crypto/openssh/misc.c

   1 /* $OpenBSD: misc.c,v 1.85 2011/03/29 18:54:17 stevesk Exp $ */
   2 /*
   3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   4  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/ioctl.h>
  31 #include <sys/socket.h>
  32 #include <sys/param.h>
  33
  34 #include <stdarg.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <time.h>
  39 #include <unistd.h>
  40
  41 #include <netinet/in.h>
  42 #include <netinet/in_systm.h>
  43 #include <netinet/ip.h>
  44 #include <netinet/tcp.h>
  45
  46 #include <errno.h>
  47 #include <fcntl.h>
  48 #include <netdb.h>
  49 #ifdef HAVE_PATHS_H
  50 # include <paths.h>
  51 #include <pwd.h>
  52 #endif
  53 #ifdef SSH_TUN_OPENBSD
  54 #include <net/if.h>
  55 #endif
  56
  57 #include "xmalloc.h"
  58 #include "misc.h"
  59 #include "log.h"
  60 #include "ssh.h"
  61
  62 /* remove newline at end of string */
  63 char *
  64 chop(char *s)
  65 {
  66         char *t = s;
  67         while (*t) {
  68                 if (*t == '\n' || *t == '\r') {
  69                         *t = '\0';
  70                         return s;
  71                 }
  72                 t++;
  73         }
  74         return s;
  75
  76 }
  77
  78 /* set/unset filedescriptor to non-blocking */
  79 int
  80 set_nonblock(int fd)
  81 {
  82         int val;
  83
  84         val = fcntl(fd, F_GETFL, 0);
  85         if (val < 0) {
  86                 error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
  87                 return (-1);
  88         }
  89         if (val & O_NONBLOCK) {
  90                 debug3("fd %d is O_NONBLOCK", fd);
  91                 return (0);
  92         }
  93         debug2("fd %d setting O_NONBLOCK", fd);
  94         val |= O_NONBLOCK;
  95         if (fcntl(fd, F_SETFL, val) == -1) {
  96                 debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
  97                     strerror(errno));
  98                 return (-1);
  99         }
 100         return (0);
 101 }
 102
 103 int
 104 unset_nonblock(int fd)
 105 {
 106         int val;
 107
 108         val = fcntl(fd, F_GETFL, 0);
 109         if (val < 0) {
 110                 error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
 111                 return (-1);
 112         }
 113         if (!(val & O_NONBLOCK)) {
 114                 debug3("fd %d is not O_NONBLOCK", fd);
 115                 return (0);
 116         }
 117         debug("fd %d clearing O_NONBLOCK", fd);
 118         val &= ~O_NONBLOCK;
 119         if (fcntl(fd, F_SETFL, val) == -1) {
 120                 debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
 121                     fd, strerror(errno));
 122                 return (-1);
 123         }
 124         return (0);
 125 }
 126
 127 const char *
 128 ssh_gai_strerror(int gaierr)
 129 {
 130         if (gaierr == EAI_SYSTEM)
 131                 return strerror(errno);
 132         return gai_strerror(gaierr);
 133 }
 134
 135 /* disable nagle on socket */
 136 void
 137 set_nodelay(int fd)
 138 {
 139         int opt;
 140         socklen_t optlen;
 141
 142         optlen = sizeof opt;
 143         if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
 144                 debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
 145                 return;
 146         }
 147         if (opt == 1) {
 148                 debug2("fd %d is TCP_NODELAY", fd);
 149                 return;
 150         }
 151         opt = 1;
 152         debug2("fd %d setting TCP_NODELAY", fd);
 153         if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
 154                 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
 155 }
 156
 157 /* Characters considered whitespace in strsep calls. */
 158 #define WHITESPACE " \t\r\n"
 159 #define QUOTE   "\""
 160
 161 /* return next token in configuration line */
 162 char *
 163 strdelim(char **s)
 164 {
 165         char *old;
 166         int wspace = 0;
 167
 168         if (*s == NULL)
