+ c->type = SSH_CHANNEL_OPEN;
+ debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
+ }
+}
+
+static void
+channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
+{
+ if (c->istate == CHAN_INPUT_OPEN &&
+ buffer_check_alloc(&c->input, CHAN_RBUF))
+ FD_SET(c->rfd, readset);
+ if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
+ /* clear buffer immediately (discard any partial packet) */
+ buffer_clear(&c->input);
+ chan_ibuf_empty(c);
+ /* Start output drain. XXX just kill chan? */
+ chan_rcvd_oclose(c);
+ }
+ if (c->ostate == CHAN_OUTPUT_OPEN ||
+ c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
+ if (buffer_len(&c->output) > 0)
+ FD_SET(c->wfd, writeset);
+ else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
+ chan_obuf_empty(c);
+ }
+}
+
+/* try to decode a socks4 header */
+/* ARGSUSED */
+static int
+channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
+{
+ char *p, *host;
+ u_int len, have, i, found, need;
+ char username[256];
+ struct {
+ u_int8_t version;
+ u_int8_t command;
+ u_int16_t dest_port;
+ struct in_addr dest_addr;
+ } s4_req, s4_rsp;
+
+ debug2("channel %d: decode socks4", c->self);
+
+ have = buffer_len(&c->input);
+ len = sizeof(s4_req);
+ if (have < len)
+ return 0;
+ p = buffer_ptr(&c->input);
+
+ need = 1;
+ /* SOCKS4A uses an invalid IP address 0.0.0.x */
+ if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
+ debug2("channel %d: socks4a request", c->self);
+ /* ... and needs an extra string (the hostname) */
+ need = 2;
+ }
+ /* Check for terminating NUL on the string(s) */
+ for (found = 0, i = len; i < have; i++) {
+ if (p[i] == '\0') {
+ found++;
+ if (found == need)
+ break;
+ }
+ if (i > 1024) {
+ /* the peer is probably sending garbage */
+ debug("channel %d: decode socks4: too long",
+ c->self);
+ return -1;
+ }
+ }
+ if (found < need)
+ return 0;
+ buffer_get(&c->input, (char *)&s4_req.version, 1);
+ buffer_get(&c->input, (char *)&s4_req.command, 1);
+ buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
+ buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
+ have = buffer_len(&c->input);
+ p = buffer_ptr(&c->input);
+ len = strlen(p);
+ debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
+ len++; /* trailing '\0' */
+ if (len > have)
+ fatal("channel %d: decode socks4: len %d > have %d",
+ c->self, len, have);
+ strlcpy(username, p, sizeof(username));
+ buffer_consume(&c->input, len);
+
+ if (c->path != NULL) {
+ xfree(c->path);
+ c->path = NULL;
+ }
+ if (need == 1) { /* SOCKS4: one string */
+ host = inet_ntoa(s4_req.dest_addr);
+ c->path = xstrdup(host);
+ } else { /* SOCKS4A: two strings */
+ have = buffer_len(&c->input);
+ p = buffer_ptr(&c->input);
+ len = strlen(p);
+ debug2("channel %d: decode socks4a: host %s/%d",
+ c->self, p, len);
+ len++; /* trailing '\0' */
+ if (len > have)
+ fatal("channel %d: decode socks4a: len %d > have %d",
+ c->self, len, have);
+ if (len > NI_MAXHOST) {
+ error("channel %d: hostname \"%.100s\" too long",
+ c->self, p);
+ return -1;
+ }
+ c->path = xstrdup(p);
+ buffer_consume(&c->input, len);
+ }
+ c->host_port = ntohs(s4_req.dest_port);
+
+ debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
+ c->self, c->path, c->host_port, s4_req.command);
+
+ if (s4_req.command != 1) {
+ debug("channel %d: cannot handle: %s cn %d",
+ c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
+ return -1;
+ }
+ s4_rsp.version = 0; /* vn: 0 for reply */
+ s4_rsp.command = 90; /* cd: req granted */
+ s4_rsp.dest_port = 0; /* ignored */
+ s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
+ buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
+ return 1;
+}
+
+/* try to decode a socks5 header */
+#define SSH_SOCKS5_AUTHDONE 0x1000
+#define SSH_SOCKS5_NOAUTH 0x00
+#define SSH_SOCKS5_IPV4 0x01
+#define SSH_SOCKS5_DOMAIN 0x03
+#define SSH_SOCKS5_IPV6 0x04
+#define SSH_SOCKS5_CONNECT 0x01
+#define SSH_SOCKS5_SUCCESS 0x00
+
+/* ARGSUSED */
+static int
+channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
+{
+ struct {
+ u_int8_t version;
+ u_int8_t command;
+ u_int8_t reserved;
+ u_int8_t atyp;
+ } s5_req, s5_rsp;
+ u_int16_t dest_port;
+ u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
+ u_int have, need, i, found, nmethods, addrlen, af;
+
+ debug2("channel %d: decode socks5", c->self);
+ p = buffer_ptr(&c->input);
+ if (p[0] != 0x05)
+ return -1;
+ have = buffer_len(&c->input);
