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6e200d55 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
5430f7f2 LP |
9 | under the terms of the GNU Lesser General Public License as published by |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
6e200d55 LP |
11 | (at your option) any later version. |
12 | ||
13 | systemd 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 | |
5430f7f2 | 16 | Lesser General Public License for more details. |
6e200d55 | 17 | |
5430f7f2 | 18 | You should have received a copy of the GNU Lesser General Public License |
6e200d55 LP |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
20 | ***/ | |
21 | ||
6e200d55 | 22 | #include <errno.h> |
07630cea | 23 | #include <fcntl.h> |
6e200d55 LP |
24 | #include <string.h> |
25 | #include <sys/stat.h> | |
07630cea | 26 | #include <unistd.h> |
6e200d55 LP |
27 | |
28 | #include "log.h" | |
49e942b2 | 29 | #include "mkdir.h" |
07630cea LP |
30 | #include "string-util.h" |
31 | #include "util.h" | |
6e200d55 | 32 | |
26192dfc LP |
33 | #define POOL_SIZE_MIN 512 |
34 | ||
6e200d55 | 35 | int main(int argc, char *argv[]) { |
ce179470 LP |
36 | _cleanup_close_ int seed_fd = -1, random_fd = -1; |
37 | _cleanup_free_ void* buf = NULL; | |
26192dfc | 38 | size_t buf_size = 0; |
ce179470 LP |
39 | ssize_t k; |
40 | int r; | |
26192dfc | 41 | FILE *f; |
1509fb87 | 42 | bool refresh_seed_file = true; |
6e200d55 LP |
43 | |
44 | if (argc != 2) { | |
45 | log_error("This program requires one argument."); | |
22f4096c | 46 | return EXIT_FAILURE; |
6e200d55 LP |
47 | } |
48 | ||
4cfa2c99 | 49 | log_set_target(LOG_TARGET_AUTO); |
6e200d55 | 50 | log_parse_environment(); |
2396fb04 | 51 | log_open(); |
6e200d55 | 52 | |
4c12626c LP |
53 | umask(0022); |
54 | ||
26192dfc | 55 | /* Read pool size, if possible */ |
ce179470 LP |
56 | f = fopen("/proc/sys/kernel/random/poolsize", "re"); |
57 | if (f) { | |
ece174c5 | 58 | if (fscanf(f, "%zu", &buf_size) > 0) |
7c2ec009 TG |
59 | /* poolsize is in bits on 2.6, but we want bytes */ |
60 | buf_size /= 8; | |
7c2ec009 | 61 | |
26192dfc LP |
62 | fclose(f); |
63 | } | |
64 | ||
65 | if (buf_size <= POOL_SIZE_MIN) | |
66 | buf_size = POOL_SIZE_MIN; | |
67 | ||
ce179470 LP |
68 | buf = malloc(buf_size); |
69 | if (!buf) { | |
70 | r = log_oom(); | |
26192dfc LP |
71 | goto finish; |
72 | } | |
73 | ||
ce179470 LP |
74 | r = mkdir_parents_label(RANDOM_SEED, 0755); |
75 | if (r < 0) { | |
da927ba9 | 76 | log_error_errno(r, "Failed to create directory " RANDOM_SEED_DIR ": %m"); |
b56e5747 GSB |
77 | goto finish; |
78 | } | |
79 | ||
6e200d55 LP |
80 | /* When we load the seed we read it and write it to the device |
81 | * and then immediately update the saved seed with new data, | |
82 | * to make sure the next boot gets seeded differently. */ | |
83 | ||
84 | if (streq(argv[1], "load")) { | |
85 | ||
ce179470 LP |
86 | seed_fd = open(RANDOM_SEED, O_RDWR|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600); |
87 | if (seed_fd < 0) { | |
88 | seed_fd = open(RANDOM_SEED, O_RDONLY|O_CLOEXEC|O_NOCTTY); | |
