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* Mandos plugin runner - Run Mandos plugins
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* Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
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* Copyright © 2008 Teddy Hogeborn & Björn Påhlsson
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* This program is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,
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EXIT_SUCCESS, realloc() */
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#include <stdbool.h> /* bool, true, false */
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#include <stdio.h> /* perror, popen(), fileno(),
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fprintf(), stderr, STDOUT_FILENO */
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#include <stdio.h> /* perror, fileno(), fprintf(),
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stderr, STDOUT_FILENO */
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#include <sys/types.h> /* DIR, opendir(), stat(), struct
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stat, waitpid(), WIFEXITED(),
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WEXITSTATUS(), wait(), pid_t,
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fcntl(), setuid(), setgid(),
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F_GETFD, F_SETFD, FD_CLOEXEC,
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access(), pipe(), fork(), close()
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dup2, STDOUT_FILENO, _exit(),
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dup2(), STDOUT_FILENO, _exit(),
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execv(), write(), read(),
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#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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volatile bool completed;
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volatile int status;
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typedef struct plugin{
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char *name; /* can be NULL or any plugin name */
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struct plugin *next;
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static plugin *getplugin(char *name, plugin **plugin_list){
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for (plugin *p = *plugin_list; p != NULL; p = p->next){
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static plugin *plugin_list = NULL;
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/* Gets an existing plugin based on name,
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or if none is found, creates a new one */
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static plugin *getplugin(char *name){
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/* Check for exiting plugin with that name */
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for (plugin *p = plugin_list; p != NULL; p = p->next){
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if ((p->name == name)
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or (p->name and name and (strcmp(p->name, name) == 0))){
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/* Add to a plugin's environment */
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static bool add_environment(plugin *p, const char *def){
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static bool add_environment(plugin *p, const char *def, bool replace){
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/* namelen = length of name of environment variable */
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size_t namelen = (size_t)(strchrnul(def, '=') - def);
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/* Search for this environment variable */
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for(char **e = p->environ; *e != NULL; e++){
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if(strncmp(*e, def, namelen + 1) == 0){
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/* It already exists */
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char *new = realloc(*e, strlen(def) + 1);
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return add_to_char_array(def, &(p->environ), &(p->envc));
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* Based on the example in the GNU LibC manual chapter 13.13 "File
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* Descriptor Flags".
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* *Note File Descriptor Flags:(libc)Descriptor Flags.
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static int set_cloexec_flag(int fd)
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static int set_cloexec_flag(int fd){
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int ret = fcntl(fd, F_GETFD, 0);
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/* If reading the flags failed, return error indication now. */
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return fcntl(fd, F_SETFD, ret | FD_CLOEXEC);
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process *process_list = NULL;
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/* Mark processes as completed when they exit, and save their exit
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void handle_sigchld(__attribute__((unused)) int sig){
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static void handle_sigchld(__attribute__((unused)) int sig){
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process *proc = process_list;
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plugin *proc = plugin_list;
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pid_t pid = waitpid(-1, &status, WNOHANG);
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bool print_out_password(const char *buffer, size_t length){
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/* Prints out a password to stdout */
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static bool print_out_password(const char *buffer, size_t length){
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if(length>0 and buffer[length-1] == '\n'){
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for(size_t written = 0; written < length; written += (size_t)ret){
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ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO, buffer + written,
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length - written));
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static void free_plugin_list(plugin *plugin_list){
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for(plugin *next; plugin_list != NULL; plugin_list = next){
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next = plugin_list->next;
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for(char **arg = plugin_list->argv; *arg != NULL; arg++){
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free(plugin_list->argv);
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for(char **env = plugin_list->environ; *env != NULL; env++){
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free(plugin_list->environ);
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/* Removes and free a plugin from the plugin list */
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static void free_plugin(plugin *plugin_node){
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for(char **arg = plugin_node->argv; *arg != NULL; arg++){
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free(plugin_node->argv);
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for(char **env = plugin_node->environ; *env != NULL; env++){
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free(plugin_node->environ);
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free(plugin_node->buffer);
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/* Removes the plugin from the singly-linked list */
