blob: 31a7f1c3ef5460aa911831cab74dae16c9595329 [file] [log] [blame]
Damien Miller040f3832000-04-03 14:50:43 +10001/*
Damien Miller62116dc2001-12-24 01:41:47 +11002 * Copyright (c) 2001 Damien Miller. All rights reserved.
Damien Miller040f3832000-04-03 14:50:43 +10003 *
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 Miller040f3832000-04-03 14:50:43 +100012 *
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 Tuckerc721d582018-11-23 14:11:20 +110027#define RANDOM_SEED_SIZE 48
28
Damien Miller72ef7c12015-01-15 02:21:31 +110029#ifdef WITH_OPENSSL
30
Darren Tuckerd82cbcb2006-03-16 07:21:35 +110031#include <sys/types.h>
Damien Millerf22019b2011-05-05 13:48:37 +100032#include <sys/socket.h>
33#ifdef HAVE_SYS_UN_H
34# include <sys/un.h>
Darren Tuckere0e4aad2006-07-11 19:01:51 +100035#endif
36
Damien Millerf22019b2011-05-05 13:48:37 +100037#include <netinet/in.h>
38#include <arpa/inet.h>
39
40#include <errno.h>
Darren Tucker23dd6582006-09-28 19:40:20 +100041#include <signal.h>
Damien Millerf22019b2011-05-05 13:48:37 +100042#include <string.h>
Darren Tuckera8d51ee2007-03-13 07:35:38 +110043#include <unistd.h>
Damien Millerf22019b2011-05-05 13:48:37 +100044#include <stddef.h> /* for offsetof */
Darren Tuckere0e4aad2006-07-11 19:01:51 +100045
Damien Miller5f056372000-04-16 12:31:48 +100046#include <openssl/rand.h>
Damien Miller767c7fc2001-02-27 09:20:57 +110047#include <openssl/crypto.h>
Darren Tuckerc6f82192005-09-27 22:46:32 +100048#include <openssl/err.h>
Damien Miller040f3832000-04-03 14:50:43 +100049
Damien Miller86687062014-07-02 15:28:02 +100050#include "openbsd-compat/openssl-compat.h"
51
Ben Lindstrom226cfa02001-01-22 05:34:40 +000052#include "ssh.h"
Damien Millera1072a82001-02-18 15:28:11 +110053#include "misc.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000054#include "xmalloc.h"
55#include "atomicio.h"
Ben Lindstromcb577332001-01-22 21:06:19 +000056#include "pathnames.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000057#include "log.h"
Damien Miller120a1ec2018-07-10 19:39:52 +100058#include "sshbuf.h"
59#include "ssherr.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000060
Damien Miller14c12cb2000-06-07 22:20:23 +100061/*
Damien Miller62116dc2001-12-24 01:41:47 +110062 * Portable OpenSSH PRNG seeding:
Damien Millera8e06ce2003-11-21 23:48:55 +110063 * If OpenSSL has not "internally seeded" itself (e.g. pulled data from
Damien Millerf22019b2011-05-05 13:48:37 +100064 * /dev/random), then collect RANDOM_SEED_SIZE bytes of randomness from
65 * PRNGd.
Damien Miller14c12cb2000-06-07 22:20:23 +100066 */
Damien Miller6c21c512002-01-22 21:57:53 +110067#ifndef OPENSSL_PRNG_ONLY
Damien Millerf22019b2011-05-05 13:48:37 +100068
Damien Millerf22019b2011-05-05 13:48:37 +100069/*
70 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
71 * listening either on 'tcp_port', or via Unix domain socket at *
72 * 'socket_path'.
73 * Either a non-zero tcp_port or a non-null socket_path must be
74 * supplied.
75 * Returns 0 on success, -1 on error
76 */
77int
78get_random_bytes_prngd(unsigned char *buf, int len,
79 unsigned short tcp_port, char *socket_path)
Damien Miller14c12cb2000-06-07 22:20:23 +100080{
Damien Millerf22019b2011-05-05 13:48:37 +100081 int fd, addr_len, rval, errors;
82 u_char msg[2];
83 struct sockaddr_storage addr;
84 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
85 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
86 mysig_t old_sigpipe;
Kevin Stevesef4eea92001-02-05 12:42:17 +000087
Damien Millerf22019b2011-05-05 13:48:37 +100088 /* Sanity checks */
89 if (socket_path == NULL && tcp_port == 0)
90 fatal("You must specify a port or a socket");
91 if (socket_path != NULL &&
92 strlen(socket_path) >= sizeof(addr_un->sun_path))
93 fatal("Random pool path is too long");
94 if (len <= 0 || len > 255)
95 fatal("Too many bytes (%d) to read from PRNGD", len);
96
97 memset(&addr, '\0', sizeof(addr));
98
99 if (tcp_port != 0) {
100 addr_in->sin_family = AF_INET;
101 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
102 addr_in->sin_port = htons(tcp_port);
103 addr_len = sizeof(*addr_in);
104 } else {
105 addr_un->sun_family = AF_UNIX;
106 strlcpy(addr_un->sun_path, socket_path,
107 sizeof(addr_un->sun_path));
108 addr_len = offsetof(struct sockaddr_un, sun_path) +
109 strlen(socket_path) + 1;
Damien Miller08006472000-06-26 13:55:31 +1000110 }
Kevin Stevesef4eea92001-02-05 12:42:17 +0000111
Darren Tucker389125b2018-02-15 21:43:01 +1100112 old_sigpipe = signal(SIGPIPE, SIG_IGN);
Damien Miller62116dc2001-12-24 01:41:47 +1100113
Damien Millerf22019b2011-05-05 13:48:37 +1000114 errors = 0;
115 rval = -1;
116reopen:
117 fd = socket(addr.ss_family, SOCK_STREAM, 0);
118 if (fd == -1) {
119 error("Couldn't create socket: %s", strerror(errno));
120 goto done;
121 }
Damien Miller62116dc2001-12-24 01:41:47 +1100122
Damien Millerf22019b2011-05-05 13:48:37 +1000123 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
124 if (tcp_port != 0) {
125 error("Couldn't connect to PRNGD port %d: %s",
126 tcp_port, strerror(errno));
127 } else {
128 error("Couldn't connect to PRNGD socket \"%s\": %s",
129 addr_un->sun_path, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100130 }
Damien Millerf22019b2011-05-05 13:48:37 +1000131 goto done;
Damien Miller62116dc2001-12-24 01:41:47 +1100132 }
133
Damien Millerf22019b2011-05-05 13:48:37 +1000134 /* Send blocking read request to PRNGD */
135 msg[0] = 0x02;
136 msg[1] = len;
Damien Miller62116dc2001-12-24 01:41:47 +1100137
Damien Millerf22019b2011-05-05 13:48:37 +1000138 if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
139 if (errno == EPIPE && errors < 10) {
140 close(fd);
141 errors++;
142 goto reopen;
143 }
144 error("Couldn't write to PRNGD socket: %s",
Damien Miller62116dc2001-12-24 01:41:47 +1100145 strerror(errno));
Damien Millerf22019b2011-05-05 13:48:37 +1000146 goto done;
147 }
Damien Miller62116dc2001-12-24 01:41:47 +1100148
Damien Millerf22019b2011-05-05 13:48:37 +1000149 if (atomicio(read, fd, buf, len) != (size_t)len) {
150 if (errno == EPIPE && errors < 10) {
151 close(fd);
152 errors++;
153 goto reopen;
154 }
155 error("Couldn't read from PRNGD socket: %s",
Damien Millerb6f72f52005-07-17 17:26:43 +1000156 strerror(errno));
Damien Millerf22019b2011-05-05 13:48:37 +1000157 goto done;
158 }
Damien Miller62116dc2001-12-24 01:41:47 +1100159
Damien Millerf22019b2011-05-05 13:48:37 +1000160 rval = 0;
161done:
Darren Tucker389125b2018-02-15 21:43:01 +1100162 signal(SIGPIPE, old_sigpipe);
Damien Millerf22019b2011-05-05 13:48:37 +1000163 if (fd != -1)
164 close(fd);
165 return rval;
Damien Miller14c12cb2000-06-07 22:20:23 +1000166}
167
Damien Millerf22019b2011-05-05 13:48:37 +1000168static int
169seed_from_prngd(unsigned char *buf, size_t bytes)
Damien Miller767c7fc2001-02-27 09:20:57 +1100170{
Damien Millerf22019b2011-05-05 13:48:37 +1000171#ifdef PRNGD_PORT
172 debug("trying egd/prngd port %d", PRNGD_PORT);
