Annotation of src/usr.bin/ssh/misc.c, Revision 1.112
1.112 ! djm 1: /* $OpenBSD: misc.c,v 1.111 2017/07/23 23:37:02 djm Exp $ */
1.1 markus 2: /*
3: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.52 djm 4: * Copyright (c) 2005,2006 Damien Miller. All rights reserved.
1.1 markus 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:
1.64 deraadt 27: #include <sys/types.h>
1.45 stevesk 28: #include <sys/ioctl.h>
1.53 stevesk 29: #include <sys/socket.h>
1.112 ! djm 30: #include <sys/stat.h>
1.101 dtucker 31: #include <sys/time.h>
1.112 ! djm 32: #include <sys/wait.h>
1.94 millert 33: #include <sys/un.h>
1.38 stevesk 34:
35: #include <net/if.h>
1.53 stevesk 36: #include <netinet/in.h>
1.83 djm 37: #include <netinet/ip.h>
1.44 stevesk 38: #include <netinet/tcp.h>
1.43 stevesk 39:
1.92 djm 40: #include <ctype.h>
1.58 stevesk 41: #include <errno.h>
1.55 stevesk 42: #include <fcntl.h>
1.66 dtucker 43: #include <netdb.h>
1.43 stevesk 44: #include <paths.h>
1.54 stevesk 45: #include <pwd.h>
1.112 ! djm 46: #include <libgen.h>
1.96 deraadt 47: #include <limits.h>
1.112 ! djm 48: #include <signal.h>
1.57 stevesk 49: #include <stdarg.h>
1.63 stevesk 50: #include <stdio.h>
1.62 stevesk 51: #include <stdlib.h>
1.60 stevesk 52: #include <string.h>
1.59 stevesk 53: #include <unistd.h>
1.1 markus 54:
1.64 deraadt 55: #include "xmalloc.h"
1.1 markus 56: #include "misc.h"
57: #include "log.h"
1.56 dtucker 58: #include "ssh.h"
1.112 ! djm 59: #include "sshbuf.h"
! 60: #include "ssherr.h"
! 61: #include "uidswap.h"
1.1 markus 62:
1.12 markus 63: /* remove newline at end of string */
1.1 markus 64: char *
65: chop(char *s)
66: {
67: char *t = s;
68: while (*t) {
1.13 deraadt 69: if (*t == '\n' || *t == '\r') {
1.1 markus 70: *t = '\0';
71: return s;
72: }
73: t++;
74: }
75: return s;
76:
77: }
78:
1.12 markus 79: /* set/unset filedescriptor to non-blocking */
1.24 djm 80: int
1.1 markus 81: set_nonblock(int fd)
82: {
83: int val;
1.8 markus 84:
1.103 krw 85: val = fcntl(fd, F_GETFL);
1.1 markus 86: if (val < 0) {
1.103 krw 87: error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
1.24 djm 88: return (-1);
1.1 markus 89: }
90: if (val & O_NONBLOCK) {
1.24 djm 91: debug3("fd %d is O_NONBLOCK", fd);
92: return (0);
1.1 markus 93: }
1.21 markus 94: debug2("fd %d setting O_NONBLOCK", fd);
1.1 markus 95: val |= O_NONBLOCK;
1.24 djm 96: if (fcntl(fd, F_SETFL, val) == -1) {
97: debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
98: strerror(errno));
99: return (-1);
100: }
101: return (0);
1.8 markus 102: }
103:
1.24 djm 104: int
1.8 markus 105: unset_nonblock(int fd)
106: {
107: int val;
108:
1.103 krw 109: val = fcntl(fd, F_GETFL);
1.8 markus 110: if (val < 0) {
1.103 krw 111: error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
1.24 djm 112: return (-1);
1.8 markus 113: }
114: if (!(val & O_NONBLOCK)) {
1.24 djm 115: debug3("fd %d is not O_NONBLOCK", fd);
116: return (0);
1.8 markus 117: }
1.10 markus 118: debug("fd %d clearing O_NONBLOCK", fd);
1.8 markus 119: val &= ~O_NONBLOCK;
1.24 djm 120: if (fcntl(fd, F_SETFL, val) == -1) {
121: debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
1.18 markus 122: fd, strerror(errno));
1.24 djm 123: return (-1);
124: }
125: return (0);
1.66 dtucker 126: }
127:
128: const char *
129: ssh_gai_strerror(int gaierr)
130: {
1.91 djm 131: if (gaierr == EAI_SYSTEM && errno != 0)
1.67 dtucker 132: return strerror(errno);
133: return gai_strerror(gaierr);
1.15 stevesk 134: }
135:
136: /* disable nagle on socket */
137: void
138: set_nodelay(int fd)
139: {
1.17 stevesk 140: int opt;
141: socklen_t optlen;
1.15 stevesk 142:
1.16 stevesk 143: optlen = sizeof opt;
144: if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
1.23 markus 145: debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
1.16 stevesk 146: return;
147: }
148: if (opt == 1) {
149: debug2("fd %d is TCP_NODELAY", fd);
150: return;
151: }
152: opt = 1;
1.20 markus 153: debug2("fd %d setting TCP_NODELAY", fd);
1.16 stevesk 154: if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
1.15 stevesk 155: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1.72 reyk 156: }
157:
1.1 markus 158: /* Characters considered whitespace in strsep calls. */
159: #define WHITESPACE " \t\r\n"
1.46 dtucker 160: #define QUOTE "\""
1.1 markus 161:
1.12 markus 162: /* return next token in configuration line */
1.1 markus 163: char *
164: strdelim(char **s)
165: {
166: char *old;
167: int wspace = 0;
168:
169: if (*s == NULL)
170: return NULL;
171:
172: old = *s;
173:
1.46 dtucker 174: *s = strpbrk(*s, WHITESPACE QUOTE "=");
1.1 markus 175: if (*s == NULL)
176: return (old);
177:
1.46 dtucker 178: if (*s[0] == '\"') {
179: memmove(*s, *s + 1, strlen(*s)); /* move nul too */
180: /* Find matching quote */
181: if ((*s = strpbrk(*s, QUOTE)) == NULL) {
182: return (NULL); /* no matching quote */
183: } else {
184: *s[0] = '\0';
1.77 djm 185: *s += strspn(*s + 1, WHITESPACE) + 1;
1.46 dtucker 186: return (old);
187: }
188: }
189:
1.1 markus 190: /* Allow only one '=' to be skipped */
191: if (*s[0] == '=')
192: wspace = 1;
193: *s[0] = '\0';
194:
1.46 dtucker 195: /* Skip any extra whitespace after first token */
1.1 markus 196: *s += strspn(*s + 1, WHITESPACE) + 1;
197: if (*s[0] == '=' && !wspace)
198: *s += strspn(*s + 1, WHITESPACE) + 1;
199:
200: return (old);
1.2 markus 201: }
202:
203: struct passwd *
204: pwcopy(struct passwd *pw)
205: {
1.49 djm 206: struct passwd *copy = xcalloc(1, sizeof(*copy));
1.4 deraadt 207:
1.2 markus 208: copy->pw_name = xstrdup(pw->pw_name);
209: copy->pw_passwd = xstrdup(pw->pw_passwd);
1.4 deraadt 210: copy->pw_gecos = xstrdup(pw->pw_gecos);
1.2 markus 211: copy->pw_uid = pw->pw_uid;
212: copy->pw_gid = pw->pw_gid;
1.11 markus 213: copy->pw_expire = pw->pw_expire;
214: copy->pw_change = pw->pw_change;
1.2 markus 215: copy->pw_class = xstrdup(pw->pw_class);
216: copy->pw_dir = xstrdup(pw->pw_dir);
217: copy->pw_shell = xstrdup(pw->pw_shell);
218: return copy;
1.5 stevesk 219: }
220:
1.12 markus 221: /*
222: * Convert ASCII string to TCP/IP port number.
