1
/* -*- coding: utf-8 -*- */
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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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* 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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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* Contact the authors at <mandos@fukt.bsnet.se>.
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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
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#include <stddef.h> /* size_t, NULL */
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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 <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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uid_t, gid_t, getuid(), getgid(),
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#include <sys/select.h> /* fd_set, select(), FD_ZERO(),
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FD_SET(), FD_ISSET(), FD_CLR */
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#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),
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#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
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#include <iso646.h> /* and, or, not */
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#include <dirent.h> /* DIR, struct dirent, opendir(),
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readdir(), closedir(), dirfd() */
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#include <unistd.h> /* struct stat, stat(), S_ISREG(),
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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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execv(), write(), read(),
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#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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#include <string.h> /* strsep, strlen(), asprintf() */
55
#include <errno.h> /* errno */
56
#include <argp.h> /* struct argp_option, struct
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argp_state, struct argp,
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argp_parse(), ARGP_ERR_UNKNOWN,
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ARGP_KEY_END, ARGP_KEY_ARG,
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#include <signal.h> /* struct sigaction, sigemptyset(),
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sigaddset(), sigaction(),
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sigprocmask(), SIG_BLOCK, SIGCHLD,
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SIG_UNBLOCK, kill() */
65
#include <errno.h> /* errno, EBADF */
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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_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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/* Variables used for running processes*/
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volatile bool completed;
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static plugin *plugin_list = NULL;
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/* Gets a 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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/* 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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char *copy_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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.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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new_plugin->argv[0] = copy_name;
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new_plugin->argv[1] = NULL;
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new_plugin->environ = malloc(sizeof(char *));
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if(new_plugin->environ == NULL){
139
free(new_plugin->argv);
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new_plugin->environ[0] = NULL;
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/* Append the new plugin to the list */
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plugin_list = new_plugin;
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/* Helper function for add_argument and add_environment */
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static bool add_to_char_array(const char *new, char ***array,
