Annotation of src/usr.bin/ssh/auth.c, Revision 1.116
1.116 ! markus 1: /* $OpenBSD: auth.c,v 1.115 2016/06/15 00:40:40 dtucker Exp $ */
1.1 markus 2: /*
1.19 deraadt 3: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.9 deraadt 4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: *
14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.1 markus 24: */
25:
1.62 stevesk 26: #include <sys/types.h>
27: #include <sys/stat.h>
1.114 djm 28: #include <sys/socket.h>
1.22 markus 29:
1.70 stevesk 30: #include <errno.h>
1.79 dtucker 31: #include <fcntl.h>
1.22 markus 32: #include <libgen.h>
1.77 djm 33: #include <login_cap.h>
1.61 stevesk 34: #include <paths.h>
1.68 stevesk 35: #include <pwd.h>
1.69 stevesk 36: #include <stdarg.h>
1.74 stevesk 37: #include <stdio.h>
1.72 stevesk 38: #include <string.h>
1.80 djm 39: #include <unistd.h>
1.109 deraadt 40: #include <limits.h>
1.114 djm 41: #include <netdb.h>
1.1 markus 42:
43: #include "xmalloc.h"
1.13 markus 44: #include "match.h"
1.14 markus 45: #include "groupaccess.h"
46: #include "log.h"
1.75 deraadt 47: #include "buffer.h"
1.106 millert 48: #include "misc.h"
1.1 markus 49: #include "servconf.h"
1.75 deraadt 50: #include "key.h"
51: #include "hostfile.h"
1.2 markus 52: #include "auth.h"
1.13 markus 53: #include "auth-options.h"
1.14 markus 54: #include "canohost.h"
1.24 markus 55: #include "uidswap.h"
1.42 markus 56: #include "packet.h"
1.75 deraadt 57: #ifdef GSSAPI
58: #include "ssh-gss.h"
59: #endif
1.85 djm 60: #include "authfile.h"
1.67 dtucker 61: #include "monitor_wrap.h"
1.107 djm 62: #include "authfile.h"
63: #include "ssherr.h"
1.103 djm 64: #include "compat.h"
1.2 markus 65:
1.1 markus 66: /* import */
67: extern ServerOptions options;
1.67 dtucker 68: extern int use_privsep;
1.1 markus 69:
1.42 markus 70: /* Debugging messages */
71: Buffer auth_debug;
72: int auth_debug_init;
73:
1.1 markus 74: /*
1.12 markus 75: * Check if the user is allowed to log in via ssh. If user is listed
76: * in DenyUsers or one of user's groups is listed in DenyGroups, false
77: * will be returned. If AllowUsers isn't empty and user isn't listed
78: * there, or if AllowGroups isn't empty and one of user's groups isn't
79: * listed there, false will be returned.
1.1 markus 80: * If the user's shell is not executable, false will be returned.
1.4 markus 81: * Otherwise true is returned.
1.1 markus 82: */
1.5 markus 83: int
1.1 markus 84: allowed_user(struct passwd * pw)
85: {
1.114 djm 86: struct ssh *ssh = active_state; /* XXX */
1.1 markus 87: struct stat st;
1.35 markus 88: const char *hostname = NULL, *ipaddr = NULL;
1.60 djm 89: u_int i;
1.1 markus 90:
91: /* Shouldn't be called if pw is NULL, but better safe than sorry... */
1.12 markus 92: if (!pw || !pw->pw_name)
1.1 markus 93: return 0;
94:
1.7 deraadt 95: /*
1.84 djm 96: * Deny if shell does not exist or is not executable unless we
97: * are chrooting.
1.7 deraadt 98: */
1.84 djm 99: if (options.chroot_directory == NULL ||
100: strcasecmp(options.chroot_directory, "none") == 0) {
101: char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
102: _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
103:
104: if (stat(shell, &st) != 0) {
105: logit("User %.100s not allowed because shell %.100s "
106: "does not exist", pw->pw_name, shell);
1.102 djm 107: free(shell);
1.84 djm 108: return 0;
109: }
110: if (S_ISREG(st.st_mode) == 0 ||
111: (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
112: logit("User %.100s not allowed because shell %.100s "
113: "is not executable", pw->pw_name, shell);
1.102 djm 114: free(shell);
1.84 djm 115: return 0;
116: }
1.102 djm 117: free(shell);
1.34 stevesk 118: }
1.1 markus 119:
1.58 dtucker 120: if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
121: options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1.114 djm 122: hostname = auth_get_canonical_hostname(ssh, options.use_dns);
123: ipaddr = ssh_remote_ipaddr(ssh);
1.35 markus 124: }
125:
1.1 markus 126: /* Return false if user is listed in DenyUsers */
127: if (options.num_deny_users > 0) {
128: for (i = 0; i < options.num_deny_users; i++)
1.39 markus 129: if (match_user(pw->pw_name, hostname, ipaddr,
1.34 stevesk 130: options.deny_users[i])) {
1.57 dtucker 131: logit("User %.100s from %.100s not allowed "
132: "because listed in DenyUsers",
133: pw->pw_name, hostname);
1.1 markus 134: return 0;
1.34 stevesk 135: }
1.1 markus 136: }
137: /* Return false if AllowUsers isn't empty and user isn't listed there */
138: if (options.num_allow_users > 0) {
139: for (i = 0; i < options.num_allow_users; i++)
1.39 markus 140: if (match_user(pw->pw_name, hostname, ipaddr,
1.26 markus 141: options.allow_users[i]))
1.1 markus 142: break;
143: /* i < options.num_allow_users iff we break for loop */
1.34 stevesk 144: if (i >= options.num_allow_users) {
1.57 dtucker 145: logit("User %.100s from %.100s not allowed because "
146: "not listed in AllowUsers", pw->pw_name, hostname);
1.1 markus 147: return 0;
1.34 stevesk 148: }
1.1 markus 149: }
150: if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1.12 markus 151: /* Get the user's group access list (primary and supplementary) */
1.34 stevesk 152: if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
1.57 dtucker 153: logit("User %.100s from %.100s not allowed because "
154: "not in any group", pw->pw_name, hostname);
1.1 markus 155: return 0;
1.34 stevesk 156: }
1.1 markus 157:
1.12 markus 158: /* Return false if one of user's groups is listed in DenyGroups */
159: if (options.num_deny_groups > 0)
160: if (ga_match(options.deny_groups,
161: options.num_deny_groups)) {
162: ga_free();
1.57 dtucker 163: logit("User %.100s from %.100s not allowed "
164: "because a group is listed in DenyGroups",
165: pw->pw_name, hostname);
1.1 markus 166: return 0;
1.12 markus 167: }
1.1 markus 168: /*
1.12 markus 169: * Return false if AllowGroups isn't empty and one of user's groups
1.1 markus 170: * isn't listed there
171: */
1.12 markus 172: if (options.num_allow_groups > 0)
173: if (!ga_match(options.allow_groups,
174: options.num_allow_groups)) {
175: ga_free();
1.57 dtucker 176: logit("User %.100s from %.100s not allowed "
177: "because none of user's groups are listed "
178: "in AllowGroups", pw->pw_name, hostname);
1.1 markus 179: return 0;
1.12 markus 180: }
181: ga_free();
1.1 markus 182: }
183: /* We found no reason not to let this user try to log on... */
184: return 1;
1.13 markus 185: }
186:
187: void
1.103 djm 188: auth_info(Authctxt *authctxt, const char *fmt, ...)
