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- Committer: Teddy Hogeborn
- Date: 2008-09-04 07:30:58 UTC
- mfrom: (24.1.87 mandos)
- Revision ID: teddy@fukt.bsnet.se-20080904073058-h21spydersnh8jml
* README: Improved wording.
- 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,
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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(),
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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(),
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sleep(), dup2() STDERR_FILENO,
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STDOUT_FILENO, _exit(),
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pause() */
45
#include <string.h> /* memcmp() */
46
#include <errno.h> /* errno */
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#include <sys/wait.h> /* waitpid(), WIFEXITED(),
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WEXITSTATUS() */
49
50
#include <sysexits.h> /* EX_OSERR, EX_OSFILE,
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EX_UNAVAILABLE */
52
53
sig_atomic_t interrupted_by_signal = 0;
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int signal_received;
55
56
static void termination_handler(int signum){
57
if(interrupted_by_signal){
58
return;
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}
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interrupted_by_signal = 1;
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signal_received = signum;
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}
63
64
int main(__attribute__((unused))int argc,
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__attribute__((unused))char **argv){
66
int ret = 0;
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char *prompt = NULL;
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DIR *proc_dir = NULL;
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pid_t splashy_pid = 0;
70
pid_t splashy_command_pid = 0;
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int exitstatus = EXIT_FAILURE;
72
73
/* Create prompt string */
74
{
75
const char *const cryptsource = getenv("cryptsource");
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const char *const crypttarget = getenv("crypttarget");
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const char *const prompt_start = "getpass "
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"Enter passphrase to unlock the disk";
79
80
if(cryptsource == NULL){
81
if(crypttarget == NULL){
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ret = asprintf(&prompt, "%s: ", prompt_start);
83
} else {
84
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
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crypttarget);
86
}
87
} else {
88
if(crypttarget == NULL){
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ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
90
} else {
91
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
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cryptsource, crypttarget);
93
}
94
}
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if(ret == -1){
96
prompt = NULL;
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exitstatus = EX_OSERR;
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goto failure;
99
}
100
}
101
102
/* Find splashy process */
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{
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const char splashy_name[] = "/sbin/splashy";
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proc_dir = opendir("/proc");
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if(proc_dir == NULL){
107
int e = errno;
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perror("opendir");
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switch(e){
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case EACCES:
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case ENOTDIR:
112
case ELOOP:
113
case ENOENT:
114
default:
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exitstatus = EX_OSFILE;
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break;
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case ENAMETOOLONG:
118
case EMFILE:
119
case ENFILE:
120
case ENOMEM:
121
exitstatus = EX_OSERR;
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break;
123
}
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goto failure;
125
}
126
for(struct dirent *proc_ent = readdir(proc_dir);
127
proc_ent != NULL;
128
proc_ent = readdir(proc_dir)){
129
pid_t pid;
130
{
131
intmax_t tmpmax;
132
char *tmp;
133
errno = 0;
134
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
135
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
136
or tmpmax != (pid_t)tmpmax){
137
/* Not a process */
138
continue;
139
}
140
pid = (pid_t)tmpmax;
141
}
142
/* Find the executable name by doing readlink() on the
143
/proc/<pid>/exe link */
144
char exe_target[sizeof(splashy_name)];
145
ssize_t sret;
146
{
147
char *exe_link;
148
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
149
if(ret == -1){
150
perror("asprintf");
151
exitstatus = EX_OSERR;
152
goto failure;
153
}
154
155
/* Check that it refers to a symlink owned by root:root */
156
struct stat exe_stat;
157
ret = lstat(exe_link, &exe_stat);
158
if(ret == -1){
159
if(errno == ENOENT){
160
free(exe_link);
161
continue;
162
}
163
int e = errno;
164
perror("lstat");
165
free(exe_link);
166
switch(e){
167
case EACCES:
168
case ENOTDIR:
169
case ELOOP:
170
default:
171
exitstatus = EX_OSFILE;