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/* Resize the pointed-to array to hold one more pointer */
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*array = realloc(*array, sizeof(char *)
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* (size_t) ((*len) + 2));
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/* Make a copy of the new string */
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char *copy = strdup(new);
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/* Insert the copy */
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(*array)[*len] = copy;
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/* Add a new terminating NULL pointer to the last element */
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(*array)[*len] = NULL;
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/* Add to a plugin's argument vector */
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static bool add_argument(plugin *p, const char *arg){
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return add_to_char_array(arg, &(p->argv), &(p->argc));
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/* Add to a plugin's environment */
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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));
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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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* *Note File Descriptor Flags:(libc)Descriptor Flags.
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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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/* Store modified flag word in the descriptor. */
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return fcntl(fd, F_SETFD, ret | FD_CLOEXEC);
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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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plugin *proc = plugin_list;
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pid_t pid = waitpid(-1, &status, WNOHANG);
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/* Only still running child processes */
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if (errno != ECHILD){
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/* No child processes */
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/* A child exited, find it in process_list */
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while(proc != NULL and proc->pid != pid){
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/* Process not found in process list */
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proc->status = status;
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proc->completed = true;
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/* Prints out a password to stdout */
256
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){
262
ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO, buffer + written,
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/* Removes and free a plugin from the plugin list */
272
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 */
285
if(plugin_node == plugin_list){
286
/* First one - simple */
287
plugin_list = plugin_list->next;
289
/* Second one or later */
290
for(plugin *p = plugin_list; p != NULL; p = p->next){
291
if(p->next == plugin_node){
292
p->next = plugin_node->next;
301
static void free_plugin_list(void){
302
while(plugin_list != NULL){
303
free_plugin(plugin_list);
307
int main(int argc, char *argv[]){
308
char *plugindir = NULL;
309
char *argfile = NULL;
313
struct dirent *dirst;
320
int exitstatus = EXIT_SUCCESS;
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struct sigaction old_sigchld_action;
322
struct sigaction sigchld_action = { .sa_handler = handle_sigchld,
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.sa_flags = SA_NOCLDSTOP };
324
char **custom_argv = NULL;
327
/* Establish a signal handler */
328
sigemptyset(&sigchld_action.sa_mask);
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ret = sigaddset(&sigchld_action.sa_mask, SIGCHLD);
332
exitstatus = EXIT_FAILURE;
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ret = sigaction(SIGCHLD, &sigchld_action, &old_sigchld_action);
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exitstatus = EXIT_FAILURE;
342
/* The options we understand. */
343
struct argp_option options[] = {
344
{ .name = "global-options", .key = 'g',
345
.arg = "OPTION[,OPTION[,...]]",
346
