/mandos/release

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/release
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
/*  -*- coding: utf-8 -*- */
/*
 * Mandos plugin runner - Run Mandos plugins
 *
 * Copyright © 2007-2008 Teddy Hogeborn & 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 <mandos@fukt.bsnet.se>.
 */

#define _GNU_SOURCE		/* TEMP_FAILURE_RETRY() */

#include <stdio.h>		/* popen(), fileno(), fprintf(),
				   stderr, STDOUT_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, struct dirent, opendir(),
				   readdir(), closedir() */
#include <sys/stat.h>		/* struct stat, stat(), S_ISREG() */
#include <unistd.h>		/* struct stat, stat(), S_ISREG(),
				   fcntl() */
#include <fcntl.h>		/* fcntl() */
#include <stddef.h>		/* NULL */
#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>		/* struct argp_option,
				   struct argp_state, struct argp,
				   argp_parse() */

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 NULL or any plugin name */
  char **argv;
  int argc;
  bool disabled;
  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->disabled = false;
  new_plugin->next = *plugin_list;
  /* Append the new plugin to the list */
  *plugin_list = new_plugin;
  return new_plugin;
}

void addargument(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;
}

/*
 * Based on the example in the GNU LibC manual chapter 13.13 "File
 * Descriptor Flags".
 * *Note File Descriptor Flags:(libc)Descriptor Flags.
 */
int set_cloexec_flag(int fd)
{
  int ret = fcntl(fd, F_GETFD, 0);
  /* If reading the flags failed, return error indication now. */
  if(ret < 0){
    return ret;
  }
  /* Store modified flag word in the descriptor. */
  return fcntl(fd, F_SETFD, ret | FD_CLOEXEC);
}


#define BUFFER_SIZE 256

const char *argp_program_version =
  "plugbasedclient 0.9";
const char *argp_program_bug_address =
  "<mandos@fukt.bsnet.se>";

int main(int argc, char *argv[]){
  const char *plugindir = "/conf/conf.d/mandos/plugins.d";
  size_t d_name_len;
  DIR *dir;
  struct dirent *dirst;
  struct stat st;
  fd_set rfds_all;
  int ret, maxfd = 0;
  process *process_list = NULL;
  bool debug = false;
  int exitstatus = EXIT_SUCCESS;
  
  /* The options we understand. */
  struct argp_option options[] = {
    { .name = "global-options", .key = 'g',
      .arg = "OPTION[,OPTION[,...]]",
      .doc = "Options passed to all plugins" },
    { .name = "options-for", .key = 'o',
      .arg = "PLUGIN:OPTION[,OPTION[,...]]",
      .doc = "Options passed only to specified plugin" },
    { .name = "disable", .key = 'd',
      .arg = "PLUGIN",
      .doc = "Disable a specific plugin", .group = 1 },
    { .name = "plugin-dir", .key = 128,
      .arg = "DIRECTORY",
      .doc = "Specify a different plugin directory", .group = 2 },
    { .name = "debug", .key = 129,
      .doc = "Debug mode", .group = 3 },
    { .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 plugin list pointer. */
    plugin **plugins = state->input;
    switch (key) {
    case 'g':
      if (arg != NULL){
	char *p = strtok(arg, ",");
	do{
	  addargument(getplugin(NULL, plugins), p);
	  p = strtok(NULL, ",");
	} while (p);
      }
      break;
    case 'o':
      if (arg != NULL){
	char *name = strtok(arg, ":");
	char *p = strtok(NULL, ":");
	if(p){
	  p = strtok(p, ",");
	  do{
	    addargument(getplugin(name, plugins), p);
	    p = strtok(NULL, ",");
	  } while (p);
	}
      }
      break;
    case 'd':
      if (arg != NULL){
	getplugin(arg, plugins)->disabled = true;
      }
      break;
    case 128:
      plugindir = arg;
      break;
    case 129:
      debug = true;
      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 = "",
		       .doc = "Mandos plugin runner -- Run plugins" };
  
  argp_parse (&argp, argc, argv, 0, 0, &plugin_list);
  
  if(debug){
    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 - 1);
      for(char **a = p->argv; *a != NULL; a++){
	fprintf(stderr, "\tArg: %s\n", *a);
      }
    }
  }
  
  dir = opendir(plugindir);
  if(dir == NULL){
    perror("Could not open plugin dir");
    exitstatus = EXIT_FAILURE;
    goto end;
  }
  /* Set the FD_CLOEXEC flag on the directory, if possible */
  {
    int dir_fd = dirfd(dir);
    if(dir_fd >= 0){
      ret = set_cloexec_flag(dir_fd);
      if(ret < 0){
	perror("set_cloexec_flag");
	exitstatus = EXIT_FAILURE;
	goto end;
      }
    }
  }
  
  if(dir == NULL){
    fprintf(stderr, "Can not open directory\n");
    return EXIT_FAILURE;
  }
  
  FD_ZERO(&rfds_all);
  
  while(true){
    dirst = readdir(dir);
    
    // All directory entries have been processed
    if(dirst == NULL){
      break;
    }
    
    d_name_len = strlen(dirst->d_name);
    
    // Ignore dotfiles, backup files and other junk
    {
      bool bad_name = false;
      
      const char const *bad_prefixes[] = { ".", "#", NULL };
      
      const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
					   ".dpkg-old",
					   ".dpkg-divert", NULL };
      for(const char **pre = bad_prefixes; *pre != NULL; pre++){
	size_t pre_len = strlen(*pre);
	if((d_name_len >= pre_len)
	   and strncmp((dirst->d_name), *pre, pre_len) == 0){
	  if(debug){
	    fprintf(stderr, "Ignoring plugin dir entry \"%s\""
		    " with bad prefix %s\n", dirst->d_name, *pre);
	  }
	  bad_name = true;
	  break;
	}
      }
      
      if(bad_name){
	continue;
      }
      
      for(const char **suf = bad_suffixes; *suf != NULL; suf++){
	size_t suf_len = strlen(*suf);
	if((d_name_len >= suf_len)
	   and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
		== 0)){
	  if(debug){
	    fprintf(stderr, "Ignoring plugin dir entry \"%s\""
		    " with bad suffix %s\n", dirst->d_name, *suf);
	  }
	  bad_name = true;
	  break;
	}
      }
      
      if(bad_name){
	continue;
      }
    }
    
    char *filename = malloc(d_name_len + strlen(plugindir) + 2);
    if (filename == NULL){
      perror("malloc");
      exitstatus = EXIT_FAILURE;
      goto end;
    }
    strcpy(filename, plugindir);
    strcat(filename, "/");
    strcat(filename, dirst->d_name);    

    stat(filename, &st);

    if (not S_ISREG(st.st_mode)	or (access(filename, X_OK) != 0)){
      if(debug){
	fprintf(stderr, "Ignoring plugin dir entry \"%s\""
		" with bad type or mode\n", filename);
      }
      continue;
    }
    if(getplugin(dirst->d_name, &plugin_list)->disabled){
      if(debug){
	fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
		dirst->d_name);
      }
      continue;
    }
    plugin *p = getplugin(dirst->d_name, &plugin_list);
    {
      /* Add global arguments to argument list for this plugin */
      plugin *g = getplugin(NULL, &plugin_list);
      for(char **a = g->argv + 1; *a != NULL; a++){
	addargument(p, *a);
      }
    }
    int pipefd[2]; 
    ret = pipe(pipefd);
    if (ret == -1){
      perror("pipe");
      exitstatus = EXIT_FAILURE;
      goto end;
    }
    ret = set_cloexec_flag(pipefd[0]);
    if(ret < 0){
      perror("set_cloexec_flag");
      exitstatus = EXIT_FAILURE;
      goto end;
    }
    ret = set_cloexec_flag(pipefd[1]);
    if(ret < 0){
      perror("set_cloexec_flag");
      exitstatus = EXIT_FAILURE;
      goto end;
    }
    // Starting a new process to be watched
    pid_t pid = fork();
    if(pid == 0){
      /* this is the child process */
      dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
      
      if(dirfd(dir) < 0){
	/* If dir has no file descriptor, we could not set FD_CLOEXEC
	   and must close it manually  */
	closedir(dir);
      }
      if(execv(filename, p->argv) < 0){
	perror("execv");
	_exit(EXIT_FAILURE);
      }
      /* no return */
    }
    /* parent process */
    close(pipefd[1]);		/* close unused write end of pipe */
    process *new_process = malloc(sizeof(process));
    if (new_process == NULL){
      perror("malloc");
      exitstatus = EXIT_FAILURE;
      goto end;
    }
    
    *new_process = (struct process){ .pid = pid,
				     .fd = pipefd[0],
				     .next = process_list };
    FD_SET(new_process->fd, &rfds_all);
    
    if (maxfd < new_process->fd){
      maxfd = new_process->fd;
    }
    
    //List handling
    process_list = new_process;
  }
  
  /* Free the plugin list */
  for(plugin *next; plugin_list != NULL; plugin_list = next){
    next = plugin_list->next;
    free(plugin_list->argv);
    free(plugin_list);
  }
  
  closedir(dir);
  
  if (process_list == NULL){
    fprintf(stderr, "No plugin processes started, exiting\n");
    return EXIT_FAILURE;
  }
  while(true){
    fd_set rfds = rfds_all;
    int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);
    if (select_ret == -1){
      perror("select");
      exitstatus = EXIT_FAILURE;
      goto end;
    }
    for(process *proc = process_list; proc ; proc = proc->next){
      if(not FD_ISSET(proc->fd, &rfds)){
	continue;
      }
      if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
	proc->buffer = realloc(proc->buffer, proc->buffer_size
			       + (size_t) BUFFER_SIZE);
	if (proc->buffer == NULL){
	  perror("malloc");
	  exitstatus = EXIT_FAILURE;
	  goto end;
	}
	proc->buffer_size += BUFFER_SIZE;
      }
      ret = read(proc->fd, proc->buffer + proc->buffer_length,
		 BUFFER_SIZE);
      if(ret < 0){
	/* Read error from this process; ignore it */
	continue;
      }
      proc->buffer_length += (size_t) ret;
      if(ret == 0){
	/* got EOF */
	/* wait for process exit */
	int status;
	waitpid(proc->pid, &status, 0);
	if(not WIFEXITED(status) or WEXITSTATUS(status) != 0){
	  FD_CLR(proc->fd, &rfds_all);
	  continue;
	}
	for(size_t written = 0;
	    written < proc->buffer_length; written += (size_t)ret){
	  ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO,
					 proc->buffer + written,
					 proc->buffer_length
					 - written));
	  if(ret < 0){
	    perror("write");
	    exitstatus = EXIT_FAILURE;
	    goto end;
	  }
	}
	goto end;
      }
    }
  }
  
 end:
  for(process *next; process_list != NULL; process_list = next){
    close(process_list->fd);
    kill(process_list->pid, SIGTERM);
    free(process_list->buffer);
    free(process_list);
  }
  
  while(true){
    int status;
    ret = wait(&status);
    if (ret == -1){
      if(errno != ECHILD){
	perror("wait");
      }
      break;
    }
  }  
  return exitstatus;
}