1.70 djm 223: * Port must be >=0 and <=65535.
224: * Return -1 if invalid.
1.12 markus 225: */
226: int
227: a2port(const char *s)
1.5 stevesk 228: {
1.70 djm 229: long long port;
230: const char *errstr;
1.5 stevesk 231:
1.70 djm 232: port = strtonum(s, 0, 65535, &errstr);
233: if (errstr != NULL)
234: return -1;
235: return (int)port;
1.9 stevesk 236: }
237:
1.36 reyk 238: int
239: a2tun(const char *s, int *remote)
240: {
241: const char *errstr = NULL;
242: char *sp, *ep;
243: int tun;
244:
245: if (remote != NULL) {
1.37 reyk 246: *remote = SSH_TUNID_ANY;
1.36 reyk 247: sp = xstrdup(s);
248: if ((ep = strchr(sp, ':')) == NULL) {
1.89 djm 249: free(sp);
1.36 reyk 250: return (a2tun(s, NULL));
251: }
252: ep[0] = '\0'; ep++;
253: *remote = a2tun(ep, NULL);
254: tun = a2tun(sp, NULL);
1.89 djm 255: free(sp);
1.37 reyk 256: return (*remote == SSH_TUNID_ERR ? *remote : tun);
1.36 reyk 257: }
258:
259: if (strcasecmp(s, "any") == 0)
1.37 reyk 260: return (SSH_TUNID_ANY);
1.36 reyk 261:
1.37 reyk 262: tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
263: if (errstr != NULL)
264: return (SSH_TUNID_ERR);
1.36 reyk 265:
266: return (tun);
267: }
268:
1.9 stevesk 269: #define SECONDS 1
270: #define MINUTES (SECONDS * 60)
271: #define HOURS (MINUTES * 60)
272: #define DAYS (HOURS * 24)
273: #define WEEKS (DAYS * 7)
274:
1.12 markus 275: /*
276: * Convert a time string into seconds; format is
277: * a sequence of:
278: * time[qualifier]
279: *
280: * Valid time qualifiers are:
281: * <none> seconds
282: * s|S seconds
283: * m|M minutes
284: * h|H hours
285: * d|D days
286: * w|W weeks
287: *
288: * Examples:
289: * 90m 90 minutes
290: * 1h30m 90 minutes
291: * 2d 2 days
292: * 1w 1 week
293: *
294: * Return -1 if time string is invalid.
295: */
296: long
297: convtime(const char *s)
1.9 stevesk 298: {
1.108 dtucker 299: long total, secs, multiplier = 1;
1.9 stevesk 300: const char *p;
301: char *endp;
302:
303: errno = 0;
304: total = 0;
305: p = s;
306:
307: if (p == NULL || *p == '\0')
308: return -1;
309:
310: while (*p) {
311: secs = strtol(p, &endp, 10);
312: if (p == endp ||
313: (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
314: secs < 0)
315: return -1;
316:
317: switch (*endp++) {
318: case '\0':
319: endp--;
1.48 deraadt 320: break;
1.9 stevesk 321: case 's':
322: case 'S':
323: break;
324: case 'm':
325: case 'M':
1.108 dtucker 326: multiplier = MINUTES;
1.9 stevesk 327: break;
328: case 'h':
329: case 'H':
1.108 dtucker 330: multiplier = HOURS;
1.9 stevesk 331: break;
332: case 'd':
333: case 'D':
1.108 dtucker 334: multiplier = DAYS;
1.9 stevesk 335: break;
336: case 'w':
337: case 'W':
1.108 dtucker 338: multiplier = WEEKS;
1.9 stevesk 339: break;
340: default:
341: return -1;
342: }
1.109 dtucker 343: if (secs >= LONG_MAX / multiplier)
1.108 dtucker 344: return -1;
345: secs *= multiplier;
1.109 dtucker 346: if (total >= LONG_MAX - secs)
1.108 dtucker 347: return -1;
1.9 stevesk 348: total += secs;
349: if (total < 0)
350: return -1;
351: p = endp;
352: }
353:
354: return total;
1.56 dtucker 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;
1.28 djm 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;
1.29 deraadt 402:
1.28 djm 403: case ':':
404: case '/':
405: *s = '\0'; /* terminate */
406: *cp = s + 1;
407: break;
1.29 deraadt 408:
1.28 djm 409: default:
410: return NULL;
411: }
412:
413: return old;
1.6 mouring 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. */
1.76 djm 432: return NULL;
1.6 mouring 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 == '/')
1.76 djm 444: return NULL;
1.6 mouring 445: }
1.76 djm 446: return NULL;
1.105 djm 447: }
448:
449: /*
450: * Parse a [user@]host[:port] string.
451: * Caller must free returned user and host.
452: * Any of the pointer return arguments may be NULL (useful for syntax checking).
453: * If user was not specified then *userp will be set to NULL.
454: * If port was not specified then *portp will be -1.
455: * Returns 0 on success, -1 on failure.
456: */
457: int
458: parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
459: {
460: char *sdup, *cp, *tmp;
461: char *user = NULL, *host = NULL;
462: int port = -1, ret = -1;
463:
464: if (userp != NULL)
465: *userp = NULL;
466: if (hostp != NULL)
467: *hostp = NULL;
468: if (portp != NULL)
469: *portp = -1;
470:
471: if ((sdup = tmp = strdup(s)) == NULL)
472: return -1;
473: /* Extract optional username */
474: if ((cp = strchr(tmp, '@')) != NULL) {
475: *cp = '\0';
476: if (*tmp == '\0')
477: goto out;
478: if ((user = strdup(tmp)) == NULL)
479: goto out;
480: tmp = cp + 1;
481: }
482: /* Extract mandatory hostname */
483: if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0')
484: goto out;
485: host = xstrdup(cleanhostname(cp));
486: /* Convert and verify optional port */
487: if (tmp != NULL && *tmp != '\0') {
488: if ((port = a2port(tmp)) <= 0)
489: goto out;
490: }
491: /* Success */
492: if (userp != NULL) {
493: *userp = user;
494: user = NULL;
495: }
496: if (hostp != NULL) {
497: *hostp = host;
498: host = NULL;
499: }
500: if (portp != NULL)
501: *portp = port;
502: ret = 0;
503: out:
504: free(sdup);
505: free(user);
506: free(host);
507: return ret;
1.7 mouring 508: }
509:
1.12 markus 510: /* function to assist building execv() arguments */
1.7 mouring 511: void
512: addargs(arglist *args, char *fmt, ...)
513: {
514: va_list ap;
1.42 djm 515: char *cp;
1.25 avsm 516: u_int nalloc;
1.42 djm 517: int r;
1.7 mouring 518:
519: va_start(ap, fmt);
1.42 djm 520: r = vasprintf(&cp, fmt, ap);
1.7 mouring 521: va_end(ap);
1.42 djm 522: if (r == -1)
523: fatal("addargs: argument too long");
1.7 mouring 524:
1.22 markus 525: nalloc = args->nalloc;
1.7 mouring 526: if (args->list == NULL) {
1.22 markus 527: nalloc = 32;
1.7 mouring 528: args->num = 0;
1.22 markus 529: } else if (args->num+2 >= nalloc)
530: nalloc *= 2;
1.7 mouring 531:
1.110 deraadt 532: args->list = xrecallocarray(args->list, args->nalloc, nalloc, sizeof(char *));
1.22 markus 533: args->nalloc = nalloc;
1.42 djm 534: args->list[args->num++] = cp;
1.7 mouring 535: args->list[args->num] = NULL;
1.42 djm 536: }
537:
538: void
539: replacearg(arglist *args, u_int which, char *fmt, ...)
540: {
541: va_list ap;
542: char *cp;
543: int r;
544:
545: va_start(ap, fmt);
546: r = vasprintf(&cp, fmt, ap);
547: va_end(ap);
548: if (r == -1)
549: fatal("replacearg: argument too long");
550:
551: if (which >= args->num)
552: fatal("replacearg: tried to replace invalid arg %d >= %d",
553: which, args->num);
1.89 djm 554: free(args->list[which]);
1.42 djm 555: args->list[which] = cp;
556: }
557:
558: void
559: freeargs(arglist *args)
560: {
561: u_int i;
562:
563: if (args->list != NULL) {
564: for (i = 0; i < args->num; i++)
1.89 djm 565: free(args->list[i]);
566: free(args->list);
1.42 djm 567: args->nalloc = args->num = 0;
568: args->list = NULL;
569: }
1.30 djm 570: }
571:
572: /*
573: * Expands tildes in the file name. Returns data allocated by xmalloc.
574: * Warning: this calls getpw*.
575: */
576: char *
577: tilde_expand_filename(const char *filename, uid_t uid)
578: {
1.87 tedu 579: const char *path, *sep;
580: char user[128], *ret;
1.30 djm 581: struct passwd *pw;
1.32 djm 582: u_int len, slash;
1.30 djm 583:
584: if (*filename != '~')
585: return (xstrdup(filename));
586: filename++;
587:
588: path = strchr(filename, '/');
589: if (path != NULL && path > filename) { /* ~user/path */
1.32 djm 590: slash = path - filename;
591: if (slash > sizeof(user) - 1)
1.30 djm 592: fatal("tilde_expand_filename: ~username too long");
1.32 djm 593: memcpy(user, filename, slash);
594: user[slash] = '\0';
1.30 djm 595: if ((pw = getpwnam(user)) == NULL)
596: fatal("tilde_expand_filename: No such user %s", user);
597: } else if ((pw = getpwuid(uid)) == NULL) /* ~/path */
1.69 dtucker 598: fatal("tilde_expand_filename: No such uid %ld", (long)uid);
1.30 djm 599:
600: /* Make sure directory has a trailing '/' */
601: len = strlen(pw->pw_dir);
1.88 tedu 602: if (len == 0 || pw->pw_dir[len - 1] != '/')
1.87 tedu 603: sep = "/";
604: else
605: sep = "";
1.30 djm 606:
607: /* Skip leading '/' from specified path */
608: if (path != NULL)
609: filename = path + 1;
1.87 tedu 610:
1.96 deraadt 611: if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX)
1.30 djm 612: fatal("tilde_expand_filename: Path too long");
613:
1.87 tedu 614: return (ret);
1.31 djm 615: }
616:
617: /*
618: * Expand a string with a set of %[char] escapes. A number of escapes may be
619: * specified as (char *escape_chars, char *replacement) pairs. The list must
1.34 dtucker 620: * be terminated by a NULL escape_char. Returns replaced string in memory
1.31 djm 621: * allocated by xmalloc.
622: */
623: char *
624: percent_expand(const char *string, ...)
625: {
626: #define EXPAND_MAX_KEYS 16
1.73 djm 627: u_int num_keys, i, j;
1.31 djm 628: struct {
629: const char *key;
630: const char *repl;
631: } keys[EXPAND_MAX_KEYS];
632: char buf[4096];
633: va_list ap;
634:
635: /* Gather keys */
636: va_start(ap, string);
637: for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
638: keys[num_keys].key = va_arg(ap, char *);
639: if (keys[num_keys].key == NULL)
640: break;
641: keys[num_keys].repl = va_arg(ap, char *);
642: if (keys[num_keys].repl == NULL)
1.73 djm 643: fatal("%s: NULL replacement", __func__);
1.31 djm 644: }
1.73 djm 645: if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
646: fatal("%s: too many keys", __func__);
1.31 djm 647: va_end(ap);
648:
649: /* Expand string */
650: *buf = '\0';
651: for (i = 0; *string != '\0'; string++) {
652: if (*string != '%') {
653: append:
654: buf[i++] = *string;
655: if (i >= sizeof(buf))
1.73 djm 656: fatal("%s: string too long", __func__);
1.31 djm 657: buf[i] = '\0';
658: continue;
659: }
660: string++;
1.73 djm 661: /* %% case */
1.31 djm 662: if (*string == '%')
663: goto append;
1.100 tobias 664: if (*string == '\0')
665: fatal("%s: invalid format", __func__);
1.31 djm 666: for (j = 0; j < num_keys; j++) {
667: if (strchr(keys[j].key, *string) != NULL) {
668: i = strlcat(buf, keys[j].repl, sizeof(buf));
669: if (i >= sizeof(buf))
1.73 djm 670: fatal("%s: string too long", __func__);
1.31 djm 671: break;
672: }
673: }
674: if (j >= num_keys)
1.73 djm 675: fatal("%s: unknown key %%%c", __func__, *string);
1.31 djm 676: }
677: return (xstrdup(buf));
678: #undef EXPAND_MAX_KEYS
1.26 dtucker 679: }
680:
681: /*
682: * Read an entire line from a public key file into a static buffer, discarding
683: * lines that exceed the buffer size. Returns 0 on success, -1 on failure.
684: */
685: int
686: read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
1.27 dtucker 687: u_long *lineno)
1.26 dtucker 688: {
689: while (fgets(buf, bufsz, f) != NULL) {
1.65 ray 690: if (buf[0] == '\0')
691: continue;
1.26 dtucker 692: (*lineno)++;
693: if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
694: return 0;
695: } else {
1.27 dtucker 696: debug("%s: %s line %lu exceeds size limit", __func__,
697: filename, *lineno);
1.26 dtucker 698: /* discard remainder of line */
1.29 deraadt 699: while (fgetc(f) != '\n' && !feof(f))
1.26 dtucker 700: ; /* nothing */
701: }
702: }
703: return -1;
1.36 reyk 704: }
705:
706: int
1.37 reyk 707: tun_open(int tun, int mode)
1.36 reyk 708: {
1.37 reyk 709: struct ifreq ifr;
1.36 reyk 710: char name[100];
1.37 reyk 711: int fd = -1, sock;
1.99 sthen 712: const char *tunbase = "tun";
713:
714: if (mode == SSH_TUNMODE_ETHERNET)
715: tunbase = "tap";
1.36 reyk 716:
1.37 reyk 717: /* Open the tunnel device */
718: if (tun <= SSH_TUNID_MAX) {
1.99 sthen 719: snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
1.37 reyk 720: fd = open(name, O_RDWR);
721: } else if (tun == SSH_TUNID_ANY) {
722: for (tun = 100; tun >= 0; tun--) {
1.99 sthen 723: snprintf(name, sizeof(name), "/dev/%s%d",
724: tunbase, tun);
1.37 reyk 725: if ((fd = open(name, O_RDWR)) >= 0)
726: break;
1.36 reyk 727: }
728: } else {
1.39 stevesk 729: debug("%s: invalid tunnel %u", __func__, tun);
1.98 djm 730: return -1;
1.37 reyk 731: }
732:
733: if (fd < 0) {
1.98 djm 734: debug("%s: %s open: %s", __func__, name, strerror(errno));
735: return -1;
1.36 reyk 736: }
1.37 reyk 737:
738: debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
739:
1.99 sthen 740: /* Bring interface up if it is not already */
741: snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
742: if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
1.37 reyk 743: goto failed;
744:
1.98 djm 745: if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
746: debug("%s: get interface %s flags: %s", __func__,
747: ifr.ifr_name, strerror(errno));
1.37 reyk 748: goto failed;
1.98 djm 749: }
1.40 reyk 750:
1.98 djm 751: if (!(ifr.ifr_flags & IFF_UP)) {
752: ifr.ifr_flags |= IFF_UP;
753: if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) {
754: debug("%s: activate interface %s: %s", __func__,
755: ifr.ifr_name, strerror(errno));
756: goto failed;
757: }
758: }
1.37 reyk 759:
760: close(sock);
1.98 djm 761: return fd;
1.37 reyk 762:
763: failed:
764: if (fd >= 0)
765: close(fd);
766: if (sock >= 0)
767: close(sock);
1.98 djm 768: return -1;
1.35 djm 769: }
770:
771: void
772: sanitise_stdfd(void)
773: {
1.41 djm 774: int nullfd, dupfd;
1.35 djm 775:
1.41 djm 776: if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1.71 tobias 777: fprintf(stderr, "Couldn't open /dev/null: %s\n",
778: strerror(errno));
1.35 djm 779: exit(1);
780: }
1.103 krw 781: while (++dupfd <= STDERR_FILENO) {
782: /* Only populate closed fds. */
783: if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
784: if (dup2(nullfd, dupfd) == -1) {
785: fprintf(stderr, "dup2: %s\n", strerror(errno));
786: exit(1);
787: }
1.35 djm 788: }
789: }
1.103 krw 790: if (nullfd > STDERR_FILENO)
1.35 djm 791: close(nullfd);
1.1 markus 792: }
1.33 djm 793:
794: char *
1.52 djm 795: tohex(const void *vp, size_t l)
1.33 djm 796: {
1.52 djm 797: const u_char *p = (const u_char *)vp;
1.33 djm 798: char b[3], *r;
1.52 djm 799: size_t i, hl;
800:
801: if (l > 65536)
802: return xstrdup("tohex: length > 65536");
1.33 djm 803:
804: hl = l * 2 + 1;
1.49 djm 805: r = xcalloc(1, hl);
1.33 djm 806: for (i = 0; i < l; i++) {
1.52 djm 807: snprintf(b, sizeof(b), "%02x", p[i]);
1.33 djm 808: strlcat(r, b, hl);
809: }
810: return (r);
811: }
812:
1.52 djm 813: u_int64_t
814: get_u64(const void *vp)
815: {
816: const u_char *p = (const u_char *)vp;
817: u_int64_t v;
818:
819: v = (u_int64_t)p[0] << 56;
820: v |= (u_int64_t)p[1] << 48;
821: v |= (u_int64_t)p[2] << 40;
822: v |= (u_int64_t)p[3] << 32;
823: v |= (u_int64_t)p[4] << 24;
824: v |= (u_int64_t)p[5] << 16;
825: v |= (u_int64_t)p[6] << 8;
826: v |= (u_int64_t)p[7];
827:
828: return (v);
829: }
830:
831: u_int32_t
832: get_u32(const void *vp)
833: {
834: const u_char *p = (const u_char *)vp;
835: u_int32_t v;
836:
837: v = (u_int32_t)p[0] << 24;
838: v |= (u_int32_t)p[1] << 16;
839: v |= (u_int32_t)p[2] << 8;
840: v |= (u_int32_t)p[3];
841:
842: return (v);
843: }
844:
1.93 djm 845: u_int32_t
846: get_u32_le(const void *vp)
847: {
848: const u_char *p = (const u_char *)vp;
849: u_int32_t v;
850:
851: v = (u_int32_t)p[0];
852: v |= (u_int32_t)p[1] << 8;
853: v |= (u_int32_t)p[2] << 16;
854: v |= (u_int32_t)p[3] << 24;
855:
856: return (v);
857: }
858:
1.52 djm 859: u_int16_t
860: get_u16(const void *vp)
861: {
862: const u_char *p = (const u_char *)vp;
863: u_int16_t v;
864:
865: v = (u_int16_t)p[0] << 8;
866: v |= (u_int16_t)p[1];
867:
868: return (v);
869: }
870:
871: void
872: put_u64(void *vp, u_int64_t v)
873: {
874: u_char *p = (u_char *)vp;
875:
876: p[0] = (u_char)(v >> 56) & 0xff;
877: p[1] = (u_char)(v >> 48) & 0xff;
878: p[2] = (u_char)(v >> 40) & 0xff;
879: p[3] = (u_char)(v >> 32) & 0xff;
880: p[4] = (u_char)(v >> 24) & 0xff;
881: p[5] = (u_char)(v >> 16) & 0xff;
882: p[6] = (u_char)(v >> 8) & 0xff;
883: p[7] = (u_char)v & 0xff;
884: }
885:
886: void
887: put_u32(void *vp, u_int32_t v)
888: {
889: u_char *p = (u_char *)vp;
890:
891: p[0] = (u_char)(v >> 24) & 0xff;
892: p[1] = (u_char)(v >> 16) & 0xff;
893: p[2] = (u_char)(v >> 8) & 0xff;
894: p[3] = (u_char)v & 0xff;
895: }
896:
1.93 djm 897: void
898: put_u32_le(void *vp, u_int32_t v)
899: {
900: u_char *p = (u_char *)vp;
901:
902: p[0] = (u_char)v & 0xff;
903: p[1] = (u_char)(v >> 8) & 0xff;
904: p[2] = (u_char)(v >> 16) & 0xff;
905: p[3] = (u_char)(v >> 24) & 0xff;
906: }
1.52 djm 907:
908: void
909: put_u16(void *vp, u_int16_t v)
910: {
911: u_char *p = (u_char *)vp;
912:
913: p[0] = (u_char)(v >> 8) & 0xff;
914: p[1] = (u_char)v & 0xff;
915: }
1.68 dtucker 916:
917: void
918: ms_subtract_diff(struct timeval *start, int *ms)
919: {
920: struct timeval diff, finish;
921:
922: gettimeofday(&finish, NULL);
923: timersub(&finish, start, &diff);
924: *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
925: }
926:
927: void
928: ms_to_timeval(struct timeval *tv, int ms)
929: {
930: if (ms < 0)
931: ms = 0;
932: tv->tv_sec = ms / 1000;
933: tv->tv_usec = (ms % 1000) * 1000;
1.90 dtucker 934: }
935:
936: time_t
937: monotime(void)
938: {
939: struct timespec ts;
940:
941: if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
942: fatal("clock_gettime: %s", strerror(errno));
943:
944: return (ts.tv_sec);
1.102 dtucker 945: }
946:
947: double
948: monotime_double(void)
949: {
950: struct timespec ts;
951:
952: if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
953: fatal("clock_gettime: %s", strerror(errno));
954:
955: return (ts.tv_sec + (double)ts.tv_nsec / 1000000000);
1.81 djm 956: }
957:
958: void
959: bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
960: {
961: bw->buflen = buflen;
962: bw->rate = kbps;
963: bw->thresh = bw->rate;
964: bw->lamt = 0;
965: timerclear(&bw->bwstart);
966: timerclear(&bw->bwend);
967: }
968:
969: /* Callback from read/write loop to insert bandwidth-limiting delays */
970: void
971: bandwidth_limit(struct bwlimit *bw, size_t read_len)
972: {
973: u_int64_t waitlen;
974: struct timespec ts, rm;
975:
976: if (!timerisset(&bw->bwstart)) {
977: gettimeofday(&bw->bwstart, NULL);
978: return;
979: }
980:
981: bw->lamt += read_len;
982: if (bw->lamt < bw->thresh)
983: return;
984:
985: gettimeofday(&bw->bwend, NULL);
986: timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
987: if (!timerisset(&bw->bwend))
988: return;
989:
990: bw->lamt *= 8;
991: waitlen = (double)1000000L * bw->lamt / bw->rate;
992:
993: bw->bwstart.tv_sec = waitlen / 1000000L;
994: bw->bwstart.tv_usec = waitlen % 1000000L;
995:
996: if (timercmp(&bw->bwstart, &bw->bwend, >)) {
997: timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
998:
999: /* Adjust the wait time */
1000: if (bw->bwend.tv_sec) {
1001: bw->thresh /= 2;
1002: if (bw->thresh < bw->buflen / 4)
1003: bw->thresh = bw->buflen / 4;
1004: } else if (bw->bwend.tv_usec < 10000) {
1005: bw->thresh *= 2;
1006: if (bw->thresh > bw->buflen * 8)
1007: bw->thresh = bw->buflen * 8;
1008: }
1009:
1010: TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
1011: while (nanosleep(&ts, &rm) == -1) {
1012: if (errno != EINTR)
1013: break;
1014: ts = rm;
1015: }
1016: }
1017:
1018: bw->lamt = 0;
1019: gettimeofday(&bw->bwstart, NULL);
1.84 djm 1020: }
1021:
1022: /* Make a template filename for mk[sd]temp() */
1023: void
1024: mktemp_proto(char *s, size_t len)
1025: {
1026: const char *tmpdir;
1027: int r;
1028:
1029: if ((tmpdir = getenv("TMPDIR")) != NULL) {
1030: r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
1031: if (r > 0 && (size_t)r < len)
1032: return;
1033: }
1034: r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
1035: if (r < 0 || (size_t)r >= len)
1036: fatal("%s: template string too short", __func__);
1.68 dtucker 1037: }
1.83 djm 1038:
1039: static const struct {
1040: const char *name;
1041: int value;
1042: } ipqos[] = {
1.111 djm 1043: { "none", INT_MAX }, /* can't use 0 here; that's CS0 */
1.83 djm 1044: { "af11", IPTOS_DSCP_AF11 },
1045: { "af12", IPTOS_DSCP_AF12 },
1046: { "af13", IPTOS_DSCP_AF13 },
1.86 djm 1047: { "af21", IPTOS_DSCP_AF21 },
1.83 djm 1048: { "af22", IPTOS_DSCP_AF22 },
1049: { "af23", IPTOS_DSCP_AF23 },
1050: { "af31", IPTOS_DSCP_AF31 },
1051: { "af32", IPTOS_DSCP_AF32 },
1052: { "af33", IPTOS_DSCP_AF33 },
1053: { "af41", IPTOS_DSCP_AF41 },
1054: { "af42", IPTOS_DSCP_AF42 },
1055: { "af43", IPTOS_DSCP_AF43 },
1056: { "cs0", IPTOS_DSCP_CS0 },
1057: { "cs1", IPTOS_DSCP_CS1 },
1058: { "cs2", IPTOS_DSCP_CS2 },
1059: { "cs3", IPTOS_DSCP_CS3 },
1060: { "cs4", IPTOS_DSCP_CS4 },
1061: { "cs5", IPTOS_DSCP_CS5 },
1062: { "cs6", IPTOS_DSCP_CS6 },
1063: { "cs7", IPTOS_DSCP_CS7 },
1064: { "ef", IPTOS_DSCP_EF },
1065: { "lowdelay", IPTOS_LOWDELAY },
1066: { "throughput", IPTOS_THROUGHPUT },
1067: { "reliability", IPTOS_RELIABILITY },
1068: { NULL, -1 }
1069: };
1070:
1071: int
1072: parse_ipqos(const char *cp)
1073: {
1074: u_int i;
1075: char *ep;
1076: long val;
1077:
1078: if (cp == NULL)
1079: return -1;
1080: for (i = 0; ipqos[i].name != NULL; i++) {
1081: if (strcasecmp(cp, ipqos[i].name) == 0)
1082: return ipqos[i].value;
1083: }
1084: /* Try parsing as an integer */
1085: val = strtol(cp, &ep, 0);
1086: if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
1087: return -1;
1088: return val;
1089: }
1090:
1.85 stevesk 1091: const char *
1092: iptos2str(int iptos)
1093: {
1094: int i;
1095: static char iptos_str[sizeof "0xff"];
1096:
1097: for (i = 0; ipqos[i].name != NULL; i++) {
1098: if (ipqos[i].value == iptos)
1099: return ipqos[i].name;
1100: }
1101: snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
1102: return iptos_str;
1.92 djm 1103: }
1104:
1105: void
1106: lowercase(char *s)
1107: {
1108: for (; *s; s++)
