/mandos/release

/*  -*- coding: utf-8 -*- */

/*

 * Mandos plugin runner - Run Mandos plugins

 *

 * Copyright © 2007-2008 Teddy Hogeborn and Björn Påhlsson.

 * 

 * This program is free software: you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation, either version 3 of the

 * License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see

 * <http://www.gnu.org/licenses/>.

 * 

 * Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and

 * <https://www.fukt.bsnet.se/~teddy/>.

 */

#define _FORTIFY_SOURCE 2

#include <stdio.h>	/* popen, fileno */

#include <iso646.h>	/* and, or, not */

#include <sys/types.h>	/* DIR, opendir, stat, struct stat, waitpid,

			   WIFEXITED, WEXITSTATUS, wait */

#include <sys/wait.h>	/* wait */

#include <dirent.h>	/* DIR, opendir */

#include <sys/stat.h>	/* stat, struct stat */

#include <unistd.h>	/* stat, struct stat, chdir */

#include <stdlib.h>	/* EXIT_FAILURE */

#include <sys/select.h>	/* fd_set, select, FD_ZERO, FD_SET,

			   FD_ISSET */

#include <string.h>	/* strlen, strcpy, strcat */

#include <stdbool.h>	/* true */

#include <sys/wait.h>	/* waitpid, WIFEXITED, WEXITSTATUS */

#include <errno.h>	/* errno */

#include <argp.h>	/* argp */

struct process;

typedef struct process{

  pid_t pid;

  int fd;

  char *buffer;

  size_t buffer_size;

  size_t buffer_length;

  struct process *next;

} process;

typedef struct plugin{

  char *name; 		/* can be "global" and any plugin name */

  char **argv;

  int argc;

  bool disable;

  struct plugin *next;

} plugin;

plugin *getplugin(char *name, plugin **plugin_list){

  for (plugin *p = *plugin_list; p != NULL; p = p->next){

    if ((p->name == name)

	or (p->name and name and (strcmp(p->name, name) == 0))){

      return p;

    }

  }

  /* Create a new plugin */

  plugin *new_plugin = malloc(sizeof(plugin));

  if (new_plugin == NULL){

    perror("malloc");

    exit(EXIT_FAILURE);

  }

  new_plugin->name = name;

  new_plugin->argv = malloc(sizeof(char *) * 2);

  if (new_plugin->argv == NULL){

    perror("malloc");

    exit(EXIT_FAILURE);

  }

  new_plugin->argv[0] = name;

  new_plugin->argv[1] = NULL;

  new_plugin->argc = 1;

  new_plugin->disable = false;

  new_plugin->next = *plugin_list;

  /* Append the new plugin to the list */

  *plugin_list = new_plugin;

  return new_plugin;

}

void addarguments(plugin *p, char *arg){

  p->argv[p->argc] = arg;

  p->argv = realloc(p->argv, sizeof(char *) * (size_t)(p->argc + 2));

  if (p->argv == NULL){

    perror("malloc");

    exit(EXIT_FAILURE);

  }

  p->argc++;

  p->argv[p->argc] = NULL;

}

#define BUFFER_SIZE 256

const char *argp_program_version =

  "plugbasedclient 0.9";

const char *argp_program_bug_address =

  "<mandos@fukt.bsnet.se>";

static char doc[] =

  "Mandos plugin runner -- Run Mandos plugins";

/* A description of the arguments we accept. */

static char args_doc[] = "";

int main(int argc, char *argv[]){

  const char *plugindir = "plugins.d";

  size_t d_name_len;

  DIR *dir;

  struct dirent *dirst;

  struct stat st;

  fd_set rfds_orig;

  int ret, maxfd = 0;

  process *process_list = NULL;

  uid_t uid = 65534;

  gid_t gid = 65534;

  /* The options we understand. */

  struct argp_option options[] = {

    { .name = "global-options", .key = 'g',

      .arg = "option[,option[,...]]", .flags = 0,

      .doc = "Options effecting all plugins" },

    { .name = "options-for", .key = 'o',

      .arg = "plugin:option[,option[,...]]", .flags = 0,

      .doc = "Options effecting only specified plugins" },

    { .name = "disable-plugin", .key = 'd',

      .arg = "Plugin[,Plugin[,...]]", .flags = 0,

      .doc = "Option to disable specififed plugins" },

    { .name = "plugin-dir", .key = 128,

      .arg = "Directory", .flags = 0,

      .doc = "Option to change directory to search for plugins" },

    { .name = "userid", .key = 129,

      .arg = "Id", .flags = 0,

      .doc = "Option to change which user id the plugins will run as" },

    { .name = "groupid", .key = 130,

      .arg = "Id", .flags = 0,

      .doc = "Option to change which group id the plugins will run as" },

    { .name = NULL }

  };

  error_t parse_opt (int key, char *arg, struct argp_state *state) {

       /* Get the INPUT argument from `argp_parse', which we

          know is a pointer to our arguments structure. */

    plugin **plugins = state->input;

    switch (key) {

    case 'g':

      if (arg != NULL){

	char *p = strtok(arg, ",");

	do{

	  addarguments(getplugin(NULL, plugins), p);

	  p = strtok(NULL, ",");

	} while (p);

      }

      break;

    case 'o':

      if (arg != NULL){

	char *name = strtok(arg, ":");

	char *p = strtok(NULL, ":");

	p = strtok(p, ",");

	do{

	  addarguments(getplugin(name, plugins), p);

	  p = strtok(NULL, ",");

	} while (p);

      }

      break;

    case 'd':

      if (arg != NULL){

	char *p = strtok(arg, ",");

	do{

	  getplugin(p, plugins)->disable = true;

	  p = strtok(NULL, ",");

	} while (p);

