crypto/openssh/misc.c

   1 /* $OpenBSD: misc.c,v 1.105 2016/07/15 00:24:30 djm 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/time.h>
  33 #include <sys/un.h>
  34
  35 #include <limits.h>
  36 #include <stdarg.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <time.h>
  41 #include <unistd.h>
  42
  43 #include <netinet/in.h>
  44 #include <netinet/in_systm.h>
  45 #include <netinet/ip.h>
  46 #include <netinet/tcp.h>
  47
  48 #include <ctype.h>
  49 #include <errno.h>
  50 #include <fcntl.h>
  51 #include <netdb.h>
  52 #ifdef HAVE_PATHS_H
  53 # include <paths.h>
  54 #include <pwd.h>
  55 #endif
  56 #ifdef SSH_TUN_OPENBSD
  57 #include <net/if.h>
  58 #endif
  59
  60 #include "xmalloc.h"
  61 #include "misc.h"
  62 #include "log.h"
  63 #include "ssh.h"
  64
  65 /* remove newline at end of string */
  66 char *
  67 chop(char *s)
  68 {
  69         char *t = s;
  70         while (*t) {
  71                 if (*t == '\n' || *t == '\r') {
  72                         *t = '\0';
  73                         return s;
  74                 }
  75                 t++;
  76         }
  77         return s;
  78
  79 }
  80
  81 /* set/unset filedescriptor to non-blocking */
  82 int
  83 set_nonblock(int fd)
  84 {
  85         int val;
  86
  87         val = fcntl(fd, F_GETFL);
  88         if (val < 0) {
  89                 error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
  90                 return (-1);
  91         }
  92         if (val & O_NONBLOCK) {
  93                 debug3("fd %d is O_NONBLOCK", fd);
  94                 return (0);
  95         }
  96         debug2("fd %d setting O_NONBLOCK", fd);
  97         val |= O_NONBLOCK;
  98         if (fcntl(fd, F_SETFL, val) == -1) {
  99                 debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
 100                     strerror(errno));
 101                 return (-1);
 102         }
 103         return (0);
 104 }
 105
 106 int
 107 unset_nonblock(int fd)
 108 {
 109         int val;
 110
 111         val = fcntl(fd, F_GETFL);
 112         if (val < 0) {
 113                 error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
 114                 return (-1);
 115         }
 116         if (!(val & O_NONBLOCK)) {
 117                 debug3("fd %d is not O_NONBLOCK", fd);
 118                 return (0);
 119         }
 120         debug("fd %d clearing O_NONBLOCK", fd);
 121         val &= ~O_NONBLOCK;
 122         if (fcntl(fd, F_SETFL, val) == -1) {
 123                 debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
 124                     fd, strerror(errno));
 125                 return (-1);
 126         }
 127         return (0);
 128 }
 129
 130 const char *
 131 ssh_gai_strerror(int gaierr)
 132 {
 133         if (gaierr == EAI_SYSTEM && errno != 0)
 134                 return strerror(errno);
 135         return gai_strerror(gaierr);
 136 }
 137
 138 /* disable nagle on socket */
 139 void
 140 set_nodelay(int fd)
 141 {
 142         int opt;
 143         socklen_t optlen;
 144
 145         optlen = sizeof opt;
 146         if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
 147                 debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
 148                 return;
 149         }
 150         if (opt == 1) {
 151                 debug2("fd %d is TCP_NODELAY", fd);
 152                 return;
 153         }
 154         opt = 1;
 155         debug2("fd %d setting TCP_NODELAY", fd);
 156         if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
 157                 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
 158 }
 159
 160 /* Characters considered whitespace in strsep calls. */
 161 #define WHITESPACE " \t\r\n"
 162 #define QUOTE   "\""
 163
 164 /* return next token in configuration line */
 165 char *
 166 strdelim(char **s)
 167 {
 168         char *old;
 169         int wspace = 0;
 170
 171         if (*s == NULL)
 172                 return NULL;
 173
 174         old = *s;
 175
 176         *s = strpbrk(*s, WHITESPACE QUOTE "=");
 177         if (*s == NULL)
 178                 return (old);
 179
 180         if (*s[0] == '\"') {
 181                 memmove(*s, *s + 1, strlen(*s)); /* move nul too */
 182                 /* Find matching quote */
 183                 if ((*s = strpbrk(*s, QUOTE)) == NULL) {
 184                         return (NULL);          /* no matching quote */
 185                 } else {
 186                         *s[0] = '\0';
 187                         *s += strspn(*s + 1, WHITESPACE) + 1;
 188                         return (old);
 189                 }
 190         }
 191
 192         /* Allow only one '=' to be skipped */
 193         if (*s[0] == '=')
 194                 wspace = 1;
 195         *s[0] = '\0';
 196
 197         /* Skip any extra whitespace after first token */
 198         *s += strspn(*s + 1, WHITESPACE) + 1;
 199         if (*s[0] == '=' && !wspace)
 200                 *s += strspn(*s + 1, WHITESPACE) + 1;
 201
 202         return (old);
 203 }
 204
 205 struct passwd *
 206 pwcopy(struct passwd *pw)
 207 {
 208         struct passwd *copy = xcalloc(1, sizeof(*copy));
 209
 210         copy->pw_name = xstrdup(pw->pw_name);
 211         copy->pw_passwd = xstrdup(pw->pw_passwd);
 212 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
 213         copy->pw_gecos = xstrdup(pw->pw_gecos);
 214 #endif
 215         copy->pw_uid = pw->pw_uid;
 216         copy->pw_gid = pw->pw_gid;
 217 #ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
 218         copy->pw_expire = pw->pw_expire;
 219 #endif
 220 #ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
 221         copy->pw_change = pw->pw_change;
 222 #endif
 223 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
 224         copy->pw_class = xstrdup(pw->pw_class);
 225 #endif
 226         copy->pw_dir = xstrdup(pw->pw_dir);
 227         copy->pw_shell = xstrdup(pw->pw_shell);
 228         return copy;
 229 }
 230
 231 /*
 232  * Convert ASCII string to TCP/IP port number.
