Annotation of src/usr.bin/ssh/auth2-pubkey.c, Revision 1.44
1.44 ! djm 1: /* $OpenBSD: auth2-pubkey.c,v 1.43 2014/12/21 22:27:56 djm Exp $ */
1.1 markus 2: /*
3: * Copyright (c) 2000 Markus Friedl. All rights reserved.
4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: *
14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24: */
25:
1.10 stevesk 26:
27: #include <sys/types.h>
28: #include <sys/stat.h>
1.31 djm 29: #include <sys/wait.h>
1.13 stevesk 30:
1.31 djm 31: #include <errno.h>
1.16 djm 32: #include <fcntl.h>
1.31 djm 33: #include <paths.h>
1.13 stevesk 34: #include <pwd.h>
1.31 djm 35: #include <signal.h>
1.14 stevesk 36: #include <stdio.h>
1.15 deraadt 37: #include <stdarg.h>
1.20 djm 38: #include <string.h>
39: #include <time.h>
1.17 dtucker 40: #include <unistd.h>
1.44 ! djm 41: #include <limits.h>
1.1 markus 42:
1.15 deraadt 43: #include "xmalloc.h"
1.8 dtucker 44: #include "ssh.h"
1.1 markus 45: #include "ssh2.h"
46: #include "packet.h"
47: #include "buffer.h"
48: #include "log.h"
1.41 millert 49: #include "misc.h"
1.1 markus 50: #include "servconf.h"
51: #include "compat.h"
1.15 deraadt 52: #include "key.h"
53: #include "hostfile.h"
1.1 markus 54: #include "auth.h"
55: #include "pathnames.h"
56: #include "uidswap.h"
57: #include "auth-options.h"
58: #include "canohost.h"
1.15 deraadt 59: #ifdef GSSAPI
60: #include "ssh-gss.h"
61: #endif
1.1 markus 62: #include "monitor_wrap.h"
1.21 djm 63: #include "authfile.h"
1.24 djm 64: #include "match.h"
1.1 markus 65:
66: /* import */
67: extern ServerOptions options;
68: extern u_char *session_id2;
1.4 markus 69: extern u_int session_id2_len;
1.1 markus 70:
1.2 markus 71: static int
1.1 markus 72: userauth_pubkey(Authctxt *authctxt)
73: {
74: Buffer b;
75: Key *key = NULL;
1.35 djm 76: char *pkalg, *userstyle;
1.1 markus 77: u_char *pkblob, *sig;
78: u_int alen, blen, slen;
79: int have_sig, pktype;
80: int authenticated = 0;
81:
82: if (!authctxt->valid) {
83: debug2("userauth_pubkey: disabled because of invalid user");
84: return 0;
85: }
86: have_sig = packet_get_char();
87: if (datafellows & SSH_BUG_PKAUTH) {
88: debug2("userauth_pubkey: SSH_BUG_PKAUTH");
89: /* no explicit pkalg given */
90: pkblob = packet_get_string(&blen);
91: buffer_init(&b);
92: buffer_append(&b, pkblob, blen);
93: /* so we have to extract the pkalg from the pkblob */
94: pkalg = buffer_get_string(&b, &alen);
95: buffer_free(&b);
96: } else {
97: pkalg = packet_get_string(&alen);
98: pkblob = packet_get_string(&blen);
99: }
100: pktype = key_type_from_name(pkalg);
101: if (pktype == KEY_UNSPEC) {
102: /* this is perfectly legal */
1.3 itojun 103: logit("userauth_pubkey: unsupported public key algorithm: %s",
1.1 markus 104: pkalg);
105: goto done;
106: }
107: key = key_from_blob(pkblob, blen);
108: if (key == NULL) {
109: error("userauth_pubkey: cannot decode key: %s", pkalg);
110: goto done;
111: }
112: if (key->type != pktype) {
113: error("userauth_pubkey: type mismatch for decoded key "
114: "(received %d, expected %d)", key->type, pktype);
1.39 djm 115: goto done;
116: }
117: if (key_type_plain(key->type) == KEY_RSA &&
118: (datafellows & SSH_BUG_RSASIGMD5) != 0) {
119: logit("Refusing RSA key because client uses unsafe "
120: "signature scheme");
1.1 markus 121: goto done;
122: }
1.44 ! djm 123: if (auth2_userkey_already_used(authctxt, key)) {
! 124: logit("refusing previously-used %s key", key_type(key));
! 125: goto done;
! 126: }
1.1 markus 127: if (have_sig) {
128: sig = packet_get_string(&slen);
129: packet_check_eom();
130: buffer_init(&b);
131: if (datafellows & SSH_OLD_SESSIONID) {
132: buffer_append(&b, session_id2, session_id2_len);
133: } else {
134: buffer_put_string(&b, session_id2, session_id2_len);
135: }
136: /* reconstruct packet */
137: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.35 djm 138: xasprintf(&userstyle, "%s%s%s", authctxt->user,
139: authctxt->style ? ":" : "",
140: authctxt->style ? authctxt->style : "");
141: buffer_put_cstring(&b, userstyle);
142: free(userstyle);
1.1 markus 143: buffer_put_cstring(&b,
144: datafellows & SSH_BUG_PKSERVICE ?