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if(plugin_node == plugin_list){
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/* First one - simple */
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plugin_list = plugin_list->next;
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/* Second one or later */
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for(plugin *p = plugin_list; p != NULL; p = p->next){
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if(p->next == plugin_node){
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p->next = plugin_node->next;
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static void free_plugin_list(void){
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while(plugin_list != NULL){
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free_plugin(plugin_list);
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{ .name = "global-options", .key = 'g',
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.arg = "OPTION[,OPTION[,...]]",
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.doc = "Options passed to all plugins" },
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{ .name = "global-envs", .key = 'e',
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{ .name = "global-env", .key = 'G',
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.arg = "VAR=value",
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.doc = "Environment variable passed to all plugins" },
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{ .name = "options-for", .key = 'o',
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.arg = "PLUGIN:OPTION[,OPTION[,...]]",
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.doc = "Options passed only to specified plugin" },
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{ .name = "envs-for", .key = 'f',
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{ .name = "env-for", .key = 'E',
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.arg = "PLUGIN:ENV=value",
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.doc = "Environment variable passed to specified plugin" },
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{ .name = "disable", .key = 'd',
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.doc = "Disable a specific plugin", .group = 1 },
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{ .name = "enable", .key = 'e',
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.doc = "Enable a specific plugin", .group = 1 },
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{ .name = "plugin-dir", .key = 128,
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.arg = "DIRECTORY",
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.doc = "Specify a different plugin directory", .group = 2 },
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error_t parse_opt (int key, char *arg, struct argp_state *state) {
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/* Get the INPUT argument from `argp_parse', which we know is a
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pointer to our plugin list pointer. */
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plugin **plugins = state->input;
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error_t parse_opt (int key, char *arg, __attribute__((unused))
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struct argp_state *state) {
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case 'g': /* --global-options */
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if (arg != NULL){
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while((p = strsep(&arg, ",")) != NULL){
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if(p[0] == '\0'){
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if(not add_argument(getplugin(NULL, plugins), p)){
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if(not add_argument(getplugin(NULL), p)){
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perror("add_argument");
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return ARGP_ERR_UNKNOWN;
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case 'G': /* --global-env */
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char *envdef = strdup(arg);
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if(not add_environment(getplugin(NULL, plugins), envdef)){
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perror("add_environment");
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if(not add_environment(getplugin(NULL), arg, true)){
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perror("add_environment");
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case 'o': /* --options-for */
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if (arg != NULL){
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char *p_name = strsep(&arg, ":");
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if(p_name[0] == '\0'){
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if(p_name[0] == '\0' or arg == NULL){
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char *opt = strsep(&arg, ":");
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if(opt[0] == '\0' or opt == NULL){
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while((p = strsep(&opt, ",")) != NULL){
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if(not add_argument(getplugin(p_name, plugins), p)){
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perror("add_argument");
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return ARGP_ERR_UNKNOWN;
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while((p = strsep(&opt, ",")) != NULL){
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if(not add_argument(getplugin(p_name), p)){
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perror("add_argument");
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return ARGP_ERR_UNKNOWN;
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case 'E': /* --env-for */
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if(envdef == NULL){
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char *p_name = strndup(arg, (size_t) (envdef-arg));
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if(not add_environment(getplugin(p_name, plugins), envdef)){
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if(not add_environment(getplugin(arg), envdef+1, true)){
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perror("add_environment");
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case 'd': /* --disable */
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if (arg != NULL){
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plugin *p = getplugin(arg, plugins);
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plugin *p = getplugin(arg);
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return ARGP_ERR_UNKNOWN;
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p->disabled = true;
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case 'e': /* --enable */
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plugin *p = getplugin(arg);
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return ARGP_ERR_UNKNOWN;
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case 128: /* --plugin-dir */
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plugindir = strdup(arg);
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if(plugindir == NULL){
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perror("strdup");
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case 129: /* --config-file */
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/* This is already done by parse_opt_config_file() */
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case 130: /* --userid */
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uid = (uid_t)strtol(arg, NULL, 10);
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case 131: /* --groupid */
