diff options
Diffstat (limited to 'tools/plink/proxy.c')
| -rw-r--r-- | tools/plink/proxy.c | 1478 |
1 files changed, 1478 insertions, 0 deletions
diff --git a/tools/plink/proxy.c b/tools/plink/proxy.c new file mode 100644 index 000000000..1f4299951 --- /dev/null +++ b/tools/plink/proxy.c @@ -0,0 +1,1478 @@ +/*
+ * 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(cfg) \
+ (cfg->proxy_dns == FORCE_ON || \
+ (cfg->proxy_dns == AUTO && cfg->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 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_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,
+ const Config *cfg)
+{
+ 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 (!cfg->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 = cfg->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,
+ const Config *cfg, int addressfamily)
+{
+ if (cfg->proxy_type != PROXY_NONE &&
+ do_proxy_dns(cfg) &&
+ proxy_for_destination(NULL, host, port, cfg)) {
+ *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, const Config *cfg)
+{
+ static const struct socket_function_table socket_fn_table = {
+ sk_proxy_plug,
+ sk_proxy_close,
+ sk_proxy_write,
+ sk_proxy_write_oob,
+ 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 (cfg->proxy_type != PROXY_NONE &&
+ proxy_for_destination(addr, hostname, port, cfg))
+ {
+ Proxy_Socket ret;
+ Proxy_Plug pplug;
+ SockAddr proxy_addr;
+ char *proxy_canonical_name;
+ Socket sret;
+
+ if ((sret = platform_new_connection(addr, hostname, port, privport,
+ oobinline, nodelay, keepalive,
+ plug, cfg)) !=
+ NULL)
+ return sret;
+
+ ret = snew(struct Socket_proxy_tag);
+ ret->fn = &socket_fn_table;
+ ret->cfg = *cfg; /* STRUCTURE COPY */
+ 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->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;
+
+ if (cfg->proxy_type == PROXY_HTTP) {
+ ret->negotiate = proxy_http_negotiate;
+ } else if (cfg->proxy_type == PROXY_SOCKS4) {
+ ret->negotiate = proxy_socks4_negotiate;
+ } else if (cfg->proxy_type == PROXY_SOCKS5) {
+ ret->negotiate = proxy_socks5_negotiate;
+ } else if (cfg->proxy_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(cfg->proxy_host,
+ &proxy_canonical_name, cfg->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, cfg->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,
+ const Config *cfg, 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];
+
+ 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);
+
+ if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
+ char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
+ char buf2[sizeof(buf)*4/3 + 100];
+ int i, j, len;
+ sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
+ len = strlen(buf);
+ 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));
+ }
+
+ 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];
+
+ 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;
+ }
+
+ length = strlen(p->cfg.proxy_username) + namelen + 9;
+ command = snewn(length, char);
+ strcpy(command + 8, p->cfg.proxy_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(p->cfg.proxy_username) + 1,
+ hostname, namelen);
+
+ sk_write(p->sub_socket, command, length);
+ 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];
+ int len;
+
+ command[0] = 5; /* version 5 */
+ if (p->cfg.proxy_username[0] || p->cfg.proxy_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) {
+ if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
+ char userpwbuf[514];
+ int ulen, plen;
+ ulen = strlen(p->cfg.proxy_username);
+ if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
+ plen = strlen(p->cfg.proxy_password);
+ if (plen > 255) plen = 255; if (plen < 1) plen = 1;
+ userpwbuf[0] = 1; /* version number of subnegotiation */
+ userpwbuf[1] = ulen;
+ memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
+ userpwbuf[ulen+2] = plen;
+ memcpy(userpwbuf+ulen+3, p->cfg.proxy_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, const Config *cfg)
+{
+ 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 (cfg->proxy_telnet_command[eo] != 0) {
+
+ /* scan forward until we hit end-of-line,
+ * or an escape character (\ or %) */
+ while (cfg->proxy_telnet_command[eo] != 0 &&
+ cfg->proxy_telnet_command[eo] != '%' &&
+ cfg->proxy_telnet_command[eo] != '\\') eo++;
+
+ /* if we hit eol, break out of our escaping loop */
+ if (cfg->proxy_telnet_command[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, cfg->proxy_telnet_command + 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 (cfg->proxy_telnet_command[eo] == 0) break;
+
+ if (cfg->proxy_telnet_command[so] == '\\') {
+
+ /* we recognize \\, \%, \r, \n, \t, \x??.
+ * anything else, we just send unescaped (including the \).
+ */
+
+ switch (cfg->proxy_telnet_command[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 (cfg->proxy_telnet_command[eo] >= '0' &&
+ cfg->proxy_telnet_command[eo] <= '9')
+ v += cfg->proxy_telnet_command[eo] - '0';
+ else if (cfg->proxy_telnet_command[eo] >= 'a' &&
+ cfg->proxy_telnet_command[eo] <= 'f')
+ v += cfg->proxy_telnet_command[eo] - 'a' + 10;
+ else if (cfg->proxy_telnet_command[eo] >= 'A' &&
+ cfg->proxy_telnet_command[eo] <= 'F')
+ v += cfg->proxy_telnet_command[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, cfg->proxy_telnet_command + 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 (cfg->proxy_telnet_command[eo] == '%') {
+ ENSURE(1);
+ ret[retlen++] = '%';
+ eo++;
+ }
+ else if (strnicmp(cfg->proxy_telnet_command + 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(cfg->proxy_telnet_command + 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(cfg->proxy_telnet_command + eo,
+ "user", 4) == 0) {
+ int userlen = strlen(cfg->proxy_username);
+ ENSURE(userlen);
+ memcpy(ret+retlen, cfg->proxy_username, userlen);
+ retlen += userlen;
+ eo += 4;
+ }
+ else if (strnicmp(cfg->proxy_telnet_command + eo,
+ "pass", 4) == 0) {
+ int passlen = strlen(cfg->proxy_password);
+ ENSURE(passlen);
+ memcpy(ret+retlen, cfg->proxy_password, passlen);
+ retlen += passlen;
+ eo += 4;
+ }
+ else if (strnicmp(cfg->proxy_telnet_command + eo,
+ "proxyhost", 9) == 0) {
+ int phlen = strlen(cfg->proxy_host);
+ ENSURE(phlen);
+ memcpy(ret+retlen, cfg->proxy_host, phlen);
+ retlen += phlen;
+ eo += 9;
+ }
+ else if (strnicmp(cfg->proxy_telnet_command + eo,
+ "proxyport", 9) == 0) {
+ char pport[50];
+ int pplen;
+ sprintf(pport, "%d", cfg->proxy_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, cfg->proxy_telnet_command + 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->cfg);
+
+ 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;
+}
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