/** * xrdp: A Remote Desktop Protocol server. * * Copyright (C) Jay Sorg 2004-2015 * * BSD process grouping by: * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland. * Copyright (c) 2000-2001 Markus Friedl. * Copyright (c) 2011-2015 Koichiro Iwao, Kyushu Institute of Technology. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** * * @file session.c * @brief Session management code * @author Jay Sorg, Simone Fedele * */ #if defined(HAVE_CONFIG_H) #include "config_ac.h" #endif #include #include "arch.h" #include "session.h" #include "sesman_auth.h" #include "sesman_config.h" #include "env.h" #include "guid.h" #include "list.h" #include "log.h" #include "login_info.h" #include "os_calls.h" #include "sesexec.h" #include "string_calls.h" #include "xauth.h" #include "xwait.h" #include "xrdp_sockets.h" struct session_data { pid_t x_server; ///< PID of X server pid_t win_mgr; ///< PID of window manager pid_t chansrv; //< PID of chansrv time_t start_time; struct session_parameters params; // Flexible array member used to store strings in params and ip_addr; #ifdef __cplusplus char strings[1]; #else char strings[]; #endif }; /******************************************************************************/ /** * Create a new session_data structure from a session_parameters object * * @param sp Session parameters passed to session_start() * @return semi-initialised session_data struct */ static struct session_data * session_data_new(const struct session_parameters *sp) { unsigned int string_length = 0; // What string length do we need? string_length += g_strlen(sp->shell) + 1; string_length += g_strlen(sp->directory) + 1; struct session_data *sd = (struct session_data *)g_malloc(sizeof(*sd) + string_length, 0); if (sd == NULL) { LOG(LOG_LEVEL_ERROR, "Out of memory allocating session data struct"); } else { sd->win_mgr = -1; sd->x_server = -1; sd->chansrv = -1; sd->start_time = 0; /* Copy all the non-string session parameters... */ sd->params = *sp; /* ...and then the strings */ char *memptr = sd->strings; #define COPY_STRING(dest,src) \ (dest) = memptr; \ strcpy(memptr, src); \ memptr += strlen(memptr) + 1 COPY_STRING(sd->params.shell, sp->shell); COPY_STRING(sd->params.directory, sp->directory); #undef COPY_STRING } return sd; } /******************************************************************************/ void session_data_free(struct session_data *session_data) { if (session_data != NULL) { #ifdef USE_DEVEL_LOGGING if (session_data->win_mgr > 0) { LOG_DEVEL(LOG_LEVEL_WARNING, "Freeing session data with valid window manager PID %d", session_data->win_mgr); } if (session_data->x_server > 0) { LOG_DEVEL(LOG_LEVEL_WARNING, "Freeing session data with valid X server PID %d", session_data->x_server); } if (session_data->chansrv > 0) { LOG_DEVEL(LOG_LEVEL_WARNING, "Freeing session data with valid chansrv PID %d", session_data->chansrv); } #endif free(session_data); } } /******************************************************************************/ /** * Creates a string consisting of all parameters that is hosted in the param list * @param self * @param outstr, allocate this buffer before you use this function * @param len the allocated len for outstr * @return */ char * dumpItemsToString(struct list *self, char *outstr, int len) { int index; int totalLen = 0; g_memset(outstr, 0, len); if (self->count == 0) { LOG_DEVEL(LOG_LEVEL_TRACE, "List is empty"); } for (index = 0; index < self->count; index++) { /* +1 = one space*/ totalLen = totalLen + g_strlen((char *)list_get_item(self, index)) + 1; if (len > totalLen) { g_strcat(outstr, (char *)list_get_item(self, index)); g_strcat(outstr, " "); } } return outstr ; } /******************************************************************************/ static void start_chansrv(struct login_info *login_info, const struct session_parameters *s) { struct list *chansrv_params = list_create(); const char *exe_path = XRDP_SBIN_PATH "/xrdp-chansrv"; if (chansrv_params != NULL) { chansrv_params->auto_free = 1; if (!list_add_strdup(chansrv_params, exe_path)) { list_delete(chansrv_params); chansrv_params = NULL; } } if (chansrv_params == NULL) { LOG(LOG_LEVEL_ERROR, "Out of memory starting chansrv"); } else { env_set_user(login_info->uid, 0, s->display, g_cfg->env_names, g_cfg->env_values); LOG_DEVEL_LEAKING_FDS("chansrv", 3, -1); /* executing chansrv */ g_execvp_list(exe_path, chansrv_params); /* should not get here */ list_delete(chansrv_params); } } /******************************************************************************/ static void start_window_manager(struct login_info *login_info, const struct session_parameters *s) { char text[256]; env_set_user(login_info->uid, 0, s->display, g_cfg->env_names, g_cfg->env_values); auth_set_env(login_info->auth_info); LOG_DEVEL_LEAKING_FDS("window manager", 3, -1); if (s->directory[0] != '\0') { if (g_cfg->sec.allow_alternate_shell) { g_set_current_dir(s->directory); } else { LOG(LOG_LEVEL_WARNING, "Directory change to %s requested, but not " "allowed by AllowAlternateShell config value.", s->directory); } } if (s->shell[0] != '\0') { if (g_cfg->sec.allow_alternate_shell) { if (g_strchr(s->shell, ' ') != 0 || g_strchr(s->shell, '\t') != 0) { LOG(LOG_LEVEL_INFO, "Using user requested window manager on " "display %u with embedded arguments using a shell: %s", s->display, s->shell); const char *argv[] = {"sh", "-c", s->shell, NULL}; g_execvp("/bin/sh", (char **)argv); } else { LOG(LOG_LEVEL_INFO, "Using user requested window manager on " "display %d: %s", s->display, s->shell); g_execlp3(s->shell, s->shell, 0); } } else { LOG(LOG_LEVEL_WARNING, "Shell %s requested by user, but not allowed by " "AllowAlternateShell config value.", s->shell); } } else { LOG(LOG_LEVEL_DEBUG, "The user session on display %u did " "not request a specific window manager", s->display); } /* try to execute user window manager if enabled */ if (g_cfg->enable_user_wm) { g_snprintf(text, sizeof(text), "%s/%s", g_getenv("HOME"), g_cfg->user_wm); if (g_file_exist(text)) { LOG(LOG_LEVEL_INFO, "Using window manager on display %u" " from user home directory: %s", s->display, text); g_execlp3(text, g_cfg->user_wm, 0); } else { LOG(LOG_LEVEL_DEBUG, "The user home directory window manager configuration " "is enabled but window manager program does not exist: %s", text); } } LOG(LOG_LEVEL_INFO, "Using the default window manager on display %u: %s", s->display, g_cfg->default_wm); g_execlp3(g_cfg->default_wm, g_cfg->default_wm, 0); /* still a problem starting window manager just start xterm */ LOG(LOG_LEVEL_WARNING, "No window manager on display %u started, " "so falling back to starting xterm for user debugging", s->display); g_execlp3("xterm", "xterm", 0); /* should not get here */ LOG(LOG_LEVEL_ERROR, "A fatal error has occurred attempting to start " "the window manager on display %u, aborting connection", s->display); } /******************************************************************************/ static struct list * prepare_xorg_xserver_params(const struct session_parameters *s, const char *authfile) { char screen[32]; /* display number */ char text[128]; const char *xserver; struct list *params = list_create(); if (params != NULL) { params->auto_free = 1; /* * Make sure Xorg doesn't run setuid root. Root access is not * needed. Xorg can fail when run as root and the user has no * console permissions. */ if (g_cfg->sec.xorg_no_new_privileges && g_no_new_privs() != 0) { LOG(LOG_LEVEL_WARNING, "[session start] (display %u): Failed to disable " "setuid on X server: %s", s->display, g_get_strerror()); } g_snprintf(screen, sizeof(screen), ":%u", s->display); /* some args are passed via env vars */ g_snprintf(text, sizeof(text), "%d", s->width); g_setenv("XRDP_START_WIDTH", text, 1); g_snprintf(text, sizeof(text), "%d", s->height); g_setenv("XRDP_START_HEIGHT", text, 1); g_snprintf(text, sizeof(text), "%d", g_cfg->sess.max_idle_time); g_setenv("XRDP_SESMAN_MAX_IDLE_TIME", text, 1); g_snprintf(text, sizeof(text), "%d", g_cfg->sess.max_disc_time); g_setenv("XRDP_SESMAN_MAX_DISC_TIME", text, 1); g_snprintf(text, sizeof(text), "%d", g_cfg->sess.kill_disconnected); g_setenv("XRDP_SESMAN_KILL_DISCONNECTED", text, 1); /* get path of Xorg from config */ xserver = (const char *)list_get_item(g_cfg->xorg_params, 0); /* these are the must have parameters */ list_add_strdup_multi(params, xserver, screen, "-auth", authfile, NULL); /* additional parameters from sesman.ini file */ list_append_list_strdup(g_cfg->xorg_params, params, 1); } return params; } /******************************************************************************/ static struct list * prepare_xvnc_xserver_params(const struct session_parameters *s, const char *authfile, const char *passwd_file) { char screen[32] = {0}; /* display number */ char geometry[32] = {0}; char depth[32] = {0}; char guid_str[GUID_STR_SIZE]; const char *xserver; struct list *params = list_create(); if (params != NULL) { params->auto_free = 1; g_snprintf(screen, sizeof(screen), ":%u", s->display); g_snprintf(geometry, sizeof(geometry), "%dx%d", s->width, s->height); g_snprintf(depth, sizeof(depth), "%d", s->bpp); guid_to_str(&s->guid, guid_str); env_check_password_file(passwd_file, guid_str); /* get path of Xvnc from config */ xserver = (const char *)list_get_item(g_cfg->vnc_params, 0); /* these are the must have parameters */ list_add_strdup_multi(params, xserver, screen, "-auth", authfile, "-geometry", geometry, "-depth", depth, "-rfbauth", passwd_file, NULL); /* additional parameters from sesman.ini file */ //config_read_xserver_params(SCP_SESSION_TYPE_XVNC, // xserver_params); list_append_list_strdup(g_cfg->vnc_params, params, 1); } return params; } /******************************************************************************/ /* Either execs the X server, or returns */ static void start_x_server(struct login_info *login_info, const struct session_parameters *s) { char authfile[256]; /* The filename for storing xauth information */ char execvpparams[2048]; char *passwd_file = NULL; struct list *xserver_params = NULL; int unknown_session_type = 0; if (s->type == SCP_SESSION_TYPE_XVNC) { env_set_user(login_info->uid, &passwd_file, s->display, g_cfg->env_names, g_cfg->env_values); } else { env_set_user(login_info->uid, 0, s->display, g_cfg->env_names, g_cfg->env_values); } /* prepare the Xauthority stuff */ if (g_getenv("XAUTHORITY") != NULL) { g_snprintf(authfile, sizeof(authfile), "%s", g_getenv("XAUTHORITY")); } else { g_snprintf(authfile, sizeof(authfile), "%s", ".Xauthority"); } /* Add the entry in XAUTHORITY file or exit if error */ if (add_xauth_cookie(s->display, authfile) != 0) { LOG(LOG_LEVEL_ERROR, "Error setting the xauth cookie for display %u in file %s", s->display, authfile); } else { switch (s->type) { case SCP_SESSION_TYPE_XORG: xserver_params = prepare_xorg_xserver_params(s, authfile); break; case SCP_SESSION_TYPE_XVNC: xserver_params = prepare_xvnc_xserver_params(s, authfile, passwd_file); break; default: unknown_session_type = 1; } g_free(passwd_file); passwd_file = NULL; if (xserver_params == NULL) { LOG(LOG_LEVEL_ERROR, "Out of memory allocating X server params"); } else if (unknown_session_type) { LOG(LOG_LEVEL_ERROR, "Unknown session type: %d", s->type); } else { /* fire up X server */ LOG(LOG_LEVEL_INFO, "Starting X server on display %u: %s", s->display, dumpItemsToString(xserver_params, execvpparams, 2048)); LOG_DEVEL_LEAKING_FDS("X server", 3, -1); g_execvp_list((const char *)xserver_params->items[0], xserver_params); } } /* should not get here */ list_delete(xserver_params); LOG(LOG_LEVEL_ERROR, "A fatal error has occurred attempting " "to start the X server on display %u, aborting connection", s->display); } /******************************************************************************/ /* * Simple helper process to fork a child and log errors */ static int fork_child( void (*runproc)(struct login_info *, const struct session_parameters *), struct login_info *login_info, const struct session_parameters *s, pid_t group_pid) { int pid = g_fork(); if (pid == 0) { /* Child process */ if (group_pid >= 0) { (void)g_setpgid(0, group_pid); } runproc(login_info, s); g_exit(0); } if (pid < 0) { LOG(LOG_LEVEL_ERROR, "Fork failed [%s]", g_get_strerror()); } return pid; } /******************************************************************************/ enum scp_screate_status session_start_wrapped(struct login_info *login_info, const struct session_parameters *s, struct session_data *sd) { int chansrv_pid; int display_pid; int window_manager_pid; enum scp_screate_status status = E_SCP_SCREATE_GENERAL_ERROR; if (auth_start_session(login_info->auth_info, s->display) != 0) { // Errors are logged by the auth module, as they are // specific to that module return E_SCP_SCREATE_GENERAL_ERROR; } #ifdef USE_BSD_SETLOGIN /** * Create a new session and process group since the 4.4BSD * setlogin() affects the entire process group */ if (g_setsid() < 0) { LOG(LOG_LEVEL_WARNING, "[session start] (display %d): setsid failed - pid %d", s->display, g_getpid()); } if (g_setlogin(login_info->username) < 0) { LOG(LOG_LEVEL_WARNING, "[session start] (display %d): setlogin failed for user %s - pid %d", s->display, login_info->username, g_getpid()); } #endif /* Set the secondary groups before starting the session to prevent * problems on PAM-based systems (see Linux pam_setcred(3)). * If we have *BSD setusercontext() this is not done here */ #ifndef HAVE_SETUSERCONTEXT if (g_initgroups(login_info->username) != 0) { LOG(LOG_LEVEL_ERROR, "Failed to initialise secondary groups for %s: %s", login_info->username, g_get_strerror()); return E_SCP_SCREATE_GENERAL_ERROR; } #endif /* start the X server in a new process group. * * We group the X server, window manager and chansrv in a single * process group, as it allows signals to be sent to the user session * without affecting sesexec (and vice-versa). This is particularly * important when debugging sesexec as we don't want a SIGINT in * the debugger to be passed to the children */ display_pid = fork_child(start_x_server, login_info, s, 0); if (display_pid > 0) { enum xwait_status xws; xws = wait_for_xserver(login_info->uid, g_cfg->env_names, g_cfg->env_values, s->display); if (xws != XW_STATUS_OK) { switch (xws) { case XW_STATUS_TIMED_OUT: LOG(LOG_LEVEL_ERROR, "Timed out waiting for X server"); break; case XW_STATUS_FAILED_TO_START: LOG(LOG_LEVEL_ERROR, "X server failed to start"); break; default: LOG(LOG_LEVEL_ERROR, "An error occurred waiting for the X server"); } status = E_SCP_SCREATE_X_SERVER_FAIL; /* Kill it anyway in case it did start and we just failed to * pick up on it */ g_sigterm(display_pid); g_waitpid(display_pid); } else { LOG(LOG_LEVEL_INFO, "X server :%d is working", s->display); LOG(LOG_LEVEL_INFO, "Starting window manager for display :%d", s->display); window_manager_pid = fork_child(start_window_manager, login_info, s, display_pid); if (window_manager_pid < 0) { g_sigterm(display_pid); g_waitpid(display_pid); } else { utmp_login(window_manager_pid, s->display, login_info->username, login_info->ip_addr); LOG(LOG_LEVEL_INFO, "Starting the xrdp channel server for display :%d", s->display); chansrv_pid = fork_child(start_chansrv, login_info, s, display_pid); // Tell the caller we've started LOG(LOG_LEVEL_INFO, "Session in progress on display :%d. Waiting until the " "window manager (pid %d) exits to end the session", s->display, window_manager_pid); sd->win_mgr = window_manager_pid; sd->x_server = display_pid; sd->chansrv = chansrv_pid; sd->start_time = g_time1(); status = E_SCP_SCREATE_OK; } } } return status; } /******************************************************************************/ enum scp_screate_status session_start(struct login_info *login_info, const struct session_parameters *sp, struct session_data **session_data) { enum scp_screate_status status = E_SCP_SCREATE_GENERAL_ERROR; /* Create the session_data struct first */ struct session_data *sd = session_data_new(sp); if (sd == NULL) { status = E_SCP_SCREATE_NO_MEMORY; } else { status = session_start_wrapped(login_info, sp, sd); if (status == E_SCP_SCREATE_OK) { *session_data = sd; } else { *session_data = NULL; session_data_free(sd); } } return status; } /******************************************************************************/ static int cleanup_sockets(int uid, int display) { LOG_DEVEL(LOG_LEVEL_INFO, "cleanup_sockets:"); char file[XRDP_SOCKETS_MAXPATH]; int error = 0; g_snprintf(file, sizeof(file), CHANSRV_PORT_OUT_STR, uid, display); if (g_file_exist(file)) { LOG(LOG_LEVEL_DEBUG, "cleanup_sockets: deleting %s", file); if (g_file_delete(file) == 0) { LOG(LOG_LEVEL_WARNING, "cleanup_sockets: failed to delete %s (%s)", file, g_get_strerror()); error++; } } g_snprintf(file, sizeof(file), CHANSRV_PORT_IN_STR, uid, display); if (g_file_exist(file)) { LOG(LOG_LEVEL_DEBUG, "cleanup_sockets: deleting %s", file); if (g_file_delete(file) == 0) { LOG(LOG_LEVEL_WARNING, "cleanup_sockets: failed to delete %s (%s)", file, g_get_strerror()); error++; } } g_snprintf(file, sizeof(file), XRDP_CHANSRV_STR, uid, display); if (g_file_exist(file)) { LOG(LOG_LEVEL_DEBUG, "cleanup_sockets: deleting %s", file); if (g_file_delete(file) == 0) { LOG(LOG_LEVEL_WARNING, "cleanup_sockets: failed to delete %s (%s)", file, g_get_strerror()); error++; } } g_snprintf(file, sizeof(file), CHANSRV_API_STR, uid, display); if (g_file_exist(file)) { LOG(LOG_LEVEL_DEBUG, "cleanup_sockets: deleting %s", file); if (g_file_delete(file) == 0) { LOG(LOG_LEVEL_WARNING, "cleanup_sockets: failed to delete %s (%s)", file, g_get_strerror()); error++; } } /* the following files should be deleted by xorgxrdp * but just in case the deletion failed */ g_snprintf(file, sizeof(file), XRDP_X11RDP_STR, uid, display); if (g_file_exist(file)) { LOG(LOG_LEVEL_DEBUG, "cleanup_sockets: deleting %s", file); if (g_file_delete(file) == 0) { LOG(LOG_LEVEL_WARNING, "cleanup_sockets: failed to delete %s (%s)", file, g_get_strerror()); error++; } } g_snprintf(file, sizeof(file), XRDP_DISCONNECT_STR, uid, display); if (g_file_exist(file)) { LOG(LOG_LEVEL_DEBUG, "cleanup_sockets: deleting %s", file); if (g_file_delete(file) == 0) { LOG(LOG_LEVEL_WARNING, "cleanup_sockets: failed to delete %s (%s)", file, g_get_strerror()); error++; } } return error; } /******************************************************************************/ static void exit_status_to_str(const struct exit_status *e, char buff[], int bufflen) { switch (e->reason) { case E_XR_STATUS_CODE: if (e->val == 0) { g_snprintf(buff, bufflen, "exit code zero"); } else { g_snprintf(buff, bufflen, "non-zero exit code %d", e->val); } break; case E_XR_SIGNAL: { char sigstr[MAXSTRSIGLEN]; g_snprintf(buff, bufflen, "signal %s", g_sig2text(e->val, sigstr)); } break; default: g_snprintf(buff, bufflen, "an unexpected error"); break; } } /******************************************************************************/ void session_process_child_exit(struct session_data *sd, int pid, const struct exit_status *e) { if (pid == sd->x_server) { LOG(LOG_LEVEL_INFO, "X server pid %d on display :%d finished", sd->x_server, sd->params.display); sd->x_server = -1; // No other action - window manager should be going soon } else if (pid == sd->chansrv) { LOG(LOG_LEVEL_INFO, "xrdp channel server pid %d on display :%d finished", sd->chansrv, sd->params.display); sd->chansrv = -1; } else if (pid == sd->win_mgr) { int wm_wait_time = g_time1() - sd->start_time; if (e->reason == E_XR_STATUS_CODE && e->val == 0) { LOG(LOG_LEVEL_INFO, "Window manager (pid %d, display %d) " "finished normally in %d secs", sd->win_mgr, sd->params.display, wm_wait_time); } else { char reason[128]; exit_status_to_str(e, reason, sizeof(reason)); LOG(LOG_LEVEL_WARNING, "Window manager (pid %d, display %d) " "exited with %s. This " "could indicate a window manager config problem", sd->win_mgr, sd->params.display, reason); } if (wm_wait_time < 10) { /* This could be a config issue. Log a significant error */ LOG(LOG_LEVEL_WARNING, "Window manager (pid %d, display %d) " "exited quickly (%d secs). This could indicate a window " "manager config problem", sd->win_mgr, sd->params.display, wm_wait_time); } utmp_logout(sd->win_mgr, sd->params.display, g_login_info->username, g_login_info->ip_addr); sd->win_mgr = -1; if (sd->x_server > 0) { LOG(LOG_LEVEL_INFO, "Terminating X server (pid %d) on display :%d", sd->x_server, sd->params.display); g_sigterm(sd->x_server); } if (sd->chansrv > 0) { LOG(LOG_LEVEL_INFO, "Terminating the xrdp channel server (pid %d) " "on display :%d", sd->chansrv, sd->params.display); g_sigterm(sd->chansrv); } } if (!session_active(sd)) { cleanup_sockets(g_login_info->uid, sd->params.display); } } /******************************************************************************/ unsigned int session_active(const struct session_data *sd) { return (sd == NULL) ? 0 : (sd->win_mgr > 0) + (sd->x_server > 0) + (sd->chansrv > 0); } /******************************************************************************/ time_t session_get_start_time(const struct session_data *sd) { return (sd == NULL) ? 0 : sd->start_time; } /******************************************************************************/ void session_send_term(struct session_data *sd) { if (sd != NULL && sd->win_mgr > 0) { g_sigterm(sd->win_mgr); } } /******************************************************************************/ static void start_reconnect_script(struct login_info *login_info, const struct session_parameters *s) { env_set_user(login_info->uid, 0, s->display, g_cfg->env_names, g_cfg->env_values); auth_set_env(login_info->auth_info); if (g_file_exist(g_cfg->reconnect_sh)) { LOG_DEVEL_LEAKING_FDS("reconnect script", 3, -1); LOG(LOG_LEVEL_INFO, "Starting session reconnection script on display %d: %s", s->display, g_cfg->reconnect_sh); g_execlp3(g_cfg->reconnect_sh, g_cfg->reconnect_sh, 0); /* should not get here */ LOG(LOG_LEVEL_ERROR, "Error starting session reconnection script on display %d: %s", s->display, g_cfg->reconnect_sh); } else { LOG(LOG_LEVEL_WARNING, "Session reconnection script file does not exist: %s", g_cfg->reconnect_sh); } } /******************************************************************************/ void session_reconnect(struct login_info *login_info, struct session_data *sd) { if (fork_child(start_reconnect_script, login_info, &sd->params, sd->x_server) < 0) { LOG(LOG_LEVEL_ERROR, "Failed to fork for session reconnection script"); } }