 233  * Port must be >=0 and <=65535.
 234  * Return -1 if invalid.
 235  */
 236 int
 237 a2port(const char *s)
 238 {
 239         long long port;
 240         const char *errstr;
 241
 242         port = strtonum(s, 0, 65535, &errstr);
 243         if (errstr != NULL)
 244                 return -1;
 245         return (int)port;
 246 }
 247
 248 int
 249 a2tun(const char *s, int *remote)
 250 {
 251         const char *errstr = NULL;
 252         char *sp, *ep;
 253         int tun;
 254
 255         if (remote != NULL) {
 256                 *remote = SSH_TUNID_ANY;
 257                 sp = xstrdup(s);
 258                 if ((ep = strchr(sp, ':')) == NULL) {
 259                         free(sp);
 260                         return (a2tun(s, NULL));
 261                 }
 262                 ep[0] = '\0'; ep++;
 263                 *remote = a2tun(ep, NULL);
 264                 tun = a2tun(sp, NULL);
 265                 free(sp);
 266                 return (*remote == SSH_TUNID_ERR ? *remote : tun);
 267         }
 268
 269         if (strcasecmp(s, "any") == 0)
 270                 return (SSH_TUNID_ANY);
 271
 272         tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
 273         if (errstr != NULL)
 274                 return (SSH_TUNID_ERR);
 275
 276         return (tun);
 277 }
 278
 279 #define SECONDS         1
 280 #define MINUTES         (SECONDS * 60)
 281 #define HOURS           (MINUTES * 60)
 282 #define DAYS            (HOURS * 24)
 283 #define WEEKS           (DAYS * 7)
 284
 285 /*
 286  * Convert a time string into seconds; format is
 287  * a sequence of:
 288  *      time[qualifier]
 289  *
 290  * Valid time qualifiers are:
 291  *      <none>  seconds
 292  *      s|S     seconds
 293  *      m|M     minutes
 294  *      h|H     hours
 295  *      d|D     days
 296  *      w|W     weeks
 297  *
 298  * Examples:
 299  *      90m     90 minutes
 300  *      1h30m   90 minutes
 301  *      2d      2 days
 302  *      1w      1 week
 303  *
 304  * Return -1 if time string is invalid.
 305  */
 306 long
 307 convtime(const char *s)
 308 {
 309         long total, secs;
 310         const char *p;
 311         char *endp;
 312
 313         errno = 0;
 314         total = 0;
 315         p = s;
 316
 317         if (p == NULL || *p == '\0')
 318                 return -1;
 319
 320         while (*p) {
 321                 secs = strtol(p, &endp, 10);
 322                 if (p == endp ||
 323                     (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
 324                     secs < 0)
 325                         return -1;
 326
 327                 switch (*endp++) {
 328                 case '\0':
 329                         endp--;
 330                         break;
 331                 case 's':
 332                 case 'S':
 333                         break;
 334                 case 'm':
 335                 case 'M':
 336                         secs *= MINUTES;
 337                         break;
 338                 case 'h':
 339                 case 'H':
 340                         secs *= HOURS;
 341                         break;
 342                 case 'd':
 343                 case 'D':
 344                         secs *= DAYS;
 345                         break;
 346                 case 'w':
 347                 case 'W':
 348                         secs *= WEEKS;
 349                         break;
 350                 default:
 351                         return -1;
 352                 }
 353                 total += secs;
 354                 if (total < 0)
 355                         return -1;
 356                 p = endp;
 357         }
 358
 359         return total;
 360 }
 361
 362 /*
 363  * Returns a standardized host+port identifier string.
 364  * Caller must free returned string.
