Annotation of src/usr.bin/ssh/auth2.c, Revision 1.58
1.1 markus 1: /*
2: * Copyright (c) 2000 Markus Friedl. All rights reserved.
3: *
4: * Redistribution and use in source and binary forms, with or without
5: * modification, are permitted provided that the following conditions
6: * are met:
7: * 1. Redistributions of source code must retain the above copyright
8: * notice, this list of conditions and the following disclaimer.
9: * 2. Redistributions in binary form must reproduce the above copyright
10: * notice, this list of conditions and the following disclaimer in the
11: * documentation and/or other materials provided with the distribution.
12: *
13: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: */
1.14 deraadt 24:
1.1 markus 25: #include "includes.h"
1.58 ! markus 26: RCSID("$OpenBSD: auth2.c,v 1.57 2001/05/18 14:13:28 markus Exp $");
1.1 markus 27:
28: #include <openssl/evp.h>
29:
1.32 markus 30: #include "ssh2.h"
1.1 markus 31: #include "xmalloc.h"
32: #include "rsa.h"
1.45 djm 33: #include "sshpty.h"
1.1 markus 34: #include "packet.h"
35: #include "buffer.h"
1.32 markus 36: #include "log.h"
1.1 markus 37: #include "servconf.h"
38: #include "compat.h"
39: #include "channels.h"
40: #include "bufaux.h"
41: #include "auth.h"
42: #include "session.h"
43: #include "dispatch.h"
44: #include "key.h"
1.32 markus 45: #include "cipher.h"
46: #include "kex.h"
1.29 markus 47: #include "pathnames.h"
1.1 markus 48: #include "uidswap.h"
1.10 markus 49: #include "auth-options.h"
1.43 markus 50: #include "misc.h"
1.52 markus 51: #include "hostfile.h"
52: #include "canohost.h"
53: #include "tildexpand.h"
1.57 markus 54: #include "match.h"
1.1 markus 55:
56: /* import */
57: extern ServerOptions options;
1.23 markus 58: extern u_char *session_id2;
1.1 markus 59: extern int session_id2_len;
60:
1.18 markus 61: static Authctxt *x_authctxt = NULL;
62: static int one = 1;
63:
64: typedef struct Authmethod Authmethod;
65: struct Authmethod {
66: char *name;
67: int (*userauth)(Authctxt *authctxt);
68: int *enabled;
69: };
70:
1.1 markus 71: /* protocol */
72:
1.15 markus 73: void input_service_request(int type, int plen, void *ctxt);
74: void input_userauth_request(int type, int plen, void *ctxt);
75: void protocol_error(int type, int plen, void *ctxt);
1.1 markus 76:
77: /* helper */
1.18 markus 78: Authmethod *authmethod_lookup(const char *name);
1.52 markus 79: char *authmethods_get(void);
1.21 markus 80: int user_key_allowed(struct passwd *pw, Key *key);
1.52 markus 81: int
1.54 markus 82: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
1.52 markus 83: Key *key);
1.1 markus 84:
1.18 markus 85: /* auth */
1.25 markus 86: void userauth_banner(void);
1.49 markus 87: void userauth_reply(Authctxt *authctxt, int authenticated);
1.18 markus 88: int userauth_none(Authctxt *authctxt);
89: int userauth_passwd(Authctxt *authctxt);
90: int userauth_pubkey(Authctxt *authctxt);
1.52 markus 91: int userauth_hostbased(Authctxt *authctxt);
1.18 markus 92: int userauth_kbdint(Authctxt *authctxt);
93:
94: Authmethod authmethods[] = {
95: {"none",
96: userauth_none,
97: &one},
98: {"publickey",
99: userauth_pubkey,
1.21 markus 100: &options.pubkey_authentication},
1.40 markus 101: {"password",
102: userauth_passwd,
103: &options.password_authentication},
1.18 markus 104: {"keyboard-interactive",
105: userauth_kbdint,
106: &options.kbd_interactive_authentication},
1.52 markus 107: {"hostbased",