 169                 return NULL;
 170
 171         old = *s;
 172
 173         *s = strpbrk(*s, WHITESPACE QUOTE "=");
 174         if (*s == NULL)
 175                 return (old);
 176
 177         if (*s[0] == '\"') {
 178                 memmove(*s, *s + 1, strlen(*s)); /* move nul too */
 179                 /* Find matching quote */
 180                 if ((*s = strpbrk(*s, QUOTE)) == NULL) {
 181                         return (NULL);          /* no matching quote */
 182                 } else {
 183                         *s[0] = '\0';
 184                         *s += strspn(*s + 1, WHITESPACE) + 1;
 185                         return (old);
 186                 }
 187         }
 188
 189         /* Allow only one '=' to be skipped */
 190         if (*s[0] == '=')
 191                 wspace = 1;
 192         *s[0] = '\0';
 193
 194         /* Skip any extra whitespace after first token */
 195         *s += strspn(*s + 1, WHITESPACE) + 1;
 196         if (*s[0] == '=' && !wspace)
 197                 *s += strspn(*s + 1, WHITESPACE) + 1;
 198
 199         return (old);
 200 }
 201
 202 struct passwd *
 203 pwcopy(struct passwd *pw)
 204 {
 205         struct passwd *copy = xcalloc(1, sizeof(*copy));
 206
 207         copy->pw_name = xstrdup(pw->pw_name);
 208         copy->pw_passwd = xstrdup(pw->pw_passwd);
 209         copy->pw_gecos = xstrdup(pw->pw_gecos);
 210         copy->pw_uid = pw->pw_uid;
 211         copy->pw_gid = pw->pw_gid;
 212 #ifdef HAVE_PW_EXPIRE_IN_PASSWD
 213         copy->pw_expire = pw->pw_expire;
 214 #endif
 215 #ifdef HAVE_PW_CHANGE_IN_PASSWD
 216         copy->pw_change = pw->pw_change;
 217 #endif
 218 #ifdef HAVE_PW_CLASS_IN_PASSWD
 219         copy->pw_class = xstrdup(pw->pw_class);
 220 #endif
 221         copy->pw_dir = xstrdup(pw->pw_dir);
 222         copy->pw_shell = xstrdup(pw->pw_shell);
 223         return copy;
 224 }
 225
 226 /*
 227  * Convert ASCII string to TCP/IP port number.
 228  * Port must be >=0 and <=65535.
 229  * Return -1 if invalid.
 230  */
 231 int
 232 a2port(const char *s)
 233 {
 234         long long port;
 235         const char *errstr;
 236
 237         port = strtonum(s, 0, 65535, &errstr);
 238         if (errstr != NULL)
 239                 return -1;
 240         return (int)port;
 241 }
 242
 243 int
 244 a2tun(const char *s, int *remote)
 245 {
 246         const char *errstr = NULL;
 247         char *sp, *ep;
 248         int tun;
 249
 250         if (remote != NULL) {
 251                 *remote = SSH_TUNID_ANY;
 252                 sp = xstrdup(s);
 253                 if ((ep = strchr(sp, ':')) == NULL) {
 254                         xfree(sp);
 255                         return (a2tun(s, NULL));
 256                 }
 257                 ep[0] = '\0'; ep++;
 258                 *remote = a2tun(ep, NULL);
 259                 tun = a2tun(sp, NULL);
 260                 xfree(sp);
 261                 return (*remote == SSH_TUNID_ERR ? *remote : tun);
 262         }
 263
 264         if (strcasecmp(s, "any") == 0)
 265                 return (SSH_TUNID_ANY);
 266
 267         tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
 268         if (errstr != NULL)
 269                 return (SSH_TUNID_ERR);
 270
 271         return (tun);
 272 }
 273
 274 #define SECONDS         1
 275 #define MINUTES         (SECONDS * 60)
 276 #define HOURS           (MINUTES * 60)
 277 #define DAYS            (HOURS * 24)
 278 #define WEEKS           (DAYS * 7)
 279
 280 /*
 281  * Convert a time string into seconds; format is
 282  * a sequence of:
 283  *      time[qualifier]
 284  *
 285  * Valid time qualifiers are:
 286  *      <none>  seconds
 287  *      s|S     seconds
 288  *      m|M     minutes
 289  *      h|H     hours
 290  *      d|D     days
 291  *      w|W     weeks
 292  *
 293  * Examples:
 294  *      90m     90 minutes
 295  *      1h30m   90 minutes
 296  *      2d      2 days
 297  *      1w      1 week
 298  *
 299  * Return -1 if time string is invalid.