 365  */
 366 char *
 367 put_host_port(const char *host, u_short port)
 368 {
 369         char *hoststr;
 370
 371         if (port == 0 || port == SSH_DEFAULT_PORT)
 372                 return(xstrdup(host));
 373         if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
 374                 fatal("put_host_port: asprintf: %s", strerror(errno));
 375         debug3("put_host_port: %s", hoststr);
 376         return hoststr;
 377 }
 378
 379 /*
 380  * Search for next delimiter between hostnames/addresses and ports.
 381  * Argument may be modified (for termination).
 382  * Returns *cp if parsing succeeds.
 383  * *cp is set to the start of the next delimiter, if one was found.
 384  * If this is the last field, *cp is set to NULL.
 385  */
 386 char *
 387 hpdelim(char **cp)
 388 {
 389         char *s, *old;
 390
 391         if (cp == NULL || *cp == NULL)
 392                 return NULL;
 393
 394         old = s = *cp;
 395         if (*s == '[') {
 396                 if ((s = strchr(s, ']')) == NULL)
 397                         return NULL;
 398                 else
 399                         s++;
 400         } else if ((s = strpbrk(s, ":/")) == NULL)
 401                 s = *cp + strlen(*cp); /* skip to end (see first case below) */
 402
 403         switch (*s) {
 404         case '\0':
 405                 *cp = NULL;     /* no more fields*/
 406                 break;
 407
 408         case ':':
 409         case '/':
 410                 *s = '\0';      /* terminate */
 411                 *cp = s + 1;
 412                 break;
 413
 414         default:
 415                 return NULL;
 416         }
 417
 418         return old;
 419 }
 420
 421 char *
 422 cleanhostname(char *host)
 423 {
 424         if (*host == '[' && host[strlen(host) - 1] == ']') {
 425                 host[strlen(host) - 1] = '\0';
 426                 return (host + 1);
 427         } else
 428                 return host;
 429 }
 430
 431 char *
 432 colon(char *cp)
 433 {
 434         int flag = 0;
 435
 436         if (*cp == ':')         /* Leading colon is part of file name. */
 437                 return NULL;
 438         if (*cp == '[')
 439                 flag = 1;
 440
 441         for (; *cp; ++cp) {
 442                 if (*cp == '@' && *(cp+1) == '[')
 443                         flag = 1;
 444                 if (*cp == ']' && *(cp+1) == ':' && flag)
 445                         return (cp+1);
 446                 if (*cp == ':' && !flag)
 447                         return (cp);
 448                 if (*cp == '/')
 449                         return NULL;
 450         }
 451         return NULL;
 452 }
 453
 454 /*
 455  * Parse a [user@]host[:port] string.
 456  * Caller must free returned user and host.
 457  * Any of the pointer return arguments may be NULL (useful for syntax checking).
 458  * If user was not specified then *userp will be set to NULL.
 459  * If port was not specified then *portp will be -1.
 460  * Returns 0 on success, -1 on failure.
 461  */
 462 int
 463 parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
 464 {
 465         char *sdup, *cp, *tmp;
 466         char *user = NULL, *host = NULL;
 467         int port = -1, ret = -1;
 468
 469         if (userp != NULL)
 470                 *userp = NULL;
 471         if (hostp != NULL)
 472                 *hostp = NULL;
 473         if (portp != NULL)
 474                 *portp = -1;
 475
 476         if ((sdup = tmp = strdup(s)) == NULL)
 477                 return -1;
 478         /* Extract optional username */
 479         if ((cp = strchr(tmp, '@')) != NULL) {
 480                 *cp = '\0';
 481                 if (*tmp == '\0')
 482                         goto out;
 483                 if ((user = strdup(tmp)) == NULL)
 484                         goto out;
 485                 tmp = cp + 1;
 486         }
 487         /* Extract mandatory hostname */
 488         if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0')
 489                 goto out;
 490         host = xstrdup(cleanhostname(cp));
 491         /* Convert and verify optional port */
 492         if (tmp != NULL && *tmp != '\0') {
 493                 if ((port = a2port(tmp)) <= 0)
 494                         goto out;
 495         }
 496         /* Success */
 497         if (userp != NULL) {
 498                 *userp = user;
 499                 user = NULL;
 500         }
 501         if (hostp != NULL) {
 502                 *hostp = host;
 503                 host = NULL;
 504         }
 505         if (portp != NULL)
 506                 *portp = port;
 507         ret = 0;
 508  out:
 509         free(sdup);
 510         free(user);
 511         free(host);
 512         return ret;
 513 }
 514
 515 /* function to assist building execv() arguments */
 516 void
 517 addargs(arglist *args, char *fmt, ...)