145: "ssh-userauth" :
146: authctxt->service);
147: if (datafellows & SSH_BUG_PKAUTH) {
148: buffer_put_char(&b, have_sig);
149: } else {
150: buffer_put_cstring(&b, "publickey");
151: buffer_put_char(&b, have_sig);
152: buffer_put_cstring(&b, pkalg);
153: }
154: buffer_put_string(&b, pkblob, blen);
155: #ifdef DEBUG_PK
156: buffer_dump(&b);
157: #endif
1.38 djm 158: pubkey_auth_info(authctxt, key, NULL);
1.37 djm 159:
1.1 markus 160: /* test for correct signature */
161: authenticated = 0;
162: if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
163: PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
1.44 ! djm 164: buffer_len(&b))) == 1) {
1.1 markus 165: authenticated = 1;
1.44 ! djm 166: /* Record the successful key to prevent reuse */
! 167: auth2_record_userkey(authctxt, key);
! 168: key = NULL; /* Don't free below */
! 169: }
1.6 markus 170: buffer_free(&b);
1.36 djm 171: free(sig);
1.1 markus 172: } else {
173: debug("test whether pkalg/pkblob are acceptable");
174: packet_check_eom();
175:
176: /* XXX fake reply and always send PK_OK ? */
177: /*
178: * XXX this allows testing whether a user is allowed
179: * to login: if you happen to have a valid pubkey this
180: * message is sent. the message is NEVER sent at all
181: * if a user is not allowed to login. is this an
182: * issue? -markus
183: */
184: if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
185: packet_start(SSH2_MSG_USERAUTH_PK_OK);
186: packet_put_string(pkalg, alen);
187: packet_put_string(pkblob, blen);
188: packet_send();
189: packet_write_wait();
190: authctxt->postponed = 1;
191: }
192: }
193: if (authenticated != 1)
194: auth_clear_options();
195: done:
196: debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
197: if (key != NULL)
198: key_free(key);
1.36 djm 199: free(pkalg);
200: free(pkblob);
1.1 markus 201: return authenticated;
202: }
203:
1.37 djm 204: void
1.38 djm 205: pubkey_auth_info(Authctxt *authctxt, const Key *key, const char *fmt, ...)
1.37 djm 206: {
1.38 djm 207: char *fp, *extra;
208: va_list ap;
209: int i;
210:
211: extra = NULL;
212: if (fmt != NULL) {
213: va_start(ap, fmt);
214: i = vasprintf(&extra, fmt, ap);
215: va_end(ap);
216: if (i < 0 || extra == NULL)
217: fatal("%s: vasprintf failed", __func__);
218: }
1.37 djm 219:
220: if (key_is_cert(key)) {
221: fp = key_fingerprint(key->cert->signature_key,
1.43 djm 222: options.fingerprint_hash, SSH_FP_DEFAULT);
1.38 djm 223: auth_info(authctxt, "%s ID %s (serial %llu) CA %s %s%s%s",
1.37 djm 224: key_type(key), key->cert->key_id,
225: (unsigned long long)key->cert->serial,
1.38 djm 226: key_type(key->cert->signature_key), fp,
227: extra == NULL ? "" : ", ", extra == NULL ? "" : extra);
1.37 djm 228: free(fp);
229: } else {
1.43 djm 230: fp = key_fingerprint(key, options.fingerprint_hash,
231: SSH_FP_DEFAULT);
1.38 djm 232: auth_info(authctxt, "%s %s%s%s", key_type(key), fp,
233: extra == NULL ? "" : ", ", extra == NULL ? "" : extra);
1.37 djm 234: free(fp);
235: }
1.38 djm 236: free(extra);
1.37 djm 237: }
238:
1.24 djm 239: static int
1.40 djm 240: match_principals_option(const char *principal_list, struct sshkey_cert *cert)
1.24 djm 241: {
242: char *result;
243: u_int i;
244:
245: /* XXX percent_expand() sequences for authorized_principals? */
246:
247: for (i = 0; i < cert->nprincipals; i++) {
248: if ((result = match_list(cert->principals[i],
249: principal_list, NULL)) != NULL) {
250: debug3("matched principal from key options \"%.100s\"",
251: result);
1.36 djm 252: free(result);
1.24 djm 253: return 1;
254: }
255: }
256: return 0;
257: }
258:
259: static int
1.40 djm 260: match_principals_file(char *file, struct passwd *pw, struct sshkey_cert *cert)
1.24 djm 261: {
262: FILE *f;
1.26 djm 263: char line[SSH_MAX_PUBKEY_BYTES], *cp, *ep, *line_opts;
1.24 djm 264: u_long linenum = 0;
265: u_int i;
266:
267: temporarily_use_uid(pw);
268: debug("trying authorized principals file %s", file);
269: if ((f = auth_openprincipals(file, pw, options.strict_modes)) == NULL) {
270: restore_uid();
271: return 0;
272: }
273: while (read_keyfile_line(f, file, line, sizeof(line), &linenum) != -1) {
1.26 djm 274: /* Skip leading whitespace. */
1.24 djm 275: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
276: ;
1.26 djm 277: /* Skip blank and comment lines. */
278: if ((ep = strchr(cp, '#')) != NULL)
279: *ep = '\0';
280: if (!*cp || *cp == '\n')
1.24 djm 281: continue;
1.26 djm 282: /* Trim trailing whitespace. */
283: ep = cp + strlen(cp) - 1;
284: while (ep > cp && (*ep == '\n' || *ep == ' ' || *ep == '\t'))
285: *ep-- = '\0';
286: /*
287: * If the line has internal whitespace then assume it has
288: * key options.
289: */
290: line_opts = NULL;
291: if ((ep = strrchr(cp, ' ')) != NULL ||
292: (ep = strrchr(cp, '\t')) != NULL) {
293: for (; *ep == ' ' || *ep == '\t'; ep++)
1.27 deraadt 294: ;
1.26 djm 295: line_opts = cp;
296: cp = ep;
297: }
1.24 djm 298: for (i = 0; i < cert->nprincipals; i++) {
299: if (strcmp(cp, cert->principals[i]) == 0) {
1.30 djm 300: debug3("matched principal \"%.100s\" "
301: "from file \"%s\" on line %lu",
1.31 djm 302: cert->principals[i], file, linenum);
1.26 djm 303: if (auth_parse_options(pw, line_opts,
304: file, linenum) != 1)
305: continue;
1.24 djm 306: fclose(f);
307: restore_uid();
308: return 1;
309: }
310: }
311: }
312: fclose(f);
313: restore_uid();
314: return 0;
1.31 djm 315: }
1.24 djm 316:
1.31 djm 317: /*
318: * Checks whether key is allowed in authorized_keys-format file,
319: * returns 1 if the key is allowed or 0 otherwise.
320: */
1.1 markus 321: static int
1.31 djm 322: check_authkeys_file(FILE *f, char *file, Key* key, struct passwd *pw)
1.1 markus 323: {
1.8 dtucker 324: char line[SSH_MAX_PUBKEY_BYTES];
1.20 djm 325: const char *reason;
1.18 dtucker 326: int found_key = 0;
1.1 markus 327: u_long linenum = 0;
328: Key *found;
329: char *fp;
330:
331: found_key = 0;
332:
1.37 djm 333: found = NULL;
1.8 dtucker 334: while (read_keyfile_line(f, file, line, sizeof(line), &linenum) != -1) {
1.7 avsm 335: char *cp, *key_options = NULL;
1.37 djm 336: if (found != NULL)
337: key_free(found);
338: found = key_new(key_is_cert(key) ? KEY_UNSPEC : key->type);
1.20 djm 339: auth_clear_options();
340:
1.1 markus 341: /* Skip leading whitespace, empty and comment lines. */
342: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
343: ;
344: if (!*cp || *cp == '\n' || *cp == '#')
345: continue;
346:
347: if (key_read(found, &cp) != 1) {
348: /* no key? check if there are options for this key */
349: int quoted = 0;
350: debug2("user_key_allowed: check options: '%s'", cp);
1.7 avsm 351: key_options = cp;
1.1 markus 352: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
353: if (*cp == '\\' && cp[1] == '"')
354: cp++; /* Skip both */
355: else if (*cp == '"')
356: quoted = !quoted;
357: }
358: /* Skip remaining whitespace. */
359: for (; *cp == ' ' || *cp == '\t'; cp++)
360: ;
361: if (key_read(found, &cp) != 1) {
362: debug2("user_key_allowed: advance: '%s'", cp);
363: /* still no key? advance to next line*/
364: continue;
365: }
366: }
1.23 djm 367: if (key_is_cert(key)) {
1.25 djm 368: if (!key_equal(found, key->cert->signature_key))
369: continue;
370: if (auth_parse_options(pw, key_options, file,
371: linenum) != 1)
372: continue;
1.20 djm 373: if (!key_is_cert_authority)
374: continue;
1.43 djm 375: fp = key_fingerprint(found, options.fingerprint_hash,
376: SSH_FP_DEFAULT);
1.22 djm 377: debug("matching CA found: file %s, line %lu, %s %s",
378: file, linenum, key_type(found), fp);
1.24 djm 379: /*
380: * If the user has specified a list of principals as
381: * a key option, then prefer that list to matching
382: * their username in the certificate principals list.
