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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 © 2008,2009 Teddy Hogeborn
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* Copyright © 2008,2009 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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sigprocmask(), SIG_BLOCK, SIGCHLD,
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SIG_UNBLOCK, kill() */
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#include <errno.h> /* errno, EBADF */
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#include <inttypes.h> /* intmax_t, SCNdMAX, PRIdMAX, */
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#define BUFFER_SIZE 256
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#define PDIR "/lib/mandos/plugins.d"
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#define AFILE "/conf/conf.d/mandos/plugin-runner.conf"
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const char *argp_program_version = "plugin-runner 1.0";
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const char *argp_program_version = "plugin-runner " VERSION;
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const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
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typedef struct plugin{
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char *name; /* can be NULL or any plugin name */
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static plugin *plugin_list = NULL;
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/* Gets a existing plugin based on name,
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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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for(plugin *p = plugin_list; p != NULL; p = p->next){
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or (p->name and name and (strcmp(p->name, name) == 0))){
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/* Create a new plugin */
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plugin *new_plugin = malloc(sizeof(plugin));
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if (new_plugin == NULL){
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if(new_plugin == NULL){
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char *copy_name = NULL;
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if(name != NULL){
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copy_name = strdup(name);
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if(copy_name == NULL){
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*new_plugin = (plugin) { .name = copy_name,
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.disabled = false,
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.next = plugin_list };
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new_plugin->argv = malloc(sizeof(char *) * 2);
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if (new_plugin->argv == NULL){
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if(new_plugin->argv == NULL){
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free(new_plugin);
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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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/* Refuse to add an existing variable */
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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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* 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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/* Prints out a password to stdout */
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bool print_out_password(const char *buffer, size_t length){
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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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{ .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-env", .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 = "env-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, __attribute__((unused))
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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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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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while((p = strsep(&arg, ",")) != NULL){
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if(p[0] == '\0'){
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case 'e': /* --global-env */
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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), 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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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), 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 'f': /* --env-for */
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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), 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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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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ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
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if(ret < 1 or tmpmax != (uid_t)tmpmax
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or arg[numchars] != '\0'){
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fprintf(stderr, "Bad user ID number: \"%s\", using %"
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PRIdMAX "\n", arg, (intmax_t)uid);
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case 131: /* --groupid */
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ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
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if(ret < 1 or tmpmax != (gid_t)tmpmax
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or arg[numchars] != '\0'){
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fprintf(stderr, "Bad group ID number: \"%s\", using %"
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PRIdMAX "\n", arg, (intmax_t)gid);
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case 132: /* --debug */
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* When adding more options before this line, remember to also add a
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* "case" to the "parse_opt_config_file" function below.
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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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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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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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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, NULL);
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if (ret == ARGP_ERR_UNKNOWN){
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/* Parse using 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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/* Opens the configfile if aviable */
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if (argfile == NULL){
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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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conffp = fopen(AFILE, "r");
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conffp = fopen(argfile, "r");
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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, NULL);
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if (ret == ARGP_ERR_UNKNOWN){
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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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for(char **a = p->argv; *a != NULL; a++){
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fprintf(stderr, "\tArg: %s\n", *a);
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fprintf(stderr, "...and %u environment variables\n", p->envc);
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fprintf(stderr, "...and %d environment variables\n", p->envc);
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for(char **a = p->environ; *a != NULL; a++){
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fprintf(stderr, "\t%s\n", *a);
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/* Strip permissions down to nobody */
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ret = setuid(uid);
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perror("setuid");
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perror("setgid");
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if (plugindir == NULL){
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if(plugindir == NULL){
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dir = opendir(PDIR);
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dir = opendir(plugindir);
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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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ret = stat(filename, &st);
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/* Ignore non-executable files */
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if (not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
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if(not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
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fprintf(stderr, "Ignoring plugin dir entry \"%s\""
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" with bad type or mode\n", filename);
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/* Block SIGCHLD until process is safely in process list */
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ret = sigprocmask (SIG_BLOCK, &sigchld_action.sa_mask, NULL);
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ret = sigprocmask(SIG_BLOCK, &sigchld_action.sa_mask, NULL);
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perror("sigprocmask");
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exitstatus = EXIT_FAILURE;
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// Starting a new process to be watched
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/* Starting a new process to be watched */
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pid_t pid = fork();
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free_plugin_list();
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/* Main loop while running plugins exist */
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while(plugin_list){
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fd_set rfds = rfds_all;
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int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);
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if (select_ret == -1){
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if(select_ret == -1){
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perror("select");
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exitstatus = EXIT_FAILURE;
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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(plugin *proc = plugin_list; proc != NULL; 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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if(proc->eof and proc->completed){
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/* Only accept the plugin output if it exited cleanly */
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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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fprintf(stderr, "Plugin %" PRIdMAX " exited with status"
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" %d\n", (intmax_t) (proc->pid),
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WEXITSTATUS(proc->status));
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} else if(WIFSIGNALED(proc->status)) {
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fprintf(stderr, "Plugin %u killed by signal %d\n",
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(unsigned int) (proc->pid),
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fprintf(stderr, "Plugin %" PRIdMAX " killed by signal"
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" %d\n", (intmax_t) (proc->pid),
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WTERMSIG(proc->status));
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} else if(WCOREDUMP(proc->status)){
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fprintf(stderr, "Plugin %d dumped core\n",
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(unsigned int) (proc->pid));
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fprintf(stderr, "Plugin %" PRIdMAX " dumped core\n",
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(intmax_t) (proc->pid));
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exitstatus = EXIT_FAILURE;
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plugin *next_plugin = proc->next;
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free_plugin(proc);
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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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ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
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perror("sigprocmask");
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exitstatus = EXIT_FAILURE;
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/* This process has not completed. Does it have any output? */
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if(proc->eof or not FD_ISSET(proc->fd, &rfds)){
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/* This process had nothing to say at this time */
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/* Before reading, make the process' data buffer large enough */
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if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
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proc->buffer = realloc(proc->buffer, proc->buffer_size
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+ (size_t) BUFFER_SIZE);
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if (proc->buffer == NULL){
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if(proc->buffer == NULL){
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perror("malloc");
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exitstatus = EXIT_FAILURE;
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proc->buffer_size += BUFFER_SIZE;
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/* Read from the process */
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ret = read(proc->fd, proc->buffer + proc->buffer_length,
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sret = read(proc->fd, proc->buffer + proc->buffer_length,
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/* Read error from this process; ignore the error */
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proc->eof = true;
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proc->buffer_length += (size_t) ret;
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proc->buffer_length += (size_t) sret;
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fprintf(stderr, "Going to fallback mode using getpass(3)\n");
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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 */
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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");
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exitstatus = EXIT_FAILURE;