 518 {
 519         va_list ap;
 520         char *cp;
 521         u_int nalloc;
 522         int r;
 523
 524         va_start(ap, fmt);
 525         r = vasprintf(&cp, fmt, ap);
 526         va_end(ap);
 527         if (r == -1)
 528                 fatal("addargs: argument too long");
 529
 530         nalloc = args->nalloc;
 531         if (args->list == NULL) {
 532                 nalloc = 32;
 533                 args->num = 0;
 534         } else if (args->num+2 >= nalloc)
 535                 nalloc *= 2;
 536
 537         args->list = xreallocarray(args->list, nalloc, sizeof(char *));
 538         args->nalloc = nalloc;
 539         args->list[args->num++] = cp;
 540         args->list[args->num] = NULL;
 541 }
 542
 543 void
 544 replacearg(arglist *args, u_int which, char *fmt, ...)
 545 {
 546         va_list ap;
 547         char *cp;
 548         int r;
 549
 550         va_start(ap, fmt);
 551         r = vasprintf(&cp, fmt, ap);
 552         va_end(ap);
 553         if (r == -1)
 554                 fatal("replacearg: argument too long");
 555
 556         if (which >= args->num)
 557                 fatal("replacearg: tried to replace invalid arg %d >= %d",
 558                     which, args->num);
 559         free(args->list[which]);
 560         args->list[which] = cp;
 561 }
 562
 563 void
 564 freeargs(arglist *args)
 565 {
 566         u_int i;
 567
 568         if (args->list != NULL) {
 569                 for (i = 0; i < args->num; i++)
 570                         free(args->list[i]);
 571                 free(args->list);
 572                 args->nalloc = args->num = 0;
 573                 args->list = NULL;
 574         }
 575 }
 576
 577 /*
 578  * Expands tildes in the file name.  Returns data allocated by xmalloc.
 579  * Warning: this calls getpw*.
 580  */
 581 char *
 582 tilde_expand_filename(const char *filename, uid_t uid)
 583 {
 584         const char *path, *sep;
 585         char user[128], *ret;
 586         struct passwd *pw;
 587         u_int len, slash;
 588
 589         if (*filename != '~')
 590                 return (xstrdup(filename));
 591         filename++;
 592
 593         path = strchr(filename, '/');
 594         if (path != NULL && path > filename) {          /* ~user/path */
 595                 slash = path - filename;
 596                 if (slash > sizeof(user) - 1)
 597                         fatal("tilde_expand_filename: ~username too long");
 598                 memcpy(user, filename, slash);
 599                 user[slash] = '\0';
 600                 if ((pw = getpwnam(user)) == NULL)
 601                         fatal("tilde_expand_filename: No such user %s", user);
 602         } else if ((pw = getpwuid(uid)) == NULL)        /* ~/path */
 603                 fatal("tilde_expand_filename: No such uid %ld", (long)uid);
 604
 605         /* Make sure directory has a trailing '/' */
 606         len = strlen(pw->pw_dir);
 607         if (len == 0 || pw->pw_dir[len - 1] != '/')
 608                 sep = "/";
 609         else
 610                 sep = "";
 611
 612         /* Skip leading '/' from specified path */
 613         if (path != NULL)
 614                 filename = path + 1;
 615
 616         if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX)
 617                 fatal("tilde_expand_filename: Path too long");
 618
 619         return (ret);
 620 }
 621
 622 /*
 623  * Expand a string with a set of %[char] escapes. A number of escapes may be
 624  * specified as (char *escape_chars, char *replacement) pairs. The list must
 625  * be terminated by a NULL escape_char. Returns replaced string in memory
 626  * allocated by xmalloc.
 627  */
 628 char *
 629 percent_expand(const char *string, ...)
