(fmt + eo, "user", 4) == 0) {
- char *username = conf_get_str(conf, CONF_proxy_username);
- int userlen = strlen(username);
- ENSURE(userlen);
- memcpy(ret+retlen, username, userlen);
- retlen += userlen;
- eo += 4;
- }
- else if (strnicmp(fmt + eo, "pass", 4) == 0) {
- char *password = conf_get_str(conf, CONF_proxy_password);
- int passlen = strlen(password);
- ENSURE(passlen);
- memcpy(ret+retlen, password, passlen);
- retlen += passlen;
- eo += 4;
- }
- else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
- char *host = conf_get_str(conf, CONF_proxy_host);
- int phlen = strlen(host);
- ENSURE(phlen);
- memcpy(ret+retlen, host, phlen);
- retlen += phlen;
- eo += 9;
- }
- else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
- int port = conf_get_int(conf, CONF_proxy_port);
- char pport[50];
- int pplen;
- sprintf(pport, "%d", port);
- pplen = strlen(pport);
- ENSURE(pplen);
- memcpy(ret+retlen, pport, pplen);
- retlen += pplen;
- eo += 9;
- }
- else {
- /* we don't escape this, so send the % now, and
- * don't advance eo, so that we'll consider the
- * text immediately following the % as unescaped.
- */
- ENSURE(1);
- ret[retlen++] = '%';
- }
- }
-
- /* resume scanning for additional escapes after this one. */
- so = eo;
- }
-
- /* if there is any unescaped text at the end of the line, send it */
- if (eo != so) {
- ENSURE(eo - so);
- memcpy(ret + retlen, fmt + so, eo - so);
- retlen += eo - so;
- }
-
- ENSURE(1);
- ret[retlen] = '\0';
- return ret;
-
-#undef ENSURE
-}
-
-int proxy_telnet_negotiate (Proxy_Socket p, int change)
-{
- if (p->state == PROXY_CHANGE_NEW) {
- char *formatted_cmd;
-
- formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
- p->conf);
-
- sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
- sfree(formatted_cmd);
-
- p->state = 1;
- return 0;
- }
-
- if (change == PROXY_CHANGE_CLOSING) {
- /* if our proxy negotiation process involves closing and opening
- * new sockets, then we would want to intercept this closing
- * callback when we were expecting it. if we aren't anticipating
- * a socket close, then some error must have occurred. we'll
- * just pass those errors up to the backend.
- */
- return plug_closing(p->plug, p->closing_error_msg,
- p->closing_error_code,
- p->closing_calling_back);
- }
-
- if (change == PROXY_CHANGE_SENT) {
- /* some (or all) of what we wrote to the proxy was sent.
- * we don't do anything new, however, until we receive the
- * proxy's response. we might want to set a timer so we can
- * timeout the proxy negotiation after a while...
- */
- return 0;
- }
-
- if (change == PROXY_CHANGE_ACCEPTING) {
- /* we should _never_ see this, as we are using our socket to
- * connect to a proxy, not accepting inbound connections.
- * what should we do? close the socket with an appropriate
- * error message?
- */
- return plug_accepting(p->plug, p->accepting_sock);
- }
-
- if (change == PROXY_CHANGE_RECEIVE) {
- /* we have received data from the underlying socket, which
- * we'll need to parse, process, and respond to appropriately.
- */
-
- /* we're done */
- proxy_activate(p);
- /* proxy activate will have dealt with
- * whatever is left of the buffer */
- return 1;
- }
-
- plug_closing(p->plug, "Proxy error: Unexpected proxy error",
- PROXY_ERROR_UNEXPECTED, 0);
- return 1;
-}
+/* + * Network proxy abstraction in PuTTY + * + * A proxy layer, if necessary, wedges itself between the network + * code and the higher level backend. + */ + +#include <assert.h> +#include <ctype.h> +#include <string.h> + +#define DEFINE_PLUG_METHOD_MACROS +#include "putty.h" +#include "network.h" +#include "proxy.h" + +#define do_proxy_dns(conf) \ + (conf_get_int(conf, CONF_proxy_dns) == FORCE_ON || \ + (conf_get_int(conf, CONF_proxy_dns) == AUTO && \ + conf_get_int(conf, CONF_proxy_type) != PROXY_SOCKS4)) + +/* + * Call this when proxy negotiation is complete, so that this + * socket can begin working normally. + */ +void proxy_activate (Proxy_Socket p) +{ + void *data; + int len; + long output_before, output_after; + + p->state = PROXY_STATE_ACTIVE; + + /* we want to ignore new receive events until we have sent + * all of our buffered receive data. + */ + sk_set_frozen(p->sub_socket, 1); + + /* how many bytes of output have we buffered? */ + output_before = bufchain_size(&p->pending_oob_output_data) + + bufchain_size(&p->pending_output_data); + /* and keep track of how many bytes do not get sent. */ + output_after = 0; + + /* send buffered OOB writes */ + while (bufchain_size(&p->pending_oob_output_data) > 0) { + bufchain_prefix(&p->pending_oob_output_data, &data, &len); + output_after += sk_write_oob(p->sub_socket, data, len); + bufchain_consume(&p->pending_oob_output_data, len); + } + + /* send buffered normal writes */ + while (bufchain_size(&p->pending_output_data) > 0) { + bufchain_prefix(&p->pending_output_data, &data, &len); + output_after += sk_write(p->sub_socket, data, len); + bufchain_consume(&p->pending_output_data, len); + } + + /* if we managed to send any data, let the higher levels know. */ + if (output_after < output_before) + plug_sent(p->plug, output_after); + + /* if we were asked to flush the output during + * the proxy negotiation process, do so now. + */ + if (p->pending_flush) sk_flush(p->sub_socket); + + /* if we have a pending EOF to send, send it */ + if (p->pending_eof) sk_write_eof(p->sub_socket); + + /* if the backend wanted the socket unfrozen, try to unfreeze. + * our set_frozen handler will flush buffered receive data before + * unfreezing the actual underlying socket. + */ + if (!p->freeze) + sk_set_frozen((Socket)p, 0); +} + +/* basic proxy socket functions */ + +static Plug sk_proxy_plug (Socket s, Plug p) +{ + Proxy_Socket ps = (Proxy_Socket) s; + Plug ret = ps->plug; + if (p) + ps->plug = p; + return ret; +} + +static void sk_proxy_close (Socket s) +{ + Proxy_Socket ps = (Proxy_Socket) s; + + sk_close(ps->sub_socket); + sk_addr_free(ps->remote_addr); + sfree(ps); +} + +static int sk_proxy_write (Socket s, const char *data, int len) +{ + Proxy_Socket ps = (Proxy_Socket) s; + + if (ps->state != PROXY_STATE_ACTIVE) { + bufchain_add(&ps->pending_output_data, data, len); + return bufchain_size(&ps->pending_output_data); + } + return sk_write(ps->sub_socket, data, len); +} + +static int sk_proxy_write_oob (Socket s, const char *data, int len) +{ + Proxy_Socket ps = (Proxy_Socket) s; + + if (ps->state != PROXY_STATE_ACTIVE) { + bufchain_clear(&ps->pending_output_data); + bufchain_clear(&ps->pending_oob_output_data); + bufchain_add(&ps->pending_oob_output_data, data, len); + return len; + } + return sk_write_oob(ps->sub_socket, data, len); +} + +static void sk_proxy_write_eof (Socket s) +{ + Proxy_Socket ps = (Proxy_Socket) s; + + if (ps->state != PROXY_STATE_ACTIVE) { + ps->pending_eof = 1; + return; + } + sk_write_eof(ps->sub_socket); +} + +static void sk_proxy_flush (Socket s) +{ + Proxy_Socket ps = (Proxy_Socket) s; + + if (ps->state != PROXY_STATE_ACTIVE) { + ps->pending_flush = 1; + return; + } + sk_flush(ps->sub_socket); +} + +static void sk_proxy_set_frozen (Socket s, int is_frozen) +{ + Proxy_Socket ps = (Proxy_Socket) s; + + if (ps->state != PROXY_STATE_ACTIVE) { + ps->freeze = is_frozen; + return; + } + + /* handle any remaining buffered recv data first */ + if (bufchain_size(&ps->pending_input_data) > 0) { + ps->freeze = is_frozen; + + /* loop while we still have buffered data, and while we are + * unfrozen. the plug_receive call in the loop could result + * in a call back into this function refreezing the socket, + * so we have to check each time. + */ + while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) { + void *data; + char databuf[512]; + int len; + bufchain_prefix(&ps->pending_input_data, &data, &len); + if (len > lenof(databuf)) + len = lenof(databuf); + memcpy(databuf, data, len); + bufchain_consume(&ps->pending_input_data, len); + plug_receive(ps->plug, 0, databuf, len); + } + + /* if we're still frozen, we'll have to wait for another + * call from the backend to finish unbuffering the data. + */ + if (ps->freeze) return; + } + + sk_set_frozen(ps->sub_socket, is_frozen); +} + +static const char * sk_proxy_socket_error (Socket s) +{ + Proxy_Socket ps = (Proxy_Socket) s; + if (ps->error != NULL || ps->sub_socket == NULL) { + return ps->error; + } + return sk_socket_error(ps->sub_socket); +} + +/* basic proxy plug functions */ + +static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port, + const char *error_msg, int error_code) +{ + Proxy_Plug pp = (Proxy_Plug) plug; + Proxy_Socket ps = pp->proxy_socket; + + plug_log(ps->plug, type, addr, port, error_msg, error_code); +} + +static int plug_proxy_closing (Plug p, const char *error_msg, + int error_code, int calling_back) +{ + Proxy_Plug pp = (Proxy_Plug) p; + Proxy_Socket ps = pp->proxy_socket; + + if (ps->state != PROXY_STATE_ACTIVE) { + ps->closing_error_msg = error_msg; + ps->closing_error_code = error_code; + ps->closing_calling_back = calling_back; + return ps->negotiate(ps, PROXY_CHANGE_CLOSING); + } + return plug_closing(ps->plug, error_msg, + error_code, calling_back); +} + +static int plug_proxy_receive (Plug p, int urgent, char *data, int len) +{ + Proxy_Plug pp = (Proxy_Plug) p; + Proxy_Socket ps = pp->proxy_socket; + + if (ps->state != PROXY_STATE_ACTIVE) { + /* we will lose the urgentness of this data, but since most, + * if not all, of this data will be consumed by the negotiation + * process, hopefully it won't affect the protocol above us + */ + bufchain_add(&ps->pending_input_data, data, len); + ps->receive_urgent = urgent; + ps->receive_data = data; + ps->receive_len = len; + return ps->negotiate(ps, PROXY_CHANGE_RECEIVE); + } + return plug_receive(ps->plug, urgent, data, len); +} + +static void plug_proxy_sent (Plug p, int bufsize) +{ + Proxy_Plug pp = (Proxy_Plug) p; + Proxy_Socket ps = pp->proxy_socket; + + if (ps->state != PROXY_STATE_ACTIVE) { + ps->sent_bufsize = bufsize; + ps->negotiate(ps, PROXY_CHANGE_SENT); + return; + } + plug_sent(ps->plug, bufsize); +} + +static int plug_proxy_accepting(Plug p, + accept_fn_t constructor, accept_ctx_t ctx) +{ + Proxy_Plug pp = (Proxy_Plug) p; + Proxy_Socket ps = pp->proxy_socket; + + if (ps->state != PROXY_STATE_ACTIVE) { + ps->accepting_constructor = constructor; + ps->accepting_ctx = ctx; + return ps->negotiate(ps, PROXY_CHANGE_ACCEPTING); + } + return plug_accepting(ps->plug, constructor, ctx); +} + +/* + * This function can accept a NULL pointer as `addr', in which case + * it will only check the host name. + */ +int proxy_for_destination (SockAddr addr, const char *hostname, + int port, Conf *conf) +{ + int s = 0, e = 0; + char