Damien Miller | 040f383 | 2000-04-03 14:50:43 +1000 | [diff] [blame] | 1 | /* |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 2 | * Copyright (c) 2001 Damien Miller. All rights reserved. |
Damien Miller | 040f383 | 2000-04-03 14:50:43 +1000 | [diff] [blame] | 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * 1. Redistributions of source code must retain the above copyright |
| 8 | * notice, this list of conditions and the following disclaimer. |
| 9 | * 2. Redistributions in binary form must reproduce the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer in the |
| 11 | * documentation and/or other materials provided with the distribution. |
Damien Miller | 040f383 | 2000-04-03 14:50:43 +1000 | [diff] [blame] | 12 | * |
| 13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 23 | */ |
| 24 | |
| 25 | #include "includes.h" |
| 26 | |
Darren Tucker | d82cbcb | 2006-03-16 07:21:35 +1100 | [diff] [blame] | 27 | #include <sys/types.h> |
| 28 | #include <sys/wait.h> |
| 29 | |
Darren Tucker | e0e4aad | 2006-07-11 19:01:51 +1000 | [diff] [blame] | 30 | #ifdef HAVE_SYS_STAT_H |
| 31 | # include <sys/stat.h> |
| 32 | #endif |
| 33 | |
| 34 | #ifdef HAVE_FCNTL_H |
| 35 | # include <fcntl.h> |
| 36 | #endif |
| 37 | |
Damien Miller | 5f05637 | 2000-04-16 12:31:48 +1000 | [diff] [blame] | 38 | #include <openssl/rand.h> |
Damien Miller | 767c7fc | 2001-02-27 09:20:57 +1100 | [diff] [blame] | 39 | #include <openssl/crypto.h> |
Darren Tucker | c6f8219 | 2005-09-27 22:46:32 +1000 | [diff] [blame] | 40 | #include <openssl/err.h> |
Damien Miller | 040f383 | 2000-04-03 14:50:43 +1000 | [diff] [blame] | 41 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 42 | #include "ssh.h" |
Damien Miller | a1072a8 | 2001-02-18 15:28:11 +1100 | [diff] [blame] | 43 | #include "misc.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 44 | #include "xmalloc.h" |
| 45 | #include "atomicio.h" |
Ben Lindstrom | cb57733 | 2001-01-22 21:06:19 +0000 | [diff] [blame] | 46 | #include "pathnames.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 47 | #include "log.h" |
Darren Tucker | c6f8219 | 2005-09-27 22:46:32 +1000 | [diff] [blame] | 48 | #include "buffer.h" |
| 49 | #include "bufaux.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 50 | |
Damien Miller | 14c12cb | 2000-06-07 22:20:23 +1000 | [diff] [blame] | 51 | /* |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 52 | * Portable OpenSSH PRNG seeding: |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 53 | * If OpenSSL has not "internally seeded" itself (e.g. pulled data from |
| 54 | * /dev/random), then we execute a "ssh-rand-helper" program which |
| 55 | * collects entropy and writes it to stdout. The child program must |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 56 | * write at least RANDOM_SEED_SIZE bytes. The child is run with stderr |
| 57 | * attached, so error/debugging output should be visible. |
| 58 | * |
| 59 | * XXX: we should tell the child how many bytes we need. |
Damien Miller | 14c12cb | 2000-06-07 22:20:23 +1000 | [diff] [blame] | 60 | */ |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 61 | |
Damien Miller | 6c21c51 | 2002-01-22 21:57:53 +1100 | [diff] [blame] | 62 | #ifndef OPENSSL_PRNG_ONLY |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 63 | #define RANDOM_SEED_SIZE 48 |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 64 | static uid_t original_uid, original_euid; |
Damien Miller | 6c21c51 | 2002-01-22 21:57:53 +1100 | [diff] [blame] | 65 | #endif |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 66 | |
Damien Miller | 14c12cb | 2000-06-07 22:20:23 +1000 | [diff] [blame] | 67 | void |
| 68 | seed_rng(void) |
| 69 | { |
Damien Miller | 6c21c51 | 2002-01-22 21:57:53 +1100 | [diff] [blame] | 70 | #ifndef OPENSSL_PRNG_ONLY |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 71 | int devnull; |
| 72 | int p[2]; |
| 73 | pid_t pid; |
| 74 | int ret; |
| 75 | unsigned char buf[RANDOM_SEED_SIZE]; |
Damien Miller | a370f4d | 2002-04-18 22:53:22 +1000 | [diff] [blame] | 76 | mysig_t old_sigchld; |
Kevin Steves | ef4eea9 | 2001-02-05 12:42:17 +0000 | [diff] [blame] | 77 | |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 78 | if (RAND_status() == 1) { |
| 79 | debug3("RNG is ready, skipping seeding"); |
| 80 | return; |
Damien Miller | 0800647 | 2000-06-26 13:55:31 +1000 | [diff] [blame] | 81 | } |
Kevin Steves | ef4eea9 | 2001-02-05 12:42:17 +0000 | [diff] [blame] | 82 | |
Kevin Steves | 5819307 | 2002-03-11 00:16:34 +0000 | [diff] [blame] | 83 | debug3("Seeding PRNG from %s", SSH_RAND_HELPER); |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 84 | |
| 85 | if ((devnull = open("/dev/null", O_RDWR)) == -1) |
| 86 | fatal("Couldn't open /dev/null: %s", strerror(errno)); |
| 87 | if (pipe(p) == -1) |
| 88 | fatal("pipe: %s", strerror(errno)); |
| 89 | |
Ben Lindstrom | 5ade9ab | 2003-08-25 01:16:21 +0000 | [diff] [blame] | 90 | old_sigchld = signal(SIGCHLD, SIG_DFL); |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 91 | if ((pid = fork()) == -1) |
| 92 | fatal("Couldn't fork: %s", strerror(errno)); |
| 93 | if (pid == 0) { |
| 94 | dup2(devnull, STDIN_FILENO); |
| 95 | dup2(p[1], STDOUT_FILENO); |
| 96 | /* Keep stderr open for errors */ |
| 97 | close(p[0]); |
| 98 | close(p[1]); |
| 99 | close(devnull); |
| 100 | |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 101 | if (original_uid != original_euid && |
| 102 | ( seteuid(getuid()) == -1 || |
Tim Rice | f02dccc | 2002-04-21 11:26:10 -0700 | [diff] [blame] | 103 | setuid(original_uid) == -1) ) { |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 104 | fprintf(stderr, "(rand child) setuid(%li): %s\n", |
Damien Miller | c46b6bc | 2003-05-16 15:51:44 +1000 | [diff] [blame] | 105 | (long int)original_uid, strerror(errno)); |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 106 | _exit(1); |
| 107 | } |
Damien Miller | 787b2ec | 2003-11-21 23:56:47 +1100 | [diff] [blame] | 108 | |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 109 | execl(SSH_RAND_HELPER, "ssh-rand-helper", NULL); |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 110 | fprintf(stderr, "(rand child) Couldn't exec '%s': %s\n", |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 111 | SSH_RAND_HELPER, strerror(errno)); |
| 112 | _exit(1); |
| 113 | } |
| 114 | |
| 115 | close(devnull); |
| 116 | close(p[1]); |
| 117 | |
| 118 | memset(buf, '\0', sizeof(buf)); |
| 119 | ret = atomicio(read, p[0], buf, sizeof(buf)); |
| 120 | if (ret == -1) |
| 121 | fatal("Couldn't read from ssh-rand-helper: %s", |
| 122 | strerror(errno)); |
| 123 | if (ret != sizeof(buf)) |
| 124 | fatal("ssh-rand-helper child produced insufficient data"); |
| 125 | |
| 126 | close(p[0]); |
| 127 | |
| 128 | if (waitpid(pid, &ret, 0) == -1) |
Damien Miller | b6f72f5 | 2005-07-17 17:26:43 +1000 | [diff] [blame] | 129 | fatal("Couldn't wait for ssh-rand-helper completion: %s", |
| 130 | strerror(errno)); |
