198937Sdes/* 298937Sdes * Copyright (c) 2001 Damien Miller. All rights reserved. 398937Sdes * 498937Sdes * Redistribution and use in source and binary forms, with or without 598937Sdes * modification, are permitted provided that the following conditions 698937Sdes * are met: 798937Sdes * 1. Redistributions of source code must retain the above copyright 898937Sdes * notice, this list of conditions and the following disclaimer. 998937Sdes * 2. Redistributions in binary form must reproduce the above copyright 1098937Sdes * notice, this list of conditions and the following disclaimer in the 1198937Sdes * documentation and/or other materials provided with the distribution. 1298937Sdes * 1398937Sdes * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1498937Sdes * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1598937Sdes * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1698937Sdes * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1798937Sdes * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 1898937Sdes * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 1998937Sdes * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2098937Sdes * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2198937Sdes * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2298937Sdes * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2398937Sdes */ 2498937Sdes 2598937Sdes#include "includes.h" 2698937Sdes 27295367Sdes#ifdef WITH_OPENSSL 28295367Sdes 29162852Sdes#include <sys/types.h> 30226046Sdes#include <sys/socket.h> 31226046Sdes#ifdef HAVE_SYS_UN_H 32226046Sdes# include <sys/un.h> 33162852Sdes#endif 34162852Sdes 35226046Sdes#include <netinet/in.h> 36226046Sdes#include <arpa/inet.h> 37226046Sdes 38226046Sdes#include <errno.h> 39226046Sdes#include <signal.h> 40181111Sdes#include <string.h> 41162852Sdes#include <unistd.h> 42226046Sdes#include <stddef.h> /* for offsetof */ 43162852Sdes 4498937Sdes#include <openssl/rand.h> 4598937Sdes#include <openssl/crypto.h> 46157016Sdes#include <openssl/err.h> 4798937Sdes 48295367Sdes#include "openbsd-compat/openssl-compat.h" 49295367Sdes 5098937Sdes#include "ssh.h" 5198937Sdes#include "misc.h" 5298937Sdes#include "xmalloc.h" 5398937Sdes#include "atomicio.h" 5498937Sdes#include "pathnames.h" 5598937Sdes#include "log.h" 56157016Sdes#include "buffer.h" 5798937Sdes 5898937Sdes/* 5998937Sdes * Portable OpenSSH PRNG seeding: 60126274Sdes * If OpenSSL has not "internally seeded" itself (e.g. pulled data from 61226046Sdes * /dev/random), then collect RANDOM_SEED_SIZE bytes of randomness from 62226046Sdes * PRNGd. 6398937Sdes */ 64226046Sdes#ifndef OPENSSL_PRNG_ONLY 6598937Sdes 6698937Sdes#define RANDOM_SEED_SIZE 48 6798937Sdes 68226046Sdes/* 69226046Sdes * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon 70226046Sdes * listening either on 'tcp_port', or via Unix domain socket at * 71226046Sdes * 'socket_path'. 72226046Sdes * Either a non-zero tcp_port or a non-null socket_path must be 73226046Sdes * supplied. 74226046Sdes * Returns 0 on success, -1 on error 75226046Sdes */ 76226046Sdesint 77226046Sdesget_random_bytes_prngd(unsigned char *buf, int len, 78226046Sdes unsigned short tcp_port, char *socket_path) 7998937Sdes{ 80226046Sdes int fd, addr_len, rval, errors; 81226046Sdes u_char msg[2]; 82226046Sdes struct sockaddr_storage addr; 83226046Sdes struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; 84226046Sdes struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; 85226046Sdes mysig_t old_sigpipe; 8698937Sdes 87226046Sdes /* Sanity checks */ 88226046Sdes if (socket_path == NULL && tcp_port == 0) 89226046Sdes fatal("You must specify a port or a socket"); 90226046Sdes if (socket_path != NULL && 91226046Sdes strlen(socket_path) >= sizeof(addr_un->sun_path)) 92226046Sdes fatal("Random pool path is too long"); 93226046Sdes if (len <= 0 || len > 255) 94226046Sdes fatal("Too many bytes (%d) to read from PRNGD", len); 95226046Sdes 96226046Sdes memset(&addr, '\0', sizeof(addr)); 97226046Sdes 98226046Sdes if (tcp_port != 0) { 99226046Sdes addr_in->sin_family = AF_INET; 100226046Sdes addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); 101226046Sdes addr_in->sin_port = htons(tcp_port); 102226046Sdes addr_len = sizeof(*addr_in); 103226046Sdes } else { 104226046Sdes addr_un->sun_family = AF_UNIX; 105226046Sdes strlcpy(addr_un->sun_path, socket_path, 106226046Sdes sizeof(addr_un->sun_path)); 107226046Sdes addr_len = offsetof(struct sockaddr_un, sun_path) + 108226046Sdes