.doc = "Options passed to all plugins" },
347
{ .name = "global-env", .key = 'G',
349
.doc = "Environment variable passed to all plugins" },
350
{ .name = "options-for", .key = 'o',
351
.arg = "PLUGIN:OPTION[,OPTION[,...]]",
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.doc = "Options passed only to specified plugin" },
353
{ .name = "env-for", .key = 'E',
354
.arg = "PLUGIN:ENV=value",
355
.doc = "Environment variable passed to specified plugin" },
356
{ .name = "disable", .key = 'd',
358
.doc = "Disable a specific plugin", .group = 1 },
359
{ .name = "enable", .key = 'e',
361
.doc = "Enable a specific plugin", .group = 1 },
362
{ .name = "plugin-dir", .key = 128,
364
.doc = "Specify a different plugin directory", .group = 2 },
365
{ .name = "config-file", .key = 129,
367
.doc = "Specify a different configuration file", .group = 2 },
368
{ .name = "userid", .key = 130,
369
.arg = "ID", .flags = 0,
370
.doc = "User ID the plugins will run as", .group = 3 },
371
{ .name = "groupid", .key = 131,
372
.arg = "ID", .flags = 0,
373
.doc = "Group ID the plugins will run as", .group = 3 },
374
{ .name = "debug", .key = 132,
375
.doc = "Debug mode", .group = 4 },
379
error_t parse_opt (int key, char *arg, __attribute__((unused))
380
struct argp_state *state) {
382
case 'g': /* --global-options */
385
while((p = strsep(&arg, ",")) != NULL){
389
if(not add_argument(getplugin(NULL), p)){
390
perror("add_argument");
391
return ARGP_ERR_UNKNOWN;
396
case 'G': /* --global-env */
401
char *envdef = strdup(arg);
405
if(not add_environment(getplugin(NULL), envdef, true)){
406
perror("add_environment");
410
case 'o': /* --options-for */
412
char *p_name = strsep(&arg, ":");
413
if(p_name[0] == '\0'){
416
char *opt = strsep(&arg, ":");
422
while((p = strsep(&opt, ",")) != NULL){
426
if(not add_argument(getplugin(p_name), p)){
427
perror("add_argument");
428
return ARGP_ERR_UNKNOWN;
434
case 'E': /* --env-for */
439
char *envdef = strchr(arg, ':');
443
char *p_name = strndup(arg, (size_t) (envdef-arg));
448
if(not add_environment(getplugin(p_name), envdef, true)){
449
perror("add_environment");
453
case 'd': /* --disable */
455
plugin *p = getplugin(arg);
457
return ARGP_ERR_UNKNOWN;
462
case 'e': /* --enable */
464
plugin *p = getplugin(arg);
466
return ARGP_ERR_UNKNOWN;
471
case 128: /* --plugin-dir */
472
plugindir = strdup(arg);
473
if(plugindir == NULL){
477
case 129: /* --config-file */
478
/* This is already done by parse_opt_config_file() */
480
case 130: /* --userid */
481
uid = (uid_t)strtol(arg, NULL, 10);
483
case 131: /* --groupid */
484
gid = (gid_t)strtol(arg, NULL, 10);
486
case 132: /* --debug */
490
fprintf(stderr, "Ignoring unknown argument \"%s\"\n", arg);
495
return ARGP_ERR_UNKNOWN;
500
/* This option parser is the same as parse_opt() above, except it
501
ignores everything but the --config-file option. */
502
error_t parse_opt_config_file (int key, char *arg,
503
__attribute__((unused))
504
struct argp_state *state) {
506
case 'g': /* --global-options */
507
case 'G': /* --global-env */
508
case 'o': /* --options-for */
509
case 'E': /* --env-for */
510
case 'd': /* --disable */
511
case 'e': /* --enable */
512
case 128: /* --plugin-dir */
514
case 129: /* --config-file */
515
argfile = strdup(arg);
520
case 130: /* --userid */
521
case 131: /* --groupid */
522
case 132: /* --debug */
527
return ARGP_ERR_UNKNOWN;
532
struct argp argp = { .options = options,
533
.parser = parse_opt_config_file,
535
.doc = "Mandos plugin runner -- Run plugins" };
537
/* Parse using the parse_opt_config_file in order to get the custom
538
config file location, if any. */
539
ret = argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
540
if (ret == ARGP_ERR_UNKNOWN){
541
fprintf(stderr, "Unknown error while parsing arguments\n");
542
exitstatus = EXIT_FAILURE;
546
/* Reset to the normal argument parser */
547
argp.parser = parse_opt;
549
/* Open the configfile if available */
550
if (argfile == NULL){
551
conffp = fopen(AFILE, "r");
553
conffp = fopen(argfile, "r");
556
char *org_line = NULL;
557
char *p, *arg, *new_arg, *line;
560
const char whitespace_delims[] = " \r\t\f\v\n";
561
const char comment_delim[] = "#";
564
custom_argv = malloc(sizeof(char*) * 2);
565
if(custom_argv == NULL){
567
exitstatus = EXIT_FAILURE;
570
custom_argv[0] = argv[0];
571
custom_argv[1] = NULL;
573
/* for each line in the config file, strip whitespace and ignore
576
sret = getline(&org_line, &size, conffp);
582
arg = strsep(&line, comment_delim);
583
while((p = strsep(&arg, whitespace_delims)) != NULL){
590
exitstatus = EXIT_FAILURE;
596
custom_argv = realloc(custom_argv, sizeof(char *)
597
* ((unsigned int) custom_argc + 1));
598
if(custom_argv == NULL){
600
exitstatus = EXIT_FAILURE;
604
custom_argv[custom_argc-1] = new_arg;
605
custom_argv[custom_argc] = NULL;
610
/* Check for harmful errors and go to fallback. Other errors might
611
not affect opening plugins */
612
if (errno == EMFILE or errno == ENFILE or errno == ENOMEM){
614
exitstatus = EXIT_FAILURE;
618
/* If there was any arguments from configuration file,
619
pass them to parser as command arguments */
620
if(custom_argv != NULL){
621
ret = argp_parse (&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
623
if (ret == ARGP_ERR_UNKNOWN){
624
fprintf(stderr, "Unknown error while parsing arguments\n");
625
exitstatus = EXIT_FAILURE;
630
/* Parse actual command line arguments, to let them override the
632
ret = argp_parse (&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
633
if (ret == ARGP_ERR_UNKNOWN){
634
fprintf(stderr, "Unknown error while parsing arguments\n");
635
exitstatus = EXIT_FAILURE;
640
for(plugin *p = plugin_list; p != NULL; p=p->next){
641
fprintf(stderr, "Plugin: %s has %d arguments\n",
642
p->name ? p->name : "Global", p->argc - 1);
643
for(char **a = p->argv; *a != NULL; a++){
644
fprintf(stderr, "\tArg: %s\n", *a);
646
fprintf(stderr, "...and %u environment variables\n", p->envc);
647
for(char **a = p->environ; *a != NULL; a++){
648
fprintf(stderr, "\t%s\n", *a);
653
/* Strip permissions down to nobody */
663
if (plugindir == NULL){
666
dir = opendir(plugindir);
670
perror("Could not open plugin dir");
671
exitstatus = EXIT_FAILURE;
675
/* Set the FD_CLOEXEC flag on the directory, if possible */
677
int dir_fd = dirfd(dir);
679
ret = set_cloexec_flag(dir_fd);
681
perror("set_cloexec_flag");
682
exitstatus = EXIT_FAILURE;
690
/* Read and execute any executable in the plugin directory*/
692
dirst = readdir(dir);
694
/* All directory entries have been processed */
698
exitstatus = EXIT_FAILURE;
704
d_name_len = strlen(dirst->d_name);
706
/* Ignore dotfiles, backup files and other junk */
708
bool bad_name = false;
710
const char const *bad_prefixes[] = { ".", "#", NULL };
712
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
714
".dpkg-divert", NULL };
715
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
716
size_t pre_len = strlen(*pre);
717
if((d_name_len >= pre_len)
718
and strncmp((dirst->d_name), *pre, pre_len) == 0){
720
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
721
" with bad prefix %s\n", dirst->d_name, *pre);
730
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
731
size_t suf_len = strlen(*suf);
732
if((d_name_len >= suf_len)
733
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
736
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
737
" with bad suffix %s\n", dirst->d_name, *suf);
750
ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);
756
ret = stat(filename, &st);
763
/* Ignore non-executable files */
764
if (not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
766
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
767
" with bad type or mode\n", filename);
773
plugin *p = getplugin(dirst->d_name);
781
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
788
/* Add global arguments to argument list for this plugin */
789
plugin *g = getplugin(NULL);
791
for(char **a = g->argv + 1; *a != NULL; a++){
792
if(not add_argument(p, *a)){
793
perror("add_argument");
796
/* Add global environment variables */
797
for(char **e = g->environ; *e != NULL; e++){
798
if(not add_environment(p, *e, false)){
799
perror("add_environment");
804
/* If this plugin has any environment variables, we will call
805
using execve and need to duplicate the environment from this
807
if(p->environ[0] != NULL){
808
for(char **e = environ; *e != NULL; e++){
809
if(not add_environment(p, *e, false)){
810
perror("add_environment");
819
exitstatus = EXIT_FAILURE;
822
/* Ask OS to automatic close the pipe on exec */
823
ret = set_cloexec_flag(pipefd[0]);
825
perror("set_cloexec_flag");
826
exitstatus = EXIT_FAILURE;
829
ret = set_cloexec_flag(pipefd[1]);
831
perror("set_cloexec_flag");
832
exitstatus = EXIT_FAILURE;
835
/* Block SIGCHLD until process is safely in process list */
836
ret = sigprocmask (SIG_BLOCK, &sigchld_action.sa_mask, NULL);
838
perror("sigprocmask");
839
exitstatus = EXIT_FAILURE;
842
/* Starting a new process to be watched */
846
exitstatus = EXIT_FAILURE;
850
/* this is the child process */
851
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
856
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
858
perror("sigprocmask");
862
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
869
/* If dir has no file descriptor, we could not set FD_CLOEXEC
870
above and must now close it manually here. */
873
if(p->environ[0] == NULL){
874
if(execv(filename, p->argv) < 0){
879
if(execve(filename, p->argv, p->environ) < 0){
887
close(pipefd[1]); /* Close unused write end of pipe */
889
plugin *new_plugin = getplugin(dirst->d_name);
890
if (new_plugin == NULL){
892
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
894
perror("sigprocmask");
896
exitstatus = EXIT_FAILURE;
900
new_plugin->pid = pid;
901
new_plugin->fd = pipefd[0];
903
/* Unblock SIGCHLD so signal handler can be run if this process
904
has already completed */
905
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
907
perror("sigprocmask");
908
exitstatus = EXIT_FAILURE;
912
FD_SET(new_plugin->fd, &rfds_all);
914
if (maxfd < new_plugin->fd){
915
maxfd = new_plugin->fd;
923
for(plugin *p = plugin_list; p != NULL; p = p->next){
928
fprintf(stderr, "No plugin processes started. Incorrect plugin"
934
/* Main loop while running plugins exist */
936
fd_set rfds = rfds_all;
937
int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);
938
if (select_ret == -1){
940
exitstatus = EXIT_FAILURE;
943
/* OK, now either a process completed, or something can be read
945
for(plugin *proc = plugin_list; proc != NULL; proc = proc->next){
946
/* Is this process completely done? */
947
if(proc->eof and proc->completed){
948
/* Only accept the plugin output if it exited cleanly */
949
if(not WIFEXITED(proc->status)
950
or WEXITSTATUS(proc->status) != 0){
951
/* Bad exit by plugin */
954
if(WIFEXITED(proc->status)){
955
fprintf(stderr, "Plugin %u exited with status %d\n",
956
(unsigned int) (proc->pid),
957
WEXITSTATUS(proc->status));
958
} else if(WIFSIGNALED(proc->status)) {
959
fprintf(stderr, "Plugin %u killed by signal %d\n",
960
(unsigned int) (proc->pid),
961
WTERMSIG(proc->status));
962
} else if(WCOREDUMP(proc->status)){
963
fprintf(stderr, "Plugin %d dumped core\n",
964
(unsigned int) (proc->pid));
968
/* Remove the plugin */
969
FD_CLR(proc->fd, &rfds_all);
971
/* Block signal while modifying process_list */
972
ret = sigprocmask(SIG_BLOCK, &sigchld_action.sa_mask, NULL);
974
perror("sigprocmask");
975
exitstatus = EXIT_FAILURE;
979
/* We are done modifying process list, so unblock signal */
980
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask,
983
perror("sigprocmask");
984
exitstatus = EXIT_FAILURE;
988
if(plugin_list == NULL){
994
/* This process exited nicely, so print its buffer */
996
bool bret = print_out_password(proc->buffer,
997
proc->buffer_length);
999
perror("print_out_password");
1000
exitstatus = EXIT_FAILURE;
1005
/* This process has not completed. Does it have any output? */
1006
if(proc->eof or not FD_ISSET(proc->fd, &rfds)){
1007
/* This process had nothing to say at this time */
1010
/* Before reading, make the process' data buffer large enough */
1011
if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
1012
proc->buffer = realloc(proc->buffer, proc->buffer_size
1013
+ (size_t) BUFFER_SIZE);
1014
if (proc->buffer == NULL){
1016
exitstatus = EXIT_FAILURE;
1019
proc->buffer_size += BUFFER_SIZE;
1021
/* Read from the process */
1022
ret = read(proc->fd, proc->buffer + proc->buffer_length,
1025
/* Read error from this process; ignore the error */
1032
proc->buffer_length += (size_t) ret;
1040
if(plugin_list == NULL or exitstatus != EXIT_SUCCESS){
1041
/* Fallback if all plugins failed, none are found or an error
1044
fprintf(stderr, "Going to fallback mode using getpass(3)\n");
1045
char *passwordbuffer = getpass("Password: ");
1046
bret = print_out_password(passwordbuffer, strlen(passwordbuffer));
1048
perror("print_out_password");
1049
exitstatus = EXIT_FAILURE;
1053
/* Restore old signal handler */
1054
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1056
perror("sigaction");
1057
exitstatus = EXIT_FAILURE;
1060
if(custom_argv != NULL){
1061
for(char **arg = custom_argv+1; *arg != NULL; arg++){
1071
/* Free the process list and kill the processes */
1072
for(plugin *p = plugin_list; p != NULL; p = p->next){
1075
ret = kill(p->pid, SIGTERM);
1076
if(ret == -1 and errno != ESRCH){
1077
/* Set-uid proccesses might not get closed */
1083
/* Wait for any remaining child processes to terminate */
1087
if(errno != ECHILD){