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gid = (gid_t)strtol(arg, NULL, 10);
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case 132: /* --debug */
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/* Cryptsetup always passes an argument, which is an empty
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string if "none" was specified in /etc/crypttab. So if
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argument was empty, we ignore it silently. */
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fprintf(stderr, "Ignoring unknown argument \"%s\"\n", arg);
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return ARGP_ERR_UNKNOWN;
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/* This option parser is the same as parse_opt() above, except it
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ignores everything but the --config-file option. */
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error_t parse_opt_config_file (int key, char *arg,
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__attribute__((unused))
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struct argp_state *state) {
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case 'g': /* --global-options */
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case 'G': /* --global-env */
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case 'o': /* --options-for */
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case 'E': /* --env-for */
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case 'd': /* --disable */
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case 'e': /* --enable */
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case 128: /* --plugin-dir */
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case 129: /* --config-file */
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argfile = strdup(arg);
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if(argfile == NULL){
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perror("strdup");
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uid = (uid_t)strtol(arg, NULL, 10);
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gid = (gid_t)strtol(arg, NULL, 10);
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case 130: /* --userid */
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case 131: /* --groupid */
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case 132: /* --debug */
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case ARGP_KEY_ARG:
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fprintf(stderr, "Ignoring unknown argument \"%s\"\n", arg);
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case ARGP_KEY_END:
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plugin *plugin_list = NULL;
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struct argp argp = { .options = options, .parser = parse_opt,
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.args_doc = "[+PLUS_SEPARATED_OPTIONS]",
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struct argp argp = { .options = options,
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.parser = parse_opt_config_file,
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.doc = "Mandos plugin runner -- Run plugins" };
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ret = argp_parse (&argp, argc, argv, 0, 0, &plugin_list);
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/* Parse using the parse_opt_config_file in order to get the custom
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config file location, if any. */
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ret = argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
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if (ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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exitstatus = EXIT_FAILURE;
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/* Reset to the normal argument parser */
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argp.parser = parse_opt;
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/* Open the configfile if available */
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if (argfile == NULL){
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conffp = fopen(AFILE, "r");
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conffp = fopen(argfile, "r");
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if(conffp != NULL){
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char *org_line = NULL;
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char *p, *arg, *new_arg, *line;
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/* If there was any arguments from configuration file,
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pass them to parser as command arguments */
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if(custom_argv != NULL){
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ret = argp_parse (&argp, custom_argc, custom_argv, 0, 0, &plugin_list);
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ret = argp_parse (&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
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if (ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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exitstatus = EXIT_FAILURE;
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/* Parse actual command line arguments, to let them override the
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ret = argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
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if (ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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exitstatus = EXIT_FAILURE;
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for(plugin *p = plugin_list; p != NULL; p=p->next){
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fprintf(stderr, "Plugin: %s has %d arguments\n",
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ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);
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if(plugindir == NULL){
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ret = asprintf(&filename, PDIR "/%s", dirst->d_name);
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ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);
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perror("asprintf");
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/* Add global arguments to argument list for this plugin */
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plugin *g = getplugin(NULL, &plugin_list);
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plugin *g = getplugin(NULL);
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for(char **a = g->argv + 1; *a != NULL; a++){
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if(not add_argument(p, *a)){
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/* Add global environment variables */
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for(char **e = g->environ; *e != NULL; e++){
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if(not add_environment(p, *e)){
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if(not add_environment(p, *e, false)){
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perror("add_environment");
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if(p->environ[0] != NULL){
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for(char **e = environ; *e != NULL; e++){
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char *copy = strdup(*e);
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if(not add_environment(p, copy)){
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if(not add_environment(p, *e, false)){
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perror("add_environment");
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close(pipefd[1]); /* Close unused write end of pipe */