189: {
190: va_list ap;
191: int i;
192:
193: free(authctxt->info);
194: authctxt->info = NULL;
195:
196: va_start(ap, fmt);
197: i = vasprintf(&authctxt->info, fmt, ap);
198: va_end(ap);
199:
200: if (i < 0 || authctxt->info == NULL)
201: fatal("vasprintf failed");
202: }
203:
204: void
1.98 djm 205: auth_log(Authctxt *authctxt, int authenticated, int partial,
1.103 djm 206: const char *method, const char *submethod)
1.13 markus 207: {
1.114 djm 208: struct ssh *ssh = active_state; /* XXX */
1.13 markus 209: void (*authlog) (const char *fmt,...) = verbose;
210: char *authmsg;
1.67 dtucker 211:
212: if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
213: return;
1.13 markus 214:
215: /* Raise logging level */
216: if (authenticated == 1 ||
217: !authctxt->valid ||
1.54 dtucker 218: authctxt->failures >= options.max_authtries / 2 ||
1.13 markus 219: strcmp(method, "password") == 0)
1.47 itojun 220: authlog = logit;
1.13 markus 221:
222: if (authctxt->postponed)
223: authmsg = "Postponed";
1.98 djm 224: else if (partial)
225: authmsg = "Partial";
1.13 markus 226: else
227: authmsg = authenticated ? "Accepted" : "Failed";
228:
1.116 ! markus 229: authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
1.13 markus 230: authmsg,
231: method,
1.98 djm 232: submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
1.56 markus 233: authctxt->valid ? "" : "invalid user ",
1.29 markus 234: authctxt->user,
1.114 djm 235: ssh_remote_ipaddr(ssh),
236: ssh_remote_port(ssh),
1.103 djm 237: authctxt->info != NULL ? ": " : "",
238: authctxt->info != NULL ? authctxt->info : "");
239: free(authctxt->info);
240: authctxt->info = NULL;
1.105 djm 241: }
242:
243: void
244: auth_maxtries_exceeded(Authctxt *authctxt)
245: {
1.114 djm 246: struct ssh *ssh = active_state; /* XXX */
247:
1.110 djm 248: error("maximum authentication attempts exceeded for "
1.116 ! markus 249: "%s%.100s from %.200s port %d ssh2",
1.105 djm 250: authctxt->valid ? "" : "invalid user ",
251: authctxt->user,
1.114 djm 252: ssh_remote_ipaddr(ssh),
1.116 ! markus 253: ssh_remote_port(ssh));
1.110 djm 254: packet_disconnect("Too many authentication failures");
1.105 djm 255: /* NOTREACHED */
1.13 markus 256: }
257:
258: /*
1.17 markus 259: * Check whether root logins are disallowed.
1.13 markus 260: */
261: int
1.98 djm 262: auth_root_allowed(const char *method)
1.13 markus 263: {
1.114 djm 264: struct ssh *ssh = active_state; /* XXX */
265:
1.17 markus 266: switch (options.permit_root_login) {
267: case PERMIT_YES:
1.13 markus 268: return 1;
1.17 markus 269: case PERMIT_NO_PASSWD:
1.112 deraadt 270: if (strcmp(method, "publickey") == 0 ||
271: strcmp(method, "hostbased") == 0 ||
1.113 djm 272: strcmp(method, "gssapi-with-mic") == 0)
1.17 markus 273: return 1;
274: break;
275: case PERMIT_FORCED_ONLY:
276: if (forced_command) {
1.47 itojun 277: logit("Root login accepted for forced command.");
1.17 markus 278: return 1;
279: }
280: break;
1.13 markus 281: }
1.114 djm 282: logit("ROOT LOGIN REFUSED FROM %.200s port %d",
283: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.22 markus 284: return 0;
285: }
286:
287:
288: /*
289: * Given a template and a passwd structure, build a filename
290: * by substituting % tokenised options. Currently, %% becomes '%',
291: * %h becomes the home directory and %u the username.
292: *
293: * This returns a buffer allocated by xmalloc.
