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 */
58 static int
get_random_bytes_prngd(unsigned char * buf,int len,unsigned short tcp_port,char * socket_path)59 get_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;
97 reopen:
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;
142 done:
143 ssh_signal(SIGPIPE, old_sigpipe);
144 if (fd != -1)
145 close(fd);
146 return rval;
147 }
148 #endif /* PRNGD_PORT || PRNGD_SOCKET */
149
150 int
seed_from_prngd(unsigned char * buf,size_t bytes)151 seed_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