 300  */
 301 long
 302 convtime(const char *s)
 303 {
 304         long total, secs;
 305         const char *p;
 306         char *endp;
 307
 308         errno = 0;
 309         total = 0;
 310         p = s;
 311
 312         if (p == NULL || *p == '\0')
 313                 return -1;
 314
 315         while (*p) {
 316                 secs = strtol(p, &endp, 10);
 317                 if (p == endp ||
 318                     (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
 319                     secs < 0)
 320                         return -1;
 321
 322                 switch (*endp++) {
 323                 case '\0':
 324                         endp--;
 325                         break;
 326                 case 's':
 327                 case 'S':
 328                         break;
 329                 case 'm':
 330                 case 'M':
 331                         secs *= MINUTES;
 332                         break;
 333                 case 'h':
 334                 case 'H':
 335                         secs *= HOURS;
 336                         break;
 337                 case 'd':
 338                 case 'D':
 339                         secs *= DAYS;
 340                         break;
 341                 case 'w':
 342                 case 'W':
 343                         secs *= WEEKS;
 344                         break;
 345                 default:
 346                         return -1;
 347                 }
 348                 total += secs;
 349                 if (total < 0)
 350                         return -1;
 351                 p = endp;
 352         }
 353
 354         return total;
 355 }
 356
 357 /*
 358  * Returns a standardized host+port identifier string.
 359  * Caller must free returned string.
 360  */
 361 char *
 362 put_host_port(const char *host, u_short port)
 363 {
 364         char *hoststr;
 365
 366         if (port == 0 || port == SSH_DEFAULT_PORT)
 367                 return(xstrdup(host));
 368         if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
 369                 fatal("put_host_port: asprintf: %s", strerror(errno));
 370         debug3("put_host_port: %s", hoststr);
 371         return hoststr;
 372 }
 373
 374 /*
 375  * Search for next delimiter between hostnames/addresses and ports.
 376  * Argument may be modified (for termination).
 377  * Returns *cp if parsing succeeds.
 378  * *cp is set to the start of the next delimiter, if one was found.
 379  * If this is the last field, *cp is set to NULL.
 380  */
 381 char *
 382 hpdelim(char **cp)
 383 {
 384         char *s, *old;
 385
 386         if (cp == NULL || *cp == NULL)
 387                 return NULL;
 388
 389         old = s = *cp;
 390         if (*s == '[') {
 391                 if ((s = strchr(s, ']')) == NULL)
 392                         return NULL;
 393                 else
 394                         s++;
 395         } else if ((s = strpbrk(s, ":/")) == NULL)
 396                 s = *cp + strlen(*cp); /* skip to end (see first case below) */
 397
 398         switch (*s) {
 399         case '\0':
 400                 *cp = NULL;     /* no more fields*/
 401                 break;
 402
 403         case ':':
 404         case '/':
 405                 *s = '\0';      /* terminate */
 406                 *cp = s + 1;
 407                 break;
 408
 409         default:
 410                 return NULL;
 411         }
 412
 413         return old;
 414 }
 415
 416 char *
 417 cleanhostname(char *host)
 418 {
 419         if (*host == '[' && host[strlen(host) - 1] == ']') {
 420                 host[strlen(host) - 1] = '\0';
 421                 return (host + 1);
 422         } else
 423                 return host;
 424 }
 425
 426 char *
 427 colon(char *cp)
 428 {
 429         int flag = 0;
 430
 431         if (*cp == ':')         /* Leading colon is part of file name. */
 432                 return NULL;
 433         if (*cp == '[')
 434                 flag = 1;
 435
 436         for (; *cp; ++cp) {
 437                 if (*cp == '@' && *(cp+1) == '[')
 438                         flag = 1;
 439                 if (*cp == ']' && *(cp+1) == ':' && flag)
 440                         return (cp+1);
 441                 if (*cp == ':' && !flag)
 442                         return (cp);
 443                 if (*cp == '/')
 444                         return NULL;
 445         }
 446         return NULL;
 447 }
 448
 449 /* function to assist building execv() arguments */
 450 void
 451 addargs(arglist *args, char *fmt, ...)
