Annotation of src/usr.bin/ssh/auth.c, Revision 1.161
1.161 ! djm 1: /* $OpenBSD: auth.c,v 1.160 2023/03/05 05:34:09 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>
1.125 markus 29: #include <sys/wait.h>
1.22 markus 30:
1.140 djm 31: #include <stdlib.h>
1.70 stevesk 32: #include <errno.h>
1.79 dtucker 33: #include <fcntl.h>
1.77 djm 34: #include <login_cap.h>
1.61 stevesk 35: #include <paths.h>
1.68 stevesk 36: #include <pwd.h>
1.69 stevesk 37: #include <stdarg.h>
1.74 stevesk 38: #include <stdio.h>
1.72 stevesk 39: #include <string.h>
1.80 djm 40: #include <unistd.h>
1.109 deraadt 41: #include <limits.h>
1.114 djm 42: #include <netdb.h>
1.135 djm 43: #include <time.h>
1.1 markus 44:
45: #include "xmalloc.h"
1.13 markus 46: #include "match.h"
1.14 markus 47: #include "groupaccess.h"
48: #include "log.h"
1.131 markus 49: #include "sshbuf.h"
1.106 millert 50: #include "misc.h"
1.1 markus 51: #include "servconf.h"
1.131 markus 52: #include "sshkey.h"
1.75 deraadt 53: #include "hostfile.h"
1.2 markus 54: #include "auth.h"
1.13 markus 55: #include "auth-options.h"
1.14 markus 56: #include "canohost.h"
1.24 markus 57: #include "uidswap.h"
1.42 markus 58: #include "packet.h"
1.75 deraadt 59: #ifdef GSSAPI
60: #include "ssh-gss.h"
61: #endif
1.85 djm 62: #include "authfile.h"
1.67 dtucker 63: #include "monitor_wrap.h"
1.107 djm 64: #include "ssherr.h"
1.126 djm 65: #include "channels.h"
1.136 djm 66:
1.1 markus 67: /* import */
68: extern ServerOptions options;
1.146 djm 69: extern struct include_list includes;
1.126 djm 70: extern struct sshauthopt *auth_opts;
1.1 markus 71:
1.42 markus 72: /* Debugging messages */
1.131 markus 73: static struct sshbuf *auth_debug;
1.42 markus 74:
1.1 markus 75: /*
1.12 markus 76: * Check if the user is allowed to log in via ssh. If user is listed
77: * in DenyUsers or one of user's groups is listed in DenyGroups, false
78: * will be returned. If AllowUsers isn't empty and user isn't listed
79: * there, or if AllowGroups isn't empty and one of user's groups isn't
80: * listed there, false will be returned.
1.1 markus 81: * If the user's shell is not executable, false will be returned.
1.4 markus 82: * Otherwise true is returned.
1.1 markus 83: */
1.5 markus 84: int
1.138 djm 85: allowed_user(struct ssh *ssh, struct passwd * pw)
1.1 markus 86: {
87: struct stat st;
1.35 markus 88: const char *hostname = NULL, *ipaddr = NULL;
1.117 djm 89: int r;
1.60 djm 90: u_int i;
1.1 markus 91:
92: /* Shouldn't be called if pw is NULL, but better safe than sorry... */
1.12 markus 93: if (!pw || !pw->pw_name)
1.1 markus 94: return 0;
95:
1.7 deraadt 96: /*
1.84 djm 97: * Deny if shell does not exist or is not executable unless we
98: * are chrooting.