294: */
1.93 djm 295: char *
1.59 djm 296: expand_authorized_keys(const char *filename, struct passwd *pw)
1.22 markus 297: {
1.109 deraadt 298: char *file, ret[PATH_MAX];
1.65 djm 299: int i;
1.22 markus 300:
1.59 djm 301: file = percent_expand(filename, "h", pw->pw_dir,
302: "u", pw->pw_name, (char *)NULL);
1.22 markus 303:
304: /*
305: * Ensure that filename starts anchored. If not, be backward
306: * compatible and prepend the '%h/'
307: */
1.59 djm 308: if (*file == '/')
309: return (file);
310:
1.65 djm 311: i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
312: if (i < 0 || (size_t)i >= sizeof(ret))
1.59 djm 313: fatal("expand_authorized_keys: path too long");
1.102 djm 314: free(file);
1.65 djm 315: return (xstrdup(ret));
1.22 markus 316: }
1.24 markus 317:
1.87 djm 318: char *
319: authorized_principals_file(struct passwd *pw)
320: {
1.111 djm 321: if (options.authorized_principals_file == NULL)
1.87 djm 322: return NULL;
323: return expand_authorized_keys(options.authorized_principals_file, pw);
324: }
325:
1.24 markus 326: /* return ok if key exists in sysfile or userfile */
327: HostStatus
328: check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
329: const char *sysfile, const char *userfile)
330: {
331: char *user_hostfile;
332: struct stat st;
1.30 stevesk 333: HostStatus host_status;
1.91 djm 334: struct hostkeys *hostkeys;
335: const struct hostkey_entry *found;
1.24 markus 336:
1.91 djm 337: hostkeys = init_hostkeys();
338: load_hostkeys(hostkeys, host, sysfile);
339: if (userfile != NULL) {
1.24 markus 340: user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
341: if (options.strict_modes &&
342: (stat(user_hostfile, &st) == 0) &&
343: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
1.31 deraadt 344: (st.st_mode & 022) != 0)) {
1.47 itojun 345: logit("Authentication refused for %.100s: "
1.24 markus 346: "bad owner or modes for %.200s",
347: pw->pw_name, user_hostfile);
1.88 djm 348: auth_debug_add("Ignored %.200s: bad ownership or modes",
349: user_hostfile);
1.24 markus 350: } else {
351: temporarily_use_uid(pw);
1.91 djm 352: load_hostkeys(hostkeys, host, user_hostfile);
1.24 markus 353: restore_uid();
354: }
1.102 djm 355: free(user_hostfile);
1.24 markus 356: }
1.91 djm 357: host_status = check_key_in_hostkeys(hostkeys, key, &found);
358: if (host_status == HOST_REVOKED)
359: error("WARNING: revoked key for %s attempted authentication",
360: found->host);
361: else if (host_status == HOST_OK)
362: debug("%s: key for %s found at %s:%ld", __func__,
363: found->host, found->file, found->line);
364: else
365: debug("%s: key for host %s not found", __func__, host);
366:
367: free_hostkeys(hostkeys);
1.24 markus 368:
369: return host_status;
370: }
371:
1.22 markus 372: /*
1.97 djm 373: * Check a given path for security. This is defined as all components
1.44 stevesk 374: * of the path to the file must be owned by either the owner of
1.23 markus 375: * of the file or root and no directories must be group or world writable.
1.22 markus 376: *
377: * XXX Should any specific check be done for sym links ?
378: *
1.101 dtucker 379: * Takes a file name, its stat information (preferably from fstat() to
1.97 djm 380: * avoid races), the uid of the expected owner, their home directory and an
1.22 markus 381: * error buffer plus max size as arguments.
382: *
383: * Returns 0 on success and -1 on failure
384: */
1.97 djm 385: int
386: auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
387: uid_t uid, char *err, size_t errlen)
1.22 markus 388: {
1.109 deraadt 389: char buf[PATH_MAX], homedir[PATH_MAX];
1.22 markus 390: char *cp;
1.46 markus 391: int comparehome = 0;
1.22 markus 392: struct stat st;
393:
1.97 djm 394: if (realpath(name, buf) == NULL) {
395: snprintf(err, errlen, "realpath %s failed: %s", name,
1.22 markus 396: strerror(errno));
397: return -1;
398: }
1.97 djm 399: if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
1.46 markus 400: comparehome = 1;
1.22 markus 401:
1.97 djm 402: if (!S_ISREG(stp->st_mode)) {
403: snprintf(err, errlen, "%s is not a regular file", buf);
404: return -1;
405: }
406: if ((stp->st_uid != 0 && stp->st_uid != uid) ||
407: (stp->st_mode & 022) != 0) {
1.22 markus 408: snprintf(err, errlen, "bad ownership or modes for file %s",
409: buf);
410: return -1;
411: }
412:
413: /* for each component of the canonical path, walking upwards */
414: for (;;) {
415: if ((cp = dirname(buf)) == NULL) {
416: snprintf(err, errlen, "dirname() failed");
417: return -1;
418: }
419: strlcpy(buf, cp, sizeof(buf));
1.25 provos 420:
1.22 markus 421: if (stat(buf, &st) < 0 ||
422: (st.st_uid != 0 && st.st_uid != uid) ||
423: (st.st_mode & 022) != 0) {
1.31 deraadt 424: snprintf(err, errlen,
1.22 markus 425: "bad ownership or modes for directory %s", buf);
426: return -1;
427: }
428:
1.82 dtucker 429: /* If are past the homedir then we can stop */
1.94 djm 430: if (comparehome && strcmp(homedir, buf) == 0)
1.27 markus 431: break;
1.94 djm 432:
1.22 markus 433: /*
434: * dirname should always complete with a "/" path,
435: * but we can be paranoid and check for "." too
436: */
437: if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
438: break;
439: }
1.17 markus 440: return 0;
1.97 djm 441: }
442:
443: /*
444: * Version of secure_path() that accepts an open file descriptor to
445: * avoid races.
446: *
447: * Returns 0 on success and -1 on failure
448: */
449: static int
450: secure_filename(FILE *f, const char *file, struct passwd *pw,
451: char *err, size_t errlen)
452: {
453: struct stat st;
454:
455: /* check the open file to avoid races */
456: if (fstat(fileno(f), &st) < 0) {
457: snprintf(err, errlen, "cannot stat file %s: %s",
1.99 dtucker 458: file, strerror(errno));
1.97 djm 459: return -1;
460: }
461: return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
1.79 dtucker 462: }
463:
1.87 djm 464: static FILE *
465: auth_openfile(const char *file, struct passwd *pw, int strict_modes,
466: int log_missing, char *file_type)
1.79 dtucker 467: {
468: char line[1024];
469: struct stat st;
470: int fd;
471: FILE *f;
472:
1.81 dtucker 473: if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
1.87 djm 474: if (log_missing || errno != ENOENT)
475: debug("Could not open %s '%s': %s", file_type, file,
1.81 dtucker 476: strerror(errno));
1.79 dtucker 477: return NULL;
1.81 dtucker 478: }
1.79 dtucker 479:
480: if (fstat(fd, &st) < 0) {
481: close(fd);
482: return NULL;
483: }
484: if (!S_ISREG(st.st_mode)) {
1.87 djm 485: logit("User %s %s %s is not a regular file",
486: pw->pw_name, file_type, file);
1.79 dtucker 487: close(fd);
488: return NULL;
489: }
490: unset_nonblock(fd);
491: if ((f = fdopen(fd, "r")) == NULL) {
492: close(fd);
493: return NULL;
494: }
1.90 djm 495: if (strict_modes &&
1.79 dtucker 496: secure_filename(f, file, pw, line, sizeof(line)) != 0) {
497: fclose(f);
498: logit("Authentication refused: %s", line);
1.88 djm 499: auth_debug_add("Ignored %s: %s", file_type, line);
1.79 dtucker 500: return NULL;
501: }
502:
503: return f;
1.87 djm 504: }
505:
506:
507: FILE *
508: auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
509: {
510: return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
511: }
512:
513: FILE *
514: auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
515: {
516: return auth_openfile(file, pw, strict_modes, 0,
517: "authorized principals");
1.37 provos 518: }
519:
520: struct passwd *
521: getpwnamallow(const char *user)
522: {
1.114 djm 523: struct ssh *ssh = active_state; /* XXX */
1.38 provos 524: extern login_cap_t *lc;
525: auth_session_t *as;
1.37 provos 526: struct passwd *pw;
1.96 dtucker 527: struct connection_info *ci = get_connection_info(1, options.use_dns);
1.71 dtucker 528:
1.96 dtucker 529: ci->user = user;
530: parse_server_match_config(&options, ci);
1.37 provos 531:
532: pw = getpwnam(user);
1.45 stevesk 533: if (pw == NULL) {
1.114 djm 534: logit("Invalid user %.100s from %.100s port %d",
535: user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.45 stevesk 536: return (NULL);
537: }
538: if (!allowed_user(pw))
1.38 provos 539: return (NULL);
540: if ((lc = login_getclass(pw->pw_class)) == NULL) {
541: debug("unable to get login class: %s", user);
542: return (NULL);
543: }
544: if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
1.43 millert 545: auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1.38 provos 546: debug("Approval failure for %s", user);
1.37 provos 547: pw = NULL;
1.38 provos 548: }
549: if (as != NULL)
550: auth_close(as);
1.41 markus 551: if (pw != NULL)
552: return (pwcopy(pw));
553: return (NULL);
1.85 djm 554: }
555:
556: /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
557: int
558: auth_key_is_revoked(Key *key)
559: {
1.107 djm 560: char *fp = NULL;
561: int r;
1.85 djm 562:
563: if (options.revoked_keys_file == NULL)
564: return 0;
1.108 djm 565: if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
566: SSH_FP_DEFAULT)) == NULL) {
1.107 djm 567: r = SSH_ERR_ALLOC_FAIL;
568: error("%s: fingerprint key: %s", __func__, ssh_err(r));
569: goto out;
570: }
571:
572: r = sshkey_check_revoked(key, options.revoked_keys_file);
573: switch (r) {
1.100 djm 574: case 0:
1.107 djm 575: break; /* not revoked */
576: case SSH_ERR_KEY_REVOKED:
577: error("Authentication key %s %s revoked by file %s",
578: sshkey_type(key), fp, options.revoked_keys_file);
579: goto out;
1.100 djm 580: default:
1.107 djm 581: error("Error checking authentication key %s %s in "
582: "revoked keys file %s: %s", sshkey_type(key), fp,
583: options.revoked_keys_file, ssh_err(r));
584: goto out;
1.100 djm 585: }
1.107 djm 586:
587: /* Success */
588: r = 0;
589:
590: out:
591: free(fp);
592: return r == 0 ? 0 : 1;
1.42 markus 593: }
594:
595: void
596: auth_debug_add(const char *fmt,...)
597: {
598: char buf[1024];
599: va_list args;
600:
601: if (!auth_debug_init)
602: return;
603:
604: va_start(args, fmt);
605: vsnprintf(buf, sizeof(buf), fmt, args);
606: va_end(args);
607: buffer_put_cstring(&auth_debug, buf);
608: }
609:
610: void
611: auth_debug_send(void)
612: {
613: char *msg;
614:
615: if (!auth_debug_init)
616: return;
617: while (buffer_len(&auth_debug)) {
618: msg = buffer_get_string(&auth_debug, NULL);
619: packet_send_debug("%s", msg);
1.102 djm 620: free(msg);
1.42 markus 621: }
622: }
623:
624: void
625: auth_debug_reset(void)
626: {
627: if (auth_debug_init)
628: buffer_clear(&auth_debug);
629: else {
630: buffer_init(&auth_debug);
631: auth_debug_init = 1;
632: }
1.49 markus 633: }
634:
635: struct passwd *
636: fakepw(void)
637: {
638: static struct passwd fake;
639:
640: memset(&fake, 0, sizeof(fake));
641: fake.pw_name = "NOUSER";
642: fake.pw_passwd =
1.51 djm 643: "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
1.49 markus 644: fake.pw_gecos = "NOUSER";
1.53 deraadt 645: fake.pw_uid = (uid_t)-1;
646: fake.pw_gid = (gid_t)-1;
1.49 markus 647: fake.pw_class = "";
648: fake.pw_dir = "/nonexist";
649: fake.pw_shell = "/nonexist";
650:
651: return (&fake);
1.114 djm 652: }
653:
654: /*
655: * Returns the remote DNS hostname as a string. The returned string must not
656: * be freed. NB. this will usually trigger a DNS query the first time it is
657: * called.
658: * This function does additional checks on the hostname to mitigate some
659: * attacks on legacy rhosts-style authentication.
660: * XXX is RhostsRSAAuthentication vulnerable to these?
661: * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
662: */
663:
664: static char *
665: remote_hostname(struct ssh *ssh)
666: {
667: struct sockaddr_storage from;
668: socklen_t fromlen;
669: struct addrinfo hints, *ai, *aitop;
670: char name[NI_MAXHOST], ntop2[NI_MAXHOST];
671: const char *ntop = ssh_remote_ipaddr(ssh);
672:
673: /* Get IP address of client. */
674: fromlen = sizeof(from);
675: memset(&from, 0, sizeof(from));
676: if (getpeername(ssh_packet_get_connection_in(ssh),
677: (struct sockaddr *)&from, &fromlen) < 0) {
678: debug("getpeername failed: %.100s", strerror(errno));
679: return strdup(ntop);
680: }
681:
682: debug3("Trying to reverse map address %.100s.", ntop);
683: /* Map the IP address to a host name. */
684: if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
685: NULL, 0, NI_NAMEREQD) != 0) {
686: /* Host name not found. Use ip address. */
687: return strdup(ntop);
688: }
689:
690: /*
691: * if reverse lookup result looks like a numeric hostname,
692: * someone is trying to trick us by PTR record like following:
693: * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
694: */
695: memset(&hints, 0, sizeof(hints));
696: hints.ai_socktype = SOCK_DGRAM; /*dummy*/
697: hints.ai_flags = AI_NUMERICHOST;
698: if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
699: logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
700: name, ntop);
701: freeaddrinfo(ai);
702: return strdup(ntop);
703: }
704:
705: /* Names are stored in lowercase. */
706: lowercase(name);
707:
708: /*
709: * Map it back to an IP address and check that the given
710: * address actually is an address of this host. This is
711: * necessary because anyone with access to a name server can
712: * define arbitrary names for an IP address. Mapping from
713: * name to IP address can be trusted better (but can still be
714: * fooled if the intruder has access to the name server of
715: * the domain).
716: */
717: memset(&hints, 0, sizeof(hints));
718: hints.ai_family = from.ss_family;
719: hints.ai_socktype = SOCK_STREAM;
720: if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
721: logit("reverse mapping checking getaddrinfo for %.700s "
1.115 dtucker 722: "[%s] failed.", name, ntop);
1.114 djm 723: return strdup(ntop);
724: }
725: /* Look for the address from the list of addresses. */
726: for (ai = aitop; ai; ai = ai->ai_next) {
727: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
728: sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
729: (strcmp(ntop, ntop2) == 0))
730: break;
731: }
732: freeaddrinfo(aitop);
733: /* If we reached the end of the list, the address was not there. */
734: if (ai == NULL) {
735: /* Address not found for the host name. */
736: logit("Address %.100s maps to %.600s, but this does not "
1.115 dtucker 737: "map back to the address.", ntop, name);
1.114 djm 738: return strdup(ntop);
739: }
740: return strdup(name);
741: }
742:
743: /*
744: * Return the canonical name of the host in the other side of the current
745: * connection. The host name is cached, so it is efficient to call this
746: * several times.
747: */
748:
749: const char *
750: auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
751: {
752: static char *dnsname;
753:
754: if (!use_dns)
755: return ssh_remote_ipaddr(ssh);
756: else if (dnsname != NULL)
757: return dnsname;
758: else {
759: dnsname = remote_hostname(ssh);
760: return dnsname;
761: }
1.1 markus 762: }
![[BACK]](/icons/back.gif){kind=icon}
Return to auth.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh