Annotation of src/usr.bin/ssh/auth2.c, Revision 1.20.2.8
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"
1.20.2.8! brad 26: RCSID("$OpenBSD: auth2.c,v 1.85 2002/02/24 19:14:59 markus Exp $");
1.1 markus 27:
28: #include <openssl/evp.h>
29:
1.20.2.1 jason 30: #include "ssh2.h"
1.1 markus 31: #include "xmalloc.h"
32: #include "rsa.h"
1.20.2.3 jason 33: #include "sshpty.h"
1.1 markus 34: #include "packet.h"
35: #include "buffer.h"
1.20.2.1 jason 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"
1.20.2.1 jason 45: #include "cipher.h"
1.1 markus 46: #include "kex.h"
1.20.2.1 jason 47: #include "pathnames.h"
1.1 markus 48: #include "uidswap.h"
1.10 markus 49: #include "auth-options.h"
1.20.2.3 jason 50: #include "misc.h"
1.20.2.4 jason 51: #include "hostfile.h"
52: #include "canohost.h"
1.20.2.5 miod 53: #include "match.h"
1.1 markus 54:
55: /* import */
56: extern ServerOptions options;
1.20.2.1 jason 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:
1.20.2.8! brad 72: static void input_service_request(int, u_int32_t, void *);
! 73: static void input_userauth_request(int, u_int32_t, void *);
1.1 markus 74:
75: /* helper */
1.20.2.5 miod 76: static Authmethod *authmethod_lookup(const char *);
77: static char *authmethods_get(void);
78: static int user_key_allowed(struct passwd *, Key *);
79: static int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
1.1 markus 80:
1.18 markus 81: /* auth */
1.20.2.5 miod 82: static void userauth_banner(void);
83: static int userauth_none(Authctxt *);
84: static int userauth_passwd(Authctxt *);
85: static int userauth_pubkey(Authctxt *);
86: static int userauth_hostbased(Authctxt *);
87: static int userauth_kbdint(Authctxt *);
1.18 markus 88:
89: Authmethod authmethods[] = {
90: {"none",
91: userauth_none,
92: &one},
93: {"publickey",
94: userauth_pubkey,
1.20.2.1 jason 95: &options.pubkey_authentication},
1.18 markus 96: {"password",
97: userauth_passwd,
98: &options.password_authentication},
1.20.2.1 jason 99: {"keyboard-interactive",
100: userauth_kbdint,
101: &options.kbd_interactive_authentication},
1.20.2.4 jason 102: {"hostbased",
103: userauth_hostbased,
104: &options.hostbased_authentication},
1.18 markus 105: {NULL, NULL, NULL}
1.1 markus 106: };
107:
108: /*
1.18 markus 109: * loop until authctxt->success == TRUE
1.1 markus 110: */
111:
112: void
1.20.2.8! brad 113: do_authentication2(void)
1.1 markus 114: {
1.20.2.1 jason 115: Authctxt *authctxt = authctxt_new();
116:
1.18 markus 117: x_authctxt = authctxt; /*XXX*/
118:
1.20.2.6 miod 119: /* challenge-response is implemented via keyboard interactive */
1.20.2.5 miod 120: if (options.challenge_response_authentication)
1.20.2.1 jason 121: options.kbd_interactive_authentication = 1;
122:
1.20.2.8! brad 123: dispatch_init(&dispatch_protocol_error);
1.1 markus 124: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 125: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.20.2.4 jason 126: do_authenticated(authctxt);
1.1 markus 127: }
128:
1.20.2.5 miod 129: static void
1.20.2.8! brad 130: input_service_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 131: {
1.18 markus 132: Authctxt *authctxt = ctxt;
1.20.2.1 jason 133: u_int len;
1.1 markus 134: int accept = 0;
135: char *service = packet_get_string(&len);
1.20.2.8! brad 136: packet_check_eom();
1.1 markus 137:
1.18 markus 138: if (authctxt == NULL)
139: fatal("input_service_request: no authctxt");
140:
1.1 markus 141: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 142: if (!authctxt->success) {
1.1 markus 143: accept = 1;
144: /* now we can handle user-auth requests */
145: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
146: }
147: }
148: /* XXX all other service requests are denied */
149:
150: if (accept) {
151: packet_start(SSH2_MSG_SERVICE_ACCEPT);
152: packet_put_cstring(service);
153: packet_send();
154: packet_write_wait();
155: } else {
156: debug("bad service request %s", service);
