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 27162852Sdes#include <sys/types.h> 28226046Sdes#include <sys/socket.h> 29226046Sdes#ifdef HAVE_SYS_UN_H 30226046Sdes# include <sys/un.h> 31162852Sdes#endif 32162852Sdes 33226046Sdes#include <netinet/in.h> 34226046Sdes#include <arpa/inet.h> 35226046Sdes 36226046Sdes#include <errno.h> 37226046Sdes#include <signal.h> 38181111Sdes#include <string.h> 39162852Sdes#include <unistd.h> 40226046Sdes#include <stddef.h> /* for offsetof */ 41162852Sdes 4298937Sdes#include <openssl/rand.h> 4398937Sdes#include <openssl/crypto.h> 44157016Sdes#include <openssl/err.h> 4598937Sdes 4698937Sdes#include "ssh.h" 4798937Sdes#include "misc.h" 4898937Sdes#include "xmalloc.h" 4998937Sdes#include "atomicio.h" 5098937Sdes#include "pathnames.h" 5198937Sdes#include "log.h" 52157016Sdes#include "buffer.h" 5398937Sdes 5498937Sdes/* 5598937Sdes * Portable OpenSSH PRNG seeding: 56126274Sdes * If OpenSSL has not "internally seeded" itself (e.g. pulled data from 57226046Sdes * /dev/random), then collect RANDOM_SEED_SIZE bytes of randomness from 58226046Sdes * PRNGd. 5998937Sdes */ 60226046Sdes#ifndef OPENSSL_PRNG_ONLY 6198937Sdes 6298937Sdes#define RANDOM_SEED_SIZE 48 6398937Sdes 64226046Sdes/* 65226046Sdes * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon 66226046Sdes * listening either on 'tcp_port', or via Unix domain socket at * 67226046Sdes * 'socket_path'. 68226046Sdes * Either a non-zero tcp_port or a non-null socket_path must be 69226046Sdes * supplied. 70226046Sdes * Returns 0 on success, -1 on error 71226046Sdes */ 72226046Sdesint 73226046Sdesget_random_bytes_prngd(unsigned char *buf, int len, 74226046Sdes unsigned short tcp_port, char *socket_path) 7598937Sdes{ 76226046Sdes int fd, addr_len, rval, errors; 77226046Sdes u_char msg[2]; 78226046Sdes struct sockaddr_storage addr; 79226046Sdes struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; 80226046Sdes struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; 81226046Sdes mysig_t old_sigpipe; 8298937Sdes 83226046Sdes /* Sanity checks */ 84226046Sdes if (socket_path == NULL && tcp_port == 0) 85226046Sdes fatal("You must specify a port or a socket"); 86226046Sdes if (socket_path != NULL && 87226046Sdes strlen(socket_path) >= sizeof(addr_un->sun_path)) 88226046Sdes fatal("Random pool path is too long"); 89226046Sdes if (len <= 0 || len > 255) 90226046Sdes fatal("Too many bytes (%d) to read from PRNGD", len); 91226046Sdes 92226046Sdes memset(&addr, '\0', sizeof(addr)); 93226046Sdes 94226046Sdes if (tcp_port != 0) { 95226046Sdes addr_in->sin_family = AF_INET; 96226046Sdes addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); 97226046Sdes addr_in->sin_port = htons(tcp_port); 98226046Sdes addr_len = sizeof(*addr_in); 99226046Sdes } else { 100226046Sdes addr_un->sun_family = AF_UNIX; 101226046Sdes strlcpy(addr_un->sun_path, socket_path, 102226046Sdes sizeof(addr_un->sun_path)); 103226046Sdes addr_len = offsetof(struct sockaddr_un, sun_path) + 104226046Sdes strlen(socket_path) + 1; 10598937Sdes } 10698937Sdes 107226046Sdes old_sigpipe = mysignal(SIGPIPE, SIG_IGN); 10898937Sdes 109226046Sdes errors = 0; 110226046Sdes rval = -1; 111226046Sdesreopen: 112226046Sdes fd = socket(addr.ss_family, SOCK_STREAM, 0); 113226046Sdes if (fd == -1) { 114226046Sdes error("Couldn't create socket: %s", strerror(errno)); 115226046Sdes goto done; 116226046Sdes } 11798937Sdes 118226046Sdes if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { 119226046Sdes if (tcp_port != 0) { 120226046Sdes error("Couldn't connect to PRNGD port %d: %s", 121226046Sdes tcp_port, strerror(errno)); 122226046Sdes } else { 123226046Sdes error("Couldn't connect to PRNGD socket \"%s\": %s", 124226046Sdes addr_un->sun_path, strerror(errno)); 12598937Sdes } 126226046Sdes goto done; 12798937Sdes } 12898937Sdes 129226046Sdes /* Send blocking read request to PRNGD */ 130226046Sdes