3
3
* Askpass-FIFO - Read a password from a FIFO and output it
5
* Copyright © 2008-2019, 2021 Teddy Hogeborn
6
* Copyright © 2008-2019, 2021 Björn Påhlsson
8
* This file is part of Mandos.
10
* Mandos is free software: you can redistribute it and/or modify it
11
* under the terms of the GNU General Public License as published by
12
* the Free Software Foundation, either version 3 of the License, or
13
* (at your option) any later version.
15
* Mandos is distributed in the hope that it will be useful, but
5
* Copyright © 2008,2009 Teddy Hogeborn
6
* Copyright © 2008,2009 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
16
14
* WITHOUT ANY WARRANTY; without even the implied warranty of
17
15
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18
16
* General Public License for more details.
20
18
* You should have received a copy of the GNU General Public License
21
* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
19
* along with this program. If not, see
20
* <http://www.gnu.org/licenses/>.
23
* Contact the authors at <mandos@recompile.se>.
22
* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
23
* <https://www.fukt.bsnet.se/~teddy/>.
26
#define _GNU_SOURCE /* vasprintf(),
27
program_invocation_short_name */
28
#include <sys/types.h> /* uid_t, gid_t, getuid(), getgid(),
30
#include <unistd.h> /* uid_t, gid_t, ssize_t, getuid(),
31
getgid(), setgid(), setuid(),
32
read(), close(), write(),
34
#include <stdarg.h> /* va_list, va_start(), vfprintf() */
35
#include <stdio.h> /* vasprintf(), fprintf(), stderr,
37
#include <errno.h> /* program_invocation_short_name,
38
errno, EACCES, ENOTDIR, ELOOP,
39
ENAMETOOLONG, ENOSPC, EROFS,
40
ENOENT, EEXIST, EFAULT, EMFILE,
41
ENFILE, ENOMEM, EBADF, EINVAL, EIO,
43
#include <string.h> /* strerror() */
44
#include <error.h> /* error() */
45
#include <stdlib.h> /* free(), realloc(), EXIT_SUCCESS */
26
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY() */
27
#include <sys/types.h> /* ssize_t */
46
28
#include <sys/stat.h> /* mkfifo(), S_IRUSR, S_IWUSR */
47
#include <sysexits.h> /* EX_OSFILE, EX_OSERR,
48
EX_UNAVAILABLE, EX_IOERR */
29
#include <iso646.h> /* and */
30
#include <errno.h> /* errno, EEXIST */
31
#include <stdio.h> /* perror() */
32
#include <stdlib.h> /* EXIT_FAILURE, NULL, size_t, free(),
33
realloc(), EXIT_SUCCESS */
49
34
#include <fcntl.h> /* open(), O_RDONLY */
50
#include <stddef.h> /* NULL, size_t */
55
/* Function to use when printing errors */
56
__attribute__((format (gnu_printf, 3, 4)))
57
void error_plus(int status, int errnum, const char *formatstring,
63
va_start(ap, formatstring);
64
ret = vasprintf(&text, formatstring, ap);
66
fprintf(stderr, "Mandos plugin %s: ",
67
program_invocation_short_name);
68
vfprintf(stderr, formatstring, ap);
69
fprintf(stderr, ": ");
70
fprintf(stderr, "%s\n", strerror(errnum));
71
error(status, errno, "vasprintf while printing error");
73
__builtin_unreachable();
77
fprintf(stderr, "Mandos plugin ");
78
error(status, errnum, "%s", text);
80
__builtin_unreachable();
35
#include <unistd.h> /* read(), close(), write(),
85
39
int main(__attribute__((unused))int argc,
86
40
__attribute__((unused))char **argv){
94
45
const char passfifo[] = "/lib/cryptsetup/passfifo";
95
ret = mkfifo(passfifo, S_IRUSR | S_IWUSR);
102
error_plus(EX_OSFILE, errno, "mkfifo");
103
__builtin_unreachable();
108
error_plus(EX_OSERR, errno, "mkfifo");
109
__builtin_unreachable();
111
/* no "/lib/cryptsetup"? */
112
error_plus(EX_UNAVAILABLE, errno, "mkfifo");
113
__builtin_unreachable();
115
break; /* not an error */
46
ret = (int)TEMP_FAILURE_RETRY(mkfifo(passfifo, S_IRUSR | S_IWUSR));
47
if(ret == -1 and errno != EEXIST){
120
int fifo_fd = open(passfifo, O_RDONLY);
53
int fifo_fd = (int)TEMP_FAILURE_RETRY(open(passfifo, O_RDONLY));
121
54
if(fifo_fd == -1){
123
error_plus(0, errno, "open");
128
return EX_UNAVAILABLE;
141
/* Lower group privileges */
142
if(setgid(gid) == -1){
143
error_plus(0, errno, "setgid");
146
/* Lower user privileges */
147
if(setuid(uid) == -1){
148
error_plus(0, errno, "setuid");
151
59
/* Read from FIFO */
155
63
size_t buf_allocated = 0;
156
64
const size_t blocksize = 1024;
158
66
if(buf_len + blocksize > buf_allocated){
159
67
char *tmp = realloc(buf, buf_allocated + blocksize);
161
error_plus(0, errno, "realloc");
166
74
buf_allocated += blocksize;
168
sret = read(fifo_fd, buf + buf_len, buf_allocated - buf_len);
76
sret = TEMP_FAILURE_RETRY(read(fifo_fd, buf + buf_len,
77
buf_allocated - buf_len));
173
error_plus(0, errno, "read");
183
return EX_UNAVAILABLE;
186
83
buf_len += (size_t)sret;
88
TEMP_FAILURE_RETRY(close(fifo_fd));
193
90
/* Print password to stdout */
194
91
size_t written = 0;
195
92
while(written < buf_len){
196
sret = write(STDOUT_FILENO, buf + written, buf_len - written);
93
sret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO, buf + written,
201
error_plus(0, errno, "write");
214
100
written += (size_t)sret;
218
ret = close(STDOUT_FILENO);
221
error_plus(0, errno, "close");
230
104
return EXIT_SUCCESS;
added
removed
plugins.d/askpass-fifo.c
