Annotation of src/usr.bin/ssh/auth2.c, Revision 1.56.2.3
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"
1.56.2.3! miod 26: RCSID("$OpenBSD: auth2.c,v 1.56.2.2 2001/11/15 00:15:19 miod 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"
1.56.2.1 jason 53: #include "match.h"
1.1 markus 54:
55: /* import */
56: extern ServerOptions options;
1.23 markus 57: extern u_char *session_id2;
1.1 markus 58: extern int session_id2_len;
59:
1.18 markus 60: static Authctxt *x_authctxt = NULL;
61: static int one = 1;
62:
63: typedef struct Authmethod Authmethod;
64: struct Authmethod {
65: char *name;
66: int (*userauth)(Authctxt *authctxt);
67: int *enabled;
68: };
69:
1.1 markus 70: /* protocol */
71:
1.56.2.1 jason 72: static void input_service_request(int, int, void *);
73: static void input_userauth_request(int, int, void *);
74: static void protocol_error(int, int, void *);
1.1 markus 75:
76: /* helper */
1.56.2.1 jason 77: static Authmethod *authmethod_lookup(const char *);
78: static char *authmethods_get(void);
79: static int user_key_allowed(struct passwd *, Key *);
80: static int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
1.1 markus 81:
1.18 markus 82: /* auth */
1.56.2.1 jason 83: static void userauth_banner(void);
84: static int userauth_none(Authctxt *);
85: static int userauth_passwd(Authctxt *);
86: static int userauth_pubkey(Authctxt *);
87: static int userauth_hostbased(Authctxt *);
88: static int userauth_kbdint(Authctxt *);
1.18 markus 89:
90: Authmethod authmethods[] = {
91: {"none",
92: userauth_none,
93: &one},
94: {"publickey",
95: userauth_pubkey,
1.21 markus 96: &options.pubkey_authentication},
1.40 markus 97: {"password",
98: userauth_passwd,
99: &options.password_authentication},
1.18 markus 100: {"keyboard-interactive",
101: userauth_kbdint,
102: &options.kbd_interactive_authentication},
1.52 markus 103: {"hostbased",
104: userauth_hostbased,
105: &options.hostbased_authentication},
1.18 markus 106: {NULL, NULL, NULL}
1.1 markus 107: };
108:
109: /*
1.18 markus 110: * loop until authctxt->success == TRUE
1.1 markus 111: */
112:
113: void
114: do_authentication2()
115: {
1.28 markus 116: Authctxt *authctxt = authctxt_new();
117:
1.18 markus 118: x_authctxt = authctxt; /*XXX*/
119:
1.56.2.2 miod 120: /* challenge-response is implemented via keyboard interactive */
1.56.2.1 jason 121: if (options.challenge_response_authentication)
1.34 markus 122: options.kbd_interactive_authentication = 1;
123:
1.1 markus 124: dispatch_init(&protocol_error);
125: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 126: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.48 markus 127: do_authenticated(authctxt);
1.1 markus 128: }
129:
1.56.2.1 jason 130: static void
1.15 markus 131: protocol_error(int type, int plen, void *ctxt)
1.1 markus 132: {
133: log("auth: protocol error: type %d plen %d", type, plen);
134: packet_start(SSH2_MSG_UNIMPLEMENTED);
135: packet_put_int(0);
136: packet_send();
137: packet_write_wait();
138: }
139:
1.56.2.1 jason 140: static void
1.15 markus 141: input_service_request(int type, int plen, void *ctxt)
1.1 markus 142: {
1.18 markus 143: Authctxt *authctxt = ctxt;
1.23 markus 144: u_int len;
1.1 markus 145: int accept = 0;
146: char *service = packet_get_string(&len);
147: packet_done();
148:
1.18 markus 149: if (authctxt == NULL)
150: fatal("input_service_request: no authctxt");
151:
1.1 markus 152: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 153: if (!authctxt->success) {
1.1 markus 154: accept = 1;
155: /* now we can handle user-auth requests */
156: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
157: }
158: }
159: /* XXX all other service requests are denied */
160:
161: if (accept) {
162: packet_start(SSH2_MSG_SERVICE_ACCEPT);
163: packet_put_cstring(service);
164: packet_send();
165: packet_write_wait();
166: } else {
167: debug("bad service request %s", service);
168: packet_disconnect("bad service request %s", service);
169: }
170: xfree(service);
171: }
172:
1.56.2.1 jason 173: static void