 452 {
 453         va_list ap;
 454         char *cp;
 455         u_int nalloc;
 456         int r;
 457
 458         va_start(ap, fmt);
 459         r = vasprintf(&cp, fmt, ap);
 460         va_end(ap);
 461         if (r == -1)
 462                 fatal("addargs: argument too long");
 463
 464         nalloc = args->nalloc;
 465         if (args->list == NULL) {
 466                 nalloc = 32;
 467                 args->num = 0;
 468         } else if (args->num+2 >= nalloc)
 469                 nalloc *= 2;
 470
 471         args->list = xrealloc(args->list, nalloc, sizeof(char *));
 472         args->nalloc = nalloc;
 473         args->list[args->num++] = cp;
 474         args->list[args->num] = NULL;
 475 }
 476
 477 void
 478 replacearg(arglist *args, u_int which, char *fmt, ...)
 479 {
 480         va_list ap;
 481         char *cp;
 482         int r;
 483
 484         va_start(ap, fmt);
 485         r = vasprintf(&cp, fmt, ap);
 486         va_end(ap);
 487         if (r == -1)
 488                 fatal("replacearg: argument too long");
 489
 490         if (which >= args->num)
 491                 fatal("replacearg: tried to replace invalid arg %d >= %d",
 492                     which, args->num);
 493         xfree(args->list[which]);
 494         args->list[which] = cp;
 495 }
 496
 497 void
 498 freeargs(arglist *args)
 499 {
 500         u_int i;
 501
 502         if (args->list != NULL) {
 503                 for (i = 0; i < args->num; i++)
 504                         xfree(args->list[i]);
 505                 xfree(args->list);
 506                 args->nalloc = args->num = 0;
 507                 args->list = NULL;
 508         }
 509 }
 510
 511 /*
 512  * Expands tildes in the file name.  Returns data allocated by xmalloc.
 513  * Warning: this calls getpw*.
 514  */
 515 char *
 516 tilde_expand_filename(const char *filename, uid_t uid)
 517 {
 518         const char *path;
 519         char user[128], ret[MAXPATHLEN];
 520         struct passwd *pw;
 521         u_int len, slash;
 522
 523         if (*filename != '~')
 524                 return (xstrdup(filename));
 525         filename++;
 526
 527         path = strchr(filename, '/');
 528         if (path != NULL && path > filename) {          /* ~user/path */
 529                 slash = path - filename;
 530                 if (slash > sizeof(user) - 1)
 531                         fatal("tilde_expand_filename: ~username too long");
 532                 memcpy(user, filename, slash);
 533                 user[slash] = '\0';
 534                 if ((pw = getpwnam(user)) == NULL)
 535                         fatal("tilde_expand_filename: No such user %s", user);
 536         } else if ((pw = getpwuid(uid)) == NULL)        /* ~/path */
 537                 fatal("tilde_expand_filename: No such uid %ld", (long)uid);
 538
 539         if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
 540                 fatal("tilde_expand_filename: Path too long");
 541
 542         /* Make sure directory has a trailing '/' */
 543         len = strlen(pw->pw_dir);
 544         if ((len == 0 || pw->pw_dir[len - 1] != '/') &&
 545             strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
 546                 fatal("tilde_expand_filename: Path too long");
 547
 548         /* Skip leading '/' from specified path */
 549         if (path != NULL)
 550                 filename = path + 1;
 551         if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
 552                 fatal("tilde_expand_filename: Path too long");
 553
 554         return (xstrdup(ret));
 555 }
 556
 557 /*
 558  * Expand a string with a set of %[char] escapes. A number of escapes may be
 559  * specified as (char *escape_chars, char *replacement) pairs. The list must
 560  * be terminated by a NULL escape_char. Returns replaced string in memory
 561  * allocated by xmalloc.
