Annotation of src/usr.bin/ssh/auth2.c, Revision 1.66
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"
1.66 ! itojun 26: RCSID("$OpenBSD: auth2.c,v 1.65 2001/06/23 03:04:43 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"
1.61 markus 39: #include "channels.h"
1.1 markus 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:
1.66 ! itojun 73: static void input_service_request(int, int, void *);
! 74: static void input_userauth_request(int, int, void *);
! 75: static void protocol_error(int, int, void *);
1.1 markus 76:
77: /* helper */
1.66 ! itojun 78: static Authmethod *authmethod_lookup(const char *);
! 79: char *authmethods_get(void);
! 80: static int user_key_allowed(struct passwd *, Key *);
! 81: static int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
1.1 markus 82:
1.18 markus 83: /* auth */
1.66 ! itojun 84: static void userauth_banner(void);
! 85: static int userauth_none(Authctxt *);
! 86: static int userauth_passwd(Authctxt *);
! 87: static int userauth_pubkey(Authctxt *);
! 88: static int userauth_hostbased(Authctxt *);
! 89: static int userauth_kbdint(Authctxt *);
1.18 markus 90:
91: Authmethod authmethods[] = {
92: {"none",
93: userauth_none,
94: &one},
95: {"publickey",
96: userauth_pubkey,
1.21 markus 97: &options.pubkey_authentication},
1.40 markus 98: {"password",
99: userauth_passwd,
100: &options.password_authentication},
1.18 markus 101: {"keyboard-interactive",
102: userauth_kbdint,
103: &options.kbd_interactive_authentication},
1.52 markus 104: {"hostbased",
105: userauth_hostbased,
106: &options.hostbased_authentication},
1.18 markus 107: {NULL, NULL, NULL}
1.1 markus 108: };
109:
110: /*
1.18 markus 111: * loop until authctxt->success == TRUE
1.1 markus 112: */
113:
114: void
115: do_authentication2()
116: {
1.28 markus 117: Authctxt *authctxt = authctxt_new();
118:
1.18 markus 119: x_authctxt = authctxt; /*XXX*/
120:
1.34 markus 121: /* challenge-reponse is implemented via keyboard interactive */
1.57 markus 122: if (options.challenge_response_authentication)
1.34 markus 123: options.kbd_interactive_authentication = 1;
124:
1.1 markus 125: dispatch_init(&protocol_error);
126: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 127: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.48 markus 128: do_authenticated(authctxt);
1.1 markus 129: }
130:
1.66 ! itojun 131: static void
1.15 markus 132: protocol_error(int type, int plen, void *ctxt)
1.1 markus 133: {
134: log("auth: protocol error: type %d plen %d", type, plen);
135: packet_start(SSH2_MSG_UNIMPLEMENTED);
136: packet_put_int(0);
137: packet_send();
138: packet_write_wait();
139: }
140:
1.66 ! itojun 141: static void
1.15 markus 142: input_service_request(int type, int plen, void *ctxt)
1.1 markus 143: {
1.18 markus 144: Authctxt *authctxt = ctxt;
1.23 markus 145: u_int len;
1.1 markus 146: int accept = 0;
147: char *service = packet_get_string(&len);
148: packet_done();
149:
1.18 markus 150: if (authctxt == NULL)
151: fatal("input_service_request: no authctxt");
152:
1.1 markus 153: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 154: if (!authctxt->success) {
1.1 markus 155: accept = 1;
156: /* now we can handle user-auth requests */
157: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
158: }
159: }
160: /* XXX all other service requests are denied */
161:
162: if (accept) {
163: packet_start(SSH2_MSG_SERVICE_ACCEPT);
164: packet_put_cstring(service);
165: packet_send();
166: packet_write_wait();
167: } else {
168: debug("bad service request %s", service);
169: packet_disconnect("bad service request %s", service);
170: }
171: xfree(service);
172: }
173:
1.66 ! itojun 174: static void
1.15 markus 175: input_userauth_request(int type, int plen, void *ctxt)
1.1 markus 176: {
1.18 markus 177: Authctxt *authctxt = ctxt;
178: Authmethod *m = NULL;
1.28 markus 179: char *user, *service, *method, *style = NULL;