157: packet_disconnect("bad service request %s", service);
158: }
159: xfree(service);
160: }
161:
1.20.2.5 miod 162: static void
1.20.2.8! brad 163: input_userauth_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 164: {
1.18 markus 165: Authctxt *authctxt = ctxt;
166: Authmethod *m = NULL;
1.20.2.1 jason 167: char *user, *service, *method, *style = NULL;
1.1 markus 168: int authenticated = 0;
169:
1.18 markus 170: if (authctxt == NULL)
171: fatal("input_userauth_request: no authctxt");
1.1 markus 172:
1.18 markus 173: user = packet_get_string(NULL);
174: service = packet_get_string(NULL);
175: method = packet_get_string(NULL);
1.1 markus 176: debug("userauth-request for user %s service %s method %s", user, service, method);
1.20.2.1 jason 177: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
178:
179: if ((style = strchr(user, ':')) != NULL)
180: *style++ = 0;
1.1 markus 181:
1.20.2.1 jason 182: if (authctxt->attempt++ == 0) {
1.18 markus 183: /* setup auth context */
184: struct passwd *pw = NULL;
185: pw = getpwnam(user);
186: if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
187: authctxt->pw = pwcopy(pw);
188: authctxt->valid = 1;
189: debug2("input_userauth_request: setting up authctxt for %s", user);
190: } else {
191: log("input_userauth_request: illegal user %s", user);
192: }
1.20.2.1 jason 193: setproctitle("%s", pw ? user : "unknown");
1.18 markus 194: authctxt->user = xstrdup(user);
195: authctxt->service = xstrdup(service);
1.20.2.5 miod 196: authctxt->style = style ? xstrdup(style) : NULL;
197: } else if (strcmp(user, authctxt->user) != 0 ||
198: strcmp(service, authctxt->service) != 0) {
199: packet_disconnect("Change of username or service not allowed: "
200: "(%s,%s) -> (%s,%s)",
201: authctxt->user, authctxt->service, user, service);
1.1 markus 202: }
1.20.2.1 jason 203: /* reset state */
1.20.2.8! brad 204: auth2_challenge_stop(authctxt);
1.20.2.1 jason 205: authctxt->postponed = 0;
1.18 markus 206:
1.20.2.1 jason 207: /* try to authenticate user */
1.18 markus 208: m = authmethod_lookup(method);
209: if (m != NULL) {
210: debug2("input_userauth_request: try method %s", method);
211: authenticated = m->userauth(authctxt);
212: }
1.20.2.4 jason 213: userauth_finish(authctxt, authenticated, method);
214:
215: xfree(service);
216: xfree(user);
217: xfree(method);
218: }
219:
220: void
221: userauth_finish(Authctxt *authctxt, int authenticated, char *method)
222: {
1.20.2.5 miod 223: char *methods;
224:
1.20.2.1 jason 225: if (!authctxt->valid && authenticated)
226: fatal("INTERNAL ERROR: authenticated invalid user %s",
227: authctxt->user);
1.18 markus 228:
229: /* Special handling for root */
1.20.2.1 jason 230: if (authenticated && authctxt->pw->pw_uid == 0 &&
231: !auth_root_allowed(method))
1.3 markus 232: authenticated = 0;
233:
1.18 markus 234: /* Log before sending the reply */
1.20.2.1 jason 235: auth_log(authctxt, authenticated, method, " ssh2");
236:
1.20.2.5 miod 237: if (authctxt->postponed)
238: return;
239:
240: /* XXX todo: check if multiple auth methods are needed */
241: if (authenticated == 1) {
242: /* turn off userauth */
1.20.2.8! brad 243: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
1.20.2.5 miod 244: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
245: packet_send();
246: packet_write_wait();
247: /* now we can break out */
248: authctxt->success = 1;
249: } else {
250: if (authctxt->failures++ > AUTH_FAIL_MAX)
251: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
252: methods = authmethods_get();
253: packet_start(SSH2_MSG_USERAUTH_FAILURE);
254: packet_put_cstring(methods);
255: packet_put_char(0); /* XXX partial success, unused */
256: packet_send();
257: packet_write_wait();
258: xfree(methods);
259: }
1.18 markus 260: }
261:
1.20.2.5 miod 262: static void
1.20.2.1 jason 263: userauth_banner(void)
1.18 markus 264: {
1.20.2.1 jason 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;