1.15 markus 174: input_userauth_request(int type, int plen, void *ctxt)
1.1 markus 175: {
1.18 markus 176: Authctxt *authctxt = ctxt;
177: Authmethod *m = NULL;
1.28 markus 178: char *user, *service, *method, *style = NULL;
1.1 markus 179: int authenticated = 0;
180:
1.18 markus 181: if (authctxt == NULL)
182: fatal("input_userauth_request: no authctxt");
1.1 markus 183:
1.18 markus 184: user = packet_get_string(NULL);
185: service = packet_get_string(NULL);
186: method = packet_get_string(NULL);
1.1 markus 187: debug("userauth-request for user %s service %s method %s", user, service, method);
1.24 markus 188: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
1.1 markus 189:
1.28 markus 190: if ((style = strchr(user, ':')) != NULL)
191: *style++ = 0;
192:
1.36 stevesk 193: if (authctxt->attempt++ == 0) {
1.18 markus 194: /* setup auth context */
195: struct passwd *pw = NULL;
196: pw = getpwnam(user);
197: if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
198: authctxt->pw = pwcopy(pw);
199: authctxt->valid = 1;
200: debug2("input_userauth_request: setting up authctxt for %s", user);
201: } else {
202: log("input_userauth_request: illegal user %s", user);
203: }
1.42 markus 204: setproctitle("%s", pw ? user : "unknown");
1.18 markus 205: authctxt->user = xstrdup(user);
206: authctxt->service = xstrdup(service);
1.56.2.1 jason 207: authctxt->style = style ? xstrdup(style) : NULL;
208: } else if (strcmp(user, authctxt->user) != 0 ||
209: strcmp(service, authctxt->service) != 0) {
210: packet_disconnect("Change of username or service not allowed: "
211: "(%s,%s) -> (%s,%s)",
212: authctxt->user, authctxt->service, user, service);
1.1 markus 213: }
1.28 markus 214: /* reset state */
215: dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error);
216: authctxt->postponed = 0;
1.47 markus 217: #ifdef BSD_AUTH
218: if (authctxt->as) {
219: auth_close(authctxt->as);
220: authctxt->as = NULL;
221: }
222: #endif
1.18 markus 223:
1.28 markus 224: /* try to authenticate user */
1.18 markus 225: m = authmethod_lookup(method);
226: if (m != NULL) {
227: debug2("input_userauth_request: try method %s", method);
228: authenticated = m->userauth(authctxt);
229: }
1.49 markus 230: userauth_finish(authctxt, authenticated, method);
231:
232: xfree(service);
233: xfree(user);
234: xfree(method);
235: }
236:
237: void
238: userauth_finish(Authctxt *authctxt, int authenticated, char *method)
239: {
1.56.2.1 jason 240: char *methods;
241:
1.28 markus 242: if (!authctxt->valid && authenticated)
243: fatal("INTERNAL ERROR: authenticated invalid user %s",
244: authctxt->user);
1.18 markus 245:
246: /* Special handling for root */
1.41 markus 247: if (authenticated && authctxt->pw->pw_uid == 0 &&
248: !auth_root_allowed(method))
1.3 markus 249: authenticated = 0;
250:
1.18 markus 251: /* Log before sending the reply */
1.28 markus 252: auth_log(authctxt, authenticated, method, " ssh2");
253:
1.56.2.1 jason 254: if (authctxt->postponed)
255: return;
256:
257: /* XXX todo: check if multiple auth methods are needed */
258: if (authenticated == 1) {
259: /* turn off userauth */
260: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
261: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
262: packet_send();
263: packet_write_wait();
264: /* now we can break out */
265: authctxt->success = 1;
266: } else {
267: if (authctxt->failures++ > AUTH_FAIL_MAX)
268: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
269: methods = authmethods_get();
270: packet_start(SSH2_MSG_USERAUTH_FAILURE);
271: packet_put_cstring(methods);
272: packet_put_char(0); /* XXX partial success, unused */
273: packet_send();
274: packet_write_wait();
275: xfree(methods);
276: }
1.18 markus 277: }
278:
1.56.2.1 jason 279: static void
1.25 markus 280: userauth_banner(void)
281: {
282: struct stat st;
283: char *banner = NULL;
284: off_t len, n;
285: int fd;
286:
287: if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
288: return;
1.50 markus 289: if ((fd = open(options.banner, O_RDONLY)) < 0)