89 | if (seed_fd < 0) { | |
1509fb87 | 90 | r = log_error_errno(errno, "Failed to open " RANDOM_SEED ": %m"); |
6e200d55 LP |
91 | goto finish; |
92 | } | |
1509fb87 LP |
93 | |
94 | refresh_seed_file = false; | |
6e200d55 LP |
95 | } |
96 | ||
ce179470 LP |
97 | random_fd = open("/dev/urandom", O_RDWR|O_CLOEXEC|O_NOCTTY, 0600); |
98 | if (random_fd < 0) { | |
99 | random_fd = open("/dev/urandom", O_WRONLY|O_CLOEXEC|O_NOCTTY, 0600); | |
100 | if (random_fd < 0) { | |
1509fb87 | 101 | r = log_error_errno(errno, "Failed to open /dev/urandom: %m"); |
6e200d55 LP |
102 | goto finish; |
103 | } | |
104 | } | |
105 | ||
ce179470 | 106 | k = loop_read(seed_fd, buf, buf_size, false); |
1509fb87 LP |
107 | if (k < 0) |
108 | r = log_error_errno(k, "Failed to read seed from " RANDOM_SEED ": %m"); | |
109 | else if (k == 0) | |
110 | log_debug("Seed file " RANDOM_SEED " not yet initialized, proceeding."); | |
111 | else { | |
112 | (void) lseek(seed_fd, 0, SEEK_SET); | |
6e200d55 | 113 | |
553acb7b ZJS |
114 | r = loop_write(random_fd, buf, (size_t) k, false); |
115 | if (r < 0) | |
116 | log_error_errno(r, "Failed to write seed to /dev/urandom: %m"); | |
6e200d55 LP |
117 | } |
118 | ||
119 | } else if (streq(argv[1], "save")) { | |
120 | ||
ce179470 LP |
121 | seed_fd = open(RANDOM_SEED, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600); |
122 | if (seed_fd < 0) { | |
1509fb87 | 123 | r = log_error_errno(errno, "Failed to open " RANDOM_SEED ": %m"); |
6e200d55 LP |
124 | goto finish; |
125 | } | |
126 | ||
ce179470 LP |
127 | random_fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY); |
128 | if (random_fd < 0) { | |
1509fb87 | 129 | r = log_error_errno(errno, "Failed to open /dev/urandom: %m"); |
6e200d55 LP |
130 | goto finish; |
131 | } | |
ce179470 | 132 | |
6e200d55 | 133 | } else { |
1509fb87 | 134 | log_error("Unknown verb '%s'.", argv[1]); |
ce179470 | 135 | r = -EINVAL; |
6e200d55 LP |
136 | goto finish; |
137 | } | |
138 | ||
1509fb87 LP |
139 | if (refresh_seed_file) { |
140 | ||
352e2098 CG |
141 | /* This is just a safety measure. Given that we are root and |
142 | * most likely created the file ourselves the mode and owner | |
143 | * should be correct anyway. */ | |
1509fb87 LP |
144 | (void) fchmod(seed_fd, 0600); |
145 | (void) fchown(seed_fd, 0, 0); | |
6e200d55 | 146 | |
352e2098 | 147 | k = loop_read(random_fd, buf, buf_size, false); |
1509fb87 LP |
148 | if (k < 0) { |
149 | r = log_error_errno(k, "Failed to read new seed from /dev/urandom: %m"); | |
150 | goto finish; | |
352e2098 | 151 | } |
1509fb87 LP |
152 | if (k == 0) { |
153 | log_error("Got EOF while reading from /dev/urandom."); | |
154 | r = -EIO; | |
155 | goto finish; | |
156 | } | |
157 | ||
158 | r = loop_write(seed_fd, buf, (size_t) k, false); | |
159 | if (r < 0) | |
160 | log_error_errno(r, "Failed to write new random seed file: %m"); | |
6e200d55 LP |
161 | } |
162 | ||
6e200d55 | 163 | finish: |
ce179470 | 164 | return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS; |
6e200d55 | 165 | } |