1.7 deraadt 99: */
1.84 djm 100: if (options.chroot_directory == NULL ||
101: strcasecmp(options.chroot_directory, "none") == 0) {
102: char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
103: _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
104:
1.139 deraadt 105: if (stat(shell, &st) == -1) {
1.84 djm 106: logit("User %.100s not allowed because shell %.100s "
107: "does not exist", pw->pw_name, shell);
1.102 djm 108: free(shell);
1.84 djm 109: return 0;
110: }
111: if (S_ISREG(st.st_mode) == 0 ||
112: (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
113: logit("User %.100s not allowed because shell %.100s "
114: "is not executable", pw->pw_name, shell);
1.102 djm 115: free(shell);
1.84 djm 116: return 0;
117: }
1.102 djm 118: free(shell);
1.34 stevesk 119: }
1.1 markus 120:
1.58 dtucker 121: if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
122: options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1.114 djm 123: hostname = auth_get_canonical_hostname(ssh, options.use_dns);
124: ipaddr = ssh_remote_ipaddr(ssh);
1.35 markus 125: }
126:
1.1 markus 127: /* Return false if user is listed in DenyUsers */
128: if (options.num_deny_users > 0) {
1.119 dtucker 129: for (i = 0; i < options.num_deny_users; i++) {
1.117 djm 130: r = match_user(pw->pw_name, hostname, ipaddr,
131: options.deny_users[i]);
132: if (r < 0) {
133: fatal("Invalid DenyUsers pattern \"%.100s\"",
134: options.deny_users[i]);
1.118 djm 135: } else if (r != 0) {
1.57 dtucker 136: logit("User %.100s from %.100s not allowed "
137: "because listed in DenyUsers",
138: pw->pw_name, hostname);
1.1 markus 139: return 0;
1.34 stevesk 140: }
1.119 dtucker 141: }
1.1 markus 142: }
143: /* Return false if AllowUsers isn't empty and user isn't listed there */
144: if (options.num_allow_users > 0) {
1.117 djm 145: for (i = 0; i < options.num_allow_users; i++) {
146: r = match_user(pw->pw_name, hostname, ipaddr,
147: options.allow_users[i]);
148: if (r < 0) {
149: fatal("Invalid AllowUsers pattern \"%.100s\"",
150: options.allow_users[i]);
151: } else if (r == 1)
1.1 markus 152: break;
1.117 djm 153: }
1.1 markus 154: /* i < options.num_allow_users iff we break for loop */
1.34 stevesk 155: if (i >= options.num_allow_users) {
1.57 dtucker 156: logit("User %.100s from %.100s not allowed because "
157: "not listed in AllowUsers", pw->pw_name, hostname);
1.1 markus 158: return 0;
1.34 stevesk 159: }
1.1 markus 160: }
161: if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1.12 markus 162: /* Get the user's group access list (primary and supplementary) */
1.34 stevesk 163: if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
1.57 dtucker 164: logit("User %.100s from %.100s not allowed because "
165: "not in any group", pw->pw_name, hostname);
1.1 markus 166: return 0;
1.34 stevesk 167: }
1.1 markus 168:
1.12 markus 169: /* Return false if one of user's groups is listed in DenyGroups */
170: if (options.num_deny_groups > 0)
171: if (ga_match(options.deny_groups,
172: options.num_deny_groups)) {
173: ga_free();
1.57 dtucker 174: logit("User %.100s from %.100s not allowed "
175: "because a group is listed in DenyGroups",
176: pw->pw_name, hostname);
1.1 markus 177: return 0;
1.12 markus 178: }
1.1 markus 179: /*
1.12 markus 180: * Return false if AllowGroups isn't empty and one of user's groups
1.1 markus 181: * isn't listed there
182: */
1.12 markus 183: if (options.num_allow_groups > 0)
184: if (!ga_match(options.allow_groups,
185: options.num_allow_groups)) {
186: ga_free();
1.57 dtucker 187: logit("User %.100s from %.100s not allowed "
188: "because none of user's groups are listed "
189: "in AllowGroups", pw->pw_name, hostname);
1.1 markus 190: return 0;
1.12 markus 191: }
192: ga_free();
1.1 markus 193: }
194: /* We found no reason not to let this user try to log on... */
195: return 1;
1.13 markus 196: }
197:
1.122 djm 198: /*
199: * Formats any key left in authctxt->auth_method_key for inclusion in
200: * auth_log()'s message. Also includes authxtct->auth_method_info if present.
