Annotation of src/usr.bin/ssh/auth.c, Revision 1.115
1.115 ! dtucker 1: /* $OpenBSD: auth.c,v 1.114 2016/03/07 19:02:43 djm 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:
1.103 djm 229: authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%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: compat20 ? "ssh2" : "ssh1",
238: authctxt->info != NULL ? ": " : "",
239: authctxt->info != NULL ? authctxt->info : "");
240: free(authctxt->info);
241: authctxt->info = NULL;
1.105 djm 242: }
243:
244: void
245: auth_maxtries_exceeded(Authctxt *authctxt)
246: {
1.114 djm 247: struct ssh *ssh = active_state; /* XXX */
248:
1.110 djm 249: error("maximum authentication attempts exceeded for "
1.105 djm 250: "%s%.100s from %.200s port %d %s",
251: authctxt->valid ? "" : "invalid user ",
252: authctxt->user,
1.114 djm 253: ssh_remote_ipaddr(ssh),
254: ssh_remote_port(ssh),
1.105 djm 255: compat20 ? "ssh2" : "ssh1");
1.110 djm 256: packet_disconnect("Too many authentication failures");
1.105 djm 257: /* NOTREACHED */
1.13 markus 258: }
259:
260: /*
1.17 markus 261: * Check whether root logins are disallowed.
1.13 markus 262: */
263: int
1.98 djm 264: auth_root_allowed(const char *method)
1.13 markus 265: {
1.114 djm 266: struct ssh *ssh = active_state; /* XXX */
267:
1.17 markus 268: switch (options.permit_root_login) {
269: case PERMIT_YES:
1.13 markus 270: return 1;
1.17 markus 271: case PERMIT_NO_PASSWD:
1.112 deraadt 272: if (strcmp(method, "publickey") == 0 ||
273: strcmp(method, "hostbased") == 0 ||
1.113 djm 274: strcmp(method, "gssapi-with-mic") == 0)
1.17 markus 275: return 1;
276: break;
277: case PERMIT_FORCED_ONLY:
278: if (forced_command) {
1.47 itojun 279: logit("Root login accepted for forced command.");
1.17 markus 280: return 1;
281: }
282: break;
1.13 markus 283: }
1.114 djm 284: logit("ROOT LOGIN REFUSED FROM %.200s port %d",
285: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.22 markus 286: return 0;
287: }
288:
289:
290: /*
291: * Given a template and a passwd structure, build a filename
292: * by substituting % tokenised options. Currently, %% becomes '%',
293: * %h becomes the home directory and %u the username.
294: *
295: * This returns a buffer allocated by xmalloc.
296: */
1.93 djm 297: char *
1.59 djm 298: expand_authorized_keys(const char *filename, struct passwd *pw)
1.22 markus 299: {
1.109 deraadt 300: char *file, ret[PATH_MAX];
1.65 djm 301: int i;
1.22 markus 302:
1.59 djm 303: file = percent_expand(filename, "h", pw->pw_dir,
304: "u", pw->pw_name, (char *)NULL);
1.22 markus 305:
306: /*
307: * Ensure that filename starts anchored. If not, be backward
308: * compatible and prepend the '%h/'
309: */
1.59 djm 310: if (*file == '/')
311: return (file);
312:
1.65 djm 313: i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
314: if (i < 0 || (size_t)i >= sizeof(ret))
1.59 djm 315: fatal("expand_authorized_keys: path too long");
1.102 djm 316: free(file);
1.65 djm 317: return (xstrdup(ret));
1.22 markus 318: }
1.24 markus 319:
1.87 djm 320: char *
321: authorized_principals_file(struct passwd *pw)
322: {
1.111 djm 323: if (options.authorized_principals_file == NULL)
1.87 djm 324: return NULL;
325: return expand_authorized_keys(options.authorized_principals_file, pw);
326: }
327:
1.24 markus 328: /* return ok if key exists in sysfile or userfile */
329: HostStatus
330: check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
331: const char *sysfile, const char *userfile)
332: {
333: char *user_hostfile;
334: struct stat st;
1.30 stevesk 335: HostStatus host_status;
1.91 djm 336: struct hostkeys *hostkeys;
337: const struct hostkey_entry *found;
1.24 markus 338:
1.91 djm 339: hostkeys = init_hostkeys();
340: load_hostkeys(hostkeys, host, sysfile);
341: if (userfile != NULL) {
1.24 markus 342: user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
343: if (options.strict_modes &&
344: (stat(user_hostfile, &st) == 0) &&
345: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
1.31 deraadt 346: (st.st_mode & 022) != 0)) {
1.47 itojun 347: logit("Authentication refused for %.100s: "
1.24 markus 348: "bad owner or modes for %.200s",
349: pw->pw_name, user_hostfile);
1.88 djm 350: auth_debug_add("Ignored %.200s: bad ownership or modes",
351: user_hostfile);
1.24 markus 352: } else {
353: temporarily_use_uid(pw);
1.91 djm 354: load_hostkeys(hostkeys, host, user_hostfile);
1.24 markus 355: restore_uid();
356: }
1.102 djm 357: free(user_hostfile);
1.24 markus 358: }
1.91 djm 359: host_status = check_key_in_hostkeys(hostkeys, key, &found);
360: if (host_status == HOST_REVOKED)
361: error("WARNING: revoked key for %s attempted authentication",
362: found->host);
363: else if (host_status == HOST_OK)
364: debug("%s: key for %s found at %s:%ld", __func__,
365: found->host, found->file, found->line);
366: else
367: debug("%s: key for host %s not found", __func__, host);
368:
369: free_hostkeys(hostkeys);
1.24 markus 370:
371: return host_status;
372: }
373:
1.22 markus 374: /*
1.97 djm 375: * Check a given path for security. This is defined as all components
1.44 stevesk 376: * of the path to the file must be owned by either the owner of
1.23 markus 377: * of the file or root and no directories must be group or world writable.