      }

      break;

    case 128:

      plugindir = arg;

      break;

    case 129:

      uid = (uid_t)strtol(arg, NULL, 10);

      break;

    case 130:

      gid = (gid_t)strtol(arg, NULL, 10);

      break;

    case ARGP_KEY_ARG:

      argp_usage (state);

      break;

    case ARGP_KEY_END:

      break;

    default:

      return ARGP_ERR_UNKNOWN;

    }

    return 0;

  }

  plugin *plugin_list = NULL;

  struct argp argp = { .options = options, .parser = parse_opt,

		       .args_doc = args_doc, .doc = doc };

  argp_parse (&argp, argc, argv, 0, 0, &plugin_list);

/*   for(plugin *p = plugin_list; p != NULL; p=p->next){ */

/*     fprintf(stderr, "Plugin: %s has %d arguments\n", p->name ? p->name : "Global", p->argc); */

/*     for(char **a = p->argv + 1; *a != NULL; a++){ */

/*       fprintf(stderr, "\tArg: %s\n", *a); */

/*     } */

/*   } */

/*   return 0; */

  ret = setuid(uid);

  if (ret == -1){

    perror("setuid");

  }

  setgid(gid);

  if (ret == -1){

    perror("setuid");

  }

  dir = opendir(plugindir);

  if(dir == NULL){

    fprintf(stderr, "Can not open directory\n");

    return EXIT_FAILURE;

  }

  FD_ZERO(&rfds_orig);

  while(true){

    dirst = readdir(dir);

    // All directory entries have been processed

    if(dirst == NULL){

      break;

    }

    d_name_len = strlen(dirst->d_name);

    // Ignore dotfiles and backup files

    if (dirst->d_name[0] == '.'

	or dirst->d_name[d_name_len - 1] == '~'){

      continue;

    }

    char *filename = malloc(d_name_len + strlen(plugindir) + 2);

    strcpy(filename, plugindir);

    strcat(filename, "/");

    strcat(filename, dirst->d_name);    

    stat(filename, &st);

    if (S_ISREG(st.st_mode)

	and (access(filename, X_OK) == 0)

	and not (getplugin(dirst->d_name, &plugin_list)->disable)){

      // Starting a new process to be watched

      process *new_process = malloc(sizeof(process));

      int pipefd[2]; 

      ret = pipe(pipefd);

      if (ret == -1){

	perror(argv[0]);

	goto end;

      }

      new_process->pid = fork();

      if(new_process->pid == 0){

	/* this is the child process */

	closedir(dir);

	close(pipefd[0]);	/* close unused read end of pipe */

	dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */

	plugin *p = getplugin(dirst->d_name, &plugin_list);

	plugin *g = getplugin(NULL, &plugin_list);

	for(char **a = g->argv + 1; *a != NULL; a++){

	  addarguments(p, *a);

	}

	if(execv(filename, p->argv) < 0){

	  perror(argv[0]);

	  close(pipefd[1]);

	  exit(EXIT_FAILURE);

	}

	/* no return */

      }

      close(pipefd[1]);		/* close unused write end of pipe */

      new_process->fd = pipefd[0];

      new_process->buffer = malloc(BUFFER_SIZE);

      if (new_process->buffer == NULL){

	perror(argv[0]);

	goto end;

      }

      new_process->buffer_size = BUFFER_SIZE;

      new_process->buffer_length = 0;

      FD_SET(new_process->fd, &rfds_orig);

      if (maxfd < new_process->fd){

	maxfd = new_process->fd;

      }

      //List handling

      new_process->next = process_list;

      process_list = new_process;

    }

  }

  closedir(dir);

  if (process_list != NULL){

    while(true){

      fd_set rfds = rfds_orig;

      int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);

      if (select_ret == -1){

	perror(argv[0]);

	goto end;

      }else{	

	for(process *process_itr = process_list; process_itr != NULL;

	    process_itr = process_itr->next){

	  if(FD_ISSET(process_itr->fd, &rfds)){

	    if(process_itr->buffer_length + BUFFER_SIZE

	       > process_itr->buffer_size){

		process_itr->buffer = realloc(process_itr->buffer,

					      process_itr->buffer_size

					      + (size_t) BUFFER_SIZE);

		if (process_itr->buffer == NULL){

		  perror(argv[0]);

		  goto end;

		}

		process_itr->buffer_size += BUFFER_SIZE;

	    }

	    ret = read(process_itr->fd, process_itr->buffer

		       + process_itr->buffer_length, BUFFER_SIZE);

	    if(ret < 0){

	      /* Read error from this process; ignore it */

	      continue;

	    }

	    process_itr->buffer_length += (size_t) ret;

	    if(ret == 0){

	      /* got EOF */

	      /* wait for process exit */

	      int status;

	      waitpid(process_itr->pid, &status, 0);

	      if(WIFEXITED(status) and WEXITSTATUS(status) == 0){

		for(size_t written = 0;

		    written < process_itr->buffer_length;){

		  ret = write(STDOUT_FILENO,

			      process_itr->buffer + written,

			      process_itr->buffer_length - written);

		  if(ret < 0){

		    perror(argv[0]);

		    goto end;

		  }

		  written += (size_t)ret;

		}

		goto end;

	      } else {

		FD_CLR(process_itr->fd, &rfds_orig);

	      }

	    }

	  }

	}

      }

    }

  }

 end:

  for(process *process_itr = process_list; process_itr != NULL;

      process_itr = process_itr->next){

    close(process_itr->fd);

    kill(process_itr->pid, SIGTERM);

    free(process_itr->buffer);

  }

  while(true){

    int status;

    ret = wait(&status);

    if (ret == -1){

      if(errno != ECHILD){

	perror("wait");

      }

      break;

    }

  }  

  return EXIT_SUCCESS;

}