 630 {
 631 #define EXPAND_MAX_KEYS 16
 632         u_int num_keys, i, j;
 633         struct {
 634                 const char *key;
 635                 const char *repl;
 636         } keys[EXPAND_MAX_KEYS];
 637         char buf[4096];
 638         va_list ap;
 639
 640         /* Gather keys */
 641         va_start(ap, string);
 642         for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
 643                 keys[num_keys].key = va_arg(ap, char *);
 644                 if (keys[num_keys].key == NULL)
 645                         break;
 646                 keys[num_keys].repl = va_arg(ap, char *);
 647                 if (keys[num_keys].repl == NULL)
 648                         fatal("%s: NULL replacement", __func__);
 649         }
 650         if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
 651                 fatal("%s: too many keys", __func__);
 652         va_end(ap);
 653
 654         /* Expand string */
 655         *buf = '\0';
 656         for (i = 0; *string != '\0'; string++) {
 657                 if (*string != '%') {
 658  append:
 659                         buf[i++] = *string;
 660                         if (i >= sizeof(buf))
 661                                 fatal("%s: string too long", __func__);
 662                         buf[i] = '\0';
 663                         continue;
 664                 }
 665                 string++;
 666                 /* %% case */
 667                 if (*string == '%')
 668                         goto append;
 669                 if (*string == '\0')
 670                         fatal("%s: invalid format", __func__);
 671                 for (j = 0; j < num_keys; j++) {
 672                         if (strchr(keys[j].key, *string) != NULL) {
 673                                 i = strlcat(buf, keys[j].repl, sizeof(buf));
 674                                 if (i >= sizeof(buf))
 675                                         fatal("%s: string too long", __func__);
 676                                 break;
 677                         }
 678                 }
 679                 if (j >= num_keys)
 680                         fatal("%s: unknown key %%%c", __func__, *string);
 681         }
 682         return (xstrdup(buf));
 683 #undef EXPAND_MAX_KEYS
 684 }
 685
 686 /*
 687  * Read an entire line from a public key file into a static buffer, discarding
 688  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
 689  */
 690 int
 691 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
 692    u_long *lineno)
 693 {
 694         while (fgets(buf, bufsz, f) != NULL) {
 695                 if (buf[0] == '\0')
 696                         continue;
 697                 (*lineno)++;
 698                 if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
 699                         return 0;
 700                 } else {
 701                         debug("%s: %s line %lu exceeds size limit", __func__,
 702                             filename, *lineno);
 703                         /* discard remainder of line */
 704                         while (fgetc(f) != '\n' && !feof(f))
 705                                 ;       /* nothing */
 706                 }
 707         }
 708         return -1;
 709 }
 710
 711 int
 712 tun_open(int tun, int mode)
 713 {
 714 #if defined(CUSTOM_SYS_TUN_OPEN)
 715         return (sys_tun_open(tun, mode));
 716 #elif defined(SSH_TUN_OPENBSD)
 717         struct ifreq ifr;
 718         char name[100];
 719         int fd = -1, sock;
 720         const char *tunbase = "tun";
 721
 722         if (mode == SSH_TUNMODE_ETHERNET)
 723                 tunbase = "tap";
 724
 725         /* Open the tunnel device */
 726         if (tun <= SSH_TUNID_MAX) {
 727                 snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
 728                 fd = open(name, O_RDWR);
 729         } else if (tun == SSH_TUNID_ANY) {
 730                 for (tun = 100; tun >= 0; tun--) {
 731                         snprintf(name, sizeof(name), "/dev/%s%d",
 732                             tunbase, tun);
 733                         if ((fd = open(name, O_RDWR)) >= 0)
 734                                 break;
 735                 }
 736         } else {
 737                 debug("%s: invalid tunnel %u", __func__, tun);
 738                 return -1;
 739         }
 740
 741         if (fd < 0) {
 742                 debug("%s: %s open: %s", __func__, name, strerror(errno));
 743                 return -1;
 744         }
 745
 746         debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
 747
 748         /* Bring interface up if it is not already */
 749         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
 750         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
 751                 goto failed;
 752
 753         if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
 754                 debug("%s: get interface %s flags: %s", __func__,
 755                     ifr.ifr_name, strerror(errno));
 756                 goto failed;
 757         }
 758
 759         if (!(ifr.ifr_flags & IFF_UP)) {
 760                 ifr.ifr_flags |= IFF_UP;
 761                 if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) {
 762                         debug("%s: activate interface %s: %s", __func__,
 763                             ifr.ifr_name, strerror(errno));
 764                         goto failed;
 765                 }
 766         }
 767
 768         close(sock);
 769         return fd;
 770
 771  failed:
 772         if (fd >= 0)
 773                 close(fd);
 774         if (sock >= 0)
 775                 close(sock);
 776         return -1;
 777 #else
 778         error("Tunnel interfaces are not supported on this platform");
 779         return (-1);
 780 #endif
 781 }
 782
 783 void
 784 sanitise_stdfd(void)
 785 {
 786         int nullfd, dupfd;
 787
 788         if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 789                 fprintf(stderr, "Couldn't open /dev/null: %s\n",
 790                     strerror(errno));
 791                 exit(1);
 792         }
 793         while (++dupfd <= STDERR_FILENO) {
 794                 /* Only populate closed fds. */
 795                 if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
 796                         if (dup2(nullfd, dupfd) == -1) {
 797                                 fprintf(stderr, "dup2: %s\n", strerror(errno));
 798                                 exit(1);
 799                         }
 800                 }
 801         }
 802         if (nullfd > STDERR_FILENO)
 803                 close(nullfd);
 804 }
 805
 806 char *
 807 tohex(const void *vp, size_t l)
 808 {
 809         const u_char *p = (const u_char *)vp;
 810         char b[3], *r;
 811         size_t i, hl;
 812
 813         if (l > 65536)
 814                 return xstrdup("tohex: length > 65536");
 815
 816         hl = l * 2 + 1;
 817         r = xcalloc(1, hl);
 818         for (i = 0; i < l; i++) {
 819                 snprintf(b, sizeof(b), "%02x", p[i]);
 820                 strlcat(r, b, hl);
 821         }
 822         return (r);
 823 }
 824
 825 u_int64_t
 826 get_u64(const void *vp)
 827 {
 828         const u_char *p = (const u_char *)vp;
 829         u_int64_t v;
 830
 831         v  = (u_int64_t)p[0] << 56;
 832         v |= (u_int64_t)p[1] << 48;
 833         v |= (u_int64_t)p[2] << 40;
 834         v |= (u_int64_t)p[3] << 32;
 835         v |= (u_int64_t)p[4] << 24;
 836         v |= (u_int64_t)p[5] << 16;
 837         v |= (u_int64_t)p[6] << 8;
 838         v |= (u_int64_t)p[7];
 839
 840         return (v);
 841 }
 842
 843 u_int32_t
 844 get_u32(const void *vp)
 845 {
 846         const u_char *p = (const u_char *)vp;
 847         u_int32_t v;
 848
 849         v  = (u_int32_t)p[0] << 24;
 850         v |= (u_int32_t)p[1] << 16;
 851         v |= (u_int32_t)p[2] << 8;
 852         v |= (u_int32_t)p[3];
 853
 854         return (v);
 855 }
 856
 857 u_int32_t
 858 get_u32_le(const void *vp)
 859 {
 860         const u_char *p = (const u_char *)vp;
 861         u_int32_t v;
 862
 863         v  = (u_int32_t)p[0];
 864         v |= (u_int32_t)p[1] << 8;
 865         v |= (u_int32_t)p[2] << 16;
 866         v |= (u_int32_t)p[3] << 24;
 867
 868         return (v);
 869 }
 870
 871 u_int16_t
 872 get_u16(const void *vp)
 873 {
 874         const u_char *p = (const u_char *)vp;
 875         u_int16_t v;
 876
 877         v  = (u_int16_t)p[0] << 8;
 878         v |= (u_int16_t)p[1];
 879
 880         return (v);
 881 }
 882
 883 void
 884 put_u64(void *vp, u_int64_t v)
 885 {
 886         u_char *p = (u_char *)vp;
 887
 888         p[0] = (u_char)(v >> 56) & 0xff;
 889         p[1] = (u_char)(v >> 48) & 0xff;
 890         p[2] = (u_char)(v >> 40) & 0xff;
 891         p[3] = (u_char)(v >> 32) & 0xff;
 892         p[4] = (u_char)(v >> 24) & 0xff;
 893         p[5] = (u_char)(v >> 16) & 0xff;
 894         p[6] = (u_char)(v >> 8) & 0xff;
 895         p[7] = (u_char)v & 0xff;
 896 }
 897
 898 void
 899 put_u32(void *vp, u_int32_t v)
 900 {
 901         u_char *p = (u_char *)vp;
 902
 903         p[0] = (u_char)(v >> 24) & 0xff;
 904         p[1] = (u_char)(v >> 16) & 0xff;
 905         p[2] = (u_char)(v >> 8) & 0xff;
 906         p[3] = (u_char)v & 0xff;
 907 }
 908
 909 void
 910 put_u32_le(void *vp, u_int32_t v)
 911 {
 912         u_char *p = (u_char *)vp;
 913
 914         p[0] = (u_char)v & 0xff;
 915         p[1] = (u_char)(v >> 8) & 0xff;
 916         p[2] = (u_char)(v >> 16) & 0xff;
 917         p[3] = (u_char)(v >> 24) & 0xff;
 918 }
 919
 920 void
 921 put_u16(void *vp, u_int16_t v)
 922 {
 923         u_char *p = (u_char *)vp;
 924
 925         p[0] = (u_char)(v >> 8) & 0xff;
 926         p[1] = (u_char)v & 0xff;
 927 }
 928
 929 void
 930 ms_subtract_diff(struct timeval *start, int *ms)
 931 {
 932         struct timeval diff, finish;
 933
 934         gettimeofday(&finish, NULL);
 935         timersub(&finish, start, &diff);
 936         *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
 937 }
 938
 939 void
 940 ms_to_timeval(struct timeval *tv, int ms)
 941 {
 942         if (ms < 0)
 943                 ms = 0;
 944         tv->tv_sec = ms / 1000;
 945         tv->tv_usec = (ms % 1000) * 1000;
 946 }
 947
 948 time_t
 949 monotime(void)
 950 {
 951 #if defined(HAVE_CLOCK_GETTIME) && \
 952     (defined(CLOCK_MONOTONIC) || defined(CLOCK_BOOTTIME))
 953         struct timespec ts;
 954         static int gettime_failed = 0;
 955
 956         if (!gettime_failed) {
 957 #if defined(CLOCK_BOOTTIME)
 958                 if (clock_gettime(CLOCK_BOOTTIME, &ts) == 0)
 959                         return (ts.tv_sec);
 960 #endif
 961 #if defined(CLOCK_MONOTONIC)
 962                 if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0)
 963                         return (ts.tv_sec);
 964 #endif
 965                 debug3("clock_gettime: %s", strerror(errno));
 966                 gettime_failed = 1;
 967         }
 968 #endif /* HAVE_CLOCK_GETTIME && (CLOCK_MONOTONIC || CLOCK_BOOTTIME */
 969
 970         return time(NULL);
 971 }
 972
 973 double
 974 monotime_double(void)
 975 {
 976 #if defined(HAVE_CLOCK_GETTIME) && \
 977     (defined(CLOCK_MONOTONIC) || defined(CLOCK_BOOTTIME))
 978         struct timespec ts;
 979         static int gettime_failed = 0;
 980
 981         if (!gettime_failed) {
 982 #if defined(CLOCK_BOOTTIME)
 983                 if (clock_gettime(CLOCK_BOOTTIME, &ts) == 0)
 984                         return (ts.tv_sec + (double)ts.tv_nsec / 1000000000);
 985 #endif
 986 #if defined(CLOCK_MONOTONIC)
 987                 if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0)
 988                         return (ts.tv_sec + (double)ts.tv_nsec / 1000000000);
 989 #endif
 990                 debug3("clock_gettime: %s", strerror(errno));
 991                 gettime_failed = 1;
 992         }
 993 #endif /* HAVE_CLOCK_GETTIME && (CLOCK_MONOTONIC || CLOCK_BOOTTIME */
 994
 995         return (double)time(NULL);
 996 }
 997
 998 void
 999 bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
1000 {
1001         bw->buflen = buflen;
1002         bw->rate = kbps;
1003         bw->thresh = bw->rate;
1004         bw->lamt = 0;
1005         timerclear(&bw->bwstart);
1006         timerclear(&bw->bwend);
1007 }
1008
1009 /* Callback from read/write loop to insert bandwidth-limiting delays */
1010 void
1011 bandwidth_limit(struct bwlimit *bw, size_t read_len)
1012 {
1013         u_int64_t waitlen;
1014         struct timespec ts, rm;
1015
1016         if (!timerisset(&bw->bwstart)) {
1017                 gettimeofday(&bw->bwstart, NULL);
1018                 return;
1019         }
1020
1021         bw->lamt += read_len;
1022         if (bw->lamt < bw->thresh)
1023                 return;
1024
1025         gettimeofday(&bw->bwend, NULL);
1026         timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
1027         if (!timerisset(&bw->bwend))
1028                 return;
1029
1030         bw->lamt *= 8;
1031         waitlen = (double)1000000L * bw->lamt / bw->rate;
1032
1033         bw->bwstart.tv_sec = waitlen / 1000000L;
1034         bw->bwstart.tv_usec = waitlen % 1000000L;
1035
1036         if (timercmp(&bw->bwstart, &bw->bwend, >)) {
1037                 timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
1038
1039                 /* Adjust the wait time */
1040                 if (bw->bwend.tv_sec) {
1041                         bw->thresh /= 2;
1042                         if (bw->thresh < bw->buflen / 4)
1043                                 bw->thresh = bw->buflen / 4;
1044                 } else if (bw->bwend.tv_usec < 10000) {
1045                         bw->thresh *= 2;
1046                         if (bw->thresh > bw->buflen * 8)
1047                                 bw->thresh = bw->buflen * 8;
1048                 }
1049
1050                 TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
1051                 while (nanosleep(&ts, &rm) == -1) {
1052                         if (errno != EINTR)
1053                                 break;
1054                         ts = rm;
1055                 }
1056         }
1057
1058         bw->lamt = 0;
1059         gettimeofday(&bw->bwstart, NULL);
1060 }
1061
1062 /* Make a template filename for mk[sd]temp() */
1063 void
1064 mktemp_proto(char *s, size_t len)
1065 {
1066         const char *tmpdir;
1067         int r;
1068
1069         if ((tmpdir = getenv("TMPDIR")) != NULL) {
1070                 r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
1071                 if (r > 0 && (size_t)r < len)
1072                         return;
1073         }
1074         r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
1075         if (r < 0 || (size_t)r >= len)
1076                 fatal("%s: template string too short", __func__);
1077 }
1078
1079 static const struct {
1080         const char *name;
1081         int value;
1082 } ipqos[] = {
1083         { "af11", IPTOS_DSCP_AF11 },
1084         { "af12", IPTOS_DSCP_AF12 },
1085         { "af13", IPTOS_DSCP_AF13 },
1086         { "af21", IPTOS_DSCP_AF21 },
1087         { "af22", IPTOS_DSCP_AF22 },
1088         { "af23", IPTOS_DSCP_AF23 },
1089         { "af31", IPTOS_DSCP_AF31 },
1090         { "af32", IPTOS_DSCP_AF32 },
1091         { "af33", IPTOS_DSCP_AF33 },
1092         { "af41", IPTOS_DSCP_AF41 },
1093         { "af42", IPTOS_DSCP_AF42 },
1094         { "af43", IPTOS_DSCP_AF43 },
1095         { "cs0", IPTOS_DSCP_CS0 },
1096         { "cs1", IPTOS_DSCP_CS1 },
1097         { "cs2", IPTOS_DSCP_CS2 },
1098         { "cs3", IPTOS_DSCP_CS3 },
1099         { "cs4", IPTOS_DSCP_CS4 },
1100         { "cs5", IPTOS_DSCP_CS5 },
1101         { "cs6", IPTOS_DSCP_CS6 },
1102         { "cs7", IPTOS_DSCP_CS7 },
1103         { "ef", IPTOS_DSCP_EF },
1104         { "lowdelay", IPTOS_LOWDELAY },
1105         { "throughput", IPTOS_THROUGHPUT },
1106         { "reliability", IPTOS_RELIABILITY },
1107         { NULL, -1 }
1108 };
1109
1110 int
1111 parse_ipqos(const char *cp)
1112 {
1113         u_int i;
1114         char *ep;
1115         long val;
1116
1117         if (cp == NULL)
1118                 return -1;
1119         for (i = 0; ipqos[i].name != NULL; i++) {
1120                 if (strcasecmp(cp, ipqos[i].name) == 0)
1121                         return ipqos[i].value;
1122         }
1123         /* Try parsing as an integer */
1124         val = strtol(cp, &ep, 0);
1125         if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
1126                 return -1;
1127         return val;
1128 }
1129
1130 const char *
1131 iptos2str(int iptos)
1132 {
1133         int i;
1134         static char iptos_str[sizeof "0xff"];
1135
1136         for (i = 0; ipqos[i].name != NULL; i++) {
1137                 if (ipqos[i].value == iptos)
1138                         return ipqos[i].name;
1139         }
1140         snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
1141         return iptos_str;
1142 }
1143
1144 void
1145 lowercase(char *s)
1146 {
1147         for (; *s; s++)
1148                 *s = tolower((u_char)*s);
1149 }
1150
1151 int
1152 unix_listener(const char *path, int backlog, int unlink_first)
1153 {
1154         struct sockaddr_un sunaddr;
1155         int saved_errno, sock;
1156
1157         memset(&sunaddr, 0, sizeof(sunaddr));
1158         sunaddr.sun_family = AF_UNIX;
1159         if (strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) {
1160                 error("%s: \"%s\" too long for Unix domain socket", __func__,
1161                     path);
1162                 errno = ENAMETOOLONG;
1163                 return -1;
1164         }
1165
1166         sock = socket(PF_UNIX, SOCK_STREAM, 0);
1167         if (sock < 0) {
1168                 saved_errno = errno;
1169                 error("socket: %.100s", strerror(errno));
1170                 errno = saved_errno;
1171                 return -1;
1172         }
1173         if (unlink_first == 1) {
1174                 if (unlink(path) != 0 && errno != ENOENT)
1175                         error("unlink(%s): %.100s", path, strerror(errno));
1176         }
1177         if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
1178                 saved_errno = errno;
1179                 error("bind: %.100s", strerror(errno));
1180                 close(sock);
1181                 error("%s: cannot bind to path: %s", __func__, path);
1182                 errno = saved_errno;
1183                 return -1;
1184         }
1185         if (listen(sock, backlog) < 0) {
1186                 saved_errno = errno;
1187                 error("listen: %.100s", strerror(errno));
1188                 close(sock);
1189                 unlink(path);
1190                 error("%s: cannot listen on path: %s", __func__, path);
1191                 errno = saved_errno;
1192                 return -1;
1193         }
1194         return sock;
1195 }
1196
1197 void
1198 sock_set_v6only(int s)
1199 {
1200 #if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
1201         int on = 1;
1202
1203         debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
1204         if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
1205                 error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
1206 #endif
1207 }
1208
1209 /*
1210  * Compares two strings that maybe be NULL. Returns non-zero if strings
1211  * are both NULL or are identical, returns zero otherwise.
1212  */
1213 static int
1214 strcmp_maybe_null(const char *a, const char *b)
1215 {
1216         if ((a == NULL && b != NULL) || (a != NULL && b == NULL))
1217                 return 0;
1218         if (a != NULL && strcmp(a, b) != 0)
1219                 return 0;
1220         return 1;
1221 }
1222
1223 /*
1224  * Compare two forwards, returning non-zero if they are identical or
1225  * zero otherwise.
1226  */
1227 int
1228 forward_equals(const struct Forward *a, const struct Forward *b)
1229 {
1230         if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0)
1231                 return 0;
1232         if (a->listen_port != b->listen_port)
1233                 return 0;
1234         if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0)
1235                 return 0;
1236         if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0)
1237                 return 0;
1238         if (a->connect_port != b->connect_port)
1239                 return 0;
1240         if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0)
1241                 return 0;
1242         /* allocated_port and handle are not checked */
1243         return 1;
1244 }
1245