1.22 markus 378: *
379: * XXX Should any specific check be done for sym links ?
380: *
1.101 dtucker 381: * Takes a file name, its stat information (preferably from fstat() to
1.97 djm 382: * avoid races), the uid of the expected owner, their home directory and an
1.22 markus 383: * error buffer plus max size as arguments.
384: *
385: * Returns 0 on success and -1 on failure
386: */
1.97 djm 387: int
388: auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
389: uid_t uid, char *err, size_t errlen)
1.22 markus 390: {
1.109 deraadt 391: char buf[PATH_MAX], homedir[PATH_MAX];
1.22 markus 392: char *cp;
1.46 markus 393: int comparehome = 0;
1.22 markus 394: struct stat st;
395:
1.97 djm 396: if (realpath(name, buf) == NULL) {
397: snprintf(err, errlen, "realpath %s failed: %s", name,
1.22 markus 398: strerror(errno));
399: return -1;
400: }
1.97 djm 401: if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
1.46 markus 402: comparehome = 1;
1.22 markus 403:
1.97 djm 404: if (!S_ISREG(stp->st_mode)) {
405: snprintf(err, errlen, "%s is not a regular file", buf);
406: return -1;
407: }
408: if ((stp->st_uid != 0 && stp->st_uid != uid) ||
409: (stp->st_mode & 022) != 0) {
1.22 markus 410: snprintf(err, errlen, "bad ownership or modes for file %s",
411: buf);
412: return -1;
413: }
414:
415: /* for each component of the canonical path, walking upwards */
416: for (;;) {
417: if ((cp = dirname(buf)) == NULL) {
418: snprintf(err, errlen, "dirname() failed");
419: return -1;
420: }
421: strlcpy(buf, cp, sizeof(buf));
1.25 provos 422:
1.22 markus 423: if (stat(buf, &st) < 0 ||
424: (st.st_uid != 0 && st.st_uid != uid) ||
425: (st.st_mode & 022) != 0) {
1.31 deraadt 426: snprintf(err, errlen,
1.22 markus 427: "bad ownership or modes for directory %s", buf);
428: return -1;
429: }
430:
1.82 dtucker 431: /* If are past the homedir then we can stop */
1.94 djm 432: if (comparehome && strcmp(homedir, buf) == 0)
1.27 markus 433: break;
1.94 djm 434:
1.22 markus 435: /*
436: * dirname should always complete with a "/" path,
437: * but we can be paranoid and check for "." too
438: */
439: if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
440: break;
441: }
1.17 markus 442: return 0;
1.97 djm 443: }
444:
445: /*
446: * Version of secure_path() that accepts an open file descriptor to
447: * avoid races.