108: userauth_hostbased,
109: &options.hostbased_authentication},
1.18 markus 110: {NULL, NULL, NULL}
1.1 markus 111: };
112:
113: /*
1.18 markus 114: * loop until authctxt->success == TRUE
1.1 markus 115: */
116:
117: void
118: do_authentication2()
119: {
1.28 markus 120: Authctxt *authctxt = authctxt_new();
121:
1.18 markus 122: x_authctxt = authctxt; /*XXX*/
123:
1.34 markus 124: /* challenge-reponse is implemented via keyboard interactive */
1.57 markus 125: if (options.challenge_response_authentication)
1.34 markus 126: options.kbd_interactive_authentication = 1;
127:
1.1 markus 128: dispatch_init(&protocol_error);
129: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 130: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.48 markus 131: do_authenticated(authctxt);
1.1 markus 132: }
133:
134: void
1.15 markus 135: protocol_error(int type, int plen, void *ctxt)
1.1 markus 136: {
137: log("auth: protocol error: type %d plen %d", type, plen);
138: packet_start(SSH2_MSG_UNIMPLEMENTED);
139: packet_put_int(0);
140: packet_send();
141: packet_write_wait();
142: }
143:
144: void
1.15 markus 145: input_service_request(int type, int plen, void *ctxt)
1.1 markus 146: {
1.18 markus 147: Authctxt *authctxt = ctxt;
1.23 markus 148: u_int len;
1.1 markus 149: int accept = 0;
150: char *service = packet_get_string(&len);
151: packet_done();
152:
1.18 markus 153: if (authctxt == NULL)
154: fatal("input_service_request: no authctxt");
155:
1.1 markus 156: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 157: if (!authctxt->success) {
1.1 markus 158: accept = 1;
159: /* now we can handle user-auth requests */
160: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
161: }
162: }
163: /* XXX all other service requests are denied */
164:
165: if (accept) {
166: packet_start(SSH2_MSG_SERVICE_ACCEPT);
167: packet_put_cstring(service);
168: packet_send();
169: packet_write_wait();
170: } else {
171: debug("bad service request %s", service);
172: packet_disconnect("bad service request %s", service);
173: }
174: xfree(service);
175: }
176:
177: void
1.15 markus 178: input_userauth_request(int type, int plen, void *ctxt)
1.1 markus 179: {
1.18 markus 180: Authctxt *authctxt = ctxt;
181: Authmethod *m = NULL;
1.28 markus 182: char *user, *service, *method, *style = NULL;
1.1 markus 183: int authenticated = 0;
184:
1.18 markus 185: if (authctxt == NULL)
186: fatal("input_userauth_request: no authctxt");
1.1 markus 187:
1.18 markus 188: user = packet_get_string(NULL);
189: service = packet_get_string(NULL);
190: method = packet_get_string(NULL);
1.1 markus 191: debug("userauth-request for user %s service %s method %s", user, service, method);
1.24 markus 192: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
1.1 markus 193:
1.28 markus 194: if ((style = strchr(user, ':')) != NULL)
195: *style++ = 0;
196:
1.36 stevesk 197: if (authctxt->attempt++ == 0) {
1.18 markus 198: /* setup auth context */
199: struct passwd *pw = NULL;
200: pw = getpwnam(user);
201: if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
202: authctxt->pw = pwcopy(pw);
203: authctxt->valid = 1;
204: debug2("input_userauth_request: setting up authctxt for %s", user);
205: } else {
206: log("input_userauth_request: illegal user %s", user);
207: }
1.42 markus 208: setproctitle("%s", pw ? user : "unknown");
1.18 markus 209: authctxt->user = xstrdup(user);
210: authctxt->service = xstrdup(service);
1.28 markus 211: authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */
1.18 markus 212: } else if (authctxt->valid) {
213: if (strcmp(user, authctxt->user) != 0 ||
214: strcmp(service, authctxt->service) != 0) {
1.52 markus 215: log("input_userauth_request: mismatch: (%s,%s)!=(%s,%s)",
1.18 markus 216: user, service, authctxt->user, authctxt->service);
217: authctxt->valid = 0;
1.1 markus 218: }
219: }
1.28 markus 220: /* reset state */
221: dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error);
222: authctxt->postponed = 0;
1.47 markus 223: #ifdef BSD_AUTH
224: if (authctxt->as) {
225: auth_close(authctxt->as);
226: authctxt->as = NULL;
227: }
228: #endif
1.18 markus 229:
1.28 markus 230: /* try to authenticate user */
1.18 markus 231: m = authmethod_lookup(method);
232: if (m != NULL) {
233: debug2("input_userauth_request: try method %s", method);
234: authenticated = m->userauth(authctxt);
235: }
1.49 markus 236: userauth_finish(authctxt, authenticated, method);
237:
238: xfree(service);
239: xfree(user);
240: xfree(method);
241: }
242:
243: void
244: userauth_finish(Authctxt *authctxt, int authenticated, char *method)
245: {
1.28 markus 246: if (!authctxt->valid && authenticated)
247: fatal("INTERNAL ERROR: authenticated invalid user %s",
248: authctxt->user);
1.18 markus 249:
250: /* Special handling for root */
1.41 markus 251: if (authenticated && authctxt->pw->pw_uid == 0 &&
252: !auth_root_allowed(method))
1.3 markus 253: authenticated = 0;
254:
1.18 markus 255: /* Log before sending the reply */
1.28 markus 256: auth_log(authctxt, authenticated, method, " ssh2");
257:
258: if (!authctxt->postponed)
259: userauth_reply(authctxt, authenticated);
1.18 markus 260: }
261:
1.25 markus 262: void
263: userauth_banner(void)
264: {
265: struct stat st;
266: char *banner = NULL;
267: off_t len, n;
268: int fd;
269:
270: if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
271: return;
1.50 markus 272: if ((fd = open(options.banner, O_RDONLY)) < 0)
1.25 markus 273: return;
274: if (fstat(fd, &st) < 0)
275: goto done;
276: len = st.st_size;
277: banner = xmalloc(len + 1);
278: if ((n = read(fd, banner, len)) < 0)
279: goto done;
280: banner[n] = '\0';
281: packet_start(SSH2_MSG_USERAUTH_BANNER);
282: packet_put_cstring(banner);
283: packet_put_cstring(""); /* language, unused */
284: packet_send();
285: debug("userauth_banner: sent");
286: done:
287: if (banner)
288: xfree(banner);
289: close(fd);
290: return;
291: }
1.18 markus 292:
1.36 stevesk 293: void
1.18 markus 294: userauth_reply(Authctxt *authctxt, int authenticated)
295: {
1.24 markus 296: char *methods;
1.28 markus 297:
1.3 markus 298: /* XXX todo: check if multiple auth methods are needed */
1.39 markus 299: if (authenticated == 1) {
1.1 markus 300: /* turn off userauth */
301: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
302: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
303: packet_send();
304: packet_write_wait();
305: /* now we can break out */
1.18 markus 306: authctxt->success = 1;
1.28 markus 307: } else {
308: if (authctxt->failures++ > AUTH_FAIL_MAX)
1.36 stevesk 309: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
1.24 markus 310: methods = authmethods_get();
1.1 markus 311: packet_start(SSH2_MSG_USERAUTH_FAILURE);
1.18 markus 312: packet_put_cstring(methods);
313: packet_put_char(0); /* XXX partial success, unused */
1.1 markus 314: packet_send();
315: packet_write_wait();
1.18 markus 316: xfree(methods);
1.1 markus 317: }
318: }
319:
320: int
1.18 markus 321: userauth_none(Authctxt *authctxt)
1.1 markus 322: {
1.18 markus 323: /* disable method "none", only allowed one time */
324: Authmethod *m = authmethod_lookup("none");
325: if (m != NULL)
326: m->enabled = NULL;
1.1 markus 327: packet_done();
1.25 markus 328: userauth_banner();
1.47 markus 329: return authctxt->valid ? auth_password(authctxt, "") : 0;
1.1 markus 330: }
1.18 markus 331:
1.1 markus 332: int
1.18 markus 333: userauth_passwd(Authctxt *authctxt)
1.1 markus 334: {
335: char *password;
336: int authenticated = 0;
337: int change;
1.23 markus 338: u_int len;
1.1 markus 339: change = packet_get_char();
340: if (change)
341: log("password change not supported");
342: password = packet_get_string(&len);
343: packet_done();
1.18 markus 344: if (authctxt->valid &&
1.47 markus 345: auth_password(authctxt, password) == 1)
1.1 markus 346: authenticated = 1;
347: memset(password, 0, len);
348: xfree(password);
349: return authenticated;
350: }
1.18 markus 351:
352: int
353: userauth_kbdint(Authctxt *authctxt)
354: {
355: int authenticated = 0;
1.57 markus 356: char *lang, *devs;
357:
1.18 markus 358: lang = packet_get_string(NULL);
359: devs = packet_get_string(NULL);
360: packet_done();
361:
1.57 markus 362: debug("keyboard-interactive devs %s", devs);
1.28 markus 363:
1.57 markus 364: if (options.challenge_response_authentication)
1.34 markus 365: authenticated = auth2_challenge(authctxt, devs);
1.28 markus 366:
1.57 markus 367: xfree(devs);
1.18 markus 368: xfree(lang);
369: return authenticated;
370: }
371:
1.1 markus 372: int
1.18 markus 373: userauth_pubkey(Authctxt *authctxt)
1.1 markus 374: {
375: Buffer b;
376: Key *key;
377: char *pkalg, *pkblob, *sig;
1.23 markus 378: u_int alen, blen, slen;
1.21 markus 379: int have_sig, pktype;
1.1 markus 380: int authenticated = 0;
381:
1.18 markus 382: if (!authctxt->valid) {
383: debug2("userauth_pubkey: disabled because of invalid user");
1.8 markus 384: return 0;
385: }
1.1 markus 386: have_sig = packet_get_char();
1.22 markus 387: if (datafellows & SSH_BUG_PKAUTH) {
388: debug2("userauth_pubkey: SSH_BUG_PKAUTH");
389: /* no explicit pkalg given */
390: pkblob = packet_get_string(&blen);
391: buffer_init(&b);
392: buffer_append(&b, pkblob, blen);
393: /* so we have to extract the pkalg from the pkblob */
394: pkalg = buffer_get_string(&b, &alen);
395: buffer_free(&b);
396: } else {
397: pkalg = packet_get_string(&alen);
398: pkblob = packet_get_string(&blen);
399: }
1.21 markus 400: pktype = key_type_from_name(pkalg);
401: if (pktype == KEY_UNSPEC) {
1.22 markus 402: /* this is perfectly legal */
403: log("userauth_pubkey: unsupported public key algorithm: %s", pkalg);
1.1 markus 404: xfree(pkalg);
1.22 markus 405: xfree(pkblob);
1.1 markus 406: return 0;
407: }
1.21 markus 408: key = key_from_blob(pkblob, blen);
1.2 markus 409: if (key != NULL) {
410: if (have_sig) {
411: sig = packet_get_string(&slen);
412: packet_done();
413: buffer_init(&b);
1.20 markus 414: if (datafellows & SSH_OLD_SESSIONID) {
415: buffer_append(&b, session_id2, session_id2_len);
416: } else {
1.11 markus 417: buffer_put_string(&b, session_id2, session_id2_len);
418: }
1.9 markus 419: /* reconstruct packet */
1.2 markus 420: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.18 markus 421: buffer_put_cstring(&b, authctxt->user);
1.9 markus 422: buffer_put_cstring(&b,
1.22 markus 423: datafellows & SSH_BUG_PKSERVICE ?
1.9 markus 424: "ssh-userauth" :
1.18 markus 425: authctxt->service);
1.22 markus 426: if (datafellows & SSH_BUG_PKAUTH) {
427: buffer_put_char(&b, have_sig);
428: } else {
429: buffer_put_cstring(&b, "publickey");
430: buffer_put_char(&b, have_sig);
1.56 markus 431: buffer_put_cstring(&b, pkalg);
1.22 markus 432: }
1.9 markus 433: buffer_put_string(&b, pkblob, blen);
1.21 markus 434: #ifdef DEBUG_PK
1.2 markus 435: buffer_dump(&b);
1.1 markus 436: #endif
1.2 markus 437: /* test for correct signature */
1.21 markus 438: if (user_key_allowed(authctxt->pw, key) &&
439: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
1.2 markus 440: authenticated = 1;
441: buffer_clear(&b);
442: xfree(sig);
443: } else {
1.18 markus 444: debug("test whether pkalg/pkblob are acceptable");
1.2 markus 445: packet_done();
1.18 markus 446:
1.2 markus 447: /* XXX fake reply and always send PK_OK ? */
1.6 markus 448: /*
449: * XXX this allows testing whether a user is allowed
450: * to login: if you happen to have a valid pubkey this
451: * message is sent. the message is NEVER sent at all
452: * if a user is not allowed to login. is this an
453: * issue? -markus
454: */
1.21 markus 455: if (user_key_allowed(authctxt->pw, key)) {
1.2 markus 456: packet_start(SSH2_MSG_USERAUTH_PK_OK);
457: packet_put_string(pkalg, alen);
458: packet_put_string(pkblob, blen);
459: packet_send();
460: packet_write_wait();
1.38 markus 461: authctxt->postponed = 1;
1.2 markus 462: }
1.1 markus 463: }
1.17 markus 464: if (authenticated != 1)
465: auth_clear_options();
1.2 markus 466: key_free(key);
1.1 markus 467: }
1.21 markus 468: debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
1.1 markus 469: xfree(pkalg);
470: xfree(pkblob);
471: return authenticated;
472: }
473:
1.52 markus 474: int
475: userauth_hostbased(Authctxt *authctxt)
476: {
477: Buffer b;
478: Key *key;
1.55 markus 479: char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
1.52 markus 480: u_int alen, blen, slen;
481: int pktype;
482: int authenticated = 0;
483:
484: if (!authctxt->valid) {
485: debug2("userauth_hostbased: disabled because of invalid user");
486: return 0;
487: }
488: pkalg = packet_get_string(&alen);
489: pkblob = packet_get_string(&blen);
490: chost = packet_get_string(NULL);
491: cuser = packet_get_string(NULL);
492: sig = packet_get_string(&slen);
493:
494: debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
495: cuser, chost, pkalg, slen);
496: #ifdef DEBUG_PK
497: debug("signature:");
498: buffer_init(&b);
499: buffer_append(&b, sig, slen);
500: buffer_dump(&b);
501: buffer_free(&b);
502: #endif
503: pktype = key_type_from_name(pkalg);
504: if (pktype == KEY_UNSPEC) {
505: /* this is perfectly legal */
506: log("userauth_hostbased: unsupported "
507: "public key algorithm: %s", pkalg);
508: goto done;
509: }
510: key = key_from_blob(pkblob, blen);
511: if (key == NULL) {
512: debug("userauth_hostbased: cannot decode key: %s", pkalg);
513: goto done;
514: }
1.55 markus 515: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
516: authctxt->service;
1.52 markus 517: buffer_init(&b);
1.55 markus 518: buffer_put_string(&b, session_id2, session_id2_len);
1.52 markus 519: /* reconstruct packet */
520: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
521: buffer_put_cstring(&b, authctxt->user);
1.55 markus 522: buffer_put_cstring(&b, service);
1.52 markus 523: buffer_put_cstring(&b, "hostbased");
524: buffer_put_string(&b, pkalg, alen);
525: buffer_put_string(&b, pkblob, blen);
526: buffer_put_cstring(&b, chost);
527: buffer_put_cstring(&b, cuser);
528: #ifdef DEBUG_PK
529: buffer_dump(&b);
530: #endif
531: /* test for allowed key and correct signature */
532: if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
533: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
534: authenticated = 1;
535:
536: buffer_clear(&b);
537: key_free(key);
538:
539: done:
540: debug2("userauth_hostbased: authenticated %d", authenticated);
541: xfree(pkalg);
542: xfree(pkblob);
543: xfree(cuser);
544: xfree(chost);
545: xfree(sig);
546: return authenticated;
547: }
548:
1.18 markus 549: /* get current user */
1.1 markus 550:
551: struct passwd*
552: auth_get_user(void)
553: {
1.18 markus 554: return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
1.1 markus 555: }
556:
1.18 markus 557: #define DELIM ","
558:
559: char *
560: authmethods_get(void)
1.1 markus 561: {
1.18 markus 562: Authmethod *method = NULL;
1.23 markus 563: u_int size = 0;
1.18 markus 564: char *list;
1.1 markus 565:
1.18 markus 566: for (method = authmethods; method->name != NULL; method++) {
567: if (strcmp(method->name, "none") == 0)
568: continue;
569: if (method->enabled != NULL && *(method->enabled) != 0) {
570: if (size != 0)
571: size += strlen(DELIM);
572: size += strlen(method->name);
1.1 markus 573: }
1.18 markus 574: }
575: size++; /* trailing '\0' */
576: list = xmalloc(size);
577: list[0] = '\0';
578:
579: for (method = authmethods; method->name != NULL; method++) {
580: if (strcmp(method->name, "none") == 0)
581: continue;
582: if (method->enabled != NULL && *(method->enabled) != 0) {
583: if (list[0] != '\0')
584: strlcat(list, DELIM, size);
585: strlcat(list, method->name, size);
1.1 markus 586: }
587: }
1.18 markus 588: return list;
589: }
590:
591: Authmethod *
592: authmethod_lookup(const char *name)
593: {
594: Authmethod *method = NULL;
595: if (name != NULL)
596: for (method = authmethods; method->name != NULL; method++)
597: if (method->enabled != NULL &&
598: *(method->enabled) != 0 &&
599: strcmp(name, method->name) == 0)
600: return method;
601: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
602: return NULL;
1.1 markus 603: }
604:
605: /* return 1 if user allows given key */
606: int
1.21 markus 607: user_key_allowed(struct passwd *pw, Key *key)
1.1 markus 608: {
1.58 ! markus 609: char line[8192], *file;
1.1 markus 610: int found_key = 0;
611: FILE *f;
1.23 markus 612: u_long linenum = 0;
1.1 markus 613: struct stat st;
614: Key *found;
615:
1.18 markus 616: if (pw == NULL)
617: return 0;
618:
1.1 markus 619: /* Temporarily use the user's uid. */
1.51 markus 620: temporarily_use_uid(pw);
1.1 markus 621:
622: /* The authorized keys. */
1.58 ! markus 623: file = authorized_keys_file2(pw);
! 624: debug("trying public key file %s", file);
1.1 markus 625:
626: /* Fail quietly if file does not exist */
627: if (stat(file, &st) < 0) {
628: /* Restore the privileged uid. */
629: restore_uid();
1.58 ! markus 630: xfree(file);
1.1 markus 631: return 0;
632: }
633: /* Open the file containing the authorized keys. */
634: f = fopen(file, "r");
635: if (!f) {
636: /* Restore the privileged uid. */
637: restore_uid();
1.58 ! markus 638: xfree(file);
1.1 markus 639: return 0;
640: }
1.58 ! markus 641: if (options.strict_modes &&
! 642: secure_filename(f, file, pw->pw_uid, line, sizeof(line)) != 0) {
! 643: xfree(file);
! 644: fclose(f);
! 645: log("Authentication refused: %s", line);
! 646: restore_uid();
! 647: return 0;
1.1 markus 648: }
1.58 ! markus 649:
1.1 markus 650: found_key = 0;
1.16 markus 651: found = key_new(key->type);
1.1 markus 652:
653: while (fgets(line, sizeof(line), f)) {
1.10 markus 654: char *cp, *options = NULL;
1.1 markus 655: linenum++;
656: /* Skip leading whitespace, empty and comment lines. */
657: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
658: ;
659: if (!*cp || *cp == '\n' || *cp == '#')
660: continue;
1.10 markus 661:
1.21 markus 662: if (key_read(found, &cp) == -1) {
1.10 markus 663: /* no key? check if there are options for this key */
664: int quoted = 0;
1.21 markus 665: debug2("user_key_allowed: check options: '%s'", cp);
1.10 markus 666: options = cp;
667: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
668: if (*cp == '\\' && cp[1] == '"')
669: cp++; /* Skip both */
670: else if (*cp == '"')
671: quoted = !quoted;
672: }
673: /* Skip remaining whitespace. */
674: for (; *cp == ' ' || *cp == '\t'; cp++)
675: ;
1.21 markus 676: if (key_read(found, &cp) == -1) {
677: debug2("user_key_allowed: advance: '%s'", cp);
1.10 markus 678: /* still no key? advance to next line*/
679: continue;
680: }
681: }
682: if (key_equal(found, key) &&
1.30 markus 683: auth_parse_options(pw, options, file, linenum) == 1) {
1.1 markus 684: found_key = 1;
685: debug("matching key found: file %s, line %ld",
686: file, linenum);
687: break;
688: }
689: }
690: restore_uid();
691: fclose(f);
1.58 ! markus 692: xfree(file);
1.1 markus 693: key_free(found);
1.46 markus 694: if (!found_key)
695: debug2("key not found");
1.1 markus 696: return found_key;
1.52 markus 697: }
698:
699: /* return 1 if given hostkey is allowed */
700: int
1.54 markus 701: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
1.52 markus 702: Key *key)
703: {
704: Key *found;
705: const char *resolvedname, *ipaddr, *lookup;
706: struct stat st;
707: char *user_hostfile;
1.53 markus 708: int host_status, len;
1.52 markus 709:
710: resolvedname = get_canonical_hostname(options.reverse_mapping_check);
711: ipaddr = get_remote_ipaddr();
712:
1.53 markus 713: debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
714: chost, resolvedname, ipaddr);
1.52 markus 715:
716: if (options.hostbased_uses_name_from_packet_only) {
717: if (auth_rhosts2(pw, cuser, chost, chost) == 0)
718: return 0;
719: lookup = chost;
720: } else {
1.53 markus 721: if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
722: debug2("stripping trailing dot from chost %s", chost);
723: chost[len - 1] = '\0';
724: }
1.52 markus 725: if (strcasecmp(resolvedname, chost) != 0)
726: log("userauth_hostbased mismatch: "
727: "client sends %s, but we resolve %s to %s",
728: chost, ipaddr, resolvedname);
729: if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
730: return 0;
731: lookup = resolvedname;
732: }
733: debug2("userauth_hostbased: access allowed by auth_rhosts2");
734:
735: /* XXX this is copied from auth-rh-rsa.c and should be shared */
736: found = key_new(key->type);
737: host_status = check_host_in_hostfile(_PATH_SSH_SYSTEM_HOSTFILE2, lookup,
738: key, found, NULL);
739:
740: if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
741: user_hostfile = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE2,
742: pw->pw_uid);
743: if (options.strict_modes &&
744: (stat(user_hostfile, &st) == 0) &&
745: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
746: (st.st_mode & 022) != 0)) {
747: log("Hostbased authentication refused for %.100s: "
748: "bad owner or modes for %.200s",
749: pw->pw_name, user_hostfile);
750: } else {
751: temporarily_use_uid(pw);
752: host_status = check_host_in_hostfile(user_hostfile,
753: lookup, key, found, NULL);
754: restore_uid();
755: }
756: xfree(user_hostfile);
757: }
758: key_free(found);
759:
760: debug2("userauth_hostbased: key %s for %s", host_status == HOST_OK ?
761: "ok" : "not found", lookup);
762: return (host_status == HOST_OK);
1.1 markus 763: }
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