1.25 markus 290: return;
291: if (fstat(fd, &st) < 0)
292: goto done;
293: len = st.st_size;
294: banner = xmalloc(len + 1);
295: if ((n = read(fd, banner, len)) < 0)
296: goto done;
297: banner[n] = '\0';
298: packet_start(SSH2_MSG_USERAUTH_BANNER);
299: packet_put_cstring(banner);
300: packet_put_cstring(""); /* language, unused */
301: packet_send();
302: debug("userauth_banner: sent");
303: done:
304: if (banner)
305: xfree(banner);
306: close(fd);
307: return;
308: }
1.18 markus 309:
1.56.2.1 jason 310: static int
1.18 markus 311: userauth_none(Authctxt *authctxt)
1.1 markus 312: {
1.18 markus 313: /* disable method "none", only allowed one time */
314: Authmethod *m = authmethod_lookup("none");
315: if (m != NULL)
316: m->enabled = NULL;
1.1 markus 317: packet_done();
1.25 markus 318: userauth_banner();
1.47 markus 319: return authctxt->valid ? auth_password(authctxt, "") : 0;
1.1 markus 320: }
1.18 markus 321:
1.56.2.1 jason 322: static int
1.18 markus 323: userauth_passwd(Authctxt *authctxt)
1.1 markus 324: {
325: char *password;
326: int authenticated = 0;
327: int change;
1.23 markus 328: u_int len;
1.1 markus 329: change = packet_get_char();
330: if (change)
331: log("password change not supported");
332: password = packet_get_string(&len);
333: packet_done();
1.18 markus 334: if (authctxt->valid &&
1.47 markus 335: auth_password(authctxt, password) == 1)
1.1 markus 336: authenticated = 1;
337: memset(password, 0, len);
338: xfree(password);
339: return authenticated;
340: }
1.18 markus 341:
1.56.2.1 jason 342: static int
1.18 markus 343: userauth_kbdint(Authctxt *authctxt)
344: {
345: int authenticated = 0;
1.56.2.1 jason 346: char *lang, *devs;
347:
1.18 markus 348: lang = packet_get_string(NULL);
349: devs = packet_get_string(NULL);
350: packet_done();
351:
1.56.2.1 jason 352: debug("keyboard-interactive devs %s", devs);
1.28 markus 353:
1.56.2.1 jason 354: if (options.challenge_response_authentication)
1.34 markus 355: authenticated = auth2_challenge(authctxt, devs);
1.28 markus 356:
1.18 markus 357: xfree(devs);
1.56.2.1 jason 358: xfree(lang);
1.18 markus 359: return authenticated;
360: }
361:
1.56.2.1 jason 362: static int
1.18 markus 363: userauth_pubkey(Authctxt *authctxt)
1.1 markus 364: {
365: Buffer b;
366: Key *key;
367: char *pkalg, *pkblob, *sig;
1.23 markus 368: u_int alen, blen, slen;
1.21 markus 369: int have_sig, pktype;
1.1 markus 370: int authenticated = 0;
371:
1.18 markus 372: if (!authctxt->valid) {
373: debug2("userauth_pubkey: disabled because of invalid user");
1.8 markus 374: return 0;
375: }
1.1 markus 376: have_sig = packet_get_char();
1.22 markus 377: if (datafellows & SSH_BUG_PKAUTH) {
378: debug2("userauth_pubkey: SSH_BUG_PKAUTH");
379: /* no explicit pkalg given */
380: pkblob = packet_get_string(&blen);
381: buffer_init(&b);
382: buffer_append(&b, pkblob, blen);
383: /* so we have to extract the pkalg from the pkblob */
384: pkalg = buffer_get_string(&b, &alen);
385: buffer_free(&b);
386: } else {
387: pkalg = packet_get_string(&alen);
388: pkblob = packet_get_string(&blen);
389: }
1.21 markus 390: pktype = key_type_from_name(pkalg);
391: if (pktype == KEY_UNSPEC) {
1.22 markus 392: /* this is perfectly legal */
393: log("userauth_pubkey: unsupported public key algorithm: %s", pkalg);
1.1 markus 394: xfree(pkalg);
1.22 markus 395: xfree(pkblob);
1.1 markus 396: return 0;
397: }
1.21 markus 398: key = key_from_blob(pkblob, blen);
1.2 markus 399: if (key != NULL) {
400: if (have_sig) {
401: sig = packet_get_string(&slen);
402: packet_done();
403: buffer_init(&b);
1.20 markus 404: if (datafellows & SSH_OLD_SESSIONID) {
405: buffer_append(&b, session_id2, session_id2_len);
406: } else {
1.11 markus 407: buffer_put_string(&b, session_id2, session_id2_len);
408: }
1.9 markus 409: /* reconstruct packet */
1.2 markus 410: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.18 markus 411: buffer_put_cstring(&b, authctxt->user);
1.9 markus 412: buffer_put_cstring(&b,
1.22 markus 413: datafellows & SSH_BUG_PKSERVICE ?
1.9 markus 414: "ssh-userauth" :
1.18 markus 415: authctxt->service);
1.22 markus 416: if (datafellows & SSH_BUG_PKAUTH) {
417: buffer_put_char(&b, have_sig);
418: } else {
419: buffer_put_cstring(&b, "publickey");
420: buffer_put_char(&b, have_sig);
1.56 markus 421: buffer_put_cstring(&b, pkalg);
1.22 markus 422: }
1.9 markus 423: buffer_put_string(&b, pkblob, blen);
1.21 markus 424: #ifdef DEBUG_PK
1.2 markus 425: buffer_dump(&b);
1.1 markus 426: #endif
1.2 markus 427: /* test for correct signature */
1.21 markus 428: if (user_key_allowed(authctxt->pw, key) &&
429: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
1.2 markus 430: authenticated = 1;
431: buffer_clear(&b);
432: xfree(sig);
433: } else {
1.18 markus 434: debug("test whether pkalg/pkblob are acceptable");
1.2 markus 435: packet_done();
1.18 markus 436:
1.2 markus 437: /* XXX fake reply and always send PK_OK ? */
1.6 markus 438: /*
439: * XXX this allows testing whether a user is allowed
440: * to login: if you happen to have a valid pubkey this
441: * message is sent. the message is NEVER sent at all
442: * if a user is not allowed to login. is this an
443: * issue? -markus
444: */
1.21 markus 445: if (user_key_allowed(authctxt->pw, key)) {
1.2 markus 446: packet_start(SSH2_MSG_USERAUTH_PK_OK);
447: packet_put_string(pkalg, alen);
448: packet_put_string(pkblob, blen);
449: packet_send();
450: packet_write_wait();
1.38 markus 451: authctxt->postponed = 1;
1.2 markus 452: }
1.1 markus 453: }
1.17 markus 454: if (authenticated != 1)
455: auth_clear_options();
1.2 markus 456: key_free(key);
1.1 markus 457: }
1.21 markus 458: debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
1.1 markus 459: xfree(pkalg);
460: xfree(pkblob);
461: return authenticated;
462: }
463:
1.56.2.1 jason 464: static int
1.52 markus 465: userauth_hostbased(Authctxt *authctxt)
466: {
467: Buffer b;
468: Key *key;
1.55 markus 469: char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
1.52 markus 470: u_int alen, blen, slen;
471: int pktype;
472: int authenticated = 0;
473:
474: if (!authctxt->valid) {
475: debug2("userauth_hostbased: disabled because of invalid user");
476: return 0;
477: }
478: pkalg = packet_get_string(&alen);
479: pkblob = packet_get_string(&blen);
480: chost = packet_get_string(NULL);
481: cuser = packet_get_string(NULL);
482: sig = packet_get_string(&slen);
483:
484: debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
485: cuser, chost, pkalg, slen);
486: #ifdef DEBUG_PK
487: debug("signature:");
488: buffer_init(&b);
489: buffer_append(&b, sig, slen);
490: buffer_dump(&b);
491: buffer_free(&b);
492: #endif
493: pktype = key_type_from_name(pkalg);
494: if (pktype == KEY_UNSPEC) {
495: /* this is perfectly legal */
496: log("userauth_hostbased: unsupported "
497: "public key algorithm: %s", pkalg);
498: goto done;
499: }
500: key = key_from_blob(pkblob, blen);
501: if (key == NULL) {
502: debug("userauth_hostbased: cannot decode key: %s", pkalg);
503: goto done;
504: }
1.55 markus 505: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
506: authctxt->service;
1.52 markus 507: buffer_init(&b);
1.55 markus 508: buffer_put_string(&b, session_id2, session_id2_len);
1.52 markus 509: /* reconstruct packet */
510: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
511: buffer_put_cstring(&b, authctxt->user);
1.55 markus 512: buffer_put_cstring(&b, service);
1.52 markus 513: buffer_put_cstring(&b, "hostbased");
514: buffer_put_string(&b, pkalg, alen);
515: buffer_put_string(&b, pkblob, blen);
516: buffer_put_cstring(&b, chost);
517: buffer_put_cstring(&b, cuser);
518: #ifdef DEBUG_PK
519: buffer_dump(&b);
520: #endif
521: /* test for allowed key and correct signature */
522: if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
523: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
524: authenticated = 1;
525:
526: buffer_clear(&b);
527: key_free(key);
528:
529: done:
530: debug2("userauth_hostbased: authenticated %d", authenticated);
531: xfree(pkalg);
532: xfree(pkblob);
533: xfree(cuser);
534: xfree(chost);
535: xfree(sig);
536: return authenticated;
537: }
538:
1.18 markus 539: /* get current user */
1.1 markus 540:
541: struct passwd*
542: auth_get_user(void)
543: {
1.18 markus 544: return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
1.1 markus 545: }
546:
1.18 markus 547: #define DELIM ","
548:
1.56.2.1 jason 549: static char *
1.18 markus 550: authmethods_get(void)
1.1 markus 551: {
1.18 markus 552: Authmethod *method = NULL;
1.23 markus 553: u_int size = 0;
1.18 markus 554: char *list;
1.1 markus 555:
1.18 markus 556: for (method = authmethods; method->name != NULL; method++) {
557: if (strcmp(method->name, "none") == 0)
558: continue;
559: if (method->enabled != NULL && *(method->enabled) != 0) {
560: if (size != 0)
561: size += strlen(DELIM);
562: size += strlen(method->name);
1.1 markus 563: }
1.18 markus 564: }
565: size++; /* trailing '\0' */
566: list = xmalloc(size);
567: list[0] = '\0';
568:
569: for (method = authmethods; method->name != NULL; method++) {
570: if (strcmp(method->name, "none") == 0)
571: continue;
572: if (method->enabled != NULL && *(method->enabled) != 0) {
573: if (list[0] != '\0')
574: strlcat(list, DELIM, size);
575: strlcat(list, method->name, size);
1.1 markus 576: }
577: }
1.18 markus 578: return list;
579: }
580:
1.56.2.1 jason 581: static Authmethod *
1.18 markus 582: authmethod_lookup(const char *name)
583: {
584: Authmethod *method = NULL;
585: if (name != NULL)
586: for (method = authmethods; method->name != NULL; method++)
587: if (method->enabled != NULL &&
588: *(method->enabled) != 0 &&
589: strcmp(name, method->name) == 0)
590: return method;
591: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
592: return NULL;
1.1 markus 593: }
594:
595: /* return 1 if user allows given key */
1.56.2.1 jason 596: static int
597: user_key_allowed2(struct passwd *pw, Key *key, char *file)
1.1 markus 598: {
1.56.2.1 jason 599: char line[8192];
1.1 markus 600: int found_key = 0;
601: FILE *f;
1.23 markus 602: u_long linenum = 0;
1.1 markus 603: struct stat st;
604: Key *found;
605:
1.18 markus 606: if (pw == NULL)
607: return 0;
608:
1.1 markus 609: /* Temporarily use the user's uid. */
1.51 markus 610: temporarily_use_uid(pw);
1.1 markus 611:
1.56.2.1 jason 612: debug("trying public key file %s", file);
1.1 markus 613:
614: /* Fail quietly if file does not exist */
615: if (stat(file, &st) < 0) {
616: /* Restore the privileged uid. */
617: restore_uid();
618: return 0;
619: }
620: /* Open the file containing the authorized keys. */
621: f = fopen(file, "r");
622: if (!f) {
623: /* Restore the privileged uid. */
624: restore_uid();
625: return 0;
626: }
1.56.2.1 jason 627: if (options.strict_modes &&
628: secure_filename(f, file, pw, line, sizeof(line)) != 0) {
629: fclose(f);
630: log("Authentication refused: %s", line);
631: restore_uid();
632: return 0;
1.1 markus 633: }
1.56.2.1 jason 634:
1.1 markus 635: found_key = 0;
1.16 markus 636: found = key_new(key->type);
1.1 markus 637:
638: while (fgets(line, sizeof(line), f)) {
1.10 markus 639: char *cp, *options = NULL;
1.1 markus 640: linenum++;
641: /* Skip leading whitespace, empty and comment lines. */