448: *
449: * Returns 0 on success and -1 on failure
450: */
451: static int
452: secure_filename(FILE *f, const char *file, struct passwd *pw,
453: char *err, size_t errlen)
454: {
455: struct stat st;
456:
457: /* check the open file to avoid races */
458: if (fstat(fileno(f), &st) < 0) {
459: snprintf(err, errlen, "cannot stat file %s: %s",
1.99 dtucker 460: file, strerror(errno));
1.97 djm 461: return -1;
462: }
463: return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
1.79 dtucker 464: }
465:
1.87 djm 466: static FILE *
467: auth_openfile(const char *file, struct passwd *pw, int strict_modes,
468: int log_missing, char *file_type)
1.79 dtucker 469: {
470: char line[1024];
471: struct stat st;
472: int fd;
473: FILE *f;
474:
1.81 dtucker 475: if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
1.87 djm 476: if (log_missing || errno != ENOENT)
477: debug("Could not open %s '%s': %s", file_type, file,
1.81 dtucker 478: strerror(errno));
1.79 dtucker 479: return NULL;
1.81 dtucker 480: }
1.79 dtucker 481:
482: if (fstat(fd, &st) < 0) {
483: close(fd);
484: return NULL;
485: }
486: if (!S_ISREG(st.st_mode)) {
1.87 djm 487: logit("User %s %s %s is not a regular file",
488: pw->pw_name, file_type, file);
1.79 dtucker 489: close(fd);
490: return NULL;
491: }
492: unset_nonblock(fd);
493: if ((f = fdopen(fd, "r")) == NULL) {
494: close(fd);
495: return NULL;
496: }
1.90 djm 497: if (strict_modes &&
1.79 dtucker 498: secure_filename(f, file, pw, line, sizeof(line)) != 0) {
499: fclose(f);
500: logit("Authentication refused: %s", line);
1.88 djm 501: auth_debug_add("Ignored %s: %s", file_type, line);
1.79 dtucker 502: return NULL;
503: }
504:
505: return f;
1.87 djm 506: }
507:
508:
509: FILE *
510: auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
511: {
512: return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
513: }
514:
515: FILE *
516: auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
517: {
518: return auth_openfile(file, pw, strict_modes, 0,
519: "authorized principals");
1.37 provos 520: }
521:
522: struct passwd *
523: getpwnamallow(const char *user)
524: {
1.114 djm 525: struct ssh *ssh = active_state; /* XXX */
1.38 provos 526: extern login_cap_t *lc;
527: auth_session_t *as;
1.37 provos 528: struct passwd *pw;
1.96 dtucker 529: struct connection_info *ci = get_connection_info(1, options.use_dns);
1.71 dtucker 530:
1.96 dtucker 531: ci->user = user;
532: parse_server_match_config(&options, ci);
1.37 provos 533:
534: pw = getpwnam(user);
1.45 stevesk 535: if (pw == NULL) {
1.114 djm 536: logit("Invalid user %.100s from %.100s port %d",
537: user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.45 stevesk 538: return (NULL);
539: }
540: if (!allowed_user(pw))
1.38 provos 541: return (NULL);
542: if ((lc = login_getclass(pw->pw_class)) == NULL) {
543: debug("unable to get login class: %s", user);
544: return (NULL);
545: }
546: if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
1.43 millert 547: auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1.38 provos 548: debug("Approval failure for %s", user);
1.37 provos 549: pw = NULL;
1.38 provos 550: }
551: if (as != NULL)
552: auth_close(as);
1.41 markus 553: if (pw != NULL)
554: return (pwcopy(pw));
555: return (NULL);
1.85 djm 556: }
557:
558: /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
559: int
560: auth_key_is_revoked(Key *key)
561: {
1.107 djm 562: char *fp = NULL;
563: int r;
1.85 djm 564:
565: if (options.revoked_keys_file == NULL)
566: return 0;
1.108 djm 567: if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
568: SSH_FP_DEFAULT)) == NULL) {
1.107 djm 569: r = SSH_ERR_ALLOC_FAIL;
570: error("%s: fingerprint key: %s", __func__, ssh_err(r));
571: goto out;
572: }
573:
574: r = sshkey_check_revoked(key, options.revoked_keys_file);
575: switch (r) {
1.100 djm 576: case 0:
1.107 djm 577: break; /* not revoked */
578: case SSH_ERR_KEY_REVOKED:
579: error("Authentication key %s %s revoked by file %s",
580: sshkey_type(key), fp, options.revoked_keys_file);
581: goto out;
1.100 djm 582: default:
1.107 djm 583: error("Error checking authentication key %s %s in "
584: "revoked keys file %s: %s", sshkey_type(key), fp,
585: options.revoked_keys_file, ssh_err(r));
586: goto out;
1.100 djm 587: }
1.107 djm 588:
589: /* Success */
590: r = 0;
591:
592: out:
593: free(fp);
594: return r == 0 ? 0 : 1;
1.42 markus 595: }
596:
597: void
598: auth_debug_add(const char *fmt,...)