+ if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
+ /* format: ver | nmethods | methods */
+ if (have < 2)
+ return 0;
+ nmethods = p[1];
+ if (have < nmethods + 2)
+ return 0;
+ /* look for method: "NO AUTHENTICATION REQUIRED" */
+ for (found = 0, i = 2; i < nmethods + 2; i++) {
+ if (p[i] == SSH_SOCKS5_NOAUTH) {
+ found = 1;
+ break;
+ }
+ }
+ if (!found) {
+ debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
+ c->self);
+ return -1;
+ }
+ buffer_consume(&c->input, nmethods + 2);
+ buffer_put_char(&c->output, 0x05); /* version */
+ buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
+ FD_SET(c->sock, writeset);
+ c->flags |= SSH_SOCKS5_AUTHDONE;
+ debug2("channel %d: socks5 auth done", c->self);
+ return 0; /* need more */
+ }
+ debug2("channel %d: socks5 post auth", c->self);
+ if (have < sizeof(s5_req)+1)
+ return 0; /* need more */
+ memcpy(&s5_req, p, sizeof(s5_req));
+ if (s5_req.version != 0x05 ||
+ s5_req.command != SSH_SOCKS5_CONNECT ||
+ s5_req.reserved != 0x00) {
+ debug2("channel %d: only socks5 connect supported", c->self);
+ return -1;
+ }
+ switch (s5_req.atyp){
+ case SSH_SOCKS5_IPV4:
+ addrlen = 4;
+ af = AF_INET;
+ break;
+ case SSH_SOCKS5_DOMAIN:
+ addrlen = p[sizeof(s5_req)];
+ af = -1;
+ break;
+ case SSH_SOCKS5_IPV6:
+ addrlen = 16;
+ af = AF_INET6;
+ break;
+ default:
+ debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
+ return -1;
+ }
+ need = sizeof(s5_req) + addrlen + 2;
+ if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
+ need++;
+ if (have < need)
+ return 0;
+ buffer_consume(&c->input, sizeof(s5_req));
+ if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
+ buffer_consume(&c->input, 1); /* host string length */
+ buffer_get(&c->input, (char *)&dest_addr, addrlen);
+ buffer_get(&c->input, (char *)&dest_port, 2);
+ dest_addr[addrlen] = '\0';
+ if (c->path != NULL) {
+ xfree(c->path);
+ c->path = NULL;
+ }
+ if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
+ if (addrlen >= NI_MAXHOST) {
+ error("channel %d: dynamic request: socks5 hostname "
+ "\"%.100s\" too long", c->self, dest_addr);
+ return -1;
+ }
+ c->path = xstrdup(dest_addr);
+ } else {
+ if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
+ return -1;
+ c->path = xstrdup(ntop);
+ }
+ c->host_port = ntohs(dest_port);
+
+ debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
+ c->self, c->path, c->host_port, s5_req.command);
+
+ s5_rsp.version = 0x05;
+ s5_rsp.command = SSH_SOCKS5_SUCCESS;
+ s5_rsp.reserved = 0; /* ignored */
+ s5_rsp.atyp = SSH_SOCKS5_IPV4;
+ ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
+ dest_port = 0; /* ignored */
+
+ buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
+ buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
+ buffer_append(&c->output, &dest_port, sizeof(dest_port));
+ return 1;
+}
+
+Channel *
+channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
+ int in, int out)
+{
+ Channel *c;
+
+ debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
+ port_to_connect);
+
+ c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
+ -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
+ 0, "stdio-forward", /*nonblock*/0);
+
+ c->path = xstrdup(host_to_connect);
+ c->host_port = port_to_connect;
+ c->listening_port = 0;
+ c->force_drain = 1;
+
+ channel_register_fds(c, in, out, -1, 0, 1, 0);
+ port_open_helper(c, "direct-tcpip");
+
+ return c;
+}
+
+/* dynamic port forwarding */
+static void
+channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
+{
+ u_char *p;
+ u_int have;
+ int ret;
+
+ have = buffer_len(&c->input);
+ debug2("channel %d: pre_dynamic: have %d", c->self, have);
+ /* buffer_dump(&c->input); */
+ /* check if the fixed size part of the packet is in buffer. */
+ if (have < 3) {
+ /* need more */
+ FD_SET(c->sock, readset);
+ return;
+ }
+ /* try to guess the protocol */
+ p = buffer_ptr(&c->input);
+ switch (p[0]) {
+ case 0x04:
+ ret = channel_decode_socks4(c, readset, writeset);
+ break;
+ case 0x05:
+ ret = channel_decode_socks5(c, readset, writeset);
+ break;
+ default:
+ ret = -1;
+ break;
+ }
+ if (ret < 0) {
+ chan_mark_dead(c);
+ } else if (ret == 0) {
+ debug2("channel %d: pre_dynamic: need more", c->self);
+ /* need more */
+ FD_SET(c->sock, readset);
+ } else {
+ /* switch to the next state */
+ c->type = SSH_CHANNEL_OPENING;
+ port_open_helper(c, "direct-tcpip");