strlen(socket_path) + 1; 10998937Sdes } 11098937Sdes 111226046Sdes old_sigpipe = mysignal(SIGPIPE, SIG_IGN); 11298937Sdes 113226046Sdes errors = 0; 114226046Sdes rval = -1; 115226046Sdesreopen: 116226046Sdes fd = socket(addr.ss_family, SOCK_STREAM, 0); 117226046Sdes if (fd == -1) { 118226046Sdes error("Couldn't create socket: %s", strerror(errno)); 119226046Sdes goto done; 120226046Sdes } 12198937Sdes 122226046Sdes if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { 123226046Sdes if (tcp_port != 0) { 124226046Sdes error("Couldn't connect to PRNGD port %d: %s", 125226046Sdes tcp_port, strerror(errno)); 126226046Sdes } else { 127226046Sdes error("Couldn't connect to PRNGD socket \"%s\": %s", 128226046Sdes addr_un->sun_path, strerror(errno)); 12998937Sdes } 130226046Sdes goto done; 13198937Sdes } 13298937Sdes 133226046Sdes /* Send blocking read request to PRNGD */ 134226046Sdes msg[0] = 0x02; 135226046Sdes msg[1] = len; 13698937Sdes 137226046Sdes if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { 138226046Sdes if (errno == EPIPE && errors < 10) { 139226046Sdes close(fd); 140226046Sdes errors++; 141226046Sdes goto reopen; 142226046Sdes } 143226046Sdes error("Couldn't write to PRNGD socket: %s", 14498937Sdes strerror(errno)); 145226046Sdes goto done; 146226046Sdes } 14798937Sdes 148226046Sdes if (atomicio(read, fd, buf, len) != (size_t)len) { 149226046Sdes if (errno == EPIPE && errors < 10) { 150226046Sdes close(fd); 151226046Sdes errors++; 152226046Sdes goto reopen; 153226046Sdes } 154226046Sdes error("Couldn't read from PRNGD socket: %s", 155149749Sdes strerror(errno)); 156226046Sdes goto done; 157226046Sdes } 15898937Sdes 159226046Sdes rval = 0; 160226046Sdesdone: 161226046Sdes mysignal(SIGPIPE, old_sigpipe); 162226046Sdes if (fd != -1) 163226046Sdes close(fd); 164226046Sdes return rval; 16598937Sdes} 16698937Sdes 167226046Sdesstatic int 168226046Sdesseed_from_prngd(unsigned char *buf, size_t bytes) 16998937Sdes{ 170226046Sdes#ifdef PRNGD_PORT 171226046Sdes debug("trying egd/prngd port %d", PRNGD_PORT); 172226046Sdes if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0) 173226046Sdes return 0; 17498937Sdes#endif 175226046Sdes#ifdef PRNGD_SOCKET 176226046Sdes debug("trying egd/prngd socket %s", PRNGD_SOCKET); 177226046Sdes if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0) 178226046Sdes return 0; 179226046Sdes#endif 180226046Sdes return -1; 18198937Sdes} 18298937Sdes 183157016Sdesvoid 184157016Sdesrexec_send_rng_seed(Buffer *m) 185157016Sdes{ 186157016Sdes u_char buf[RANDOM_SEED_SIZE]; 187157016Sdes 188157016Sdes if (RAND_bytes(buf, sizeof(buf)) <= 0) { 189157016Sdes error("Couldn't obtain random bytes (error %ld)", 190157016Sdes ERR_get_error()); 191157016Sdes buffer_put_string(m, "", 0); 192157016Sdes } else 193157016Sdes buffer_put_string(m, buf, sizeof(buf)); 194157016Sdes} 195157016Sdes 196157016Sdesvoid 197157016Sdesrexec_recv_rng_seed(Buffer *m) 198157016Sdes{ 199157016Sdes u_char *buf; 200157016Sdes u_int len; 201157016Sdes 202157016Sdes buf = buffer_get_string_ret(m, &len); 203157016Sdes if (buf != NULL) { 204157016Sdes debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len); 205157016Sdes RAND_add(buf, len, len); 206157016Sdes } 207157016Sdes} 208226046Sdes#endif /* OPENSSL_PRNG_ONLY */ 209226046Sdes 210226046Sdesvoid 211226046Sdesseed_rng(void) 212226046Sdes{ 213226046Sdes#ifndef OPENSSL_PRNG_ONLY 214226046Sdes unsigned char buf[RANDOM_SEED_SIZE]; 215157016Sdes#endif 216295367Sdes if (!ssh_compatible_openssl(OPENSSL_VERSION_NUMBER, SSLeay())) 217226046Sdes fatal("OpenSSL version mismatch. Built against %lx, you " 218226046Sdes "have %lx", (u_long)OPENSSL_VERSION_NUMBER, SSLeay()); 219226046Sdes 220226046Sdes#ifndef OPENSSL_PRNG_ONLY 221226046Sdes if (RAND_status() == 1) { 222226046Sdes debug3("RNG is ready, skipping seeding"); 223226046Sdes return; 224226046Sdes } 225226046Sdes 226226046Sdes if (seed_from_prngd(buf, sizeof(buf)) == -1) 227226046Sdes fatal("Could not obtain seed from PRNGd"); 228226046Sdes RAND_add(buf, sizeof(buf), sizeof(buf)); 229226046Sdes memset(buf, '\0', sizeof(buf)); 230226046Sdes 231226046Sdes#endif /* OPENSSL_PRNG_ONLY */ 232226046Sdes if (RAND_status() != 1) 233226046Sdes fatal("PRNG is not seeded"); 234226046Sdes} 235295367Sdes 236295367Sdes#else /* WITH_OPENSSL */ 237295367Sdes 238295367Sdes/* Handled in arc4random() */ 239295367Sdesvoid 240295367Sdesseed_rng(void) 241295367Sdes{ 242295367Sdes} 243295367Sdes 244295367Sdes#endif /* WITH_OPENSSL */ 245