 562  */
 563 char *
 564 percent_expand(const char *string, ...)
 565 {
 566 #define EXPAND_MAX_KEYS 16
 567         u_int num_keys, i, j;
 568         struct {
 569                 const char *key;
 570                 const char *repl;
 571         } keys[EXPAND_MAX_KEYS];
 572         char buf[4096];
 573         va_list ap;
 574
 575         /* Gather keys */
 576         va_start(ap, string);
 577         for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
 578                 keys[num_keys].key = va_arg(ap, char *);
 579                 if (keys[num_keys].key == NULL)
 580                         break;
 581                 keys[num_keys].repl = va_arg(ap, char *);
 582                 if (keys[num_keys].repl == NULL)
 583                         fatal("%s: NULL replacement", __func__);
 584         }
 585         if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
 586                 fatal("%s: too many keys", __func__);
 587         va_end(ap);
 588
 589         /* Expand string */
 590         *buf = '\0';
 591         for (i = 0; *string != '\0'; string++) {
 592                 if (*string != '%') {
 593  append:
 594                         buf[i++] = *string;
 595                         if (i >= sizeof(buf))
 596                                 fatal("%s: string too long", __func__);
 597                         buf[i] = '\0';
 598                         continue;
 599                 }
 600                 string++;
 601                 /* %% case */
 602                 if (*string == '%')
 603                         goto append;
 604                 for (j = 0; j < num_keys; j++) {
 605                         if (strchr(keys[j].key, *string) != NULL) {
 606                                 i = strlcat(buf, keys[j].repl, sizeof(buf));
 607                                 if (i >= sizeof(buf))
 608                                         fatal("%s: string too long", __func__);
 609                                 break;
 610                         }
 611                 }
 612                 if (j >= num_keys)
 613                         fatal("%s: unknown key %%%c", __func__, *string);
 614         }
 615         return (xstrdup(buf));
 616 #undef EXPAND_MAX_KEYS
 617 }
 618
 619 /*
 620  * Read an entire line from a public key file into a static buffer, discarding
 621  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
 622  */
 623 int
 624 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
 625    u_long *lineno)
 626 {
 627         while (fgets(buf, bufsz, f) != NULL) {
 628                 if (buf[0] == '\0')
 629                         continue;
 630                 (*lineno)++;
 631                 if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
 632                         return 0;
 633                 } else {
 634                         debug("%s: %s line %lu exceeds size limit", __func__,
 635                             filename, *lineno);
 636                         /* discard remainder of line */
 637                         while (fgetc(f) != '\n' && !feof(f))
 638                                 ;       /* nothing */
 639                 }
 640         }
 641         return -1;
 642 }
 643
 644 int
 645 tun_open(int tun, int mode)
 646 {
 647 #if defined(CUSTOM_SYS_TUN_OPEN)
 648         return (sys_tun_open(tun, mode));
 649 #elif defined(SSH_TUN_OPENBSD)
 650         struct ifreq ifr;
 651         char name[100];
 652         int fd = -1, sock;
 653
 654         /* Open the tunnel device */
 655         if (tun <= SSH_TUNID_MAX) {
 656                 snprintf(name, sizeof(name), "/dev/tun%d", tun);
 657                 fd = open(name, O_RDWR);
 658         } else if (tun == SSH_TUNID_ANY) {
 659                 for (tun = 100; tun >= 0; tun--) {
 660                         snprintf(name, sizeof(name), "/dev/tun%d", tun);
 661                         if ((fd = open(name, O_RDWR)) >= 0)
 662                                 break;
 663                 }
 664         } else {
 665                 debug("%s: invalid tunnel %u", __func__, tun);
 666                 return (-1);
 667         }
 668
 669         if (fd < 0) {
 670                 debug("%s: %s open failed: %s", __func__, name, strerror(errno));
 671                 return (-1);
 672         }
 673
 674         debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
 675
 676         /* Set the tunnel device operation mode */
 677         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tun%d", tun);
 678         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
 679                 goto failed;
 680
 681         if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
 682                 goto failed;
 683
 684         /* Set interface mode */
 685         ifr.ifr_flags &= ~IFF_UP;
 686         if (mode == SSH_TUNMODE_ETHERNET)
 687                 ifr.ifr_flags |= IFF_LINK0;
 688         else
 689                 ifr.ifr_flags &= ~IFF_LINK0;
 690         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 691                 goto failed;
 692
 693         /* Bring interface up */
 694         ifr.ifr_flags |= IFF_UP;
 695         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 696                 goto failed;
 697
 698         close(sock);
 699         return (fd);
 700
 701  failed:
 702         if (fd >= 0)
 703                 close(fd);
 704         if (sock >= 0)
 705                 close(sock);
 706         debug("%s: failed to set %s mode %d: %s", __func__, name,
 707             mode, strerror(errno));
 708         return (-1);
 709 #else
 710         error("Tunnel interfaces are not supported on this platform");
 711         return (-1);
 712 #endif
 713 }
 714
 715 void
 716 sanitise_stdfd(void)
 717 {
 718         int nullfd, dupfd;
 719
 720         if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 721                 fprintf(stderr, "Couldn't open /dev/null: %s\n",
 722                     strerror(errno));
 723                 exit(1);
 724         }
 725         while (++dupfd <= 2) {
 726                 /* Only clobber closed fds */
 727                 if (fcntl(dupfd, F_GETFL, 0) >= 0)
 728                         continue;
 729                 if (dup2(nullfd, dupfd) == -1) {
 730                         fprintf(stderr, "dup2: %s\n", strerror(errno));
 731                         exit(1);
 732                 }
 733         }
 734         if (nullfd > 2)
 735                 close(nullfd);
 736 }
 737
 738 char *
 739 tohex(const void *vp, size_t l)
 740 {
 741         const u_char *p = (const u_char *)vp;
 742         char b[3], *r;
 743         size_t i, hl;
 744
 745         if (l > 65536)
 746                 return xstrdup("tohex: length > 65536");
 747
 748         hl = l * 2 + 1;
 749         r = xcalloc(1, hl);
 750         for (i = 0; i < l; i++) {
 751                 snprintf(b, sizeof(b), "%02x", p[i]);
 752                 strlcat(r, b, hl);
 753         }
 754         return (r);
 755 }
 756
 757 u_int64_t
 758 get_u64(const void *vp)
 759 {
 760         const u_char *p = (const u_char *)vp;
 761         u_int64_t v;
 762
 763         v  = (u_int64_t)p[0] << 56;
 764         v |= (u_int64_t)p[1] << 48;
 765         v |= (u_int64_t)p[2] << 40;
 766         v |= (u_int64_t)p[3] << 32;
 767         v |= (u_int64_t)p[4] << 24;
 768         v |= (u_int64_t)p[5] << 16;
 769         v |= (u_int64_t)p[6] << 8;