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close(pipefd[1]); /* close unused write end of pipe */
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process *new_process = malloc(sizeof(process));
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if (new_process == NULL){
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plugin *new_plugin = getplugin(dirst->d_name);
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if (new_plugin == NULL){
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ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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perror("sigprocmask");
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perror("sigprocmask");
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exitstatus = EXIT_FAILURE;
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*new_process = (struct process){ .pid = pid,
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.next = process_list };
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process_list = new_process;
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new_plugin->pid = pid;
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new_plugin->fd = pipefd[0];
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/* Unblock SIGCHLD so signal handler can be run if this process
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has already completed */
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ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
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FD_SET(new_process->fd, &rfds_all);
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FD_SET(new_plugin->fd, &rfds_all);
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if (maxfd < new_process->fd){
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maxfd = new_process->fd;
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if (maxfd < new_plugin->fd){
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maxfd = new_plugin->fd;
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free_plugin_list(plugin_list);
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if (process_list == NULL){
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fprintf(stderr, "No plugin processes started. Incorrect plugin"
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for(plugin *p = plugin_list; p != NULL; p = p->next){
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fprintf(stderr, "No plugin processes started. Incorrect plugin"
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/* Main loop while running plugins exist */
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fd_set rfds = rfds_all;
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int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);
843
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if (select_ret == -1){
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/* OK, now either a process completed, or something can be read
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from one of them */
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for(process *proc = process_list; proc ; proc = proc->next){
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for(plugin *proc = plugin_list; proc != NULL;){
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/* Is this process completely done? */
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940
if(proc->eof and proc->completed){
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/* Only accept the plugin output if it exited cleanly */
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if(not WIFEXITED(proc->status)
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or WEXITSTATUS(proc->status) != 0){
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/* Bad exit by plugin */
858
947
if(WIFEXITED(proc->status)){
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fprintf(stderr, "Plugin %u exited with status %d\n",
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(unsigned int) (proc->pid));
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/* Remove the plugin */
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FD_CLR(proc->fd, &rfds_all);
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/* Block signal while modifying process_list */
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ret = sigprocmask(SIG_BLOCK, &sigchld_action.sa_mask, NULL);
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exitstatus = EXIT_FAILURE;
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/* Delete this process entry from the list */
881
if(process_list == proc){
882
/* First one - simple */
883
process_list = proc->next;
885
/* Second one or later */
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for(process *p = process_list; p != NULL; p = p->next){
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p->next = proc->next;
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/* We are done modifying process list, so unblock signal */
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ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask,
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perror("sigprocmask");
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/* We deleted this process from the list, so we can't go
902
proc->next. Therefore, start over from the beginning of
977
exitstatus = EXIT_FAILURE;
981
if(plugin_list == NULL){
985
plugin *next_plugin = proc->next;
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/* This process exited nicely, so print its buffer */
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bool bret = print_out_password(proc->buffer,
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if(process_list == NULL or exitstatus != EXIT_SUCCESS){
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if(plugin_list == NULL or exitstatus != EXIT_SUCCESS){
952
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/* Fallback if all plugins failed, none are found or an error
955
1043
fprintf(stderr, "Going to fallback mode using getpass(3)\n");
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1044
char *passwordbuffer = getpass("Password: ");
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bret = print_out_password(passwordbuffer, strlen(passwordbuffer));
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size_t len = strlen(passwordbuffer);
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/* Strip trailing newline */
1047
if(len > 0 and passwordbuffer[len-1] == '\n'){
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passwordbuffer[len-1] = '\0'; /* not strictly necessary */
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bret = print_out_password(passwordbuffer, len);
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perror("print_out_password");
960
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exitstatus = EXIT_FAILURE;
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free(custom_argv);
977
free_plugin_list(plugin_list);
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if(dir != NULL){
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/* Free the process list and kill the processes */
984
for(process *next; process_list != NULL; process_list = next){
985
next = process_list->next;
986
close(process_list->fd);
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ret = kill(process_list->pid, SIGTERM);
988
if(ret == -1 and errno != ESRCH){
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/* set-uid proccesses migth not get closed */
1077
for(plugin *p = plugin_list; p != NULL; p = p->next){
1080
ret = kill(p->pid, SIGTERM);
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if(ret == -1 and errno != ESRCH){
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/* Set-uid proccesses might not get closed */
992
free(process_list->buffer);
996
1088
/* Wait for any remaining child processes to terminate */