642: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
643: ;
644: if (!*cp || *cp == '\n' || *cp == '#')
645: continue;
1.10 markus 646:
1.56.2.1 jason 647: if (key_read(found, &cp) != 1) {
1.10 markus 648: /* no key? check if there are options for this key */
649: int quoted = 0;
1.21 markus 650: debug2("user_key_allowed: check options: '%s'", cp);
1.10 markus 651: options = cp;
652: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
653: if (*cp == '\\' && cp[1] == '"')
654: cp++; /* Skip both */
655: else if (*cp == '"')
656: quoted = !quoted;
657: }
658: /* Skip remaining whitespace. */
659: for (; *cp == ' ' || *cp == '\t'; cp++)
660: ;
1.56.2.1 jason 661: if (key_read(found, &cp) != 1) {
1.21 markus 662: debug2("user_key_allowed: advance: '%s'", cp);
1.10 markus 663: /* still no key? advance to next line*/
664: continue;
665: }
666: }
667: if (key_equal(found, key) &&
1.30 markus 668: auth_parse_options(pw, options, file, linenum) == 1) {
1.1 markus 669: found_key = 1;
1.56.2.1 jason 670: debug("matching key found: file %s, line %lu",
1.1 markus 671: file, linenum);
672: break;
673: }
674: }
675: restore_uid();
676: fclose(f);
677: key_free(found);
1.46 markus 678: if (!found_key)
679: debug2("key not found");
1.1 markus 680: return found_key;
1.52 markus 681: }
682:
1.56.2.1 jason 683: /* check whether given key is in .ssh/authorized_keys* */
684: static int
685: user_key_allowed(struct passwd *pw, Key *key)
686: {
687: int success;
688: char *file;
689:
690: file = authorized_keys_file(pw);
691: success = user_key_allowed2(pw, key, file);
692: xfree(file);
693: if (success)
694: return success;
695:
696: /* try suffix "2" for backward compat, too */
697: file = authorized_keys_file2(pw);
698: success = user_key_allowed2(pw, key, file);
699: xfree(file);
700: return success;
701: }
702:
1.52 markus 703: /* return 1 if given hostkey is allowed */
1.56.2.1 jason 704: static int
1.54 markus 705: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
1.52 markus 706: Key *key)
707: {
708: const char *resolvedname, *ipaddr, *lookup;
1.53 markus 709: int host_status, len;
1.52 markus 710:
711: resolvedname = get_canonical_hostname(options.reverse_mapping_check);
712: ipaddr = get_remote_ipaddr();
713:
1.53 markus 714: debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
715: chost, resolvedname, ipaddr);
1.52 markus 716:
717: if (options.hostbased_uses_name_from_packet_only) {
718: if (auth_rhosts2(pw, cuser, chost, chost) == 0)
719: return 0;
720: lookup = chost;
721: } else {
1.53 markus 722: if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
723: debug2("stripping trailing dot from chost %s", chost);
724: chost[len - 1] = '\0';
725: }
1.52 markus 726: if (strcasecmp(resolvedname, chost) != 0)
727: log("userauth_hostbased mismatch: "
728: "client sends %s, but we resolve %s to %s",
729: chost, ipaddr, resolvedname);
730: if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
731: return 0;
732: lookup = resolvedname;
733: }
734: debug2("userauth_hostbased: access allowed by auth_rhosts2");
735:
1.56.2.1 jason 736: host_status = check_key_in_hostfiles(pw, key, lookup,
737: _PATH_SSH_SYSTEM_HOSTFILE,
738: options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
739:
740: /* backward compat if no key has been found. */
741: if (host_status == HOST_NEW)
742: host_status = check_key_in_hostfiles(pw, key, lookup,
743: _PATH_SSH_SYSTEM_HOSTFILE2,
744: options.ignore_user_known_hosts ? NULL :
745: _PATH_SSH_USER_HOSTFILE2);
1.52 markus 746:
747: return (host_status == HOST_OK);
1.1 markus 748: }
1.56.2.1 jason 749:
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