/mandos/trunk

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/trunk
237.1.2 by Teddy Hogeborn
Further steps towards a D-Bus server interface, plus minor syntax
1
/*  -*- coding: utf-8 -*- */
2
/*
261 by Teddy Hogeborn
* plugins.d/askpass-fifo.c: Fix name in header.
3
 * Splashy - Read a password from splashy and output it
237.1.2 by Teddy Hogeborn
Further steps towards a D-Bus server interface, plus minor syntax
4
 * 
246 by Teddy Hogeborn
* README: Update copyright year; add "2009".
5
 * Copyright © 2008,2009 Teddy Hogeborn
6
 * Copyright © 2008,2009 Björn Påhlsson
237.1.2 by Teddy Hogeborn
Further steps towards a D-Bus server interface, plus minor syntax
7
 * 
8
 * This program is free software: you can redistribute it and/or
9
 * modify it under the terms of the GNU General Public License as
10
 * published by the Free Software Foundation, either version 3 of the
11
 * License, or (at your option) any later version.
12
 * 
13
 * This program is distributed in the hope that it will be useful, but
14
 * WITHOUT ANY WARRANTY; without even the implied warranty of
15
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16
 * General Public License for more details.
17
 * 
18
 * You should have received a copy of the GNU General Public License
19
 * along with this program.  If not, see
20
 * <http://www.gnu.org/licenses/>.
21
 * 
22
 * Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
23
 * <https://www.fukt.bsnet.se/~teddy/>.
24
 */
25
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
26
#define _GNU_SOURCE		/* asprintf() */
27
#include <signal.h>		/* sig_atomic_t, struct sigaction,
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
28
				   sigemptyset(), sigaddset(), SIGINT,
29
				   SIGHUP, SIGTERM, sigaction,
30
				   SIG_IGN, kill(), SIGKILL */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
31
#include <stddef.h>		/* NULL */
32
#include <stdlib.h>		/* getenv() */
264 by Teddy Hogeborn
* plugin-runner.c (main): Use "sscanf" instead of "strtol"; using the
33
#include <stdio.h>		/* asprintf(), perror(), sscanf() */
34
#include <stdlib.h>		/* EXIT_FAILURE, free(),
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
35
				   EXIT_SUCCESS */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
36
#include <sys/types.h>		/* pid_t, DIR, struct dirent,
37
				   ssize_t */
38
#include <dirent.h>		/* opendir(), readdir(), closedir() */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
39
#include <sys/stat.h>		/* struct stat, lstat(), S_ISLNK */
40
#include <iso646.h>		/* not, or, and */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
41
#include <unistd.h>		/* readlink(), fork(), execl(),
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
42
				   sleep(), dup2() STDERR_FILENO,
43
				   STDOUT_FILENO, _exit() */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
44
#include <string.h>		/* memcmp() */
45
#include <errno.h>		/* errno */
46
#include <sys/wait.h>		/* waitpid(), WIFEXITED(),
47
				   WEXITSTATUS() */
48
49
sig_atomic_t interrupted_by_signal = 0;
50
51
static void termination_handler(__attribute__((unused))int signum){
52
  interrupted_by_signal = 1;
53
}
54
208 by Teddy Hogeborn
* Makefile (PLUGINS): Added "plugins.d/usplash".
55
int main(__attribute__((unused))int argc,
56
	 __attribute__((unused))char **argv){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
57
  int ret = 0;
58
  
59
  /* Create prompt string */
60
  char *prompt = NULL;
61
  {
62
    const char *const cryptsource = getenv("cryptsource");
63
    const char *const crypttarget = getenv("crypttarget");
64
    const char *const prompt_start = "getpass "
65
      "Enter passphrase to unlock the disk";
66
    
67
    if(cryptsource == NULL){
68
      if(crypttarget == NULL){
69
	ret = asprintf(&prompt, "%s: ", prompt_start);
70
      } else {
71
	ret = asprintf(&prompt, "%s (%s): ", prompt_start,
72
		       crypttarget);
73
      }
74
    } else {
75
      if(crypttarget == NULL){
76
	ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
77
      } else {
78
	ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
79
		       cryptsource, crypttarget);
80
      }
81
    }
82
    if(ret == -1){
83
      return EXIT_FAILURE;
84
    }
85
  }
86
  
87
  /* Find splashy process */
88
  pid_t splashy_pid = 0;
89
  {
90
    const char splashy_name[] = "/sbin/splashy";
91
    DIR *proc_dir = opendir("/proc");
92
    if(proc_dir == NULL){
93
      free(prompt);
94
      perror("opendir");
95
      return EXIT_FAILURE;
96
    }
97
    for(struct dirent *proc_ent = readdir(proc_dir);
98
	proc_ent != NULL;
99
	proc_ent = readdir(proc_dir)){
264 by Teddy Hogeborn
* plugin-runner.c (main): Use "sscanf" instead of "strtol"; using the
100
      pid_t pid;
101
      /* In the GNU C library, pid_t is always int */
102
      ret = sscanf(proc_ent->d_name, "%d", &pid);
103
      if(ret != 1){ 
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
104
	/* Not a process */
105
	continue;
106
      }
107
      /* Find the executable name by doing readlink() on the
108
	 /proc/<pid>/exe link */
109
      char exe_target[sizeof(splashy_name)];
208 by Teddy Hogeborn
* Makefile (PLUGINS): Added "plugins.d/usplash".
110
      ssize_t sret;
111
      {
112
	char *exe_link;
113
	ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
114
	if(ret == -1){
115
	  perror("asprintf");
116
	  free(prompt);
117
	  closedir(proc_dir);
118
	  return EXIT_FAILURE;
119
	}
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
120
	
121
	/* Check that it refers to a symlink owned by root:root */
122
	struct stat exe_stat;
123
	ret = lstat(exe_link, &exe_stat);
124
	if(ret == -1){
262 by Teddy Hogeborn
* plugins.d/splashy.c (main): Do not abort if a process vanishes while
125
	  if(errno == ENOENT){
126
	    free(exe_link);
127
	    continue;
128
	  }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
129
	  perror("lstat");
130
	  free(exe_link);
131
	  free(prompt);
132
	  closedir(proc_dir);
133
	  return EXIT_FAILURE;
134
	}
135
	if(not S_ISLNK(exe_stat.st_mode)
136
	   or exe_stat.st_uid != 0
137
	   or exe_stat.st_gid != 0){
138
	  free(exe_link);
139
	  continue;
140
	}
141
	
208 by Teddy Hogeborn
* Makefile (PLUGINS): Added "plugins.d/usplash".
142
	sret = readlink(exe_link, exe_target, sizeof(exe_target));
143
	free(exe_link);
144
      }
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
145
      if((sret == ((ssize_t)sizeof(exe_target)-1))
146
	 and (memcmp(splashy_name, exe_target,
147
		     sizeof(exe_target)-1) == 0)){
148
	splashy_pid = pid;
149
	break;
150
      }
151
    }
152
    closedir(proc_dir);
153
  }
154
  if(splashy_pid == 0){
155
    free(prompt);
156
    return EXIT_FAILURE;
157
  }
158
  
159
  /* Set up the signal handler */
160
  {
161
    struct sigaction old_action,
162
      new_action = { .sa_handler = termination_handler,
163
		     .sa_flags = 0 };
164
    sigemptyset(&new_action.sa_mask);
165
    sigaddset(&new_action.sa_mask, SIGINT);
166
    sigaddset(&new_action.sa_mask, SIGHUP);
167
    sigaddset(&new_action.sa_mask, SIGTERM);
168
    ret = sigaction(SIGINT, NULL, &old_action);
169
    if(ret == -1){
170
      perror("sigaction");
171
      free(prompt);
172
      return EXIT_FAILURE;
173
    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
174
    if(old_action.sa_handler != SIG_IGN){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
175
      ret = sigaction(SIGINT, &new_action, NULL);
176
      if(ret == -1){
177
	perror("sigaction");
178
	free(prompt);
179
	return EXIT_FAILURE;
180
      }
181
    }
182
    ret = sigaction(SIGHUP, NULL, &old_action);
183
    if(ret == -1){
184
      perror("sigaction");
185
      free(prompt);
186
      return EXIT_FAILURE;
187
    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
188
    if(old_action.sa_handler != SIG_IGN){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
189
      ret = sigaction(SIGHUP, &new_action, NULL);
190
      if(ret == -1){
191
	perror("sigaction");
192
	free(prompt);
193
	return EXIT_FAILURE;
194
      }
195
    }
196
    ret = sigaction(SIGTERM, NULL, &old_action);
197
    if(ret == -1){
198
      perror("sigaction");
199
      free(prompt);
200
      return EXIT_FAILURE;
201
    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
202
    if(old_action.sa_handler != SIG_IGN){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
203
      ret = sigaction(SIGTERM, &new_action, NULL);
204
      if(ret == -1){
205
	perror("sigaction");
206
	free(prompt);
207
	return EXIT_FAILURE;
208
      }
209
    }
210
  }
211
  
212
  /* Fork off the splashy command to prompt for password */
213
  pid_t splashy_command_pid = 0;
214
  if(not interrupted_by_signal){
215
    splashy_command_pid = fork();
216
    if(splashy_command_pid == -1){
217
      if(not interrupted_by_signal){
218
	perror("fork");
219
      }
220
      return EXIT_FAILURE;
221
    }
222
    /* Child */
223
    if(splashy_command_pid == 0){
224
      const char splashy_command[] = "/sbin/splashy_update";
225
      ret = execl(splashy_command, splashy_command, prompt,
226
		  (char *)NULL);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
227
      if(not interrupted_by_signal){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
228
	perror("execl");
229
      }
230
      free(prompt);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
231
      _exit(EXIT_FAILURE);
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
232
    }
233
  }
234
  
235
  /* Parent */
236
  free(prompt);
237
  
238
  /* Wait for command to complete */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
239
  if(not interrupted_by_signal and splashy_command_pid != 0){
240
    int status;
241
    ret = waitpid(splashy_command_pid, &status, 0);
242
    if(ret == -1){
243
      if(errno != EINTR){
244
	perror("waitpid");
245
      }
246
      if(errno == ECHILD){
247
	splashy_command_pid = 0;
248
      }
249
    } else {
250
      /* The child process has exited */
251
      splashy_command_pid = 0;
252
      if(not interrupted_by_signal and WIFEXITED(status)
253
	 and WEXITSTATUS(status)==0){
254
	return EXIT_SUCCESS;
255
      }
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
256
    }
257
  }
258
  kill(splashy_pid, SIGTERM);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
259
  if(interrupted_by_signal and splashy_command_pid != 0){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
260
    kill(splashy_command_pid, SIGTERM);
261
  }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
262
  sleep(2);
263
  while(kill(splashy_pid, 0) == 0){
264
    kill(splashy_pid, SIGKILL);
265
    sleep(1);
266
  }
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
267
  pid_t new_splashy_pid = fork();
268
  if(new_splashy_pid == 0){
207 by Teddy Hogeborn
* plugins.d/splashy.c (main): Bug fix: free "exe_link".
269
    /* Child; will become new splashy process */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
270
    
271
    /* Make the effective user ID (root) the only user ID instead of
265 by Teddy Hogeborn
* plugin-runner.c (main): Bug fix; do not accept a "d" character after
272
       the real user ID (_mandos) */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
273
    ret = setuid(geteuid());
274
    if(ret == -1){
275
      perror("setuid");
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
276
    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
277
    
278
    setsid();
279
    ret = chdir("/");
280
/*     if(fork() != 0){ */
281
/*       _exit(EXIT_SUCCESS); */
282
/*     } */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
283
    ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
284
    if(ret == -1){
285
      perror("dup2");
286
      _exit(EXIT_FAILURE);
287
    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
288
    
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
289
    execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
290
    if(not interrupted_by_signal){
291
      perror("execl");
292
    }
293
    _exit(EXIT_FAILURE);
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
294
  }
295
  
296
  return EXIT_FAILURE;
297
}