1.20.2.4 jason 272: if ((fd = open(options.banner, O_RDONLY)) < 0)
1.20.2.1 jason 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;
1.18 markus 291: }
1.6 markus 292:
1.20.2.5 miod 293: static int
1.18 markus 294: userauth_none(Authctxt *authctxt)
1.1 markus 295: {
1.18 markus 296: /* disable method "none", only allowed one time */
297: Authmethod *m = authmethod_lookup("none");
298: if (m != NULL)
299: m->enabled = NULL;
1.20.2.8! brad 300: packet_check_eom();
1.20.2.1 jason 301: userauth_banner();
1.20.2.4 jason 302: return authctxt->valid ? auth_password(authctxt, "") : 0;
1.1 markus 303: }
1.18 markus 304:
1.20.2.5 miod 305: static int
1.18 markus 306: userauth_passwd(Authctxt *authctxt)
1.1 markus 307: {
308: char *password;
309: int authenticated = 0;
310: int change;
1.20.2.1 jason 311: u_int len;
1.1 markus 312: change = packet_get_char();
313: if (change)
314: log("password change not supported");
315: password = packet_get_string(&len);
1.20.2.8! brad 316: packet_check_eom();
1.18 markus 317: if (authctxt->valid &&
1.20.2.4 jason 318: auth_password(authctxt, password) == 1)
1.1 markus 319: authenticated = 1;
320: memset(password, 0, len);
321: xfree(password);
322: return authenticated;
323: }
1.18 markus 324:
1.20.2.5 miod 325: static int
1.18 markus 326: userauth_kbdint(Authctxt *authctxt)
327: {
328: int authenticated = 0;
1.20.2.5 miod 329: char *lang, *devs;
1.20.2.8! brad 330:
1.18 markus 331: lang = packet_get_string(NULL);
332: devs = packet_get_string(NULL);
1.20.2.8! brad 333: packet_check_eom();
1.18 markus 334:
1.20.2.5 miod 335: debug("keyboard-interactive devs %s", devs);
1.20.2.1 jason 336:
1.20.2.5 miod 337: if (options.challenge_response_authentication)
1.20.2.1 jason 338: authenticated = auth2_challenge(authctxt, devs);
339:
1.18 markus 340: xfree(devs);
1.20.2.5 miod 341: xfree(lang);
1.18 markus 342: return authenticated;
343: }
344:
1.20.2.5 miod 345: static int
1.18 markus 346: userauth_pubkey(Authctxt *authctxt)
1.1 markus 347: {
348: Buffer b;
1.20.2.8! brad 349: Key *key = NULL;
! 350: char *pkalg;
! 351: u_char *pkblob, *sig;
1.20.2.1 jason 352: u_int alen, blen, slen;
353: int have_sig, pktype;
1.1 markus 354: int authenticated = 0;
355:
1.18 markus 356: if (!authctxt->valid) {
357: debug2("userauth_pubkey: disabled because of invalid user");
1.8 markus 358: return 0;
359: }
1.1 markus 360: have_sig = packet_get_char();
1.20.2.1 jason 361: if (datafellows & SSH_BUG_PKAUTH) {
362: debug2("userauth_pubkey: SSH_BUG_PKAUTH");
363: /* no explicit pkalg given */
364: pkblob = packet_get_string(&blen);
365: buffer_init(&b);
366: buffer_append(&b, pkblob, blen);
367: /* so we have to extract the pkalg from the pkblob */
368: pkalg = buffer_get_string(&b, &alen);
369: buffer_free(&b);
370: } else {
371: pkalg = packet_get_string(&alen);
372: pkblob = packet_get_string(&blen);
373: }
374: pktype = key_type_from_name(pkalg);
375: if (pktype == KEY_UNSPEC) {
376: /* this is perfectly legal */
1.20.2.8! brad 377: log("userauth_pubkey: unsupported public key algorithm: %s",
! 378: pkalg);
! 379: goto done;
1.1 markus 380: }
1.20.2.1 jason 381: key = key_from_blob(pkblob, blen);
1.20.2.8! brad 382: if (key == NULL) {
! 383: error("userauth_pubkey: cannot decode key: %s", pkalg);
! 384: goto done;
! 385: }
! 386: if (key->type != pktype) {
! 387: error("userauth_pubkey: type mismatch for decoded key "
! 388: "(received %d, expected %d)", key->type, pktype);
! 389: goto done;
! 390: }
! 391: if (have_sig) {
! 392: sig = packet_get_string(&slen);
! 393: packet_check_eom();
! 394: buffer_init(&b);
! 395: if (datafellows & SSH_OLD_SESSIONID) {
! 396: buffer_append(&b, session_id2, session_id2_len);
! 397: } else {
! 398: buffer_put_string(&b, session_id2, session_id2_len);
! 399: }
! 400: /* reconstruct packet */
! 401: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
! 402: buffer_put_cstring(&b, authctxt->user);
! 403: buffer_put_cstring(&b,
! 404: datafellows & SSH_BUG_PKSERVICE ?
! 405: "ssh-userauth" :
! 406: authctxt->service);
! 407: if (datafellows & SSH_BUG_PKAUTH) {
! 408: buffer_put_char(&b, have_sig);
! 409: } else {
! 410: buffer_put_cstring(&b, "publickey");
! 411: buffer_put_char(&b, have_sig);
! 412: buffer_put_cstring(&b, pkalg);
! 413: }
! 414: buffer_put_string(&b, pkblob, blen);
1.20.2.1 jason 415: #ifdef DEBUG_PK
1.20.2.8! brad 416: buffer_dump(&b);
1.1 markus 417: #endif
1.20.2.8! brad 418: /* test for correct signature */
! 419: if (user_key_allowed(authctxt->pw, key) &&
! 420: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
! 421: authenticated = 1;
! 422: buffer_clear(&b);
! 423: xfree(sig);
! 424: } else {
! 425: debug("test whether pkalg/pkblob are acceptable");
! 426: packet_check_eom();
1.18 markus 427:
1.20.2.8! brad 428: /* XXX fake reply and always send PK_OK ? */
! 429: /*
! 430: * XXX this allows testing whether a user is allowed
! 431: * to login: if you happen to have a valid pubkey this
! 432: * message is sent. the message is NEVER sent at all
! 433: * if a user is not allowed to login. is this an
! 434: * issue? -markus
! 435: */
! 436: if (user_key_allowed(authctxt->pw, key)) {
! 437: packet_start(SSH2_MSG_USERAUTH_PK_OK);
! 438: packet_put_string(pkalg, alen);
! 439: packet_put_string(pkblob, blen);
! 440: packet_send();
! 441: packet_write_wait();
! 442: authctxt->postponed = 1;
1.1 markus 443: }
444: }
1.20.2.8! brad 445: if (authenticated != 1)
! 446: auth_clear_options();
! 447: done:
1.20.2.1 jason 448: debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
1.20.2.8! brad 449: if (key != NULL)
! 450: key_free(key);
1.1 markus 451: xfree(pkalg);
452: xfree(pkblob);
453: return authenticated;
454: }
455:
1.20.2.5 miod 456: static int
1.20.2.4 jason 457: userauth_hostbased(Authctxt *authctxt)
458: {
459: Buffer b;
1.20.2.8! brad 460: Key *key = NULL;
! 461: char *pkalg, *cuser, *chost, *service;
! 462: u_char *pkblob, *sig;
1.20.2.4 jason 463: u_int alen, blen, slen;
464: int pktype;
465: int authenticated = 0;
466:
467: if (!authctxt->valid) {
468: debug2("userauth_hostbased: disabled because of invalid user");
469: return 0;
470: }
471: pkalg = packet_get_string(&alen);
472: pkblob = packet_get_string(&blen);
473: chost = packet_get_string(NULL);
474: cuser = packet_get_string(NULL);
475: sig = packet_get_string(&slen);
476:
477: debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
478: cuser, chost, pkalg, slen);
479: #ifdef DEBUG_PK
480: debug("signature:");
481: buffer_init(&b);
482: buffer_append(&b, sig, slen);
483: buffer_dump(&b);
484: buffer_free(&b);
485: #endif
486: pktype = key_type_from_name(pkalg);
487: if (pktype == KEY_UNSPEC) {
488: /* this is perfectly legal */
489: log("userauth_hostbased: unsupported "
490: "public key algorithm: %s", pkalg);
491: goto done;
492: }
493: key = key_from_blob(pkblob, blen);
494: if (key == NULL) {
1.20.2.8! brad 495: error("userauth_hostbased: cannot decode key: %s", pkalg);
! 496: goto done;
! 497: }
! 498: if (key->type != pktype) {
! 499: error("userauth_hostbased: type mismatch for decoded key "
! 500: "(received %d, expected %d)", key->type, pktype);
1.20.2.4 jason 501: goto done;
502: }
503: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
504: authctxt->service;
505: buffer_init(&b);
506: buffer_put_string(&b, session_id2, session_id2_len);
507: /* reconstruct packet */
508: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
509: buffer_put_cstring(&b, authctxt->user);
510: buffer_put_cstring(&b, service);
511: buffer_put_cstring(&b, "hostbased");
512: buffer_put_string(&b, pkalg, alen);
513: buffer_put_string(&b, pkblob, blen);
514: buffer_put_cstring(&b, chost);
515: buffer_put_cstring(&b, cuser);