Ben Lindstrom | 5ade9ab | 2003-08-25 01:16:21 +0000 | [diff] [blame] | 131 | signal(SIGCHLD, old_sigchld); |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 132 | |
| 133 | /* We don't mind if the child exits upon a SIGPIPE */ |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 134 | if (!WIFEXITED(ret) && |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 135 | (!WIFSIGNALED(ret) || WTERMSIG(ret) != SIGPIPE)) |
| 136 | fatal("ssh-rand-helper terminated abnormally"); |
| 137 | if (WEXITSTATUS(ret) != 0) |
| 138 | fatal("ssh-rand-helper exit with exit status %d", ret); |
| 139 | |
| 140 | RAND_add(buf, sizeof(buf), sizeof(buf)); |
Damien Miller | 14c12cb | 2000-06-07 22:20:23 +1000 | [diff] [blame] | 141 | memset(buf, '\0', sizeof(buf)); |
Damien Miller | 6c21c51 | 2002-01-22 21:57:53 +1100 | [diff] [blame] | 142 | |
| 143 | #endif /* OPENSSL_PRNG_ONLY */ |
| 144 | if (RAND_status() != 1) |
| 145 | fatal("PRNG is not seeded"); |
Damien Miller | 14c12cb | 2000-06-07 22:20:23 +1000 | [diff] [blame] | 146 | } |
| 147 | |
Damien Miller | 60bc517 | 2001-03-19 09:38:15 +1100 | [diff] [blame] | 148 | void |
Damien Miller | a8e06ce | 2003-11-21 23:48:55 +1100 | [diff] [blame] | 149 | init_rng(void) |
Damien Miller | 767c7fc | 2001-02-27 09:20:57 +1100 | [diff] [blame] | 150 | { |
Damien Miller | bb7c976 | 2001-02-26 20:49:58 +1100 | [diff] [blame] | 151 | /* |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 152 | * OpenSSL version numbers: MNNFFPPS: major minor fix patch status |
| 153 | * We match major, minor, fix and status (not patch) |
Damien Miller | bb7c976 | 2001-02-26 20:49:58 +1100 | [diff] [blame] | 154 | */ |
Damien Miller | 62116dc | 2001-12-24 01:41:47 +1100 | [diff] [blame] | 155 | if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L) |
| 156 | fatal("OpenSSL version mismatch. Built against %lx, you " |
| 157 | "have %lx", OPENSSL_VERSION_NUMBER, SSLeay()); |
Kevin Steves | ef4eea9 | 2001-02-05 12:42:17 +0000 | [diff] [blame] | 158 | |
Damien Miller | 6c21c51 | 2002-01-22 21:57:53 +1100 | [diff] [blame] | 159 | #ifndef OPENSSL_PRNG_ONLY |
Darren Tucker | f1377bd | 2005-09-27 19:50:25 +1000 | [diff] [blame] | 160 | original_uid = getuid(); |
| 161 | original_euid = geteuid(); |
Damien Miller | 6c21c51 | 2002-01-22 21:57:53 +1100 | [diff] [blame] | 162 | #endif |
Damien Miller | f9b625c | 2000-07-09 22:42:32 +1000 | [diff] [blame] | 163 | } |
Damien Miller | 6c21c51 | 2002-01-22 21:57:53 +1100 | [diff] [blame] | 164 | |
Darren Tucker | c6f8219 | 2005-09-27 22:46:32 +1000 | [diff] [blame] | 165 | #ifndef OPENSSL_PRNG_ONLY |
| 166 | void |
| 167 | rexec_send_rng_seed(Buffer *m) |
| 168 | { |
| 169 | u_char buf[RANDOM_SEED_SIZE]; |
| 170 | |
| 171 | if (RAND_bytes(buf, sizeof(buf)) <= 0) { |
| 172 | error("Couldn't obtain random bytes (error %ld)", |
| 173 | ERR_get_error()); |
| 174 | buffer_put_string(m, "", 0); |
| 175 | } else |
| 176 | buffer_put_string(m, buf, sizeof(buf)); |
| 177 | } |
| 178 | |
| 179 | void |
| 180 | rexec_recv_rng_seed(Buffer *m) |
| 181 | { |
Darren Tucker | 46e7ba5 | 2005-09-28 08:26:30 +1000 | [diff] [blame] | 182 | u_char *buf; |
Darren Tucker | c6f8219 | 2005-09-27 22:46:32 +1000 | [diff] [blame] | 183 | u_int len; |
| 184 | |
| 185 | buf = buffer_get_string_ret(m, &len); |
| 186 | if (buf != NULL) { |
| 187 | debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len); |
| 188 | RAND_add(buf, len, len); |
| 189 | } |
| 190 | } |
| 191 | #endif |