599: {
600: char buf[1024];
601: va_list args;
602:
603: if (!auth_debug_init)
604: return;
605:
606: va_start(args, fmt);
607: vsnprintf(buf, sizeof(buf), fmt, args);
608: va_end(args);
609: buffer_put_cstring(&auth_debug, buf);
610: }
611:
612: void
613: auth_debug_send(void)
614: {
615: char *msg;
616:
617: if (!auth_debug_init)
618: return;
619: while (buffer_len(&auth_debug)) {
620: msg = buffer_get_string(&auth_debug, NULL);
621: packet_send_debug("%s", msg);
1.102 djm 622: free(msg);
1.42 markus 623: }
624: }
625:
626: void
627: auth_debug_reset(void)
628: {
629: if (auth_debug_init)
630: buffer_clear(&auth_debug);
631: else {
632: buffer_init(&auth_debug);
633: auth_debug_init = 1;
634: }
1.49 markus 635: }
636:
637: struct passwd *
638: fakepw(void)
639: {
640: static struct passwd fake;
641:
642: memset(&fake, 0, sizeof(fake));
643: fake.pw_name = "NOUSER";
644: fake.pw_passwd =
1.51 djm 645: "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
1.49 markus 646: fake.pw_gecos = "NOUSER";
1.53 deraadt 647: fake.pw_uid = (uid_t)-1;
648: fake.pw_gid = (gid_t)-1;
1.49 markus 649: fake.pw_class = "";
650: fake.pw_dir = "/nonexist";
651: fake.pw_shell = "/nonexist";
652:
653: return (&fake);
1.114 djm 654: }
655:
656: /*
657: * Returns the remote DNS hostname as a string. The returned string must not
658: * be freed. NB. this will usually trigger a DNS query the first time it is
659: * called.
660: * This function does additional checks on the hostname to mitigate some
661: * attacks on legacy rhosts-style authentication.
662: * XXX is RhostsRSAAuthentication vulnerable to these?
663: * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
664: */
665:
666: static char *
667: remote_hostname(struct ssh *ssh)
668: {
669: struct sockaddr_storage from;
670: socklen_t fromlen;
671: struct addrinfo hints, *ai, *aitop;
672: char name[NI_MAXHOST], ntop2[NI_MAXHOST];
673: const char *ntop = ssh_remote_ipaddr(ssh);
674:
675: /* Get IP address of client. */
676: fromlen = sizeof(from);
677: memset(&from, 0, sizeof(from));
678: if (getpeername(ssh_packet_get_connection_in(ssh),
679: (struct sockaddr *)&from, &fromlen) < 0) {
680: debug("getpeername failed: %.100s", strerror(errno));
681: return strdup(ntop);
682: }
683:
684: debug3("Trying to reverse map address %.100s.", ntop);
685: /* Map the IP address to a host name. */
686: if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
687: NULL, 0, NI_NAMEREQD) != 0) {
688: /* Host name not found. Use ip address. */
689: return strdup(ntop);
690: }
691:
692: /*
693: * if reverse lookup result looks like a numeric hostname,
694: * someone is trying to trick us by PTR record like following:
695: * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
696: */
697: memset(&hints, 0, sizeof(hints));
698: hints.ai_socktype = SOCK_DGRAM; /*dummy*/
699: hints.ai_flags = AI_NUMERICHOST;
700: if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
701: logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
702: name, ntop);
703: freeaddrinfo(ai);
704: return strdup(ntop);
705: }
706:
707: /* Names are stored in lowercase. */
708: lowercase(name);
709:
710: /*
711: * Map it back to an IP address and check that the given
712: * address actually is an address of this host. This is
713: * necessary because anyone with access to a name server can
714: * define arbitrary names for an IP address. Mapping from
715: * name to IP address can be trusted better (but can still be
716: * fooled if the intruder has access to the name server of
717: * the domain).
718: */
719: memset(&hints, 0, sizeof(hints));
720: hints.ai_family = from.ss_family;
721: hints.ai_socktype = SOCK_STREAM;
722: if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
723: logit("reverse mapping checking getaddrinfo for %.700s "
1.115 ! dtucker 724: "[%s] failed.", name, ntop);
1.114 djm 725: return strdup(ntop);
726: }
727: /* Look for the address from the list of addresses. */
728: for (ai = aitop; ai; ai = ai->ai_next) {
729: if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
730: sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
731: (strcmp(ntop, ntop2) == 0))
732: break;
733: }
734: freeaddrinfo(aitop);
735: /* If we reached the end of the list, the address was not there. */
736: if (ai == NULL) {
737: /* Address not found for the host name. */
738: logit("Address %.100s maps to %.600s, but this does not "
1.115 ! dtucker 739: "map back to the address.", ntop, name);
1.114 djm 740: return strdup(ntop);
741: }
742: return strdup(name);
743: }
744:
745: /*
746: * Return the canonical name of the host in the other side of the current
747: * connection. The host name is cached, so it is efficient to call this
748: * several times.
749: */
750:
751: const char *
752: auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
753: {
754: static char *dnsname;
755:
756: if (!use_dns)
757: return ssh_remote_ipaddr(ssh);
758: else if (dnsname != NULL)
759: return dnsname;
760: else {
761: dnsname = remote_hostname(ssh);
762: return dnsname;
763: }
1.1 markus 764: }
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