516: #ifdef DEBUG_PK
517: buffer_dump(&b);
518: #endif
519: /* test for allowed key and correct signature */
520: if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
521: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
522: authenticated = 1;
523:
524: buffer_clear(&b);
525: done:
526: debug2("userauth_hostbased: authenticated %d", authenticated);
1.20.2.8! brad 527: if (key != NULL)
! 528: key_free(key);
1.20.2.4 jason 529: xfree(pkalg);
530: xfree(pkblob);
531: xfree(cuser);
532: xfree(chost);
533: xfree(sig);
534: return authenticated;
535: }
536:
1.18 markus 537: /* get current user */
1.1 markus 538:
539: struct passwd*
540: auth_get_user(void)
541: {
1.18 markus 542: return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
1.1 markus 543: }
544:
1.18 markus 545: #define DELIM ","
546:
1.20.2.5 miod 547: static char *
1.18 markus 548: authmethods_get(void)
1.1 markus 549: {
1.18 markus 550: Authmethod *method = NULL;
1.20.2.8! brad 551: Buffer b;
1.18 markus 552: char *list;
1.1 markus 553:
1.20.2.8! brad 554: buffer_init(&b);
1.18 markus 555: for (method = authmethods; method->name != NULL; method++) {
556: if (strcmp(method->name, "none") == 0)
557: continue;
558: if (method->enabled != NULL && *(method->enabled) != 0) {
1.20.2.8! brad 559: if (buffer_len(&b) > 0)
! 560: buffer_append(&b, ",", 1);
! 561: buffer_append(&b, method->name, strlen(method->name));
1.1 markus 562: }
563: }
1.20.2.8! brad 564: buffer_append(&b, "\0", 1);
! 565: list = xstrdup(buffer_ptr(&b));
! 566: buffer_free(&b);
1.18 markus 567: return list;
568: }
569:
1.20.2.5 miod 570: static Authmethod *
1.18 markus 571: authmethod_lookup(const char *name)
572: {
573: Authmethod *method = NULL;
574: if (name != NULL)
575: for (method = authmethods; method->name != NULL; method++)
576: if (method->enabled != NULL &&
577: *(method->enabled) != 0 &&
578: strcmp(name, method->name) == 0)
579: return method;
580: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
581: return NULL;
1.1 markus 582: }
583:
584: /* return 1 if user allows given key */
1.20.2.5 miod 585: static int
586: user_key_allowed2(struct passwd *pw, Key *key, char *file)
1.1 markus 587: {
1.20.2.5 miod 588: char line[8192];
1.1 markus 589: int found_key = 0;
590: FILE *f;
1.20.2.1 jason 591: u_long linenum = 0;
1.1 markus 592: struct stat st;
593: Key *found;
1.20.2.8! brad 594: char *fp;
1.1 markus 595:
1.18 markus 596: if (pw == NULL)
597: return 0;
598:
1.1 markus 599: /* Temporarily use the user's uid. */
1.20.2.4 jason 600: temporarily_use_uid(pw);
1.1 markus 601:
1.20.2.5 miod 602: debug("trying public key file %s", file);
1.1 markus 603:
604: /* Fail quietly if file does not exist */
605: if (stat(file, &st) < 0) {
606: /* Restore the privileged uid. */
607: restore_uid();
608: return 0;
609: }
610: /* Open the file containing the authorized keys. */
611: f = fopen(file, "r");
612: if (!f) {
613: /* Restore the privileged uid. */
614: restore_uid();
615: return 0;
616: }
1.20.2.5 miod 617: if (options.strict_modes &&
618: secure_filename(f, file, pw, line, sizeof(line)) != 0) {
619: fclose(f);
620: log("Authentication refused: %s", line);
621: restore_uid();
622: return 0;
1.1 markus 623: }
1.20.2.5 miod 624:
1.1 markus 625: found_key = 0;
1.16 markus 626: found = key_new(key->type);
1.1 markus 627:
628: while (fgets(line, sizeof(line), f)) {
1.10 markus 629: char *cp, *options = NULL;
1.1 markus 630: linenum++;
631: /* Skip leading whitespace, empty and comment lines. */
632: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
633: ;
634: if (!*cp || *cp == '\n' || *cp == '#')
635: continue;
1.10 markus 636:
1.20.2.5 miod 637: if (key_read(found, &cp) != 1) {
