1/*
2 * Copyright (c) 2001 Damien Miller.  All rights reserved.
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.
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
27#include <sys/types.h>
28#include <sys/socket.h>
29#ifdef HAVE_SYS_UN_H
30# include <sys/un.h>
31#endif
32
33#include <netinet/in.h>
34#include <arpa/inet.h>
35
36#include <errno.h>
37#include <signal.h>
38#include <stdlib.h>
39#include <string.h>
40#include <unistd.h>
41#include <stddef.h> /* for offsetof */
42
43#include "atomicio.h"
44#include "misc.h"
45#include "log.h"
46
47#if defined(PRNGD_PORT) || defined(PRNGD_SOCKET)
48/*
49 * EGD/PRNGD interface.
50 *
51 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
52 * listening either on 'tcp_port', or via Unix domain socket at *
53 * 'socket_path'.
54 * Either a non-zero tcp_port or a non-null socket_path must be
55 * supplied.
56 * Returns 0 on success, -1 on error
57 */
58static int
59get_random_bytes_prngd(unsigned char *buf, int len,
60    unsigned short tcp_port, char *socket_path)
61{
62	int fd, addr_len, rval, errors;
63	u_char msg[2];
64	struct sockaddr_storage addr;
65	struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
66	struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
67	sshsig_t old_sigpipe;
68
69	/* Sanity checks */
70	if (socket_path == NULL && tcp_port == 0)
71		fatal("You must specify a port or a socket");
72	if (socket_path != NULL &&
73	    strlen(socket_path) >= sizeof(addr_un->sun_path))
74		fatal("Random pool path is too long");
75	if (len <= 0 || len > 255)
76		fatal("Too many bytes (%d) to read from PRNGD", len);
77
78	memset(&addr, '\0', sizeof(addr));
79
80	if (tcp_port != 0) {
81		addr_in->sin_family = AF_INET;
82		addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
83		addr_in->sin_port = htons(tcp_port);
84		addr_len = sizeof(*addr_in);
85	} else {
86		addr_un->sun_family = AF_UNIX;
87		strlcpy(addr_un->sun_path, socket_path,
88		    sizeof(addr_un->sun_path));
89		addr_len = offsetof(struct sockaddr_un, sun_path) +
90		    strlen(socket_path) + 1;
91	}
92
93	old_sigpipe = ssh_signal(SIGPIPE, SIG_IGN);
94
95	errors = 0;
96	rval = -1;
97reopen:
98	fd = socket(addr.ss_family, SOCK_STREAM, 0);
99	if (fd == -1) {
100		error("Couldn't create socket: %s", strerror(errno));
101		goto done;
102	}
103
104	if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
105		if (tcp_port != 0) {
106			error("Couldn't connect to PRNGD port %d: %s",
107			    tcp_port, strerror(errno));
108		} else {
109			error("Couldn't connect to PRNGD socket \"%s\": %s",
110			    addr_un->sun_path, strerror(errno));
111		}
112		goto done;
113	}
114
115	/* Send blocking read request to PRNGD */
116	msg[0] = 0x02;
117	msg[1] = len;
118
119	if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
120		if (errno == EPIPE && errors < 10) {
121			close(fd);
122			errors++;
123			goto reopen;
124		}
125		error("Couldn't write to PRNGD socket: %s",
126		    strerror(errno));
127		goto done;
128	}
129
130	if (atomicio(read, fd, buf, len) != (size_t)len) {
131		if (errno == EPIPE && errors < 10) {
132			close(fd);
133			errors++;
134			goto reopen;
135		}
136		error("Couldn't read from PRNGD socket: %s",
137		    strerror(errno));
138		goto done;
139	}
140
141	rval = 0;
142done:
143	ssh_signal(SIGPIPE, old_sigpipe);
144	if (fd != -1)
145		close(fd);
146	return rval;
147}
148#endif /* PRNGD_PORT || PRNGD_SOCKET */
149
150int
151seed_from_prngd(unsigned char *buf, size_t bytes)
152{
153#ifdef PRNGD_PORT
154	debug("trying egd/prngd port %d", PRNGD_PORT);
155	if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
156		return 0;
157#endif
158#ifdef PRNGD_SOCKET
159	debug("trying egd/prngd socket %s", PRNGD_SOCKET);
160	if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
161		return 0;
162#endif
163	return -1;
164}
165