1.1 markus 180: int authenticated = 0;
181:
1.18 markus 182: if (authctxt == NULL)
183: fatal("input_userauth_request: no authctxt");
1.1 markus 184:
1.18 markus 185: user = packet_get_string(NULL);
186: service = packet_get_string(NULL);
187: method = packet_get_string(NULL);
1.1 markus 188: debug("userauth-request for user %s service %s method %s", user, service, method);
1.24 markus 189: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
1.1 markus 190:
1.28 markus 191: if ((style = strchr(user, ':')) != NULL)
192: *style++ = 0;
193:
1.36 stevesk 194: if (authctxt->attempt++ == 0) {
1.18 markus 195: /* setup auth context */
196: struct passwd *pw = NULL;
197: pw = getpwnam(user);
198: if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
199: authctxt->pw = pwcopy(pw);
200: authctxt->valid = 1;
201: debug2("input_userauth_request: setting up authctxt for %s", user);
202: } else {
203: log("input_userauth_request: illegal user %s", user);
204: }
1.42 markus 205: setproctitle("%s", pw ? user : "unknown");
1.18 markus 206: authctxt->user = xstrdup(user);
207: authctxt->service = xstrdup(service);
1.62 markus 208: authctxt->style = style ? xstrdup(style) : NULL;
209: } else if (strcmp(user, authctxt->user) != 0 ||
210: strcmp(service, authctxt->service) != 0) {
211: packet_disconnect("Change of username or service not allowed: "
212: "(%s,%s) -> (%s,%s)",
213: authctxt->user, authctxt->service, user, service);
1.1 markus 214: }
1.28 markus 215: /* reset state */
216: dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error);
217: authctxt->postponed = 0;
1.47 markus 218: #ifdef BSD_AUTH
219: if (authctxt->as) {
220: auth_close(authctxt->as);
221: authctxt->as = NULL;
222: }
223: #endif
1.18 markus 224:
1.28 markus 225: /* try to authenticate user */
1.18 markus 226: m = authmethod_lookup(method);
227: if (m != NULL) {
228: debug2("input_userauth_request: try method %s", method);
229: authenticated = m->userauth(authctxt);
230: }
1.49 markus 231: userauth_finish(authctxt, authenticated, method);
232:
233: xfree(service);
234: xfree(user);
235: xfree(method);
236: }
237:
238: void
239: userauth_finish(Authctxt *authctxt, int authenticated, char *method)
240: {
1.60 markus 241: char *methods;
242:
1.28 markus 243: if (!authctxt->valid && authenticated)
244: fatal("INTERNAL ERROR: authenticated invalid user %s",
245: authctxt->user);
1.18 markus 246:
247: /* Special handling for root */
1.41 markus 248: if (authenticated && authctxt->pw->pw_uid == 0 &&
249: !auth_root_allowed(method))
1.3 markus 250: authenticated = 0;
251:
1.18 markus 252: /* Log before sending the reply */
1.28 markus 253: auth_log(authctxt, authenticated, method, " ssh2");
254:
1.60 markus 255: if (authctxt->postponed)
256: return;
257:
258: /* XXX todo: check if multiple auth methods are needed */
259: if (authenticated == 1) {
260: /* turn off userauth */
261: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
262: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
263: packet_send();
264: packet_write_wait();
265: /* now we can break out */
266: authctxt->success = 1;
267: } else {
268: if (authctxt->failures++ > AUTH_FAIL_MAX)
269: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
270: methods = authmethods_get();
271: packet_start(SSH2_MSG_USERAUTH_FAILURE);
272: packet_put_cstring(methods);
273: packet_put_char(0); /* XXX partial success, unused */
274: packet_send();
275: packet_write_wait();
276: xfree(methods);
277: }
1.18 markus 278: }
279:
1.66 ! itojun 280: static void
1.25 markus 281: userauth_banner(void)
282: {
283: struct stat st;
284: char *banner = NULL;
285: off_t len, n;
286: int fd;
287:
288: if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
289: return;
1.50 markus 290: if ((fd = open(options.banner, O_RDONLY)) < 0)
1.25 markus 291: return;
292: if (fstat(fd, &st) < 0)
293: goto done;
294: len = st.st_size;
295: banner = xmalloc(len + 1);
296: if ((n = read(fd, banner, len)) < 0)
297: goto done;
298: banner[n] = '\0';
299: packet_start(SSH2_MSG_USERAUTH_BANNER);
300: packet_put_cstring(banner);
301: packet_put_cstring(""); /* language, unused */
302: packet_send();
303: debug("userauth_banner: sent");
304: done:
305: if (banner)
306: xfree(banner);
307: close(fd);
308: return;
1.1 markus 309: }
310:
1.66 ! itojun 311: static int
1.18 markus 312: userauth_none(Authctxt *authctxt)
1.1 markus 313: {
1.18 markus 314: /* disable method "none", only allowed one time */
315: Authmethod *m = authmethod_lookup("none");
316: if (m != NULL)
317: m->enabled = NULL;
1.1 markus 318: packet_done();
1.25 markus 319: userauth_banner();
1.47 markus 320: return authctxt->valid ? auth_password(authctxt, "") : 0;
1.1 markus 321: }
1.18 markus 322:
1.66 ! itojun 323: static int
1.18 markus 324: userauth_passwd(Authctxt *authctxt)
1.1 markus 325: {
326: char *password;
327: int authenticated = 0;
328: int change;
1.23 markus 329: u_int len;
1.1 markus 330: change = packet_get_char();
331: if (change)
332: log("password change not supported");
333: password = packet_get_string(&len);
334: packet_done();
1.18 markus 335: if (authctxt->valid &&
1.47 markus 336: auth_password(authctxt, password) == 1)
1.1 markus 337: authenticated = 1;
338: memset(password, 0, len);
339: xfree(password);
340: return authenticated;
341: }
1.18 markus 342:
1.66 ! itojun 343: static int
1.18 markus 344: userauth_kbdint(Authctxt *authctxt)
345: {
346: int authenticated = 0;
1.57 markus 347: char *lang, *devs;
348:
1.18 markus 349: lang = packet_get_string(NULL);
350: devs = packet_get_string(NULL);
351: packet_done();
352:
1.57 markus 353: debug("keyboard-interactive devs %s", devs);
1.28 markus 354:
1.57 markus 355: if (options.challenge_response_authentication)
1.34 markus 356: authenticated = auth2_challenge(authctxt, devs);
1.28 markus 357:
1.57 markus 358: xfree(devs);
1.18 markus 359: xfree(lang);
360: return authenticated;
361: }
362:
1.66 ! itojun 363: static int
1.18 markus 364: userauth_pubkey(Authctxt *authctxt)
1.1 markus 365: {
366: Buffer b;
367: Key *key;
368: char *pkalg, *pkblob, *sig;
1.23 markus 369: u_int alen, blen, slen;
1.21 markus 370: int have_sig, pktype;
1.1 markus 371: int authenticated = 0;
372:
1.18 markus 373: if (!authctxt->valid) {
374: debug2("userauth_pubkey: disabled because of invalid user");
1.8 markus 375: return 0;
376: }
1.1 markus 377: have_sig = packet_get_char();
1.22 markus 378: if (datafellows & SSH_BUG_PKAUTH) {
379: debug2("userauth_pubkey: SSH_BUG_PKAUTH");
380: /* no explicit pkalg given */
381: pkblob = packet_get_string(&blen);
382: buffer_init(&b);
383: buffer_append(&b, pkblob, blen);
384: /* so we have to extract the pkalg from the pkblob */
385: pkalg = buffer_get_string(&b, &alen);
386: buffer_free(&b);
387: } else {
388: pkalg = packet_get_string(&alen);
389: pkblob = packet_get_string(&blen);
390: }
1.21 markus 391: pktype = key_type_from_name(pkalg);
392: if (pktype == KEY_UNSPEC) {
1.22 markus 393: /* this is perfectly legal */
394: log("userauth_pubkey: unsupported public key algorithm: %s", pkalg);
1.1 markus 395: xfree(pkalg);
1.22 markus 396: xfree(pkblob);
1.1 markus 397: return 0;
398: }
1.21 markus 399: key = key_from_blob(pkblob, blen);
1.2 markus 400: if (key != NULL) {
401: if (have_sig) {
402: sig = packet_get_string(&slen);
403: packet_done();
404: buffer_init(&b);
1.20 markus 405: if (datafellows & SSH_OLD_SESSIONID) {
406: buffer_append(&b, session_id2, session_id2_len);
407: } else {
1.11 markus 408: buffer_put_string(&b, session_id2, session_id2_len);
409: }
1.9 markus 410: /* reconstruct packet */
1.2 markus 411: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.18 markus 412: buffer_put_cstring(&b, authctxt->user);
1.9 markus 413: buffer_put_cstring(&b,
1.22 markus 414: datafellows & SSH_BUG_PKSERVICE ?
1.9 markus 415: "ssh-userauth" :
1.18 markus 416: authctxt->service);
1.22 markus 417: if (datafellows & SSH_BUG_PKAUTH) {
418: buffer_put_char(&b, have_sig);
419: } else {
420: buffer_put_cstring(&b, "publickey");
421: buffer_put_char(&b, have_sig);
1.56 markus 422: buffer_put_cstring(&b, pkalg);
1.22 markus 423: }
1.9 markus 424: buffer_put_string(&b, pkblob, blen);
1.21 markus 425: #ifdef DEBUG_PK
1.2 markus 426: buffer_dump(&b);
1.1 markus 427: #endif
1.2 markus 428: /* test for correct signature */
1.21 markus 429: if (user_key_allowed(authctxt->pw, key) &&
430: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
1.2 markus 431: authenticated = 1;
432: buffer_clear(&b);
433: xfree(sig);
434: } else {
1.18 markus 435: debug("test whether pkalg/pkblob are acceptable");
1.2 markus 436: packet_done();
1.18 markus 437:
1.2 markus 438: /* XXX fake reply and always send PK_OK ? */
1.6 markus 439: /*
440: * XXX this allows testing whether a user is allowed
441: * to login: if you happen to have a valid pubkey this
442: * message is sent. the message is NEVER sent at all
443: * if a user is not allowed to login. is this an
444: * issue? -markus
445: */
1.21 markus 446: if (user_key_allowed(authctxt->pw, key)) {
1.2 markus 447: packet_start(SSH2_MSG_USERAUTH_PK_OK);
448: packet_put_string(pkalg, alen);
449: packet_put_string(pkblob, blen);
450: packet_send();
451: packet_write_wait();
1.38 markus 452: authctxt->postponed = 1;
1.2 markus 453: }
1.1 markus 454: }
1.17 markus 455: if (authenticated != 1)
456: auth_clear_options();
1.2 markus 457: key_free(key);
1.1 markus 458: }
1.21 markus 459: debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
1.1 markus 460: xfree(pkalg);
461: xfree(pkblob);
462: return authenticated;
463: }
464:
1.66 ! itojun 465: static int
1.52 markus 466: userauth_hostbased(Authctxt *authctxt)
467: {
468: Buffer b;
469: Key *key;
1.55 markus 470: char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
1.52 markus 471: u_int alen, blen, slen;
472: int pktype;
473: int authenticated = 0;
474:
475: if (!authctxt->valid) {
476: debug2("userauth_hostbased: disabled because of invalid user");
477: return 0;
478: }
479: pkalg = packet_get_string(&alen);
480: pkblob = packet_get_string(&blen);
481: chost = packet_get_string(NULL);
482: cuser = packet_get_string(NULL);
483: sig = packet_get_string(&slen);
484:
485: debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
486: cuser, chost, pkalg, slen);
487: #ifdef DEBUG_PK
488: debug("signature:");
489: buffer_init(&b);
490: buffer_append(&b, sig, slen);
491: buffer_dump(&b);
492: buffer_free(&b);
493: #endif
494: pktype = key_type_from_name(pkalg);
495: if (pktype == KEY_UNSPEC) {
496: /* this is perfectly legal */
497: log("userauth_hostbased: unsupported "
498: "public key algorithm: %s", pkalg);
499: goto done;
500: }
501: key = key_from_blob(pkblob, blen);
502: if (key == NULL) {
503: debug("userauth_hostbased: cannot decode key: %s", pkalg);
504: goto done;
505: }
1.55 markus 506: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
507: authctxt->service;
1.52 markus 508: buffer_init(&b);
1.55 markus 509: buffer_put_string(&b, session_id2, session_id2_len);
1.52 markus 510: /* reconstruct packet */
511: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
512: buffer_put_cstring(&b, authctxt->user);
1.55 markus 513: buffer_put_cstring(&b, service);
1.52 markus 514: buffer_put_cstring(&b, "hostbased");
515: buffer_put_string(&b, pkalg, alen);
516: buffer_put_string(&b, pkblob, blen);
517: buffer_put_cstring(&b, chost);
518: buffer_put_cstring(&b, cuser);
519: #ifdef DEBUG_PK
520: buffer_dump(&b);
521: #endif
522: /* test for allowed key and correct signature */
523: if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
524: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
525: authenticated = 1;
526:
527: buffer_clear(&b);
528: key_free(key);
529:
530: done:
531: debug2("userauth_hostbased: authenticated %d", authenticated);
532: xfree(pkalg);
533: xfree(pkblob);
534: xfree(cuser);
535: xfree(chost);
536: xfree(sig);
537: return authenticated;
538: }
539:
1.18 markus 540: /* get current user */
1.1 markus 541:
542: struct passwd*
543: auth_get_user(void)
544: {
1.18 markus 545: return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
1.1 markus 546: }
547:
1.18 markus 548: #define DELIM ","
549:
550: char *
551: authmethods_get(void)
1.1 markus 552: {
1.18 markus 553: Authmethod *method = NULL;
1.23 markus 554: u_int size = 0;
1.18 markus 555: char *list;
1.1 markus 556:
1.18 markus 557: for (method = authmethods; method->name != NULL; method++) {
558: if (strcmp(method->name, "none") == 0)
559: continue;
560: if (method->enabled != NULL && *(method->enabled) != 0) {
561: if (size != 0)
562: size += strlen(DELIM);
563: size += strlen(method->name);
1.1 markus 564: }
1.18 markus 565: }
566: size++; /* trailing '\0' */
567: list = xmalloc(size);
568: list[0] = '\0';
569:
570: for (method = authmethods; method->name != NULL; method++) {
571: if (strcmp(method->name, "none") == 0)
572: continue;
573: if (method->enabled != NULL && *(method->enabled) != 0) {
574: if (list[0] != '\0')
575: strlcat(list, DELIM, size);
576: strlcat(list, method->name, size);
1.1 markus 577: }
578: }
1.18 markus 579: return list;
580: }
581:
1.66 ! itojun 582: static Authmethod *
1.18 markus 583: authmethod_lookup(const char *name)
584: {
585: Authmethod *method = NULL;
586: if (name != NULL)
587: for (method = authmethods; method->name != NULL; method++)
588: if (method->enabled != NULL &&
589: *(method->enabled) != 0 &&
590: strcmp(name, method->name) == 0)
591: return method;
592: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
593: return NULL;
1.1 markus 594: }
595:
596: /* return 1 if user allows given key */
1.66 ! itojun 597: static int
1.63 markus 598: user_key_allowed2(struct passwd *pw, Key *key, char *file)
1.1 markus 599: {
1.63 markus 600: char line[8192];
1.1 markus 601: int found_key = 0;
602: FILE *f;
1.23 markus 603: u_long linenum = 0;
1.1 markus 604: struct stat st;
605: Key *found;
606:
1.18 markus 607: if (pw == NULL)
608: return 0;
609:
1.1 markus 610: /* Temporarily use the user's uid. */
1.51 markus 611: temporarily_use_uid(pw);
1.1 markus 612:
1.58 markus 613: debug("trying public key file %s", file);
1.1 markus 614:
615: /* Fail quietly if file does not exist */
616: if (stat(file, &st) < 0) {
617: /* Restore the privileged uid. */
618: restore_uid();
619: return 0;
620: }
621: /* Open the file containing the authorized keys. */
622: f = fopen(file, "r");
623: if (!f) {
624: /* Restore the privileged uid. */
625: restore_uid();
626: return 0;
627: }
1.58 markus 628: if (options.strict_modes &&
629: secure_filename(f, file, pw->pw_uid, line, sizeof(line)) != 0) {
630: fclose(f);
631: log("Authentication refused: %s", line);
632: restore_uid();
633: return 0;
1.1 markus 634: }
1.58 markus 635:
1.1 markus 636: found_key = 0;
1.16 markus 637: found = key_new(key->type);
1.1 markus 638:
639: while (fgets(line, sizeof(line), f)) {
1.10 markus 640: char *cp, *options = NULL;
1.1 markus 641: linenum++;
642: /* Skip leading whitespace, empty and comment lines. */
643: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
644: ;
645: if (!*cp || *cp == '\n' || *cp == '#')
646: continue;
1.10 markus 647:
1.21 markus 648: if (key_read(found, &cp) == -1) {
1.10 markus 649: /* no key? check if there are options for this key */
650: int quoted = 0;
1.21 markus 651: debug2("user_key_allowed: check options: '%s'", cp);
1.10 markus 652: options = cp;
653: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
654: if (*cp == '\\' && cp[1] == '"')
655: cp++; /* Skip both */
656: else if (*cp == '"')
657: quoted = !quoted;
658: }
659: /* Skip remaining whitespace. */
660: for (; *cp == ' ' || *cp == '\t'; cp++)
661: ;
1.21 markus 662: if (key_read(found, &cp) == -1) {
663: debug2("user_key_allowed: advance: '%s'", cp);
1.10 markus 664: /* still no key? advance to next line*/
665: continue;
666: }
667: }
668: if (key_equal(found, key) &&
1.30 markus 669: auth_parse_options(pw, options, file, linenum) == 1) {
1.1 markus 670: found_key = 1;
671: debug("matching key found: file %s, line %ld",
672: file, linenum);
673: break;
674: }
675: }
676: restore_uid();
677: fclose(f);
678: key_free(found);
1.46 markus 679: if (!found_key)
680: debug2("key not found");
1.1 markus 681: return found_key;
1.63 markus 682: }
683:
684: /* check whether given key is in .ssh/authorized_keys* */
1.66 ! itojun 685: static int
1.63 markus 686: user_key_allowed(struct passwd *pw, Key *key)
687: {
688: int success;
689: char *file;
690:
691: file = authorized_keys_file(pw);
692: success = user_key_allowed2(pw, key, file);
693: xfree(file);
694: if (success)
695: return success;
696:
697: /* try suffix "2" for backward compat, too */
698: file = authorized_keys_file2(pw);
699: success = user_key_allowed2(pw, key, file);
700: xfree(file);
701: return success;
1.52 markus 702: }
703:
704: /* return 1 if given hostkey is allowed */
1.66 ! itojun 705: static int
1.54 markus 706: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
1.52 markus 707: Key *key)
708: {
709: const char *resolvedname, *ipaddr, *lookup;
1.53 markus 710: int host_status, len;
1.52 markus 711:
712: resolvedname = get_canonical_hostname(options.reverse_mapping_check);
713: ipaddr = get_remote_ipaddr();
714:
1.53 markus 715: debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
716: chost, resolvedname, ipaddr);
1.52 markus 717:
718: if (options.hostbased_uses_name_from_packet_only) {
719: if (auth_rhosts2(pw, cuser, chost, chost) == 0)
720: return 0;
721: lookup = chost;
722: } else {
1.53 markus 723: if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
724: debug2("stripping trailing dot from chost %s", chost);
725: chost[len - 1] = '\0';
726: }
1.52 markus 727: if (strcasecmp(resolvedname, chost) != 0)
728: log("userauth_hostbased mismatch: "
729: "client sends %s, but we resolve %s to %s",
730: chost, ipaddr, resolvedname);
731: if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
732: return 0;
733: lookup = resolvedname;
734: }
735: debug2("userauth_hostbased: access allowed by auth_rhosts2");
736:
1.64 markus 737: host_status = check_key_in_hostfiles(pw, key, lookup,
738: _PATH_SSH_SYSTEM_HOSTFILE,
1.65 markus 739: options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
1.64 markus 740:
741: /* backward compat if no key has been found. */
742: if (host_status == HOST_NEW)
743: host_status = check_key_in_hostfiles(pw, key, lookup,
744: _PATH_SSH_SYSTEM_HOSTFILE2,
1.65 markus 745: options.ignore_user_known_hosts ? NULL :
746: _PATH_SSH_USER_HOSTFILE2);
1.52 markus 747:
748: return (host_status == HOST_OK);
1.1 markus 749: }
1.64 markus 750:
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