172
break;
173
case ENAMETOOLONG:
174
exitstatus = EX_OSERR;
175
break;
176
}
177
goto failure;
178
}
179
if(not S_ISLNK(exe_stat.st_mode)
180
or exe_stat.st_uid != 0
181
or exe_stat.st_gid != 0){
182
free(exe_link);
183
continue;
184
}
185
186
sret = readlink(exe_link, exe_target, sizeof(exe_target));
187
free(exe_link);
188
}
189
if((sret == ((ssize_t)sizeof(exe_target)-1))
190
and (memcmp(splashy_name, exe_target,
191
sizeof(exe_target)-1) == 0)){
192
splashy_pid = pid;
193
break;
194
}
195
}
196
closedir(proc_dir);
197
proc_dir = NULL;
198
}
199
if(splashy_pid == 0){
200
exitstatus = EX_UNAVAILABLE;
201
goto failure;
202
}
203
204
/* Set up the signal handler */
205
{
206
struct sigaction old_action,
207
new_action = { .sa_handler = termination_handler,
208
.sa_flags = 0 };
209
sigemptyset(&new_action.sa_mask);
210
ret = sigaddset(&new_action.sa_mask, SIGINT);
211
if(ret == -1){
212
perror("sigaddset");
213
exitstatus = EX_OSERR;
214
goto failure;
215
}
216
ret = sigaddset(&new_action.sa_mask, SIGHUP);
217
if(ret == -1){
218
perror("sigaddset");
219
exitstatus = EX_OSERR;
220
goto failure;
221
}
222
ret = sigaddset(&new_action.sa_mask, SIGTERM);
223
if(ret == -1){
224
perror("sigaddset");
225
exitstatus = EX_OSERR;
226
goto failure;
227
}
228
ret = sigaction(SIGINT, NULL, &old_action);
229
if(ret == -1){
230
perror("sigaction");
231
exitstatus = EX_OSERR;
232
goto failure;
233
}
234
if(old_action.sa_handler != SIG_IGN){
235
ret = sigaction(SIGINT, &new_action, NULL);
236
if(ret == -1){
237
perror("sigaction");
238
exitstatus = EX_OSERR;
239
goto failure;
240
}
241
}
242
ret = sigaction(SIGHUP, NULL, &old_action);
243
if(ret == -1){
244
perror("sigaction");
245
exitstatus = EX_OSERR;
246
goto failure;
247
}
248
if(old_action.sa_handler != SIG_IGN){
249
ret = sigaction(SIGHUP, &new_action, NULL);
250
if(ret == -1){
251
perror("sigaction");
252
exitstatus = EX_OSERR;
253
goto failure;
254
}
255
}
256
ret = sigaction(SIGTERM, NULL, &old_action);
257
if(ret == -1){
258
perror("sigaction");
259
exitstatus = EX_OSERR;
260
goto failure;
261
}
262
if(old_action.sa_handler != SIG_IGN){
263
ret = sigaction(SIGTERM, &new_action, NULL);
264
if(ret == -1){
265
perror("sigaction");
266
exitstatus = EX_OSERR;
267
goto failure;
268
}
269
}
270
}
271
272
if(interrupted_by_signal){
273
goto failure;
274
}
275
276
/* Fork off the splashy command to prompt for password */
277
splashy_command_pid = fork();
278
if(splashy_command_pid != 0 and interrupted_by_signal){
279
goto failure;
280
}
281
if(splashy_command_pid == -1){
282
perror("fork");
283
exitstatus = EX_OSERR;
284
goto failure;
285
}
286
/* Child */
287
if(splashy_command_pid == 0){
288
if(not interrupted_by_signal){
289
const char splashy_command[] = "/sbin/splashy_update";
290
execl(splashy_command, splashy_command, prompt, (char *)NULL);
291
perror("execl");
292
}
293
free(prompt);
294
_exit(EXIT_FAILURE);
295
}
296
297
/* Parent */
298
free(prompt);
299
prompt = NULL;
300
301
if(interrupted_by_signal){
302
goto failure;
303
}
304
305
/* Wait for command to complete */
306
{
307
int status;
308
do {
309
ret = waitpid(splashy_command_pid, &status, 0);
310
} while(ret == -1 and errno == EINTR
311
and not interrupted_by_signal);
312
if(interrupted_by_signal){
313
goto failure;
314
}
315
if(ret == -1){
316
perror("waitpid");
317
if(errno == ECHILD){
318
splashy_command_pid = 0;
319
}
320
} else {
321
/* The child process has exited */
322
splashy_command_pid = 0;
323
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
324
return EXIT_SUCCESS;
325
}
326
}
327
}
328
329
failure:
330
331
free(prompt);
332
333
if(proc_dir != NULL){
334
TEMP_FAILURE_RETRY(closedir(proc_dir));
335
}
336
337
if(splashy_command_pid != 0){
338
TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
339
340
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
341
sleep(2);
342
while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
343
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
344
sleep(1);
345
}
346
pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
347
if(new_splashy_pid == 0){
348
/* Child; will become new splashy process */
349
350
/* Make the effective user ID (root) the only user ID instead of
351
the real user ID (_mandos) */
352
ret = setuid(geteuid());
353
if(ret == -1){
354
perror("setuid");
355
}
356
357
setsid();
358
ret = chdir("/");
359
if(ret == -1){
360
perror("chdir");
361
}
362
/* if(fork() != 0){ */
363
/* _exit(EXIT_SUCCESS); */
364
/* } */
365
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
366
if(ret == -1){
367
perror("dup2");
368
_exit(EX_OSERR);
369
}
370
371
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
372
{
373
int e = errno;
374
perror("execl");
375
switch(e){
376
case EACCES:
377
case ENOENT:
378
case ENOEXEC:
379
default:
380
_exit(EX_UNAVAILABLE);
381
case ENAMETOOLONG:
382
case E2BIG:
383
case ENOMEM:
384
_exit(EX_OSERR);
385
case ENOTDIR:
386
case ELOOP:
387
_exit(EX_OSFILE);
388
}
389
}
390
}
391
}
392
393
if(interrupted_by_signal){
394
struct sigaction signal_action;
395
sigemptyset(&signal_action.sa_mask);
396
signal_action.sa_handler = SIG_DFL;
397
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
398
&signal_action, NULL));
399
if(ret == -1){
400
perror("sigaction");
401
}
402
do {
403
ret = raise(signal_received);
404
} while(ret != 0 and errno == EINTR);
405
if(ret != 0){
406
perror("raise");
407
abort();
408
}
409
TEMP_FAILURE_RETRY(pause());
410
}
411
412
return exitstatus;
413
}
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