201: */
202: static char *
203: format_method_key(Authctxt *authctxt)
1.103 djm 204: {
1.122 djm 205: const struct sshkey *key = authctxt->auth_method_key;
206: const char *methinfo = authctxt->auth_method_info;
1.133 djm 207: char *fp, *cafp, *ret = NULL;
1.122 djm 208:
209: if (key == NULL)
210: return NULL;
211:
1.131 markus 212: if (sshkey_is_cert(key)) {
1.133 djm 213: fp = sshkey_fingerprint(key,
1.122 djm 214: options.fingerprint_hash, SSH_FP_DEFAULT);
1.133 djm 215: cafp = sshkey_fingerprint(key->cert->signature_key,
216: options.fingerprint_hash, SSH_FP_DEFAULT);
217: xasprintf(&ret, "%s %s ID %s (serial %llu) CA %s %s%s%s",
218: sshkey_type(key), fp == NULL ? "(null)" : fp,
219: key->cert->key_id,
1.122 djm 220: (unsigned long long)key->cert->serial,
221: sshkey_type(key->cert->signature_key),
1.133 djm 222: cafp == NULL ? "(null)" : cafp,
1.122 djm 223: methinfo == NULL ? "" : ", ",
224: methinfo == NULL ? "" : methinfo);
225: free(fp);
1.133 djm 226: free(cafp);
1.122 djm 227: } else {
228: fp = sshkey_fingerprint(key, options.fingerprint_hash,
229: SSH_FP_DEFAULT);
230: xasprintf(&ret, "%s %s%s%s", sshkey_type(key),
231: fp == NULL ? "(null)" : fp,
232: methinfo == NULL ? "" : ", ",
233: methinfo == NULL ? "" : methinfo);
234: free(fp);
235: }
236: return ret;
1.103 djm 237: }
238:
239: void
1.138 djm 240: auth_log(struct ssh *ssh, int authenticated, int partial,
1.103 djm 241: const char *method, const char *submethod)
1.13 markus 242: {
1.138 djm 243: Authctxt *authctxt = (Authctxt *)ssh->authctxt;
1.133 djm 244: int level = SYSLOG_LEVEL_VERBOSE;
1.122 djm 245: const char *authmsg;
246: char *extra = NULL;
1.67 dtucker 247:
1.161 ! djm 248: if (!mm_is_monitor() && !authctxt->postponed)
1.67 dtucker 249: return;
1.13 markus 250:
251: /* Raise logging level */
252: if (authenticated == 1 ||
253: !authctxt->valid ||
1.54 dtucker 254: authctxt->failures >= options.max_authtries / 2 ||
1.13 markus 255: strcmp(method, "password") == 0)
1.133 djm 256: level = SYSLOG_LEVEL_INFO;
1.13 markus 257:
258: if (authctxt->postponed)
259: authmsg = "Postponed";
1.98 djm 260: else if (partial)
261: authmsg = "Partial";
1.13 markus 262: else
263: authmsg = authenticated ? "Accepted" : "Failed";
264:
1.122 djm 265: if ((extra = format_method_key(authctxt)) == NULL) {
266: if (authctxt->auth_method_info != NULL)
267: extra = xstrdup(authctxt->auth_method_info);
268: }
269:
1.133 djm 270: do_log2(level, "%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
1.13 markus 271: authmsg,
272: method,
1.98 djm 273: submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
1.56 markus 274: authctxt->valid ? "" : "invalid user ",
1.29 markus 275: authctxt->user,
1.114 djm 276: ssh_remote_ipaddr(ssh),
277: ssh_remote_port(ssh),
1.122 djm 278: extra != NULL ? ": " : "",
279: extra != NULL ? extra : "");
280:
281: free(extra);
1.105 djm 282: }
283:
284: void
1.138 djm 285: auth_maxtries_exceeded(struct ssh *ssh)
1.105 djm 286: {
1.138 djm 287: Authctxt *authctxt = (Authctxt *)ssh->authctxt;
1.114 djm 288:
1.110 djm 289: error("maximum authentication attempts exceeded for "
1.116 markus 290: "%s%.100s from %.200s port %d ssh2",
1.105 djm 291: authctxt->valid ? "" : "invalid user ",
292: authctxt->user,
1.114 djm 293: ssh_remote_ipaddr(ssh),
1.116 markus 294: ssh_remote_port(ssh));
1.138 djm 295: ssh_packet_disconnect(ssh, "Too many authentication failures");
1.105 djm 296: /* NOTREACHED */
1.13 markus 297: }
298:
299: /*
1.17 markus 300: * Check whether root logins are disallowed.
