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 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 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