1109: *s = tolower((u_char)*s);
1.94 millert 1110: }
1111:
1112: int
1113: unix_listener(const char *path, int backlog, int unlink_first)
1114: {
1115: struct sockaddr_un sunaddr;
1116: int saved_errno, sock;
1117:
1118: memset(&sunaddr, 0, sizeof(sunaddr));
1119: sunaddr.sun_family = AF_UNIX;
1120: if (strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) {
1121: error("%s: \"%s\" too long for Unix domain socket", __func__,
1122: path);
1123: errno = ENAMETOOLONG;
1124: return -1;
1125: }
1126:
1127: sock = socket(PF_UNIX, SOCK_STREAM, 0);
1128: if (sock < 0) {
1129: saved_errno = errno;
1130: error("socket: %.100s", strerror(errno));
1131: errno = saved_errno;
1132: return -1;
1133: }
1134: if (unlink_first == 1) {
1135: if (unlink(path) != 0 && errno != ENOENT)
1136: error("unlink(%s): %.100s", path, strerror(errno));
1137: }
1138: if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
1139: saved_errno = errno;
1140: error("bind: %.100s", strerror(errno));
1141: close(sock);
1142: error("%s: cannot bind to path: %s", __func__, path);
1143: errno = saved_errno;
1144: return -1;
1145: }
1146: if (listen(sock, backlog) < 0) {
1147: saved_errno = errno;
1148: error("listen: %.100s", strerror(errno));
1149: close(sock);
1150: unlink(path);
1151: error("%s: cannot listen on path: %s", __func__, path);
1152: errno = saved_errno;
1153: return -1;
1154: }
1155: return sock;
1.85 stevesk 1156: }
1.104 djm 1157:
1158: /*
1159: * Compares two strings that maybe be NULL. Returns non-zero if strings
1160: * are both NULL or are identical, returns zero otherwise.
1161: */
1162: static int
1163: strcmp_maybe_null(const char *a, const char *b)
1164: {
1165: if ((a == NULL && b != NULL) || (a != NULL && b == NULL))
1166: return 0;
1167: if (a != NULL && strcmp(a, b) != 0)
1168: return 0;
1169: return 1;
1170: }
1171:
1172: /*
1173: * Compare two forwards, returning non-zero if they are identical or
1174: * zero otherwise.
1175: */
1176: int
1177: forward_equals(const struct Forward *a, const struct Forward *b)
1178: {
1179: if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0)
1180: return 0;
1181: if (a->listen_port != b->listen_port)
1182: return 0;
1183: if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0)
1184: return 0;
1185: if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0)
1186: return 0;
1187: if (a->connect_port != b->connect_port)
1188: return 0;
1189: if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0)
1190: return 0;
1191: /* allocated_port and handle are not checked */
1192: return 1;
1193: }
1194:
1.106 dtucker 1195: /* returns 1 if bind to specified port by specified user is permitted */
1196: int
1197: bind_permitted(int port, uid_t uid)
1198: {
1199: if (port < IPPORT_RESERVED && uid != 0)
1200: return 0;
1.107 dtucker 1201: return 1;
1202: }
1203:
1204: /* returns 1 if process is already daemonized, 0 otherwise */
1205: int
1206: daemonized(void)
1207: {
1208: int fd;
1209:
1210: if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) {
1211: close(fd);
1212: return 0; /* have controlling terminal */
1213: }
1214: if (getppid() != 1)
1215: return 0; /* parent is not init */
1216: if (getsid(0) != getpid())
1217: return 0; /* not session leader */
1218: debug3("already daemonized");
1.106 dtucker 1219: return 1;
1220: }
1.112 ! djm 1221:
! 1222:
! 1223: /*
! 1224: * Splits 's' into an argument vector. Handles quoted string and basic
! 1225: * escape characters (\\, \", \'). Caller must free the argument vector
! 1226: * and its members.
! 1227: */
! 1228: int
! 1229: argv_split(const char *s, int *argcp, char ***argvp)
! 1230: {
! 1231: int r = SSH_ERR_INTERNAL_ERROR;
! 1232: int argc = 0, quote, i, j;
! 1233: char *arg, **argv = xcalloc(1, sizeof(*argv));
! 1234:
! 1235: *argvp = NULL;
! 1236: *argcp = 0;
! 1237:
! 1238: for (i = 0; s[i] != '\0'; i++) {
! 1239: /* Skip leading whitespace */
! 1240: if (s[i] == ' ' || s[i] == '\t')
! 1241: continue;
! 1242:
! 1243: /* Start of a token */
! 1244: quote = 0;
! 1245: if (s[i] == '\\' &&
! 1246: (s[i + 1] == '\'' || s[i + 1] == '\"' || s[i + 1] == '\\'))
! 1247: i++;
! 1248: else if (s[i] == '\'' || s[i] == '"')
! 1249: quote = s[i++];
! 1250:
! 1251: argv = xreallocarray(argv, (argc + 2), sizeof(*argv));
! 1252: arg = argv[argc++] = xcalloc(1, strlen(s + i) + 1);
! 1253: argv[argc] = NULL;
! 1254:
! 1255: /* Copy the token in, removing escapes */
! 1256: for (j = 0; s[i] != '\0'; i++) {
! 1257: if (s[i] == '\\') {
! 1258: if (s[i + 1] == '\'' ||
! 1259: s[i + 1] == '\"' ||
! 1260: s[i + 1] == '\\') {
! 1261: i++; /* Skip '\' */
! 1262: arg[j++] = s[i];
! 1263: } else {
! 1264: /* Unrecognised escape */
! 1265: arg[j++] = s[i];
! 1266: }
! 1267: } else if (quote == 0 && (s[i] == ' ' || s[i] == '\t'))
! 1268: break; /* done */
! 1269: else if (quote != 0 && s[i] == quote)
! 1270: break; /* done */
! 1271: else
! 1272: arg[j++] = s[i];
! 1273: }
! 1274: if (s[i] == '\0') {
! 1275: if (quote != 0) {
! 1276: /* Ran out of string looking for close quote */
! 1277: r = SSH_ERR_INVALID_FORMAT;
! 1278: goto out;
! 1279: }
! 1280: break;
! 1281: }
! 1282: }
! 1283: /* Success */
! 1284: *argcp = argc;
! 1285: *argvp = argv;
! 1286: argc = 0;
! 1287: argv = NULL;
! 1288: r = 0;
! 1289: out:
! 1290: if (argc != 0 && argv != NULL) {
! 1291: for (i = 0; i < argc; i++)
! 1292: free(argv[i]);
! 1293: free(argv);
! 1294: }
! 1295: return r;
! 1296: }
! 1297:
! 1298: /*
! 1299: * Reassemble an argument vector into a string, quoting and escaping as
! 1300: * necessary. Caller must free returned string.
! 1301: */
! 1302: char *
! 1303: argv_assemble(int argc, char **argv)
! 1304: {
! 1305: int i, j, ws, r;
! 1306: char c, *ret;
! 1307: struct sshbuf *buf, *arg;
! 1308:
! 1309: if ((buf = sshbuf_new()) == NULL || (arg = sshbuf_new()) == NULL)
! 1310: fatal("%s: sshbuf_new failed", __func__);
! 1311:
! 1312: for (i = 0; i < argc; i++) {
! 1313: ws = 0;
! 1314: sshbuf_reset(arg);
! 1315: for (j = 0; argv[i][j] != '\0'; j++) {
! 1316: r = 0;
! 1317: c = argv[i][j];
! 1318: switch (c) {
! 1319: case ' ':
! 1320: case '\t':
! 1321: ws = 1;
! 1322: r = sshbuf_put_u8(arg, c);
! 1323: break;
! 1324: case '\\':
! 1325: case '\'':
! 1326: case '"':
! 1327: if ((r = sshbuf_put_u8(arg, '\\')) != 0)
! 1328: break;
! 1329: /* FALLTHROUGH */
! 1330: default:
! 1331: r = sshbuf_put_u8(arg, c);
! 1332: break;
! 1333: }
! 1334: if (r != 0)
! 1335: fatal("%s: sshbuf_put_u8: %s",
! 1336: __func__, ssh_err(r));
! 1337: }
! 1338: if ((i != 0 && (r = sshbuf_put_u8(buf, ' ')) != 0) ||
! 1339: (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0) ||
! 1340: (r = sshbuf_putb(buf, arg)) != 0 ||
! 1341: (ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0))
! 1342: fatal("%s: buffer error: %s", __func__, ssh_err(r));
! 1343: }
! 1344: if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL)
! 1345: fatal("%s: malloc failed", __func__);
! 1346: memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf));
! 1347: ret[sshbuf_len(buf)] = '\0';
! 1348: sshbuf_free(buf);
! 1349: sshbuf_free(arg);
! 1350: return ret;
! 1351: }
! 1352:
! 1353: /*
! 1354: * Runs command in a subprocess wuth a minimal environment.
! 1355: * Returns pid on success, 0 on failure.
! 1356: * The child stdout and stderr maybe captured, left attached or sent to
! 1357: * /dev/null depending on the contents of flags.
! 1358: * "tag" is prepended to log messages.
! 1359: * NB. "command" is only used for logging; the actual command executed is
! 1360: * av[0].
! 1361: */
! 1362: pid_t
! 1363: subprocess(const char *tag, struct passwd *pw, const char *command,
! 1364: int ac, char **av, FILE **child, u_int flags)
! 1365: {
! 1366: FILE *f = NULL;
! 1367: struct stat st;
! 1368: int fd, devnull, p[2], i;
! 1369: pid_t pid;
! 1370: char *cp, errmsg[512];
! 1371: u_int envsize;
! 1372: char **child_env;
! 1373:
! 1374: if (child != NULL)
! 1375: *child = NULL;
! 1376:
! 1377: debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__,
! 1378: tag, command, pw->pw_name, flags);
! 1379:
! 1380: /* Check consistency */
! 1381: if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
! 1382: (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
! 1383: error("%s: inconsistent flags", __func__);
! 1384: return 0;
! 1385: }
! 1386: if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
! 1387: error("%s: inconsistent flags/output", __func__);
! 1388: return 0;
! 1389: }
! 1390:
! 1391: /*
! 1392: * If executing an explicit binary, then verify the it exists
! 1393: * and appears safe-ish to execute
! 1394: */
! 1395: if (*av[0] != '/') {
! 1396: error("%s path is not absolute", tag);
! 1397: return 0;
! 1398: }
! 1399: temporarily_use_uid(pw);
! 1400: if (stat(av[0], &st) < 0) {
! 1401: error("Could not stat %s \"%s\": %s", tag,
! 1402: av[0], strerror(errno));
! 1403: restore_uid();
! 1404: return 0;
! 1405: }
! 1406: if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
! 1407: error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
! 1408: restore_uid();
! 1409: return 0;
! 1410: }
! 1411: /* Prepare to keep the child's stdout if requested */
! 1412: if (pipe(p) != 0) {
! 1413: error("%s: pipe: %s", tag, strerror(errno));
! 1414: restore_uid();
! 1415: return 0;
! 1416: }
! 1417: restore_uid();
! 1418:
! 1419: switch ((pid = fork())) {
! 1420: case -1: /* error */
! 1421: error("%s: fork: %s", tag, strerror(errno));
! 1422: close(p[0]);
! 1423: close(p[1]);
! 1424: return 0;
! 1425: case 0: /* child */
! 1426: /* Prepare a minimal environment for the child. */
! 1427: envsize = 5;
! 1428: child_env = xcalloc(sizeof(*child_env), envsize);
! 1429: child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH);
! 1430: child_set_env(&child_env, &envsize, "USER", pw->pw_name);
! 1431: child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name);
! 1432: child_set_env(&child_env, &envsize, "HOME", pw->pw_dir);
! 1433: if ((cp = getenv("LANG")) != NULL)
! 1434: child_set_env(&child_env, &envsize, "LANG", cp);
! 1435:
! 1436: for (i = 0; i < NSIG; i++)
! 1437: signal(i, SIG_DFL);
! 1438:
! 1439: if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
! 1440: error("%s: open %s: %s", tag, _PATH_DEVNULL,
! 1441: strerror(errno));
! 1442: _exit(1);
! 1443: }
! 1444: if (dup2(devnull, STDIN_FILENO) == -1) {
! 1445: error("%s: dup2: %s", tag, strerror(errno));
! 1446: _exit(1);
! 1447: }
! 1448:
! 1449: /* Set up stdout as requested; leave stderr in place for now. */
! 1450: fd = -1;
! 1451: if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
! 1452: fd = p[1];
! 1453: else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
! 1454: fd = devnull;
! 1455: if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
! 1456: error("%s: dup2: %s", tag, strerror(errno));
! 1457: _exit(1);
! 1458: }
! 1459: closefrom(STDERR_FILENO + 1);
! 1460:
! 1461: /* Don't use permanently_set_uid() here to avoid fatal() */
! 1462: if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
! 1463: error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
! 1464: strerror(errno));
! 1465: _exit(1);
! 1466: }
! 1467: if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
! 1468: error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
! 1469: strerror(errno));
! 1470: _exit(1);
! 1471: }
! 1472: /* stdin is pointed to /dev/null at this point */
! 1473: if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
! 1474: dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
! 1475: error("%s: dup2: %s", tag, strerror(errno));
! 1476: _exit(1);
! 1477: }
! 1478:
! 1479: execve(av[0], av, child_env);
! 1480: error("%s exec \"%s\": %s", tag, command, strerror(errno));
! 1481: _exit(127);
! 1482: default: /* parent */
! 1483: break;
! 1484: }
! 1485:
! 1486: close(p[1]);
! 1487: if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
! 1488: close(p[0]);
! 1489: else if ((f = fdopen(p[0], "r")) == NULL) {
! 1490: error("%s: fdopen: %s", tag, strerror(errno));
! 1491: close(p[0]);
! 1492: /* Don't leave zombie child */
! 1493: kill(pid, SIGTERM);
! 1494: while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
! 1495: ;
! 1496: return 0;
! 1497: }
! 1498: /* Success */
! 1499: debug3("%s: %s pid %ld", __func__, tag, (long)pid);
! 1500: if (child != NULL)
! 1501: *child = f;
! 1502: return pid;
! 1503: }
! 1504:
! 1505: /* Returns 0 if pid exited cleanly, non-zero otherwise */
! 1506: int
! 1507: exited_cleanly(pid_t pid, const char *tag, const char *cmd)
! 1508: {
! 1509: int status;
! 1510:
! 1511: while (waitpid(pid, &status, 0) == -1) {
! 1512: if (errno != EINTR) {
! 1513: error("%s: waitpid: %s", tag, strerror(errno));
! 1514: return -1;
! 1515: }
! 1516: }
! 1517: if (WIFSIGNALED(status)) {
! 1518: error("%s %s exited on signal %d", tag, cmd, WTERMSIG(status));
! 1519: return -1;
! 1520: } else if (WEXITSTATUS(status) != 0) {
! 1521: error("%s %s failed, status %d", tag, cmd, WEXITSTATUS(status));
! 1522: return -1;
! 1523: }
! 1524: return 0;
! 1525: }
! 1526:
! 1527: /*
! 1528: * Check a given path for security. This is defined as all components
! 1529: * of the path to the file must be owned by either the owner of
! 1530: * of the file or root and no directories must be group or world writable.
! 1531: *
! 1532: * XXX Should any specific check be done for sym links ?
! 1533: *
! 1534: * Takes a file name, its stat information (preferably from fstat() to
! 1535: * avoid races), the uid of the expected owner, their home directory and an
! 1536: * error buffer plus max size as arguments.
! 1537: *
! 1538: * Returns 0 on success and -1 on failure
! 1539: */
! 1540: int
! 1541: safe_path(const char *name, struct stat *stp, const char *pw_dir,
! 1542: uid_t uid, char *err, size_t errlen)
! 1543: {
! 1544: char buf[PATH_MAX], homedir[PATH_MAX];
! 1545: char *cp;
! 1546: int comparehome = 0;
! 1547: struct stat st;
! 1548:
! 1549: if (realpath(name, buf) == NULL) {
! 1550: snprintf(err, errlen, "realpath %s failed: %s", name,
! 1551: strerror(errno));
! 1552: return -1;
! 1553: }
! 1554: if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
! 1555: comparehome = 1;
! 1556:
! 1557: if (!S_ISREG(stp->st_mode)) {
! 1558: snprintf(err, errlen, "%s is not a regular file", buf);
! 1559: return -1;
! 1560: }
! 1561: if ((stp->st_uid != 0 && stp->st_uid != uid) ||
! 1562: (stp->st_mode & 022) != 0) {
! 1563: snprintf(err, errlen, "bad ownership or modes for file %s",
! 1564: buf);
! 1565: return -1;
! 1566: }
! 1567:
! 1568: /* for each component of the canonical path, walking upwards */
! 1569: for (;;) {
! 1570: if ((cp = dirname(buf)) == NULL) {
! 1571: snprintf(err, errlen, "dirname() failed");
! 1572: return -1;
! 1573: }
! 1574: strlcpy(buf, cp, sizeof(buf));
! 1575:
! 1576: if (stat(buf, &st) < 0 ||
! 1577: (st.st_uid != 0 && st.st_uid != uid) ||
! 1578: (st.st_mode & 022) != 0) {
! 1579: snprintf(err, errlen,
! 1580: "bad ownership or modes for directory %s", buf);
! 1581: return -1;
! 1582: }
! 1583:
! 1584: /* If are past the homedir then we can stop */
! 1585: if (comparehome && strcmp(homedir, buf) == 0)
! 1586: break;
! 1587:
! 1588: /*
! 1589: * dirname should always complete with a "/" path,
! 1590: * but we can be paranoid and check for "." too
! 1591: */
! 1592: if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
! 1593: break;
! 1594: }
! 1595: return 0;
! 1596: }
! 1597:
! 1598: /*
! 1599: * Version of safe_path() that accepts an open file descriptor to
! 1600: * avoid races.
! 1601: *
! 1602: * Returns 0 on success and -1 on failure
! 1603: */
! 1604: int
! 1605: safe_path_fd(int fd, const char *file, struct passwd *pw,
! 1606: char *err, size_t errlen)
! 1607: {
! 1608: struct stat st;
! 1609:
! 1610: /* check the open file to avoid races */
! 1611: if (fstat(fd, &st) < 0) {
! 1612: snprintf(err, errlen, "cannot stat file %s: %s",
! 1613: file, strerror(errno));
! 1614: return -1;
! 1615: }
! 1616: return safe_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
! 1617: }
! 1618:
! 1619: /*
! 1620: * Sets the value of the given variable in the environment. If the variable
! 1621: * already exists, its value is overridden.
! 1622: */
! 1623: void
! 1624: child_set_env(char ***envp, u_int *envsizep, const char *name,
! 1625: const char *value)
! 1626: {
! 1627: char **env;
! 1628: u_int envsize;
! 1629: u_int i, namelen;
! 1630:
! 1631: if (strchr(name, '=') != NULL) {
! 1632: error("Invalid environment variable \"%.100s\"", name);
! 1633: return;
! 1634: }
! 1635:
! 1636: /*
! 1637: * Find the slot where the value should be stored. If the variable
! 1638: * already exists, we reuse the slot; otherwise we append a new slot
! 1639: * at the end of the array, expanding if necessary.
! 1640: */
! 1641: env = *envp;
! 1642: namelen = strlen(name);
! 1643: for (i = 0; env[i]; i++)
! 1644: if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
! 1645: break;
! 1646: if (env[i]) {
! 1647: /* Reuse the slot. */
! 1648: free(env[i]);
! 1649: } else {
! 1650: /* New variable. Expand if necessary. */
! 1651: envsize = *envsizep;
! 1652: if (i >= envsize - 1) {
! 1653: if (envsize >= 1000)
! 1654: fatal("child_set_env: too many env vars");
! 1655: envsize += 50;
! 1656: env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
! 1657: *envsizep = envsize;
! 1658: }
! 1659: /* Need to set the NULL pointer at end of array beyond the new slot. */
! 1660: env[i + 1] = NULL;
! 1661: }
! 1662:
! 1663: /* Allocate space and format the variable in the appropriate slot. */
! 1664: env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
! 1665: snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
! 1666: }
! 1667:
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