1.13 markus 301: */
302: int
1.126 djm 303: auth_root_allowed(struct ssh *ssh, const char *method)
1.13 markus 304: {
1.17 markus 305: switch (options.permit_root_login) {
306: case PERMIT_YES:
1.13 markus 307: return 1;
1.17 markus 308: case PERMIT_NO_PASSWD:
1.112 deraadt 309: if (strcmp(method, "publickey") == 0 ||
310: strcmp(method, "hostbased") == 0 ||
1.113 djm 311: strcmp(method, "gssapi-with-mic") == 0)
1.17 markus 312: return 1;
313: break;
314: case PERMIT_FORCED_ONLY:
1.126 djm 315: if (auth_opts->force_command != NULL) {
1.47 itojun 316: logit("Root login accepted for forced command.");
1.17 markus 317: return 1;
318: }
319: break;
1.13 markus 320: }
1.114 djm 321: logit("ROOT LOGIN REFUSED FROM %.200s port %d",
322: ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.22 markus 323: return 0;
324: }
325:
326:
327: /*
328: * Given a template and a passwd structure, build a filename
329: * by substituting % tokenised options. Currently, %% becomes '%',
330: * %h becomes the home directory and %u the username.
331: *
332: * This returns a buffer allocated by xmalloc.
333: */
1.93 djm 334: char *
1.59 djm 335: expand_authorized_keys(const char *filename, struct passwd *pw)
1.22 markus 336: {
1.129 djm 337: char *file, uidstr[32], ret[PATH_MAX];
1.65 djm 338: int i;
1.22 markus 339:
1.129 djm 340: snprintf(uidstr, sizeof(uidstr), "%llu",
341: (unsigned long long)pw->pw_uid);
1.59 djm 342: file = percent_expand(filename, "h", pw->pw_dir,
1.129 djm 343: "u", pw->pw_name, "U", uidstr, (char *)NULL);
1.22 markus 344:
345: /*
346: * Ensure that filename starts anchored. If not, be backward
347: * compatible and prepend the '%h/'
348: */
1.134 djm 349: if (path_absolute(file))
1.59 djm 350: return (file);
351:
1.65 djm 352: i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
353: if (i < 0 || (size_t)i >= sizeof(ret))
1.59 djm 354: fatal("expand_authorized_keys: path too long");
1.102 djm 355: free(file);
1.65 djm 356: return (xstrdup(ret));
1.22 markus 357: }
1.24 markus 358:
1.87 djm 359: char *
360: authorized_principals_file(struct passwd *pw)
361: {
1.111 djm 362: if (options.authorized_principals_file == NULL)
1.87 djm 363: return NULL;
364: return expand_authorized_keys(options.authorized_principals_file, pw);
365: }
366:
1.24 markus 367: /* return ok if key exists in sysfile or userfile */
368: HostStatus
1.121 markus 369: check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host,
1.24 markus 370: const char *sysfile, const char *userfile)
371: {
372: char *user_hostfile;
373: struct stat st;
1.30 stevesk 374: HostStatus host_status;
1.91 djm 375: struct hostkeys *hostkeys;
376: const struct hostkey_entry *found;
1.24 markus 377:
1.91 djm 378: hostkeys = init_hostkeys();
1.150 djm 379: load_hostkeys(hostkeys, host, sysfile, 0);
1.91 djm 380: if (userfile != NULL) {
1.24 markus 381: user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
382: if (options.strict_modes &&
383: (stat(user_hostfile, &st) == 0) &&
384: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
1.31 deraadt 385: (st.st_mode & 022) != 0)) {
1.47 itojun 386: logit("Authentication refused for %.100s: "
1.24 markus 387: "bad owner or modes for %.200s",
388: pw->pw_name, user_hostfile);
1.88 djm 389: auth_debug_add("Ignored %.200s: bad ownership or modes",
390: user_hostfile);
1.24 markus 391: } else {
392: temporarily_use_uid(pw);