173 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
174 return 0;
Damien Miller6c21c512002-01-22 21:57:53 +1100175#endif
Damien Millerf22019b2011-05-05 13:48:37 +1000176#ifdef PRNGD_SOCKET
177 debug("trying egd/prngd socket %s", PRNGD_SOCKET);
178 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
179 return 0;
180#endif
181 return -1;
Damien Millerf9b625c2000-07-09 22:42:32 +1000182}
Damien Miller6c21c512002-01-22 21:57:53 +1100183
Darren Tuckerc6f82192005-09-27 22:46:32 +1000184void
Damien Miller120a1ec2018-07-10 19:39:52 +1000185rexec_send_rng_seed(struct sshbuf *m)
Darren Tuckerc6f82192005-09-27 22:46:32 +1000186{
187 u_char buf[RANDOM_SEED_SIZE];
Damien Miller120a1ec2018-07-10 19:39:52 +1000188 size_t len = sizeof(buf);
189 int r;
Darren Tuckerc6f82192005-09-27 22:46:32 +1000190
191 if (RAND_bytes(buf, sizeof(buf)) <= 0) {
192 error("Couldn't obtain random bytes (error %ld)",
193 ERR_get_error());
Damien Miller120a1ec2018-07-10 19:39:52 +1000194 len = 0;
195 }
196 if ((r = sshbuf_put_string(m, buf, len)) != 0)
197 fatal("%s: buffer error: %s", __func__, ssh_err(r));
198 explicit_bzero(buf, sizeof(buf));
Darren Tuckerc6f82192005-09-27 22:46:32 +1000199}
200
201void
Damien Miller120a1ec2018-07-10 19:39:52 +1000202rexec_recv_rng_seed(struct sshbuf *m)
Darren Tuckerc6f82192005-09-27 22:46:32 +1000203{
Damien Miller120a1ec2018-07-10 19:39:52 +1000204 u_char *buf = NULL;
205 size_t len = 0;
206 int r;
Darren Tuckerc6f82192005-09-27 22:46:32 +1000207
Damien Miller120a1ec2018-07-10 19:39:52 +1000208 if ((r = sshbuf_get_string_direct(m, &buf, &len)) != 0
209 fatal("%s: buffer error: %s", __func__, ssh_err(r));
210
211 debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len);
212 RAND_add(buf, len, len);
Darren Tuckerc6f82192005-09-27 22:46:32 +1000213}
Damien Millerf22019b2011-05-05 13:48:37 +1000214#endif /* OPENSSL_PRNG_ONLY */
215
216void
217seed_rng(void)
218{
Damien Millerf22019b2011-05-05 13:48:37 +1000219 unsigned char buf[RANDOM_SEED_SIZE];
Damien Miller42c5ec42018-11-23 10:40:06 +1100220
221 /* Initialise libcrypto */
222 ssh_libcrypto_init();
223
Damien Miller859754b2018-10-23 17:10:41 +1100224 if (!ssh_compatible_openssl(OPENSSL_VERSION_NUMBER,
225 OpenSSL_version_num()))
Damien Millerf22019b2011-05-05 13:48:37 +1000226 fatal("OpenSSL version mismatch. Built against %lx, you "
Damien Miller859754b2018-10-23 17:10:41 +1100227 "have %lx", (u_long)OPENSSL_VERSION_NUMBER,
228 OpenSSL_version_num());
Damien Millerf22019b2011-05-05 13:48:37 +1000229
230#ifndef OPENSSL_PRNG_ONLY
Damien Miller42c5ec42018-11-23 10:40:06 +1100231 if (RAND_status() == 1)
Damien Millerf22019b2011-05-05 13:48:37 +1000232 debug3("RNG is ready, skipping seeding");
Damien Miller42c5ec42018-11-23 10:40:06 +1100233 else {
234 if (seed_from_prngd(buf, sizeof(buf)) == -1)
235 fatal("Could not obtain seed from PRNGd");
236 RAND_add(buf, sizeof(buf), sizeof(buf));
Damien Millerf22019b2011-05-05 13:48:37 +1000237 }
Damien Millerf22019b2011-05-05 13:48:37 +1000238#endif /* OPENSSL_PRNG_ONLY */
Damien Miller42c5ec42018-11-23 10:40:06 +1100239
Damien Millerf22019b2011-05-05 13:48:37 +1000240 if (RAND_status() != 1)
241 fatal("PRNG is not seeded");
Damien Miller42c5ec42018-11-23 10:40:06 +1100242
243 /* Ensure arc4random() is primed */
244 arc4random_buf(buf, sizeof(buf));
245 explicit_bzero(buf, sizeof(buf));
Damien Millerf22019b2011-05-05 13:48:37 +1000246}
Damien Miller72ef7c12015-01-15 02:21:31 +1100247
248#else /* WITH_OPENSSL */
249
Damien Miller42c5ec42018-11-23 10:40:06 +1100250/* Acutal initialisation is handled in arc4random() */
Damien Miller72ef7c12015-01-15 02:21:31 +1100251void
252seed_rng(void)
253{
Damien Miller42c5ec42018-11-23 10:40:06 +1100254 unsigned char buf[RANDOM_SEED_SIZE];
255
256 /* Ensure arc4random() is primed */
257 arc4random_buf(buf, sizeof(buf));
258 explicit_bzero(buf, sizeof(buf));
Damien Miller72ef7c12015-01-15 02:21:31 +1100259}
260
261#endif /* WITH_OPENSSL */