1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include "log.h"
#include "util.h"
#define POOL_SIZE_MIN 512
int main(int argc, char *argv[]) {
int seed_fd = -1, random_fd = -1;
int ret = EXIT_FAILURE;
void* buf;
size_t buf_size = 0;
ssize_t r;
FILE *f;
if (argc != 2) {
log_error("This program requires one argument.");
return EXIT_FAILURE;
}
log_set_target(LOG_TARGET_AUTO);
log_parse_environment();
log_open();
umask(0022);
/* Read pool size, if possible */
if ((f = fopen("/proc/sys/kernel/random/poolsize", "re"))) {
if (fscanf(f, "%zu", &buf_size) > 0) {
/* poolsize is in bits on 2.6, but we want bytes */
buf_size /= 8;
}
fclose(f);
}
if (buf_size <= POOL_SIZE_MIN)
buf_size = POOL_SIZE_MIN;
if (!(buf = malloc(buf_size))) {
log_error("Failed to allocate buffer.");
goto finish;
}
if (mkdir_parents(RANDOM_SEED, 0755) < 0) {
log_error("Failed to create directories parents of %s: %m", RANDOM_SEED);
goto finish;
}
/* When we load the seed we read it and write it to the device
* and then immediately update the saved seed with new data,
* to make sure the next boot gets seeded differently. */
if (streq(argv[1], "load")) {
if ((seed_fd = open(RANDOM_SEED, O_RDWR|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600)) < 0) {
if ((seed_fd = open(RANDOM_SEED, O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) {
log_error("Failed to open random seed: %m");
goto finish;
}
}
if ((random_fd = open("/dev/urandom", O_RDWR|O_CLOEXEC|O_NOCTTY, 0600)) < 0) {
if ((random_fd = open("/dev/urandom", O_WRONLY|O_CLOEXEC|O_NOCTTY, 0600)) < 0) {
log_error("Failed to open /dev/urandom: %m");
goto finish;
}
}
if ((r = loop_read(seed_fd, buf, buf_size, false)) <= 0) {
if (r != 0)
log_error("Failed to read seed file: %m");
} else {
lseek(seed_fd, 0, SEEK_SET);
if ((r = loop_write(random_fd, buf, (size_t) r, false)) <= 0)
log_error("Failed to write seed to /dev/random: %s", r < 0 ? strerror(errno) : "short write");
}
} else if (streq(argv[1], "save")) {
if ((seed_fd = open(RANDOM_SEED, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600)) < 0) {
log_error("Failed to open random seed: %m");
goto finish;
}
if ((random_fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY)) < 0) {
log_error("Failed to open /dev/urandom: %m");
goto finish;
}
} else {
log_error("Unknown verb %s.", argv[1]);
goto finish;
}
/* This is just a safety measure. Given that we are root and
* most likely created the file ourselves the mode and owner
* should be correct anyway. */
fchmod(seed_fd, 0600);
fchown(seed_fd, 0, 0);
if ((r = loop_read(random_fd, buf, buf_size, false)) <= 0)
log_error("Failed to read new seed from /dev/urandom: %s", r < 0 ? strerror(errno) : "EOF");
else {
if ((r = loop_write(seed_fd, buf, (size_t) r, false)) <= 0)
log_error("Failed to write new random seed file: %s", r < 0 ? strerror(errno) : "short write");
}
ret = EXIT_SUCCESS;
finish:
if (random_fd >= 0)
close_nointr_nofail(random_fd);
if (seed_fd >= 0)
close_nointr_nofail(seed_fd);
free(buf);
return ret;
}
|
