1
/* -*- coding: utf-8 -*- */
3
* Splashy - Read a password from splashy and output it
5
* Copyright © 2008-2017 Teddy Hogeborn
6
* Copyright © 2008-2017 Björn Påhlsson
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.
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.
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/>.
22
* Contact the authors at <mandos@recompile.se>.
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(), vasprintf(), vprintf(),
34
#include <stdlib.h> /* EXIT_FAILURE, free(),
36
#include <sys/types.h> /* pid_t, DIR, struct dirent,
38
#include <dirent.h> /* opendir(), readdir(), closedir() */
39
#include <inttypes.h> /* intmax_t, strtoimax() */
40
#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
41
#include <iso646.h> /* not, or, and */
42
#include <unistd.h> /* readlink(), fork(), execl(),
43
sleep(), dup2() STDERR_FILENO,
44
STDOUT_FILENO, _exit(),
46
#include <string.h> /* memcmp(), strerror() */
47
#include <errno.h> /* errno, EACCES, ENOTDIR, ELOOP,
48
ENOENT, ENAMETOOLONG, EMFILE,
49
ENFILE, ENOMEM, ENOEXEC, EINVAL,
50
E2BIG, EFAULT, EIO, ETXTBSY,
51
EISDIR, ELIBBAD, EPERM, EINTR,
53
#include <error.h> /* error() */
54
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
56
#include <sysexits.h> /* EX_OSERR, EX_OSFILE,
58
#include <stdarg.h> /* va_list, va_start(), ... */
60
sig_atomic_t interrupted_by_signal = 0;
63
/* Function to use when printing errors */
64
__attribute__((format (gnu_printf, 3, 4)))
65
void error_plus(int status, int errnum, const char *formatstring,
71
va_start(ap, formatstring);
72
ret = vasprintf(&text, formatstring, ap);
74
fprintf(stderr, "Mandos plugin %s: ",
75
program_invocation_short_name);
76
vfprintf(stderr, formatstring, ap);
77
fprintf(stderr, ": ");
78
fprintf(stderr, "%s\n", strerror(errnum));
79
error(status, errno, "vasprintf while printing error");
82
fprintf(stderr, "Mandos plugin ");
83
error(status, errnum, "%s", text);
88
static void termination_handler(int signum){
89
if(interrupted_by_signal){
92
interrupted_by_signal = 1;
93
signal_received = signum;
96
int main(__attribute__((unused))int argc,
97
__attribute__((unused))char **argv){
100
DIR *proc_dir = NULL;
101
pid_t splashy_pid = 0;
102
pid_t splashy_command_pid = 0;
103
int exitstatus = EXIT_FAILURE;
105
/* Create prompt string */
107
const char *const cryptsource = getenv("cryptsource");
108
const char *const crypttarget = getenv("crypttarget");
109
const char *const prompt_start = "getpass "
110
"Enter passphrase to unlock the disk";
112
if(cryptsource == NULL){
113
if(crypttarget == NULL){
114
ret = asprintf(&prompt, "%s: ", prompt_start);
116
ret = asprintf(&prompt, "%s (%s): ", prompt_start,
120
if(crypttarget == NULL){
121
ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
123
ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
124
cryptsource, crypttarget);
129
exitstatus = EX_OSERR;
134
/* Find splashy process */
136
const char splashy_name[] = "/sbin/splashy";
137
proc_dir = opendir("/proc");
138
if(proc_dir == NULL){
140
error_plus(0, errno, "opendir");
147
exitstatus = EX_OSFILE;
153
exitstatus = EX_OSERR;
158
for(struct dirent *proc_ent = readdir(proc_dir);
160
proc_ent = readdir(proc_dir)){
166
tmpmax = strtoimax(proc_ent->d_name, &tmp, 10);
167
if(errno != 0 or tmp == proc_ent->d_name or *tmp != '\0'
168
or tmpmax != (pid_t)tmpmax){
174
/* Find the executable name by doing readlink() on the
175
/proc/<pid>/exe link */
176
char exe_target[sizeof(splashy_name)];
180
ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
182
error_plus(0, errno, "asprintf");
183
exitstatus = EX_OSERR;
187
/* Check that it refers to a symlink owned by root:root */
188
struct stat exe_stat;
189
ret = lstat(exe_link, &exe_stat);
196
error_plus(0, errno, "lstat");
203
exitstatus = EX_OSFILE;
206
exitstatus = EX_OSERR;
211
if(not S_ISLNK(exe_stat.st_mode)
212
or exe_stat.st_uid != 0
213
or exe_stat.st_gid != 0){
218
sret = readlink(exe_link, exe_target, sizeof(exe_target));
221
if((sret == ((ssize_t)sizeof(exe_target)-1))
222
and (memcmp(splashy_name, exe_target,
223
sizeof(exe_target)-1) == 0)){
231
if(splashy_pid == 0){
232
exitstatus = EX_UNAVAILABLE;
236
/* Set up the signal handler */
238
struct sigaction old_action,
239
new_action = { .sa_handler = termination_handler,
241
sigemptyset(&new_action.sa_mask);
242
ret = sigaddset(&new_action.sa_mask, SIGINT);
244
error_plus(0, errno, "sigaddset");
245
exitstatus = EX_OSERR;
248
ret = sigaddset(&new_action.sa_mask, SIGHUP);
250
error_plus(0, errno, "sigaddset");
251
exitstatus = EX_OSERR;
254
ret = sigaddset(&new_action.sa_mask, SIGTERM);
256
error_plus(0, errno, "sigaddset");
257
exitstatus = EX_OSERR;
260
ret = sigaction(SIGINT, NULL, &old_action);
262
error_plus(0, errno, "sigaction");
263
exitstatus = EX_OSERR;
266
if(old_action.sa_handler != SIG_IGN){
267
ret = sigaction(SIGINT, &new_action, NULL);
269
error_plus(0, errno, "sigaction");
270
exitstatus = EX_OSERR;
274
ret = sigaction(SIGHUP, NULL, &old_action);
276
error_plus(0, errno, "sigaction");
277
exitstatus = EX_OSERR;
280
if(old_action.sa_handler != SIG_IGN){
281
ret = sigaction(SIGHUP, &new_action, NULL);
283
error_plus(0, errno, "sigaction");
284
exitstatus = EX_OSERR;
288
ret = sigaction(SIGTERM, NULL, &old_action);
290
error_plus(0, errno, "sigaction");
291
exitstatus = EX_OSERR;
294
if(old_action.sa_handler != SIG_IGN){
295
ret = sigaction(SIGTERM, &new_action, NULL);
297
error_plus(0, errno, "sigaction");
298
exitstatus = EX_OSERR;
304
if(interrupted_by_signal){
308
/* Fork off the splashy command to prompt for password */
309
splashy_command_pid = fork();
310
if(splashy_command_pid != 0 and interrupted_by_signal){
313
if(splashy_command_pid == -1){
314
error_plus(0, errno, "fork");
315
exitstatus = EX_OSERR;
319
if(splashy_command_pid == 0){
320
if(not interrupted_by_signal){
321
const char splashy_command[] = "/sbin/splashy_update";
322
execl(splashy_command, splashy_command, prompt, (char *)NULL);
324
error_plus(0, errno, "execl");
330
_exit(EX_UNAVAILABLE);
345
case ELIBBAD: /* Linux only */
359
if(interrupted_by_signal){
363
/* Wait for command to complete */
367
ret = waitpid(splashy_command_pid, &status, 0);
368
} while(ret == -1 and errno == EINTR
369
and not interrupted_by_signal);
370
if(interrupted_by_signal){
374
error_plus(0, errno, "waitpid");
376
splashy_command_pid = 0;
379
/* The child process has exited */
380
splashy_command_pid = 0;
381
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
391
if(proc_dir != NULL){
392
TEMP_FAILURE_RETRY(closedir(proc_dir));
395
if(splashy_command_pid != 0){
396
TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
398
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
400
while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
401
TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
404
pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
405
if(new_splashy_pid == 0){
406
/* Child; will become new splashy process */
408
/* Make the effective user ID (root) the only user ID instead of
409
the real user ID (_mandos) */
410
ret = setuid(geteuid());
412
error_plus(0, errno, "setuid");
418
error_plus(0, errno, "chdir");
420
/* if(fork() != 0){ */
421
/* _exit(EXIT_SUCCESS); */
423
ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
425
error_plus(0, errno, "dup2");
429
execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
432
error_plus(0, errno, "execl");
438
_exit(EX_UNAVAILABLE);
451
if(interrupted_by_signal){
452
struct sigaction signal_action;
453
sigemptyset(&signal_action.sa_mask);
454
signal_action.sa_handler = SIG_DFL;
455
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
456
&signal_action, NULL));
458
error_plus(0, errno, "sigaction");
461
ret = raise(signal_received);
462
} while(ret != 0 and errno == EINTR);
464
error_plus(0, errno, "raise");
467
TEMP_FAILURE_RETRY(pause());
added
removed
plugins.d/splashy.c