hostip[64]; + int hostip_len, hostname_len; + const char *exclude_list; + + /* + * Special local connections such as Unix-domain sockets + * unconditionally cannot be proxied, even in proxy-localhost + * mode. There just isn't any way to ask any known proxy type for + * them. + */ + if (addr && sk_address_is_special_local(addr)) + return 0; /* do not proxy */ + + /* + * Check the host name and IP against the hard-coded + * representations of `localhost'. + */ + if (!conf_get_int(conf, CONF_even_proxy_localhost) && + (sk_hostname_is_local(hostname) || + (addr && sk_address_is_local(addr)))) + return 0; /* do not proxy */ + + /* we want a string representation of the IP address for comparisons */ + if (addr) { + sk_getaddr(addr, hostip, 64); + hostip_len = strlen(hostip); + } else + hostip_len = 0; /* placate gcc; shouldn't be required */ + + hostname_len = strlen(hostname); + + exclude_list = conf_get_str(conf, CONF_proxy_exclude_list); + + /* now parse the exclude list, and see if either our IP + * or hostname matches anything in it. + */ + + while (exclude_list[s]) { + while (exclude_list[s] && + (isspace((unsigned char)exclude_list[s]) || + exclude_list[s] == ',')) s++; + + if (!exclude_list[s]) break; + + e = s; + + while (exclude_list[e] && + (isalnum((unsigned char)exclude_list[e]) || + exclude_list[e] == '-' || + exclude_list[e] == '.' || + exclude_list[e] == '*')) e++; + + if (exclude_list[s] == '*') { + /* wildcard at beginning of entry */ + + if ((addr && strnicmp(hostip + hostip_len - (e - s - 1), + exclude_list + s + 1, e - s - 1) == 0) || + strnicmp(hostname + hostname_len - (e - s - 1), + exclude_list + s + 1, e - s - 1) == 0) + return 0; /* IP/hostname range excluded. do not use proxy. */ + + } else if (exclude_list[e-1] == '*') { + /* wildcard at end of entry */ + + if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) || + strnicmp(hostname, exclude_list + s, e - s - 1) == 0) + return 0; /* IP/hostname range excluded. do not use proxy. */ + + } else { + /* no wildcard at either end, so let's try an absolute + * match (ie. a specific IP) + */ + + if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0) + return 0; /* IP/hostname excluded. do not use proxy. */ + if (strnicmp(hostname, exclude_list + s, e - s) == 0) + return 0; /* IP/hostname excluded. do not use proxy. */ + } + + s = e; + + /* Make sure we really have reached the next comma or end-of-string */ + while (exclude_list[s] && + !isspace((unsigned char)exclude_list[s]) && + exclude_list[s] != ',') s++; + } + + /* no matches in the exclude list, so use the proxy */ + return 1; +} + +SockAddr name_lookup(char *host, int port, char **canonicalname, + Conf *conf, int addressfamily) +{ + if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE && + do_proxy_dns(conf) && + proxy_for_destination(NULL, host, port, conf)) { + *canonicalname = dupstr(host); + return sk_nonamelookup(host); + } + + return sk_namelookup(host, canonicalname, addressfamily); +} + +Socket new_connection(SockAddr addr, char *hostname, + int port, int privport, + int oobinline, int nodelay, int keepalive, + Plug plug, Conf *conf) +{ + static const struct socket_function_table socket_fn_table = { + sk_proxy_plug, + sk_proxy_close, + sk_proxy_write, + sk_proxy_write_oob, + sk_proxy_write_eof, + sk_proxy_flush, + sk_proxy_set_frozen, + sk_proxy_socket_error + }; + + static const struct plug_function_table plug_fn_table = { + plug_proxy_log, + plug_proxy_closing, + plug_proxy_receive, + plug_proxy_sent, + plug_proxy_accepting + }; + + if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE && + proxy_for_destination(addr, hostname, port, conf)) + { + Proxy_Socket ret; + Proxy_Plug pplug; + SockAddr proxy_addr; + char *proxy_canonical_name; + Socket sret; + int type; + + if ((sret = platform_new_connection(addr, hostname, port, privport, + oobinline, nodelay, keepalive, + plug, conf)) != + NULL) + return sret; + + ret = snew(struct Socket_proxy_tag); + ret->fn = &socket_fn_table; + ret->conf = conf_copy(conf); + ret->plug = plug; + ret->remote_addr = addr; /* will need to be freed on close */ + ret->remote_port = port; + + ret->error = NULL; + ret->pending_flush = 0; + ret->pending_eof = 0; + ret->freeze = 0; + + bufchain_init(&ret->pending_input_data); + bufchain_init(&ret->pending_output_data); + bufchain_init(&ret->pending_oob_output_data); + + ret->sub_socket = NULL; + ret->state = PROXY_STATE_NEW; + ret->negotiate = NULL; + + type = conf_get_int(conf, CONF_proxy_type); + if (type == PROXY_HTTP) { + ret->negotiate = proxy_http_negotiate; + } else if (type == PROXY_SOCKS4) { + ret->negotiate = proxy_socks4_negotiate; + } else if (type == PROXY_SOCKS5) { + ret->negotiate = proxy_socks5_negotiate; + } else if (type == PROXY_TELNET) { + ret->negotiate = proxy_telnet_negotiate; + } else { + ret->error = "Proxy error: Unknown proxy method"; + return (Socket) ret; + } + + /* create the proxy plug to map calls from the actual + * socket into our proxy socket layer */ + pplug = snew(struct Plug_proxy_tag); + pplug->fn = &plug_fn_table; + pplug->proxy_socket = ret; + + /* look-up proxy */ + proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host), + &proxy_canonical_name, + conf_get_int(conf, CONF_addressfamily)); + if (sk_addr_error(proxy_addr) != NULL) { + ret->error = "Proxy error: Unable to