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- Committer: Teddy Hogeborn
- Date: 2009-09-17 04:16:32 UTC
- Revision ID: teddy@fukt.bsnet.se-20090917041632-7m1rm83pxguw5zw7
* plugins.d/usplash.c (main): Bug fix: only close FIFO if opened.
- files added:
- debian/watch
- files removed:
- debian/mandos-client.config
- files modified:
- INSTALL
added
removed
plugins.d/splashy.c
1
#define _GNU_SOURCE /* asprintf() */
1
/* -*- coding: utf-8 -*- */
2
/*
3
* Splashy - Read a password from splashy and output it
4
*
5
* Copyright © 2008,2009 Teddy Hogeborn
6
* Copyright © 2008,2009 Björn Påhlsson
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 <mandos@fukt.bsnet.se>.
23
*/
24
25
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
2
26
#include <signal.h> /* sig_atomic_t, struct sigaction,
3
27
sigemptyset(), sigaddset(), SIGINT,
4
28
SIGHUP, SIGTERM, sigaction,
6
30
#include <stddef.h> /* NULL */
7
31
#include <stdlib.h> /* getenv() */
8
32
#include <stdio.h> /* asprintf(), perror() */
9
#include <stdlib.h> /* EXIT_FAILURE, free(), strtoul(),
33
#include <stdlib.h> /* EXIT_FAILURE, free(),
10
34
EXIT_SUCCESS */
11
35
#include <sys/types.h> /* pid_t, DIR, struct dirent,
12
36
ssize_t */
13
37
#include <dirent.h> /* opendir(), readdir(), closedir() */
38
#include <inttypes.h> /* intmax_t, strtoimax() */
14
39
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
15
40
#include <iso646.h> /* not, or, and */
16
41
#include <unistd.h> /* readlink(), fork(), execl(),
17
42
sleep(), dup2() STDERR_FILENO,
18
STDOUT_FILENO, _exit() */
43
STDOUT_FILENO, _exit(),
44
pause() */
19
45
#include <string.h> /* memcmp() */
20
46
#include <errno.h> /* errno */
21
47
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
22
48
WEXITSTATUS() */
23
49
24
50
sig_atomic_t interrupted_by_signal = 0;
51
int signal_received;
25
52
26
static void termination_handler(__attribute__((unused))int signum){
53
static void termination_handler(int signum){
54
if(interrupted_by_signal){
55
return;
56
}
27
57
interrupted_by_signal = 1;
58
signal_received = signum;
28
59
}
29
60
30
61
int main(__attribute__((unused))int argc,
31
62
__attribute__((unused))char **argv){
32
63
int ret = 0;
64
char *prompt = NULL;
65
DIR *proc_dir = NULL;
66
pid_t splashy_pid = 0;
67
pid_t splashy_command_pid = 0;
33
68
34
69
/* Create prompt string */
35
char *prompt = NULL;
36
70
{
37
71
const char *const cryptsource = getenv("cryptsource");
38
72
const char *const crypttarget = getenv("crypttarget");
55
89
}
56
90
}
57
91
if(ret == -1){
58
return EXIT_FAILURE;
92
prompt = NULL;
93
goto failure;
59
94
}
60
95
}
61
96
62
97
/* Find splashy process */
63
pid_t splashy_pid = 0;
64
98
{
65
99
const char splashy_name[] = "/sbin/splashy";
66
DIR *proc_dir = opendir("/proc");
100
proc_dir = opendir("/proc");
67
101
if(proc_dir == NULL){
68
free(prompt);
69
102
perror("opendir");
70
return EXIT_FAILURE;
103
goto failure;
71
104
}
72
105
for(struct dirent *proc_ent = readdir(proc_dir);
73
106
proc_ent != NULL;
74
107
proc_ent = readdir(proc_dir)){
75
pid_t pid = (pid_t) strtoul(proc_ent->d_name, NULL, 10);
76
if(pid == 0){
77
/* Not a process */
78
continue;
108
pid_t pid;
109
{
110
intmax_t tmpmax;
111
char *tmp;
112
errno = 0;
113
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
114
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
115
or tmpmax != (pid_t)tmpmax){
116
/* Not a process */
117
continue;
118
}
119
pid = (pid_t)tmpmax;
79
120
}
80
121
/* Find the executable name by doing readlink() on the
81
122
/proc/<pid>/exe link */
86
127
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
87
128
if(ret == -1){
88
129
perror("asprintf");
89
free(prompt);
90
closedir(proc_dir);
91
return EXIT_FAILURE;
130
goto failure;
92
131
}
93
132
94
133
/* Check that it refers to a symlink owned by root:root */
95
134
struct stat exe_stat;
96
135
ret = lstat(exe_link, &exe_stat);
97
136
if(ret == -1){
137
if(errno == ENOENT){
138
free(exe_link);
139
continue;
140
}
98
141
perror("lstat");
99
142
free(exe_link);
100
free(prompt);
101
closedir(proc_dir);
102
return EXIT_FAILURE;
143
goto failure;
103
144
}
104
145
if(not S_ISLNK(exe_stat.st_mode)
105
146
or exe_stat.st_uid != 0
119
160
}
120
161
}
121
162
closedir(proc_dir);
163
proc_dir = NULL;
122
164
}
123
165
if(splashy_pid == 0){
124
free(prompt);
125
return EXIT_FAILURE;
166
goto failure;
126
167
}
127
168
128
169
/* Set up the signal handler */
131
172
new_action = { .sa_handler = termination_handler,
132
173
.sa_flags = 0 };
133
174
sigemptyset(&new_action.sa_mask);
134
sigaddset(&new_action.sa_mask, SIGINT);
135
sigaddset(&new_action.sa_mask, SIGHUP);
136
sigaddset(&new_action.sa_mask, SIGTERM);
175
ret = sigaddset(&new_action.sa_mask, SIGINT);
176
if(ret == -1){
177
perror("sigaddset");
178
goto failure;
179
}
180
ret = sigaddset(&new_action.sa_mask, SIGHUP);
181
if(ret == -1){
182
perror("sigaddset");
183
goto failure;
184
}
185
ret = sigaddset(&new_action.sa_mask, SIGTERM);
186
if(ret == -1){
187
perror("sigaddset");
188
goto failure;
189
}
137
190
ret = sigaction(SIGINT, NULL, &old_action);
138
191
if(ret == -1){
139
192
perror("sigaction");
140
free(prompt);
141
return EXIT_FAILURE;
193
goto failure;
142
194
}
143
195
if(old_action.sa_handler != SIG_IGN){
144
196
ret = sigaction(SIGINT, &new_action, NULL);
145
197
if(ret == -1){
146
198
perror("sigaction");
147
free(prompt);
148
return EXIT_FAILURE;
199
goto failure;
149
200
}
150
201
}
151
202
ret = sigaction(SIGHUP, NULL, &old_action);
152
203
if(ret == -1){
153
204
perror("sigaction");
154
free(prompt);
155
return EXIT_FAILURE;
205
goto failure;
156
206
}
157
207
if(old_action.sa_handler != SIG_IGN){
158
208
ret = sigaction(SIGHUP, &new_action, NULL);
159
209
if(ret == -1){
160
210
perror("sigaction");
161
free(prompt);
162
return EXIT_FAILURE;
211
goto failure;
163
212
}
164
213
}
165
214
ret = sigaction(SIGTERM, NULL, &old_action);
166
215
if(ret == -1){
167
216
perror("sigaction");
168
free(prompt);
169
return EXIT_FAILURE;
217
goto failure;
170
218
}
171
219
if(old_action.sa_handler != SIG_IGN){
172
220
ret = sigaction(SIGTERM, &new_action, NULL);
173
221
if(ret == -1){
174
222
perror("sigaction");
175
free(prompt);
176
return EXIT_FAILURE;
223
goto failure;
177
224
}
178
225
}
179
226
}
180
227
228
if(interrupted_by_signal){
229
goto failure;
230
}
231
181
232
/* Fork off the splashy command to prompt for password */
182
pid_t splashy_command_pid = 0;
183
if(not interrupted_by_signal){
184
splashy_command_pid = fork();
185
if(splashy_command_pid == -1){
186
if(not interrupted_by_signal){
187
perror("fork");
188
}
189
return EXIT_FAILURE;
190
}
191
/* Child */
192
if(splashy_command_pid == 0){
233
splashy_command_pid = fork();
234
if(splashy_command_pid != 0 and interrupted_by_signal){
235
goto failure;
236
}
237
if(splashy_command_pid == -1){
238
perror("fork");
239
goto failure;
240
}
241
/* Child */
242
if(splashy_command_pid == 0){
243
if(not interrupted_by_signal){
193
244
const char splashy_command[] = "/sbin/splashy_update";
194
ret = execl(splashy_command, splashy_command, prompt,
195
(char *)NULL);
196
if(not interrupted_by_signal){
197
perror("execl");
198
}
199
free(prompt);
200
_exit(EXIT_FAILURE);
245
execl(splashy_command, splashy_command, prompt, (char *)NULL);
246
perror("execl");
201
247
}
248
free(prompt);
249
_exit(EXIT_FAILURE);
202
250
}
203
251
204
252
/* Parent */
205
253
free(prompt);
254
prompt = NULL;
255
256
if(interrupted_by_signal){
257
goto failure;
258
}
206
259
207
260
/* Wait for command to complete */
208
if(not interrupted_by_signal and splashy_command_pid != 0){
261
{
209
262
int status;
210
ret = waitpid(splashy_command_pid, &status, 0);
263
do {
264
ret = waitpid(splashy_command_pid, &status, 0);
265
} while(ret == -1 and errno == EINTR
266
and not interrupted_by_signal);
267
if(interrupted_by_signal){
268
goto failure;
269
}
211
270
if(ret == -1){
212
if(errno != EINTR){
213
perror("waitpid");
214
}
271
perror("waitpid");
215
272
if(errno == ECHILD){
216
273
splashy_command_pid = 0;
217
274
}
218
275
} else {
219
276
/* The child process has exited */
220
277
splashy_command_pid = 0;
221
if(not interrupted_by_signal and WIFEXITED(status)
222
and WEXITSTATUS(status)==0){
278
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
223
279
return EXIT_SUCCESS;
224
280
}
225
281
}
226
282
}
227
kill(splashy_pid, SIGTERM);
228
if(interrupted_by_signal and splashy_command_pid != 0){
229
kill(splashy_command_pid, SIGTERM);
230
}
231
sleep(2);
232
while(kill(splashy_pid, 0) == 0){
233
kill(splashy_pid, SIGKILL);
234
sleep(1);
235
}
236
pid_t new_splashy_pid = fork();
237
if(new_splashy_pid == 0){
238
/* Child; will become new splashy process */
283
284
failure:
285
286
free(prompt);
287
288
if(proc_dir != NULL){
289
TEMP_FAILURE_RETRY(closedir(proc_dir));
290
}
291
292
if(splashy_command_pid != 0){
293
TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
239
294
240
/* Make the effective user ID (root) the only user ID instead of
241
the real user ID (mandos) */
242
ret = setuid(geteuid());
243
if(ret == -1){
244
perror("setuid");
295
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
296
sleep(2);
297
while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
298
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
299
sleep(1);
245
300
}
301
pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
302
if(new_splashy_pid == 0){
303
/* Child; will become new splashy process */
304
305
/* Make the effective user ID (root) the only user ID instead of
306
the real user ID (_mandos) */
307
ret = setuid(geteuid());
308
if(ret == -1){
309
perror("setuid");
310
}
311
312
setsid();
313
ret = chdir("/");
314
if(ret == -1){
315
perror("chdir");
316
}
317
/* if(fork() != 0){ */
318
/* _exit(EXIT_SUCCESS); */
319
/* } */
320
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
321
if(ret == -1){
322
perror("dup2");
323
_exit(EXIT_FAILURE);
324
}
246
325
247
setsid();
248
ret = chdir("/");
249
/* if(fork() != 0){ */
250
/* _exit(EXIT_SUCCESS); */
251
/* } */
252
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
253
if(ret == -1){
254
perror("dup2");
326
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
327
perror("execl");
255
328
_exit(EXIT_FAILURE);
256
329
}
257
258
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
259
if(not interrupted_by_signal){
260
perror("execl");
261
}
262
_exit(EXIT_FAILURE);
330
}
331
332
if(interrupted_by_signal){
333
struct sigaction signal_action;
334
sigemptyset(&signal_action.sa_mask);
335
signal_action.sa_handler = SIG_DFL;
336
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
337
&signal_action, NULL));
338
if(ret == -1){
339
perror("sigaction");
340
}
341
do {
342
ret = raise(signal_received);
343
} while(ret != 0 and errno == EINTR);
344
if(ret != 0){
345
perror("raise");
346
abort();
347
}
348
TEMP_FAILURE_RETRY(pause());
263
349
}
264
350
265
351
return EXIT_FAILURE;
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