- if (getpeereid(client_fd, &euid, &egid) < 0) {
- error("%s getpeereid failed: %s", __func__, strerror(errno));
- close(client_fd);
- return;
- }
- if ((euid != 0) && (getuid() != euid)) {
- error("control mode uid mismatch: peer euid %u != uid %u",
- (u_int) euid, (u_int) getuid());
- close(client_fd);
- return;
- }
-
- unset_nonblock(client_fd);
-
- /* Read command */
- buffer_init(&m);
- if (ssh_msg_recv(client_fd, &m) == -1) {
- error("%s: client msg_recv failed", __func__);
- close(client_fd);
- buffer_free(&m);
- return;
- }
- if ((ver = buffer_get_char(&m)) != SSHMUX_VER) {
- error("%s: wrong client version %d", __func__, ver);
- buffer_free(&m);
- close(client_fd);
- return;
- }
-
- allowed = 1;
- command = buffer_get_int(&m);
- flags = buffer_get_int(&m);
-
- buffer_clear(&m);
-
- switch (command) {
- case SSHMUX_COMMAND_OPEN:
- if (options.control_master == SSHCTL_MASTER_ASK ||
- options.control_master == SSHCTL_MASTER_AUTO_ASK)
- allowed = ask_permission("Allow shared connection "
- "to %s? ", host);
- /* continue below */
- break;
- case SSHMUX_COMMAND_TERMINATE:
- if (options.control_master == SSHCTL_MASTER_ASK ||
- options.control_master == SSHCTL_MASTER_AUTO_ASK)
- allowed = ask_permission("Terminate shared connection "
- "to %s? ", host);
- if (allowed)
- quit_pending = 1;
- /* FALLTHROUGH */
- case SSHMUX_COMMAND_ALIVE_CHECK:
- /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */
- buffer_clear(&m);
- buffer_put_int(&m, allowed);
- buffer_put_int(&m, getpid());
- if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
- error("%s: client msg_send failed", __func__);
- close(client_fd);
- buffer_free(&m);
- return;
- }
- buffer_free(&m);
- close(client_fd);
- return;
- default:
- error("Unsupported command %d", command);
- buffer_free(&m);
- close(client_fd);
- return;
- }
-
- /* Reply for SSHMUX_COMMAND_OPEN */
- buffer_clear(&m);
- buffer_put_int(&m, allowed);
- buffer_put_int(&m, getpid());
- if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
- error("%s: client msg_send failed", __func__);
- close(client_fd);
- buffer_free(&m);
- return;
- }
-
- if (!allowed) {
- error("Refused control connection");
- close(client_fd);
- buffer_free(&m);
- return;
- }
-
- buffer_clear(&m);
- if (ssh_msg_recv(client_fd, &m) == -1) {
- error("%s: client msg_recv failed", __func__);
- close(client_fd);
- buffer_free(&m);
- return;
- }
- if ((ver = buffer_get_char(&m)) != SSHMUX_VER) {
- error("%s: wrong client version %d", __func__, ver);
- buffer_free(&m);
- close(client_fd);
- return;
- }
-
- cctx = xcalloc(1, sizeof(*cctx));
- cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
- cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
- cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0;
- cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0;
- cctx->term = buffer_get_string(&m, &len);
-
- cmd = buffer_get_string(&m, &len);
- buffer_init(&cctx->cmd);
- buffer_append(&cctx->cmd, cmd, strlen(cmd));
-
- env_len = buffer_get_int(&m);
- env_len = MIN(env_len, 4096);
- debug3("%s: receiving %d env vars", __func__, env_len);
- if (env_len != 0) {
- cctx->env = xcalloc(env_len + 1, sizeof(*cctx->env));
- for (i = 0; i < env_len; i++)
- cctx->env[i] = buffer_get_string(&m, &len);
- cctx->env[i] = NULL;
- }
-
- debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
- cctx->want_tty, cctx->want_subsys, cmd);
- xfree(cmd);
-
- /* Gather fds from client */
- new_fd[0] = mm_receive_fd(client_fd);
- new_fd[1] = mm_receive_fd(client_fd);
- new_fd[2] = mm_receive_fd(client_fd);
-
- debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
- new_fd[0], new_fd[1], new_fd[2]);
-
- /* Try to pick up ttymodes from client before it goes raw */
- if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
- error("%s: tcgetattr: %s", __func__, strerror(errno));
-
- /* This roundtrip is just for synchronisation of ttymodes */
- buffer_clear(&m);
- if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) {
- error("%s: client msg_send failed", __func__);
- close(client_fd);
- close(new_fd[0]);
- close(new_fd[1]);
- close(new_fd[2]);
- buffer_free(&m);
- xfree(cctx->term);
- if (env_len != 0) {
- for (i = 0; i < env_len; i++)
- xfree(cctx->env[i]);
- xfree(cctx->env);
- }
- return;
- }
- buffer_free(&m);
-
- /* enable nonblocking unless tty */
- if (!isatty(new_fd[0]))
- set_nonblock(new_fd[0]);
- if (!isatty(new_fd[1]))
- set_nonblock(new_fd[1]);
- if (!isatty(new_fd[2]))
- set_nonblock(new_fd[2]);
-
- set_nonblock(client_fd);
-
- c = channel_new("session", SSH_CHANNEL_OPENING,
- new_fd[0], new_fd[1], new_fd[2],
- CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
- CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
-
- /* XXX */
- c->ctl_fd = client_fd;
-
- debug3("%s: channel_new: %d", __func__, c->self);
-
- channel_send_open(c->self);
- channel_register_confirm(c->self, client_extra_session2_setup, cctx);