 770         v |= (u_int64_t)p[7];
 771
 772         return (v);
 773 }
 774
 775 u_int32_t
 776 get_u32(const void *vp)
 777 {
 778         const u_char *p = (const u_char *)vp;
 779         u_int32_t v;
 780
 781         v  = (u_int32_t)p[0] << 24;
 782         v |= (u_int32_t)p[1] << 16;
 783         v |= (u_int32_t)p[2] << 8;
 784         v |= (u_int32_t)p[3];
 785
 786         return (v);
 787 }
 788
 789 u_int16_t
 790 get_u16(const void *vp)
 791 {
 792         const u_char *p = (const u_char *)vp;
 793         u_int16_t v;
 794
 795         v  = (u_int16_t)p[0] << 8;
 796         v |= (u_int16_t)p[1];
 797
 798         return (v);
 799 }
 800
 801 void
 802 put_u64(void *vp, u_int64_t v)
 803 {
 804         u_char *p = (u_char *)vp;
 805
 806         p[0] = (u_char)(v >> 56) & 0xff;
 807         p[1] = (u_char)(v >> 48) & 0xff;
 808         p[2] = (u_char)(v >> 40) & 0xff;
 809         p[3] = (u_char)(v >> 32) & 0xff;
 810         p[4] = (u_char)(v >> 24) & 0xff;
 811         p[5] = (u_char)(v >> 16) & 0xff;
 812         p[6] = (u_char)(v >> 8) & 0xff;
 813         p[7] = (u_char)v & 0xff;
 814 }
 815
 816 void
 817 put_u32(void *vp, u_int32_t v)
 818 {
 819         u_char *p = (u_char *)vp;
 820
 821         p[0] = (u_char)(v >> 24) & 0xff;
 822         p[1] = (u_char)(v >> 16) & 0xff;
 823         p[2] = (u_char)(v >> 8) & 0xff;
 824         p[3] = (u_char)v & 0xff;
 825 }
 826
 827
 828 void
 829 put_u16(void *vp, u_int16_t v)
 830 {
 831         u_char *p = (u_char *)vp;
 832
 833         p[0] = (u_char)(v >> 8) & 0xff;
 834         p[1] = (u_char)v & 0xff;
 835 }
 836
 837 void
 838 ms_subtract_diff(struct timeval *start, int *ms)
 839 {
 840         struct timeval diff, finish;
 841
 842         gettimeofday(&finish, NULL);
 843         timersub(&finish, start, &diff);
 844         *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
 845 }
 846
 847 void
 848 ms_to_timeval(struct timeval *tv, int ms)
 849 {
 850         if (ms < 0)
 851                 ms = 0;
 852         tv->tv_sec = ms / 1000;
 853         tv->tv_usec = (ms % 1000) * 1000;
 854 }
 855
 856 void
 857 bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
 858 {
 859         bw->buflen = buflen;
 860         bw->rate = kbps;
 861         bw->thresh = bw->rate;
 862         bw->lamt = 0;
 863         timerclear(&bw->bwstart);
 864         timerclear(&bw->bwend);
 865 }
 866
 867 /* Callback from read/write loop to insert bandwidth-limiting delays */
 868 void
 869 bandwidth_limit(struct bwlimit *bw, size_t read_len)
 870 {
 871         u_int64_t waitlen;
 872         struct timespec ts, rm;
 873
 874         if (!timerisset(&bw->bwstart)) {
 875                 gettimeofday(&bw->bwstart, NULL);
 876                 return;
 877         }
 878
 879         bw->lamt += read_len;
 880         if (bw->lamt < bw->thresh)
 881                 return;
 882
 883         gettimeofday(&bw->bwend, NULL);
 884         timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
 885         if (!timerisset(&bw->bwend))
 886                 return;
 887
 888         bw->lamt *= 8;
 889         waitlen = (double)1000000L * bw->lamt / bw->rate;
 890
 891         bw->bwstart.tv_sec = waitlen / 1000000L;
 892         bw->bwstart.tv_usec = waitlen % 1000000L;
 893
 894         if (timercmp(&bw->bwstart, &bw->bwend, >)) {
 895                 timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
 896
 897                 /* Adjust the wait time */
 898                 if (bw->bwend.tv_sec) {
 899                         bw->thresh /= 2;
 900                         if (bw->thresh < bw->buflen / 4)
 901                                 bw->thresh = bw->buflen / 4;
 902                 } else if (bw->bwend.tv_usec < 10000) {
 903                         bw->thresh *= 2;
 904                         if (bw->thresh > bw->buflen * 8)
 905                                 bw->thresh = bw->buflen * 8;
 906                 }
 907
 908                 TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
 909                 while (nanosleep(&ts, &rm) == -1) {
 910                         if (errno != EINTR)
 911                                 break;
 912                         ts = rm;
 913                 }
 914         }
 915
 916         bw->lamt = 0;
 917         gettimeofday(&bw->bwstart, NULL);
 918 }
 919
 920 /* Make a template filename for mk[sd]temp() */
 921 void
 922 mktemp_proto(char *s, size_t len)
 923 {
 924         const char *tmpdir;
 925         int r;
 926
 927         if ((tmpdir = getenv("TMPDIR")) != NULL) {
 928                 r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
 929                 if (r > 0 && (size_t)r < len)
 930                         return;
 931         }
 932         r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
 933         if (r < 0 || (size_t)r >= len)
 934                 fatal("%s: template string too short", __func__);
 935 }
 936
 937 static const struct {
 938         const char *name;
 939         int value;
 940 } ipqos[] = {
 941         { "af11", IPTOS_DSCP_AF11 },
 942         { "af12", IPTOS_DSCP_AF12 },
 943         { "af13", IPTOS_DSCP_AF13 },
 944         { "af14", IPTOS_DSCP_AF21 },
 945         { "af22", IPTOS_DSCP_AF22 },
 946         { "af23", IPTOS_DSCP_AF23 },
 947         { "af31", IPTOS_DSCP_AF31 },
 948         { "af32", IPTOS_DSCP_AF32 },
 949         { "af33", IPTOS_DSCP_AF33 },
 950         { "af41", IPTOS_DSCP_AF41 },
 951         { "af42", IPTOS_DSCP_AF42 },
 952         { "af43", IPTOS_DSCP_AF43 },
 953         { "cs0", IPTOS_DSCP_CS0 },
 954         { "cs1", IPTOS_DSCP_CS1 },
 955         { "cs2", IPTOS_DSCP_CS2 },
 956         { "cs3", IPTOS_DSCP_CS3 },
 957         { "cs4", IPTOS_DSCP_CS4 },
 958         { "cs5", IPTOS_DSCP_CS5 },
 959         { "cs6", IPTOS_DSCP_CS6 },
 960         { "cs7", IPTOS_DSCP_CS7 },
 961         { "ef", IPTOS_DSCP_EF },
 962         { "lowdelay", IPTOS_LOWDELAY },
 963         { "throughput", IPTOS_THROUGHPUT },
 964         { "reliability", IPTOS_RELIABILITY },
 965         { NULL, -1 }
 966 };
 967
 968 int
 969 parse_ipqos(const char *cp)
 970 {
 971         u_int i;
 972         char *ep;
 973         long val;
 974
 975         if (cp == NULL)
 976                 return -1;
 977         for (i = 0; ipqos[i].name != NULL; i++) {
 978                 if (strcasecmp(cp, ipqos[i].name) == 0)
 979                         return ipqos[i].value;
 980         }
 981         /* Try parsing as an integer */
 982         val = strtol(cp, &ep, 0);
 983         if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
 984                 return -1;
 985         return val;
 986 }
 987
 988 const char *
 989 iptos2str(int iptos)
 990 {
 991         int i;
 992         static char iptos_str[sizeof "0xff"];
 993
 994         for (i = 0; ipqos[i].name != NULL; i++) {
 995                 if (ipqos[i].value == iptos)
 996                         return ipqos[i].name;
 997         }
 998         snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
 999         return iptos_str;
1000 }
1001 void
1002 sock_set_v6only(int s)
1003 {
1004 #ifdef IPV6_V6ONLY
1005         int on = 1;
1006
1007         debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
1008         if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
1009                 error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
1010 #endif
1011 }