resolve proxy host name"; + sfree(pplug); + sk_addr_free(proxy_addr); + return (Socket)ret; + } + sfree(proxy_canonical_name); + + /* create the actual socket we will be using, + * connected to our proxy server and port. + */ + ret->sub_socket = sk_new(proxy_addr, + conf_get_int(conf, CONF_proxy_port), + privport, oobinline, + nodelay, keepalive, (Plug) pplug); + if (sk_socket_error(ret->sub_socket) != NULL) + return (Socket) ret; + + /* start the proxy negotiation process... */ + sk_set_frozen(ret->sub_socket, 0); + ret->negotiate(ret, PROXY_CHANGE_NEW); + + return (Socket) ret; + } + + /* no proxy, so just return the direct socket */ + return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug); +} + +Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only, + Conf *conf, int addressfamily) +{ + /* TODO: SOCKS (and potentially others) support inbound + * TODO: connections via the proxy. support them. + */ + + return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily); +} + +/* ---------------------------------------------------------------------- + * HTTP CONNECT proxy type. + */ + +static int get_line_end (char * data, int len) +{ + int off = 0; + + while (off < len) + { + if (data[off] == '\n') { + /* we have a newline */ + off++; + + /* is that the only thing on this line? */ + if (off <= 2) return off; + + /* if not, then there is the possibility that this header + * continues onto the next line, if it starts with a space + * or a tab. + */ + + if (off + 1 < len && + data[off+1] != ' ' && + data[off+1] != '\t') return off; + + /* the line does continue, so we have to keep going + * until we see an the header's "real" end of line. + */ + off++; + } + + off++; + } + + return -1; +} + +int proxy_http_negotiate (Proxy_Socket p, int change) +{ + if (p->state == PROXY_STATE_NEW) { + /* we are just beginning the proxy negotiate process, + * so we'll send off the initial bits of the request. + * for this proxy method, it's just a simple HTTP + * request + */ + char *buf, dest[512]; + char *username, *password; + + sk_getaddr(p->remote_addr, dest, lenof(dest)); + + buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n", + dest, p->remote_port, dest, p->remote_port); + sk_write(p->sub_socket, buf, strlen(buf)); + sfree(buf); + + username = conf_get_str(p->conf, CONF_proxy_username); + password = conf_get_str(p->conf, CONF_proxy_password); + if (username[0] || password[0]) { + char *buf, *buf2; + int i, j, len; + buf = dupprintf("%s:%s", username, password); + len = strlen(buf); + buf2 = snewn(len * 4 / 3 + 100, char); + sprintf(buf2, "Proxy-Authorization: Basic "); + for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4) + base64_encode_atom((unsigned char *)(buf+i), + (len-i > 3 ? 3 : len-i), buf2+j); + strcpy(buf2+j, "\r\n"); + sk_write(p->sub_socket, buf2, strlen(buf2)); + sfree(buf); + sfree(buf2); + } + + sk_write(p->sub_socket, "\r\n", 2); + + p->state = 1; + return 0; + } + + if (change == PROXY_CHANGE_CLOSING) { + /* if our proxy negotiation process involves closing and opening + * new sockets, then we would want to intercept this closing + * callback when we were expecting it. if we aren't anticipating + * a socket close, then some error must have occurred. we'll + * just pass those errors up to the backend. + */ + return plug_closing(p->plug, p->closing_error_msg, + p->closing_error_code, + p->closing_calling_back); + } + + if (change == PROXY_CHANGE_SENT) { + /* some (or all) of what we wrote to the proxy was sent. + * we don't do anything new, however, until we receive the + * proxy's response. we might want to set a timer so we can + * timeout the proxy negotiation after a while... + */ + return 0; + } + + if (change == PROXY_CHANGE_ACCEPTING) { + /* we should _never_ see this, as we are using our socket to + * connect to a proxy, not accepting inbound connections. + * what should we do? close the socket with an appropriate + * error message? + */ + return plug_accepting(p->plug, + p->accepting_constructor, p->accepting_ctx); + } + + if (change == PROXY_CHANGE_RECEIVE) { + /* we have received data from the underlying socket, which + * we'll need to parse, process, and respond to appropriately. + */ + + char *data, *datap; + int len; + int eol; + + if (p->state == 1) { + + int min_ver, maj_ver, status; + + /* get the status line */ + len = bufchain_size(&p->pending_input_data); + assert(len > 0); /* or we wouldn't be here */ + data = snewn(len+1, char); + bufchain_fetch(&p->pending_input_data, data, len); + /* + * We must NUL-terminate this data, because Windows + * sscanf appears to require a NUL at the end of the + * string because it strlens it _first_. Sigh. + */ + data[len] = '\0'; + + eol = get_line_end(data, len); + if (eol < 0) { + sfree(data); + return 1; + } + + status = -1; + /* We can't rely on whether the %n incremented the sscanf return */ + if (sscanf((char *)data, "HTTP/%i.%i %n", + &maj_ver, &min_ver, &status) < 2 || status == -1) { + plug_closing(p->plug, "Proxy error: HTTP response was absent", + PROXY_ERROR_GENERAL, 0); + sfree(data); + return 1; + } + + /* remove the status line from the input buffer. */ + bufchain_consume(&p->pending_input_data, eol); + if (data[status] != '2') { + /* error */ + char *buf; + data[eol] = '\0'; + while (eol > status && + (data[eol-1] == '\r' || data[eol-1] == '\n')) + data[--eol] = '\0'; + buf = dupprintf("Proxy error: %s", data+status); + plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); + sfree(buf); + sfree(data); + return 1; + } + + sfree(data); + + p->state = 2; + } + + if (p->state == 2) { + + /* get headers. we're done when we get a + * header of length 2, (ie. just "\r\n") + */ + + len = bufchain_size(&p->pending_input_data); + assert(len > 0); /* or we wouldn't be here */ + data = snewn(len, char); + datap = data; + bufchain_fetch(&p->pending_input_data, data, len); + + eol = get_line_end(datap, len); + if (eol < 0) { + sfree(data); + return 1; + } + while (eol > 2) + { + bufchain_consume(&p->pending_input_data, eol); + datap += eol; + len -= eol; + eol = get_line_end(datap, len); + } + + if (eol == 2) { + /* we're done */ + bufchain_consume(&p->pending_input_data, 2); + proxy_activate(p); + /* proxy activate will have dealt with + * whatever is left of the buffer */ + sfree(data); + return 1; + } + + sfree(data); + return 1; + } + } + + plug_closing(p->plug, "Proxy error: unexpected proxy error", + PROXY_ERROR_UNEXPECTED, 0); + return 1; +} + +/* ---------------------------------------------------------------------- + * SOCKS proxy type. + */ + +/* SOCKS version 4 */ +int proxy_socks4_negotiate (Proxy_Socket p, int change) +{ + if (p->state == PROXY_CHANGE_NEW) { + + /* request format: + * version number (1 byte) = 4 + * command code (1 byte) + * 1 = CONNECT + * 2 = BIND + * dest. port (2 bytes) [network order] + * dest. address (4 bytes) + * user ID (variable length, null terminated string) + */ + + int length, type, namelen; + char *command, addr[4], hostname[512]; + char *username; + + type = sk_addrtype(p->remote_addr); + if (type == ADDRTYPE_IPV6) { + p->error = "Proxy error: SOCKS version 4 does not support IPv6"; + return 1; + } else if (type == ADDRTYPE_IPV4) { + namelen = 0; + sk_addrcopy(p->remote_addr, addr); + } else { /* type == ADDRTYPE_NAME */ + assert(type == ADDRTYPE_NAME); + sk_getaddr(p->remote_addr, hostname, lenof(hostname)); + namelen = strlen(hostname) + 1; /* include the NUL */ + addr[0] = addr[1] = addr[2] = 0; + addr[3] = 1; + } + + username = conf_get_str(p->conf, CONF_proxy_username); + length = strlen(username) + namelen + 9; + command = snewn(length, char); + strcpy(command + 8, username); + + command[0] = 4; /* version 4 */ + command[1] = 1; /* CONNECT command */ + + /* port */ + command[2] = (char) (p->remote_port >> 8) & 0xff; + command[3] = (char) p->remote_port & 0xff; + + /* address */ + memcpy(command + 4, addr, 4); + + /* hostname */ + memcpy(command + 8 + strlen(username) + 1, + hostname, namelen); + + sk_write(p->sub_socket, command, length); + sfree(username); + sfree(command); + + p->state = 1; + return 0; + } + + if (change == PROXY_CHANGE_CLOSING) { + /* if our proxy negotiation process involves closing and opening + * new sockets, then we would want to intercept this closing + * callback when we were expecting it. if we aren't anticipating + * a socket close, then some error must have occurred. we'll + * just pass those errors up to the backend. + */ + return plug_closing(p->plug, p->closing_error_msg, + p->closing_error_code, + p->closing_calling_back); + } + + if (change == PROXY_CHANGE_SENT) { + /* some (or all) of what we wrote to the proxy was sent. + * we don't do anything new, however, until we receive the + * proxy's response. we might want to set a timer so we can + * timeout the proxy negotiation after a while... + */ + return 0; + } + + if (change == PROXY_CHANGE_ACCEPTING) { + /* we should _never_ see this, as we are using our socket to + * connect to a proxy, not accepting inbound connections. + * what should we do? close the socket with an appropriate + * error message? + */ + return plug_accepting(p->plug, + p->accepting_constructor, p->accepting_ctx); + } + + if (change == PROXY_CHANGE_RECEIVE) { + /* we have received data from the underlying socket, which + * we'll need to parse, process, and respond to appropriately. + */ + + if (p->state == 1) { + /* response format: + * version number (1 byte) = 4 + * reply code (1 byte) + * 90 = request granted + * 91 = request rejected or failed + * 92 = request rejected due to lack of IDENTD on client + * 93 = request rejected due to difference in user ID + * (what we sent vs. what IDENTD said) + * dest. port (2 bytes) + * dest. address (4 bytes) + */ + + char data[8]; + + if (bufchain_size(&p->pending_input_data) < 8) + return 1; /* not got anything yet */ + + /* get the response */ + bufchain_fetch(&p->pending_input_data, data, 8); + + if (data[0] != 0) { + plug_closing(p->plug, "Proxy error: SOCKS proxy responded with " + "unexpected reply code version", + PROXY_ERROR_GENERAL, 0); + return 1; + } + + if (data[1] != 90) { + + switch (data[1]) { + case 92: + plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client", + PROXY_ERROR_GENERAL, 0); + break; + case 93: + plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree", + PROXY_ERROR_GENERAL, 0); + break; + case 91: + default: + plug_closing(p->plug, "Proxy error: Error while communicating with proxy", + PROXY_ERROR_GENERAL, 0); + break; + } + + return 1; + } + bufchain_consume(&p->pending_input_data, 8); + + /* we're done */ + proxy_activate(p); + /* proxy activate will have dealt with + * whatever