msg[0] = 0x02; 131226046Sdes msg[1] = len; 13298937Sdes 133226046Sdes if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { 134226046Sdes if (errno == EPIPE && errors < 10) { 135226046Sdes close(fd); 136226046Sdes errors++; 137226046Sdes goto reopen; 138226046Sdes } 139226046Sdes error("Couldn't write to PRNGD socket: %s", 14098937Sdes strerror(errno)); 141226046Sdes goto done; 142226046Sdes } 14398937Sdes 144226046Sdes if (atomicio(read, fd, buf, len) != (size_t)len) { 145226046Sdes if (errno == EPIPE && errors < 10) { 146226046Sdes close(fd); 147226046Sdes errors++; 148226046Sdes goto reopen; 149226046Sdes } 150226046Sdes error("Couldn't read from PRNGD socket: %s", 151149749Sdes strerror(errno)); 152226046Sdes goto done; 153226046Sdes } 15498937Sdes 155226046Sdes rval = 0; 156226046Sdesdone: 157226046Sdes mysignal(SIGPIPE, old_sigpipe); 158226046Sdes if (fd != -1) 159226046Sdes close(fd); 160226046Sdes return rval; 16198937Sdes} 16298937Sdes 163226046Sdesstatic int 164226046Sdesseed_from_prngd(unsigned char *buf, size_t bytes) 16598937Sdes{ 166226046Sdes#ifdef PRNGD_PORT 167226046Sdes debug("trying egd/prngd port %d", PRNGD_PORT); 168226046Sdes if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0) 169226046Sdes return 0; 17098937Sdes#endif 171226046Sdes#ifdef PRNGD_SOCKET 172226046Sdes debug("trying egd/prngd socket %s", PRNGD_SOCKET); 173226046Sdes if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0) 174226046Sdes return 0; 175226046Sdes#endif 176226046Sdes return -1; 17798937Sdes} 17898937Sdes 179157016Sdesvoid 180157016Sdesrexec_send_rng_seed(Buffer *m) 181157016Sdes{ 182157016Sdes u_char buf[RANDOM_SEED_SIZE]; 183157016Sdes 184157016Sdes if (RAND_bytes(buf, sizeof(buf)) <= 0) { 185157016Sdes error("Couldn't obtain random bytes (error %ld)", 186157016Sdes ERR_get_error()); 187157016Sdes buffer_put_string(m, "", 0); 188157016Sdes } else 189157016Sdes buffer_put_string(m, buf, sizeof(buf)); 190157016Sdes} 191157016Sdes 192157016Sdesvoid 193157016Sdesrexec_recv_rng_seed(Buffer *m) 194157016Sdes{ 195157016Sdes u_char *buf; 196157016Sdes u_int len; 197157016Sdes 198157016Sdes buf = buffer_get_string_ret(m, &len); 199157016Sdes if (buf != NULL) { 200157016Sdes debug3("rexec_recv_rng_seed: seeding rng with %u bytes", len); 201157016Sdes RAND_add(buf, len, len); 202157016Sdes } 203157016Sdes} 204226046Sdes#endif /* OPENSSL_PRNG_ONLY */ 205226046Sdes 206226046Sdesvoid 207226046Sdesseed_rng(void) 208226046Sdes{ 209226046Sdes#ifndef OPENSSL_PRNG_ONLY 210226046Sdes unsigned char buf[RANDOM_SEED_SIZE]; 211157016Sdes#endif 212226046Sdes /* 213226046Sdes * OpenSSL version numbers: MNNFFPPS: major minor fix patch status 214240075Sdes * We match major, minor, fix and status (not patch) for <1.0.0. 215240075Sdes * After that, we acceptable compatible fix versions (so we 216240075Sdes * allow 1.0.1 to work with 1.0.0). Going backwards is only allowed 217240075Sdes * within a patch series. 218226046Sdes */ 219240075Sdes u_long version_mask = SSLeay() >= 0x1000000f ? ~0xffff0L : ~0xff0L; 220240075Sdes if (((SSLeay() ^ OPENSSL_VERSION_NUMBER) & version_mask) || 221240075Sdes (SSLeay() >> 12) < (OPENSSL_VERSION_NUMBER >> 12)) 222226046Sdes fatal("OpenSSL version mismatch. Built against %lx, you " 223226046Sdes "have %lx", (u_long)OPENSSL_VERSION_NUMBER, SSLeay()); 224226046Sdes 225226046Sdes#ifndef OPENSSL_PRNG_ONLY 226226046Sdes if (RAND_status() == 1) { 227226046Sdes debug3("RNG is ready, skipping seeding"); 228226046Sdes return; 229226046Sdes } 230226046Sdes 231226046Sdes if (seed_from_prngd(buf, sizeof(buf)) == -1) 232226046Sdes fatal("Could not obtain seed from PRNGd"); 233226046Sdes RAND_add(buf, sizeof(buf), sizeof(buf)); 234226046Sdes memset(buf, '\0', sizeof(buf)); 235226046Sdes 236226046Sdes#endif /* OPENSSL_PRNG_ONLY */ 237226046Sdes if (RAND_status() != 1) 238226046Sdes fatal("PRNG is not seeded"); 239226046Sdes} 240