1.150 djm 393: load_hostkeys(hostkeys, host, user_hostfile, 0);
1.24 markus 394: restore_uid();
395: }
1.102 djm 396: free(user_hostfile);
1.24 markus 397: }
1.91 djm 398: host_status = check_key_in_hostkeys(hostkeys, key, &found);
399: if (host_status == HOST_REVOKED)
400: error("WARNING: revoked key for %s attempted authentication",
1.142 djm 401: host);
1.91 djm 402: else if (host_status == HOST_OK)
1.149 djm 403: debug_f("key for %s found at %s:%ld",
1.91 djm 404: found->host, found->file, found->line);
405: else
1.149 djm 406: debug_f("key for host %s not found", host);
1.91 djm 407:
408: free_hostkeys(hostkeys);
1.24 markus 409:
410: return host_status;
1.37 provos 411: }
412:
413: struct passwd *
1.138 djm 414: getpwnamallow(struct ssh *ssh, const char *user)
1.37 provos 415: {
1.38 provos 416: extern login_cap_t *lc;
417: auth_session_t *as;
1.37 provos 418: struct passwd *pw;
1.137 djm 419: struct connection_info *ci;
1.148 djm 420: u_int i;
1.71 dtucker 421:
1.161 ! djm 422: ci = server_get_connection_info(ssh, 1, options.use_dns);
1.96 dtucker 423: ci->user = user;
1.146 djm 424: parse_server_match_config(&options, &includes, ci);
1.120 djm 425: log_change_level(options.log_level);
1.148 djm 426: log_verbose_reset();
427: for (i = 0; i < options.num_log_verbose; i++)
428: log_verbose_add(options.log_verbose[i]);
1.161 ! djm 429: server_process_permitopen(ssh);
1.37 provos 430:
431: pw = getpwnam(user);
1.45 stevesk 432: if (pw == NULL) {
1.114 djm 433: logit("Invalid user %.100s from %.100s port %d",
434: user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1.45 stevesk 435: return (NULL);
436: }
1.138 djm 437: if (!allowed_user(ssh, pw))
1.38 provos 438: return (NULL);
439: if ((lc = login_getclass(pw->pw_class)) == NULL) {
440: debug("unable to get login class: %s", user);
441: return (NULL);
442: }
443: if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
1.43 millert 444: auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1.38 provos 445: debug("Approval failure for %s", user);
1.37 provos 446: pw = NULL;
1.38 provos 447: }
448: if (as != NULL)
449: auth_close(as);
1.41 markus 450: if (pw != NULL)
451: return (pwcopy(pw));
452: return (NULL);
1.85 djm 453: }
454:
455: /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
456: int
1.121 markus 457: auth_key_is_revoked(struct sshkey *key)
1.85 djm 458: {
1.107 djm 459: char *fp = NULL;
460: int r;
1.85 djm 461:
462: if (options.revoked_keys_file == NULL)
463: return 0;
1.108 djm 464: if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
465: SSH_FP_DEFAULT)) == NULL) {
1.107 djm 466: r = SSH_ERR_ALLOC_FAIL;
1.149 djm 467: error_fr(r, "fingerprint key");
1.107 djm 468: goto out;
469: }
470:
471: r = sshkey_check_revoked(key, options.revoked_keys_file);
472: switch (r) {
1.100 djm 473: case 0:
1.107 djm 474: break; /* not revoked */
475: case SSH_ERR_KEY_REVOKED:
476: error("Authentication key %s %s revoked by file %s",
477: sshkey_type(key), fp, options.revoked_keys_file);
478: goto out;
1.100 djm 479: default:
1.149 djm 480: error_r(r, "Error checking authentication key %s %s in "
481: "revoked keys file %s", sshkey_type(key), fp,
482: options.revoked_keys_file);
1.107 djm 483: goto out;
1.100 djm 484: }
1.107 djm 485:
486: /* Success */
487: r = 0;
488:
489: out:
490: free(fp);
491: return r == 0 ? 0 : 1;
1.42 markus 492: }
493:
494: void
495: auth_debug_add(const char *fmt,...)
496: {
497: char buf[1024];
498: va_list args;
1.131 markus 499: int r;
1.42 markus 500:
501: va_start(args, fmt);
502: vsnprintf(buf, sizeof(buf), fmt, args);
503: va_end(args);
1.159 dtucker 504: debug3("%s", buf);
505: if (auth_debug != NULL)
506: if ((r = sshbuf_put_cstring(auth_debug, buf)) != 0)
507: fatal_fr(r, "sshbuf_put_cstring");
1.42 markus 508: }
509:
510: void
1.138 djm 511: auth_debug_send(struct ssh *ssh)
1.42 markus 512: {
513: char *msg;
1.131 markus 514: int r;
1.42 markus 515:
1.131 markus 516: if (auth_debug == NULL)
1.42 markus 517: return;
1.131 markus 518: while (sshbuf_len(auth_debug) != 0) {
519: if ((r = sshbuf_get_cstring(auth_debug, &msg, NULL)) != 0)
1.149 djm 520: fatal_fr(r, "sshbuf_get_cstring");
1.131 markus 521: ssh_packet_send_debug(ssh, "%s", msg);
1.102 djm 522: free(msg);
1.42 markus 523: }
524: }
525:
526: void
527: auth_debug_reset(void)
528: {
1.131 markus 529: if (auth_debug != NULL)
530: sshbuf_reset(auth_debug);
531: else if ((auth_debug = sshbuf_new()) == NULL)
1.149 djm 532: fatal_f("sshbuf_new failed");
1.49 markus 533: }
534:
535: struct passwd *
536: fakepw(void)
537: {
1.154 djm 538: static int done = 0;
1.49 markus 539: static struct passwd fake;
1.154 djm 540: const char hashchars[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZ"
541: "abcdefghijklmnopqrstuvwxyz0123456789"; /* from bcrypt.c */
542: char *cp;
543:
544: if (done)
545: return (&fake);
1.49 markus 546:
547: memset(&fake, 0, sizeof(fake));
548: fake.pw_name = "NOUSER";
1.154 djm 549: fake.pw_passwd = xstrdup("$2a$10$"
550: "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
551: for (cp = fake.pw_passwd + 7; *cp != '\0'; cp++)
552: *cp = hashchars[arc4random_uniform(sizeof(hashchars) - 1)];
1.49 markus 553: fake.pw_gecos = "NOUSER";
1.53 deraadt 554: fake.pw_uid = (uid_t)-1;
555: fake.pw_gid = (gid_t)-1;
1.49 markus 556: fake.pw_class = "";
557: fake.pw_dir = "/nonexist";
558: fake.pw_shell = "/nonexist";
1.154 djm 559: done = 1;
1.49 markus 560:
561: return (&fake);
1.114 djm 562: }
563:
564: /*
565: * Return the canonical name of the host in the other side of the current
566: * connection. The host name is cached, so it is efficient to call this
567: * several times.
568: */
569:
570: const char *
571: auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
572: {
573: static char *dnsname;
574:
575: if (!use_dns)
576: return ssh_remote_ipaddr(ssh);
1.161 ! djm 577: if (dnsname != NULL)
1.114 djm 578: return dnsname;
1.161 ! djm 579: dnsname = ssh_remote_hostname(ssh);
! 580: return dnsname;
1.126 djm 581: }
582:
583: /* These functions link key/cert options to the auth framework */
584:
585: /* Log sshauthopt options locally and (optionally) for remote transmission */
586: void
587: auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote)
588: {
589: int do_env = options.permit_user_env && opts->nenv > 0;
590: int do_permitopen = opts->npermitopen > 0 &&
591: (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0;
1.130 djm 592: int do_permitlisten = opts->npermitlisten > 0 &&
593: (options.allow_tcp_forwarding & FORWARD_REMOTE) != 0;
1.126 djm 594: size_t i;
1.127 djm 595: char msg[1024], buf[64];
1.126 djm 596:
1.127 djm 597: snprintf(buf, sizeof(buf), "%d", opts->force_tun_device);
1.126 djm 598: /* Try to keep this alphabetically sorted */
1.147 djm 599: snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
1.126 djm 600: opts->permit_agent_forwarding_flag ? " agent-forwarding" : "",
601: opts->force_command == NULL ? "" : " command",
602: do_env ? " environment" : "",
1.127 djm 603: opts->valid_before == 0 ? "" : "expires",
1.147 djm 604: opts->no_require_user_presence ? " no-touch-required" : "",
1.126 djm 605: do_permitopen ? " permitopen" : "",
1.130 djm 606: do_permitlisten ? " permitlisten" : "",
1.126 djm 607: opts->permit_port_forwarding_flag ? " port-forwarding" : "",
608: opts->cert_principals == NULL ? "" : " principals",
609: opts->permit_pty_flag ? " pty" : "",
1.147 djm 610: opts->require_verify ? " uv" : "",
1.126 djm 611: opts->force_tun_device == -1 ? "" : " tun=",
1.127 djm 612: opts->force_tun_device == -1 ? "" : buf,
1.126 djm 613: opts->permit_user_rc ? " user-rc" : "",
1.147 djm 614: opts->permit_x11_forwarding_flag ? " x11-forwarding" : "");
1.126 djm 615:
616: debug("%s: %s", loc, msg);
617: if (do_remote)
618: auth_debug_add("%s: %s", loc, msg);
619:
620: if (options.permit_user_env) {
621: for (i = 0; i < opts->nenv; i++) {
622: debug("%s: environment: %s", loc, opts->env[i]);
623: if (do_remote) {
624: auth_debug_add("%s: environment: %s",
625: loc, opts->env[i]);
626: }
627: }
628: }
629:
630: /* Go into a little more details for the local logs. */
1.127 djm 631: if (opts->valid_before != 0) {
632: format_absolute_time(opts->valid_before, buf, sizeof(buf));
633: debug("%s: expires at %s", loc, buf);
634: }
1.126 djm 635: if (opts->cert_principals != NULL) {
636: debug("%s: authorized principals: \"%s\"",
637: loc, opts->cert_principals);
638: }
639: if (opts->force_command != NULL)
640: debug("%s: forced command: \"%s\"", loc, opts->force_command);
1.130 djm 641: if (do_permitopen) {
1.126 djm 642: for (i = 0; i < opts->npermitopen; i++) {
643: debug("%s: permitted open: %s",
644: loc, opts->permitopen[i]);
1.130 djm 645: }
646: }
647: if (do_permitlisten) {
648: for (i = 0; i < opts->npermitlisten; i++) {
649: debug("%s: permitted listen: %s",
650: loc, opts->permitlisten[i]);
1.126 djm 651: }
652: }
653: }
654:
655: /* Activate a new set of key/cert options; merging with what is there. */
656: int
657: auth_activate_options(struct ssh *ssh, struct sshauthopt *opts)
658: {
659: struct sshauthopt *old = auth_opts;
660: const char *emsg = NULL;
661:
1.149 djm 662: debug_f("setting new authentication options");
1.126 djm 663: if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) {
664: error("Inconsistent authentication options: %s", emsg);
665: return -1;
666: }
667: return 0;
668: }
669:
670: /* Disable forwarding, etc for the session */
671: void
672: auth_restrict_session(struct ssh *ssh)
673: {
674: struct sshauthopt *restricted;
675:
1.149 djm 676: debug_f("restricting session");
1.126 djm 677:
678: /* A blank sshauthopt defaults to permitting nothing */
1.155 dtucker 679: if ((restricted = sshauthopt_new()) == NULL)
680: fatal_f("sshauthopt_new failed");
1.128 djm 681: restricted->permit_pty_flag = 1;
1.126 djm 682: restricted->restricted = 1;
683:
684: if (auth_activate_options(ssh, restricted) != 0)
1.149 djm 685: fatal_f("failed to restrict session");
1.126 djm 686: sshauthopt_free(restricted);
1.1 markus 687: }
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