1.10 markus 638: /* no key? check if there are options for this key */
639: int quoted = 0;
1.20.2.1 jason 640: debug2("user_key_allowed: check options: '%s'", cp);
1.10 markus 641: options = cp;
642: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
643: if (*cp == '\\' && cp[1] == '"')
644: cp++; /* Skip both */
645: else if (*cp == '"')
646: quoted = !quoted;
647: }
648: /* Skip remaining whitespace. */
649: for (; *cp == ' ' || *cp == '\t'; cp++)
650: ;
1.20.2.5 miod 651: if (key_read(found, &cp) != 1) {
1.20.2.1 jason 652: debug2("user_key_allowed: advance: '%s'", cp);
1.10 markus 653: /* still no key? advance to next line*/
654: continue;
655: }
656: }
657: if (key_equal(found, key) &&
1.20.2.1 jason 658: auth_parse_options(pw, options, file, linenum) == 1) {
1.1 markus 659: found_key = 1;
1.20.2.5 miod 660: debug("matching key found: file %s, line %lu",
1.1 markus 661: file, linenum);
1.20.2.8! brad 662: fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
! 663: verbose("Found matching %s key: %s",
! 664: key_type(found), fp);
! 665: xfree(fp);
1.1 markus 666: break;
667: }
668: }
669: restore_uid();
670: fclose(f);
671: key_free(found);
1.20.2.3 jason 672: if (!found_key)
673: debug2("key not found");
1.1 markus 674: return found_key;
1.20.2.4 jason 675: }
676:
1.20.2.5 miod 677: /* check whether given key is in .ssh/authorized_keys* */
678: static int
679: user_key_allowed(struct passwd *pw, Key *key)
680: {
681: int success;
682: char *file;
683:
684: file = authorized_keys_file(pw);
685: success = user_key_allowed2(pw, key, file);
686: xfree(file);
687: if (success)
688: return success;
689:
690: /* try suffix "2" for backward compat, too */
691: file = authorized_keys_file2(pw);
692: success = user_key_allowed2(pw, key, file);
693: xfree(file);
694: return success;
695: }
696:
1.20.2.4 jason 697: /* return 1 if given hostkey is allowed */
1.20.2.5 miod 698: static int
1.20.2.4 jason 699: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
700: Key *key)
701: {
702: const char *resolvedname, *ipaddr, *lookup;
1.20.2.8! brad 703: HostStatus host_status;
! 704: int len;
1.20.2.4 jason 705:
1.20.2.8! brad 706: resolvedname = get_canonical_hostname(options.verify_reverse_mapping);
1.20.2.4 jason 707: ipaddr = get_remote_ipaddr();
708:
709: debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
710: chost, resolvedname, ipaddr);
711:
712: if (options.hostbased_uses_name_from_packet_only) {
713: if (auth_rhosts2(pw, cuser, chost, chost) == 0)
714: return 0;
715: lookup = chost;
716: } else {
717: if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
718: debug2("stripping trailing dot from chost %s", chost);
719: chost[len - 1] = '\0';
720: }
721: if (strcasecmp(resolvedname, chost) != 0)
722: log("userauth_hostbased mismatch: "
723: "client sends %s, but we resolve %s to %s",
724: chost, ipaddr, resolvedname);
725: if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
726: return 0;
727: lookup = resolvedname;
728: }
729: debug2("userauth_hostbased: access allowed by auth_rhosts2");
730:
1.20.2.5 miod 731: host_status = check_key_in_hostfiles(pw, key, lookup,
732: _PATH_SSH_SYSTEM_HOSTFILE,
733: options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
734:
735: /* backward compat if no key has been found. */
736: if (host_status == HOST_NEW)
737: host_status = check_key_in_hostfiles(pw, key, lookup,
738: _PATH_SSH_SYSTEM_HOSTFILE2,
739: options.ignore_user_known_hosts ? NULL :
740: _PATH_SSH_USER_HOSTFILE2);
1.20.2.4 jason 741:
742: return (host_status == HOST_OK);
1.1 markus 743: }
![[BACK]](/icons/back.gif){kind=icon}
Return to auth2.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh