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- Committer: Teddy Hogeborn
- Date: 2008-09-05 18:37:28 UTC
- Revision ID: teddy@fukt.bsnet.se-20080905183728-l0m8v3vqa302uwrw
* mandos (main): Use EAFP with pidfile.
- files added:
- plugins.d/usplash
- files removed:
- .bzr-builddeb
- debian
- debian/po
- files renamed:
- plugins.d/mandos-client.c => plugins.d/password-request.c
- plugins.d/mandos-client.xml => plugins.d/password-request.xml
- files modified:
- .bzrignore
added
removed
plugins.d/splashy.c
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() */
26
#include <signal.h> /* sig_atomic_t, struct sigaction,
27
sigemptyset(), sigaddset(), SIGINT,
28
SIGHUP, SIGTERM, sigaction,
29
SIG_IGN, kill(), SIGKILL */
30
#include <stddef.h> /* NULL */
31
#include <stdlib.h> /* getenv() */
32
#include <stdio.h> /* asprintf(), perror() */
33
#include <stdlib.h> /* EXIT_FAILURE, free(),
34
EXIT_SUCCESS */
35
#include <sys/types.h> /* pid_t, DIR, struct dirent,
36
ssize_t */
37
#include <dirent.h> /* opendir(), readdir(), closedir() */
38
#include <inttypes.h> /* intmax_t, strtoimax() */
39
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
40
#include <iso646.h> /* not, or, and */
41
#include <unistd.h> /* readlink(), fork(), execl(),
42
sleep(), dup2() STDERR_FILENO,
43
STDOUT_FILENO, _exit(),
44
pause() */
45
#include <string.h> /* memcmp() */
46
#include <errno.h> /* errno, EACCES, ENOTDIR, ELOOP,
47
ENOENT, ENAMETOOLONG, EMFILE,
48
ENFILE, ENOMEM, ENOEXEC, EINVAL,
49
E2BIG, EFAULT, EIO, ETXTBSY,
50
EISDIR, ELIBBAD, EPERM, EINTR,
51
ECHILD */
52
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
53
WEXITSTATUS() */
54
#include <sysexits.h> /* EX_OSERR, EX_OSFILE,
55
EX_UNAVAILABLE */
56
57
sig_atomic_t interrupted_by_signal = 0;
58
int signal_received;
59
60
static void termination_handler(int signum){
61
if(interrupted_by_signal){
62
return;
63
}
64
interrupted_by_signal = 1;
65
signal_received = signum;
66
}
67
68
int main(__attribute__((unused))int argc,
69
__attribute__((unused))char **argv){
70
int ret = 0;
71
char *prompt = NULL;
72
DIR *proc_dir = NULL;
73
pid_t splashy_pid = 0;
74
pid_t splashy_command_pid = 0;
75
int exitstatus = EXIT_FAILURE;
76
77
/* Create prompt string */
78
{
79
const char *const cryptsource = getenv("cryptsource");
80
const char *const crypttarget = getenv("crypttarget");
81
const char *const prompt_start = "getpass "
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"Enter passphrase to unlock the disk";
83
84
if(cryptsource == NULL){
85
if(crypttarget == NULL){
86
ret = asprintf(&prompt, "%s: ", prompt_start);
87
} else {
88
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
89
crypttarget);
90
}
91
} else {
92
if(crypttarget == NULL){
93
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
94
} else {
95
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
96
cryptsource, crypttarget);
97
}
98
}
99
if(ret == -1){
100
prompt = NULL;
101
exitstatus = EX_OSERR;
102
goto failure;
103
}
104
}
105
106
/* Find splashy process */
107
{
108
const char splashy_name[] = "/sbin/splashy";
109
proc_dir = opendir("/proc");
110
if(proc_dir == NULL){
111
int e = errno;
112
perror("opendir");
113
switch(e){
114
case EACCES:
115
case ENOTDIR:
116
case ELOOP:
117
case ENOENT:
118
default:
119
exitstatus = EX_OSFILE;
120
break;
121
case ENAMETOOLONG:
122
case EMFILE:
123
case ENFILE:
124
case ENOMEM:
125
exitstatus = EX_OSERR;
126
break;
127
}
128
goto failure;
129
}
130
for(struct dirent *proc_ent = readdir(proc_dir);
131
proc_ent != NULL;
132
proc_ent = readdir(proc_dir)){
133
pid_t pid;
134
{
135
intmax_t tmpmax;
136
char *tmp;
137
errno = 0;
138
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
139
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
140
or tmpmax != (pid_t)tmpmax){
141
/* Not a process */
142
continue;
143
}
144
pid = (pid_t)tmpmax;
145
}
146
/* Find the executable name by doing readlink() on the
147
/proc/<pid>/exe link */
148
char exe_target[sizeof(splashy_name)];
149
ssize_t sret;
150
{
151
char *exe_link;
152
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
153
if(ret == -1){
154
perror("asprintf");
155
exitstatus = EX_OSERR;
156
goto failure;
157
}
158
159
/* Check that it refers to a symlink owned by root:root */
160
struct stat exe_stat;
161
ret = lstat(exe_link, &exe_stat);
162
if(ret == -1){
163
if(errno == ENOENT){
164
free(exe_link);
165
continue;
166
}
167
int e = errno;
168
perror("lstat");
169
free(exe_link);
170
switch(e){
171
case EACCES:
172
case ENOTDIR:
173
case ELOOP:
174
default:
175
exitstatus = EX_OSFILE;
176
break;
177
case ENAMETOOLONG:
178
exitstatus = EX_OSERR;
179
break;
180
}
181
goto failure;
182
}
183
if(not S_ISLNK(exe_stat.st_mode)
184
or exe_stat.st_uid != 0
185
or exe_stat.st_gid != 0){
186
free(exe_link);
187
continue;
188
}
189
190
sret = readlink(exe_link, exe_target, sizeof(exe_target));
191
free(exe_link);
192
}
193
if((sret == ((ssize_t)sizeof(exe_target)-1))
194
and (memcmp(splashy_name, exe_target,
195
sizeof(exe_target)-1) == 0)){
196
splashy_pid = pid;
197
break;
198
}
199
}
200
closedir(proc_dir);
201
proc_dir = NULL;
202
}
203
if(splashy_pid == 0){
204
exitstatus = EX_UNAVAILABLE;
205
goto failure;
206
}
207
208
/* Set up the signal handler */
209
{
210
struct sigaction old_action,
211
new_action = { .sa_handler = termination_handler,
212
.sa_flags = 0 };
213
sigemptyset(&new_action.sa_mask);
214
ret = sigaddset(&new_action.sa_mask, SIGINT);
215
if(ret == -1){
216
perror("sigaddset");
217
exitstatus = EX_OSERR;
218
goto failure;
219
}
220
ret = sigaddset(&new_action.sa_mask, SIGHUP);
221
if(ret == -1){
222
perror("sigaddset");
223
exitstatus = EX_OSERR;
224
goto failure;
225
}
226
ret = sigaddset(&new_action.sa_mask, SIGTERM);
227
if(ret == -1){
228
perror("sigaddset");
229
exitstatus = EX_OSERR;
230
goto failure;
231
}
232
ret = sigaction(SIGINT, NULL, &old_action);
233
if(ret == -1){
234
perror("sigaction");
235
exitstatus = EX_OSERR;
236
goto failure;
237
}
238
if(old_action.sa_handler != SIG_IGN){
239
ret = sigaction(SIGINT, &new_action, NULL);
240
if(ret == -1){
241
perror("sigaction");
242
exitstatus = EX_OSERR;
243
goto failure;
244
}
245
}
246
ret = sigaction(SIGHUP, NULL, &old_action);
247
if(ret == -1){
248
perror("sigaction");
249
exitstatus = EX_OSERR;
250
goto failure;
251
}
252
if(old_action.sa_handler != SIG_IGN){
253
ret = sigaction(SIGHUP, &new_action, NULL);
254
if(ret == -1){
255
perror("sigaction");
256
exitstatus = EX_OSERR;
257
goto failure;
258
}
259
}
260
ret = sigaction(SIGTERM, NULL, &old_action);
261
if(ret == -1){
262
perror("sigaction");
263
exitstatus = EX_OSERR;
264
goto failure;
265
}
266
if(old_action.sa_handler != SIG_IGN){
267
ret = sigaction(SIGTERM, &new_action, NULL);
268
if(ret == -1){
269
perror("sigaction");
270
exitstatus = EX_OSERR;
271
goto failure;
272
}
273
}
274
}
275
276
if(interrupted_by_signal){
277
goto failure;
278
}
279
280
/* Fork off the splashy command to prompt for password */
281
splashy_command_pid = fork();
282
if(splashy_command_pid != 0 and interrupted_by_signal){
283
goto failure;
284
}
285
if(splashy_command_pid == -1){
286
perror("fork");
287
exitstatus = EX_OSERR;
288
goto failure;
289
}
290
/* Child */
291
if(splashy_command_pid == 0){
292
if(not interrupted_by_signal){
293
const char splashy_command[] = "/sbin/splashy_update";
294
execl(splashy_command, splashy_command, prompt, (char *)NULL);
295
int e = errno;
296
perror("execl");
297
switch(e){
298
case EACCES:
299
case ENOENT:
300
case ENOEXEC:
301
case EINVAL:
302
_exit(EX_UNAVAILABLE);
303
case ENAMETOOLONG:
304
case E2BIG:
305
case ENOMEM:
306
case EFAULT:
307
case EIO:
308
case EMFILE:
309
case ENFILE:
310
case ETXTBSY:
311
default:
312
_exit(EX_OSERR);
313
case ENOTDIR:
314
case ELOOP:
315
case EISDIR:
316
case ELIBBAD:
317
case EPERM:
318
_exit(EX_OSFILE);
319
}
320
}
321
free(prompt);
322
_exit(EXIT_FAILURE);
323
}
324
325
/* Parent */
326
free(prompt);
327
prompt = NULL;
328
329
if(interrupted_by_signal){
330
goto failure;
331
}
332
333
/* Wait for command to complete */
334
{
335
int status;
336
do {
337
ret = waitpid(splashy_command_pid, &status, 0);
338
} while(ret == -1 and errno == EINTR
339
and not interrupted_by_signal);
340
if(interrupted_by_signal){
341
goto failure;
342
}
343
if(ret == -1){
344
perror("waitpid");
345
if(errno == ECHILD){
346
splashy_command_pid = 0;
347
}
348
} else {
349
/* The child process has exited */
350
splashy_command_pid = 0;
351
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
352
return EXIT_SUCCESS;
353
}
354
}
355
}
356
357
failure:
358
359
free(prompt);
360
361
if(proc_dir != NULL){
362
TEMP_FAILURE_RETRY(closedir(proc_dir));
363
}
364
365
if(splashy_command_pid != 0){
366
TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
367
368
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
369
sleep(2);
370
while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
371
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
372
sleep(1);
373
}
374
pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
375
if(new_splashy_pid == 0){
376
/* Child; will become new splashy process */
377
378
/* Make the effective user ID (root) the only user ID instead of
379
the real user ID (_mandos) */
380
ret = setuid(geteuid());
381
if(ret == -1){
382
perror("setuid");
383
}
384
385
setsid();
386
ret = chdir("/");
387
if(ret == -1){
388
perror("chdir");
389
}
390
/* if(fork() != 0){ */
391
/* _exit(EXIT_SUCCESS); */
392
/* } */
393
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
394
if(ret == -1){
395
perror("dup2");
396
_exit(EX_OSERR);
397
}
398
399
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
400
{
401
int e = errno;
402
perror("execl");
403
switch(e){
404
case EACCES:
405
case ENOENT:
406
case ENOEXEC:
407
default:
408
_exit(EX_UNAVAILABLE);
409
case ENAMETOOLONG:
410
case E2BIG:
411
case ENOMEM:
412
_exit(EX_OSERR);
413
case ENOTDIR:
414
case ELOOP:
415
_exit(EX_OSFILE);
416
}
417
}
418
}
419
}
420
421
if(interrupted_by_signal){
422
struct sigaction signal_action;
423
sigemptyset(&signal_action.sa_mask);
424
signal_action.sa_handler = SIG_DFL;
425
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
426
&signal_action, NULL));
427
if(ret == -1){
428
perror("sigaction");
429
}
430
do {
431
ret = raise(signal_received);
432
} while(ret != 0 and errno == EINTR);
433
if(ret != 0){
434
perror("raise");
435
abort();
436
}
437
TEMP_FAILURE_RETRY(pause());
438
}
439
440
return exitstatus;
441
}
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