is left of the buffer */ + return 1; + } + } + + plug_closing(p->plug, "Proxy error: unexpected proxy error", + PROXY_ERROR_UNEXPECTED, 0); + return 1; +} + +/* SOCKS version 5 */ +int proxy_socks5_negotiate (Proxy_Socket p, int change) +{ + if (p->state == PROXY_CHANGE_NEW) { + + /* initial command: + * version number (1 byte) = 5 + * number of available authentication methods (1 byte) + * available authentication methods (1 byte * previous value) + * authentication methods: + * 0x00 = no authentication + * 0x01 = GSSAPI + * 0x02 = username/password + * 0x03 = CHAP + */ + + char command[5]; + char *username, *password; + int len; + + command[0] = 5; /* version 5 */ + username = conf_get_str(p->conf, CONF_proxy_username); + password = conf_get_str(p->conf, CONF_proxy_password); + if (username[0] || password[0]) { + command[2] = 0x00; /* no authentication */ + len = 3; + proxy_socks5_offerencryptedauth (command, &len); + command[len++] = 0x02; /* username/password */ + command[1] = len - 2; /* Number of methods supported */ + } else { + command[1] = 1; /* one methods supported: */ + command[2] = 0x00; /* no authentication */ + len = 3; + } + + sk_write(p->sub_socket, command, len); + + p->state = 1; + return 0; + } + + if (change == PROXY_CHANGE_CLOSING) { + /* if our proxy negotiation process involves closing and opening + * new sockets, then we would want to intercept this closing + * callback when we were expecting it. if we aren't anticipating + * a socket close, then some error must have occurred. we'll + * just pass those errors up to the backend. + */ + return plug_closing(p->plug, p->closing_error_msg, + p->closing_error_code, + p->closing_calling_back); + } + + if (change == PROXY_CHANGE_SENT) { + /* some (or all) of what we wrote to the proxy was sent. + * we don't do anything new, however, until we receive the + * proxy's response. we might want to set a timer so we can + * timeout the proxy negotiation after a while... + */ + return 0; + } + + if (change == PROXY_CHANGE_ACCEPTING) { + /* we should _never_ see this, as we are using our socket to + * connect to a proxy, not accepting inbound connections. + * what should we do? close the socket with an appropriate + * error message? + */ + return plug_accepting(p->plug, + p->accepting_constructor, p->accepting_ctx); + } + + if (change == PROXY_CHANGE_RECEIVE) { + /* we have received data from the underlying socket, which + * we'll need to parse, process, and respond to appropriately. + */ + + if (p->state == 1) { + + /* initial response: + * version number (1 byte) = 5 + * authentication method (1 byte) + * authentication methods: + * 0x00 = no authentication + * 0x01 = GSSAPI + * 0x02 = username/password + * 0x03 = CHAP + * 0xff = no acceptable methods + */ + char data[2]; + + if (bufchain_size(&p->pending_input_data) < 2) + return 1; /* not got anything yet */ + + /* get the response */ + bufchain_fetch(&p->pending_input_data, data, 2); + + if (data[0] != 5) { + plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version", + PROXY_ERROR_GENERAL, 0); + return 1; + } + + if (data[1] == 0x00) p->state = 2; /* no authentication needed */ + else if (data[1] == 0x01) p->state = 4; /* GSSAPI authentication */ + else if (data[1] == 0x02) p->state = 5; /* username/password authentication */ + else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */ + else { + plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication", + PROXY_ERROR_GENERAL, 0); + return 1; + } + bufchain_consume(&p->pending_input_data, 2); + } + + if (p->state == 7) { + + /* password authentication reply format: + * version number (1 bytes) = 1 + * reply code (1 byte) + * 0 = succeeded + * >0 = failed + */ + char data[2]; + + if (bufchain_size(&p->pending_input_data) < 2) + return 1; /* not got anything yet */ + + /* get the response */ + bufchain_fetch(&p->pending_input_data, data, 2); + + if (data[0] != 1) { + plug_closing(p->plug, "Proxy error: SOCKS password " + "subnegotiation contained wrong version number", + PROXY_ERROR_GENERAL, 0); + return 1; + } + + if (data[1] != 0) { + + plug_closing(p->plug, "Proxy error: SOCKS proxy refused" + " password authentication", + PROXY_ERROR_GENERAL, 0); + return 1; + } + + bufchain_consume(&p->pending_input_data, 2); + p->state = 2; /* now proceed as authenticated */ + } + + if (p->state == 8) { + int ret; + ret = proxy_socks5_handlechap(p); + if (ret) return ret; + } + + if (p->state == 2) { + + /* request format: + * version number (1 byte) = 5 + * command code (1 byte) + * 1 = CONNECT + * 2 = BIND + * 3 = UDP ASSOCIATE + * reserved (1 byte) = 0x00 + * address type (1 byte) + * 1 = IPv4 + * 3 = domainname (first byte has length, no terminating null) + * 4 = IPv6 + * dest. address (variable) + * dest. port (2 bytes) [network order] + */ + + char command[512]; + int len; + int type; + + type = sk_addrtype(p->remote_addr); + if (type == ADDRTYPE_IPV4) { + len = 10; /* 4 hdr + 4 addr + 2 trailer */ + command[3] = 1; /* IPv4 */ + sk_addrcopy(p->remote_addr, command+4); + } else if (type == ADDRTYPE_IPV6) { + len = 22; /* 4 hdr + 16 addr + 2 trailer */ + command[3] = 4; /* IPv6 */ + sk_addrcopy(p->remote_addr, command+4); + } else { + assert(type == ADDRTYPE_NAME); + command[3] = 3; + sk_getaddr(p->remote_addr, command+5, 256); + command[4] = strlen(command+5); + len = 7 + command[4]; /* 4 hdr, 1 len, N addr, 2 trailer */ + } + + command[0] = 5; /* version 5 */ + command[1] = 1; /* CONNECT command */ + command[2] = 0x00; + + /* port */ + command[len-2] = (char) (p->remote_port >> 8) & 0xff; + command[len-1] = (char) p->remote_port & 0xff; + + sk_write(p->sub_socket, command, len); + + p->state = 3; + return 1; + } + + if (p->state == 3) { + + /* reply format: + * version number (1 bytes) = 5 + * reply code (1 byte) + * 0 = succeeded + * 1 = general SOCKS server failure + * 2 = connection not allowed by ruleset + * 3 = network unreachable + * 4 = host unreachable + * 5 = connection refused + * 6 = TTL expired + * 7 = command not supported + * 8 = address type not supported + * reserved (1 byte) = x00 + * address type (1 byte) + * 1 = IPv4 + * 3 = domainname (first byte has length, no terminating null) + * 4 = IPv6 + * server bound address (variable) + * server bound port (2 bytes) [network order] + */ + char data[5]; + int len; + + /* First 5 bytes of packet are enough to tell its length. */ + if (bufchain_size(&p->pending_input_data) < 5) + return 1; /* not got anything yet */ + + /* get the response */ + bufchain_fetch(&p->pending_input_data, data, 5); + + if (data[0] != 5) { + plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number", + PROXY_ERROR_GENERAL, 0); + return 1; + } + + if (data[1] != 0) { + char buf[256]; + + strcpy(buf, "Proxy error: "); + + switch (data[1]) { + case 1: strcat(buf, "General SOCKS server failure"); break; + case 2: strcat(buf, "Connection not allowed by ruleset"); break; + case 3: strcat(buf, "Network unreachable"); break; + case 4: strcat(buf, "Host unreachable"); break; + case 5: strcat(buf, "Connection refused"); break; + case 6: strcat(buf, "TTL expired"); break; + case 7: strcat(buf, "Command not supported"); break; + case 8: strcat(buf, "Address type not supported"); break; + default: sprintf(buf+strlen(buf), + "Unrecognised SOCKS error code %d", + data[1]); + break; + } + plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); + + return 1; + } + + /* + * Eat the rest of the reply packet. + */ + len = 6; /* first 4 bytes, last 2 */ + switch (data[3]) { + case 1: len += 4; break; /* IPv4 address */ + case 4: len += 16; break;/* IPv6 address */ + case 3: len += (unsigned char)data[4]; break; /* domain name */ + default: + plug_closing(p->plug, "Proxy error: SOCKS proxy returned " + "unrecognised address format", + PROXY_ERROR_GENERAL, 0); + return 1; + } + if (bufchain_size(&p->pending_input_data) < len) + return 1; /* not got whole reply yet */ + bufchain_consume(&p->pending_input_data, len); + + /* we're done */ + proxy_activate(p); + return 1; + } + + if (p->state == 4) { + /* TODO: Handle GSSAPI authentication */ + plug_closing(p->plug, "Proxy error: We don't support GSSAPI authentication", + PROXY_ERROR_GENERAL, 0); + return 1; + } + + if (p->state == 5) { + char *username = conf_get_str(p->conf, CONF_proxy_username); + char *password = conf_get_str(p->conf, CONF_proxy_password); + if (username[0] || password[0]) { + char userpwbuf[255 + 255 + 3]; + int ulen, plen; + ulen = strlen(username); + if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1; + plen = strlen(password); + if (plen > 255) plen = 255; if (plen < 1) plen = 1; + userpwbuf[0] = 1; /* version number of subnegotiation */ + userpwbuf[1] = ulen; + memcpy(userpwbuf+2, username, ulen); + userpwbuf[ulen+2] = plen; + memcpy(userpwbuf+ulen+3, password, plen); + sk_write(p->sub_socket, userpwbuf, ulen + plen + 3); + p->state = 7; + } else + plug_closing(p->plug, "Proxy error: Server chose " + "username/password authentication but we " + "didn't offer it!", + PROXY_ERROR_GENERAL, 0); + return 1; + } + + if (p->state == 6) { + int ret; + ret = proxy_socks5_selectchap(p); + if (ret) return ret; + } + + } + + plug_closing(p->plug, "Proxy error: Unexpected proxy error", + PROXY_ERROR_UNEXPECTED, 0); + return 1; +} + +/* ---------------------------------------------------------------------- + * `Telnet' proxy type. + * + * (This is for ad-hoc proxies where you connect to the proxy's + * telnet port and send a command such as `connect host port'. The + * command is configurable, since this proxy type is typically not + * standardised or at all well-defined.) + */ + +char *format_telnet_command(SockAddr addr, int port, Conf *conf) +{ + char *fmt = conf_get_str(conf, CONF_proxy_telnet_command); + char *ret = NULL; + int retlen = 0, retsize = 0; + int so = 0, eo = 0; +#define ENSURE(n) do { \ + if (retsize < retlen + n) { \ + retsize = retlen + n + 512; \ + ret = sresize(ret, retsize, char); \ + } \ +} while (0) + + /* we need to escape \\, \%, \r, \n, \t, \x??, \0???, + * %%, %host, %port, %user, and %pass + */ + + while (fmt[eo] != 0) { + + /* scan forward until we hit end-of-line, + * or an escape character (\ or %) */ + while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\') + eo++; + + /* if we hit eol, break out of our escaping loop */ + if (fmt[eo] == 0) break; + + /* if there was any unescaped text before the escape + * character, send that now */ + if (eo != so) { + ENSURE(eo - so); + memcpy(ret + retlen, fmt + so, eo - so); + retlen += eo - so; + } + + so = eo++; + + /* if the escape character was the last character of + * the line, we'll just stop and send it. */ + if (fmt[eo] == 0) break; + + if (fmt[so] == '\\') { + + /* we recognize \\, \%, \r, \n, \t, \x??. + * anything else, we just send unescaped (including the \). + */ + + switch (fmt[eo]) { + + case '\\': + ENSURE(1); + ret[retlen++] = '\\'; + eo++; + break; + + case '%': + ENSURE(1); + ret[retlen++] = '%'; + eo++; + break; + + case 'r': + ENSURE(1); + ret[retlen++] = '\r'; + eo++; + break; + + case 'n': + ENSURE(1); + ret[retlen++] = '\n'; + eo++; + break; + + case 't': + ENSURE(1); + ret[retlen++] = '\t'; + eo++; + break; + + case 'x': + case 'X': + { + /* escaped hexadecimal value (ie. \xff) */ + unsigned char v = 0; + int i = 0; + + for (;;) { + eo++; + if (fmt[eo] >= '0' && fmt[eo] <= '9') + v += fmt[eo] - '0'; + else if (fmt[eo] >= 'a' && fmt[eo] <= 'f') + v += fmt[eo] - 'a' + 10; + else if (fmt[eo] >= 'A' && fmt[eo] <= 'F') + v += fmt[eo] - 'A' + 10; + else { + /* non hex character, so we abort and just + * send the whole thing unescaped (including \x) + */ + ENSURE(1); + ret[retlen++] = '\\'; + eo = so + 1; + break; + } + + /* we only extract two hex characters */ + if (i == 1) { + ENSURE(1); + ret[retlen++] = v; + eo++; + break; + } + + i++; + v <<= 4; + } + } + break; + + default: + ENSURE(2); + memcpy(ret+retlen, fmt + so, 2); + retlen += 2; + eo++; + break; + } + } else { + + /* % escape. we recognize %%, %host, %port, %user, %pass. + * %proxyhost, %proxyport. Anything else we just send + * unescaped (including the %). + */ + + if (fmt[eo] == '%') { + ENSURE(1); + ret[retlen++] = '%'; + eo++; + } + else if (strnicmp(fmt + eo, "host", 4) == 0) { + char dest[512]; + int destlen; + sk_getaddr(addr, dest, lenof(dest)); + destlen = strlen(dest); + ENSURE(destlen); + memcpy(ret+retlen, dest, destlen); + retlen += destlen; + eo += 4; + } + else if (strnicmp(fmt + eo, "port", 4) == 0) { + char portstr[8], portlen; + portlen = sprintf(portstr, "%i", port); + ENSURE(portlen); + memcpy(ret + retlen, portstr, portlen); + retlen += portlen; + eo += 4; + } + else if (strnicmp(fmt + eo, "user", 4) == 0) { + char *username = conf_get_str(conf, CONF_proxy_username); + int userlen = strlen(username); + ENSURE(userlen); + memcpy(ret+retlen, username, userlen); + retlen += userlen; + eo += 4; + } + else if (strnicmp(fmt + eo, "pass", 4) == 0) { + char *password = conf_get_str(conf, CONF_proxy_password); + int passlen = strlen(password); + ENSURE(passlen); + memcpy(ret+retlen, password, passlen); + retlen += passlen; + eo += 4; + } + else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) { + char *host = conf_get_str(conf, CONF_proxy_host); + int phlen = strlen(host); + ENSURE(phlen); + memcpy(ret+retlen, host, phlen); + retlen += phlen; + eo += 9; + } + else if (strnicmp(fmt + eo, "proxyport", 9) == 0) { + int port = conf_get_int(conf, CONF_proxy_port); + char pport[50]; + int pplen; + sprintf(pport, "%d", port); + pplen = strlen(pport); + ENSURE(pplen); + memcpy(ret+retlen, pport, pplen); + retlen += pplen; + eo += 9; + } + else { + /* we don't escape this, so send the % now, and + * don't advance eo, so that we'll consider the + * text immediately following the % as unescaped. + */ + ENSURE(1); + ret[retlen++] = '%'; + } + } + + /* resume scanning for additional escapes after this one. */ + so = eo; + } + + /* if there is any unescaped text at the end of the line, send it */ + if (eo != so) { + ENSURE(eo - so); + memcpy(ret + retlen, fmt + so, eo - so); + retlen += eo - so; + } + + ENSURE(1); + ret[retlen] = '\0'; + return ret; + +#undef ENSURE +} + +int proxy_telnet_negotiate (Proxy_Socket p, int change) +{ + if (p->state == PROXY_CHANGE_NEW) { + char *formatted_cmd; + + formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port, + p->conf); + + sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd)); + sfree(formatted_cmd); + + p->state = 1; + return 0; + } + + if (change == PROXY_CHANGE_CLOSING) { + /* if our proxy negotiation process involves closing and opening + * new sockets, then we would want to intercept this closing + * callback when we were expecting it. if we aren't anticipating + * a socket close, then some error must have occurred. we'll + * just pass those errors up to the backend. + */ + return plug_closing(p->plug, p->closing_error_msg, + p->closing_error_code, + p->closing_calling_back); + } + + if (change == PROXY_CHANGE_SENT) { + /* some (or all) of what we wrote to the proxy was sent. + * we don't do anything new, however, until we receive the + * proxy's response. we might want to set a timer so we can + * timeout the proxy negotiation after a while... + */ + return 0; + } + + if (change == PROXY_CHANGE_ACCEPTING) { + /* we should _never_ see this, as we are using our socket to + * connect to a proxy, not accepting inbound connections. + * what should we do? close the socket with an appropriate + * error message? + */ + return plug_accepting(p->plug, + p->accepting_constructor, p->accepting_ctx); + } + + if (change == PROXY_CHANGE_RECEIVE) { + /* we have received data from the underlying socket, which + * we'll need to parse, process, and respond to appropriately. + */ + + /* we're done */ + proxy_activate(p); + /* proxy activate will have dealt with + * whatever is left of the buffer */ + return 1; + } + + plug_closing(p->plug, "Proxy error: Unexpected proxy error", + PROXY_ERROR_UNEXPECTED, 0); + return 1; +} |