383: */
384: if (authorized_principals != NULL &&
385: !match_principals_option(authorized_principals,
386: key->cert)) {
387: reason = "Certificate does not contain an "
388: "authorized principal";
389: fail_reason:
1.36 djm 390: free(fp);
1.20 djm 391: error("%s", reason);
392: auth_debug_add("%s", reason);
393: continue;
394: }
1.24 djm 395: if (key_cert_check_authority(key, 0, 0,
396: authorized_principals == NULL ? pw->pw_name : NULL,
397: &reason) != 0)
398: goto fail_reason;
1.23 djm 399: if (auth_cert_options(key, pw) != 0) {
1.36 djm 400: free(fp);
1.20 djm 401: continue;
1.22 djm 402: }
403: verbose("Accepted certificate ID \"%s\" "
404: "signed by %s CA %s via %s", key->cert->key_id,
405: key_type(found), fp, file);
1.36 djm 406: free(fp);
1.20 djm 407: found_key = 1;
408: break;
1.25 djm 409: } else if (key_equal(found, key)) {
410: if (auth_parse_options(pw, key_options, file,
411: linenum) != 1)
412: continue;
413: if (key_is_cert_authority)
414: continue;
1.1 markus 415: found_key = 1;
1.43 djm 416: fp = key_fingerprint(found, options.fingerprint_hash,
417: SSH_FP_DEFAULT);
1.37 djm 418: debug("matching key found: file %s, line %lu %s %s",
419: file, linenum, key_type(found), fp);
1.36 djm 420: free(fp);
1.1 markus 421: break;
422: }
423: }
1.37 djm 424: if (found != NULL)
425: key_free(found);
1.1 markus 426: if (!found_key)
427: debug2("key not found");
428: return found_key;
429: }
430:
1.21 djm 431: /* Authenticate a certificate key against TrustedUserCAKeys */
432: static int
433: user_cert_trusted_ca(struct passwd *pw, Key *key)
434: {
1.24 djm 435: char *ca_fp, *principals_file = NULL;
1.21 djm 436: const char *reason;
437: int ret = 0;
438:
439: if (!key_is_cert(key) || options.trusted_user_ca_keys == NULL)
440: return 0;
441:
1.22 djm 442: ca_fp = key_fingerprint(key->cert->signature_key,
1.43 djm 443: options.fingerprint_hash, SSH_FP_DEFAULT);
1.21 djm 444:
1.42 djm 445: if (sshkey_in_file(key->cert->signature_key,
446: options.trusted_user_ca_keys, 1, 0) != 0) {
1.21 djm 447: debug2("%s: CA %s %s is not listed in %s", __func__,
448: key_type(key->cert->signature_key), ca_fp,
449: options.trusted_user_ca_keys);
450: goto out;
451: }
1.24 djm 452: /*
453: * If AuthorizedPrincipals is in use, then compare the certificate
454: * principals against the names in that file rather than matching
455: * against the username.
456: */
457: if ((principals_file = authorized_principals_file(pw)) != NULL) {
458: if (!match_principals_file(principals_file, pw, key->cert)) {
459: reason = "Certificate does not contain an "
460: "authorized principal";
461: fail_reason:
462: error("%s", reason);
463: auth_debug_add("%s", reason);
464: goto out;
465: }
1.21 djm 466: }
1.24 djm 467: if (key_cert_check_authority(key, 0, 1,
468: principals_file == NULL ? pw->pw_name : NULL, &reason) != 0)
469: goto fail_reason;
1.23 djm 470: if (auth_cert_options(key, pw) != 0)
1.21 djm 471: goto out;
472:
1.22 djm 473: verbose("Accepted certificate ID \"%s\" signed by %s CA %s via %s",
474: key->cert->key_id, key_type(key->cert->signature_key), ca_fp,
475: options.trusted_user_ca_keys);
1.21 djm 476: ret = 1;
477:
478: out:
1.36 djm 479: free(principals_file);
480: free(ca_fp);
1.21 djm 481: return ret;
482: }
483:
1.31 djm 484: /*
485: * Checks whether key is allowed in file.
486: * returns 1 if the key is allowed or 0 otherwise.
487: */
488: static int
489: user_key_allowed2(struct passwd *pw, Key *key, char *file)
490: {
491: FILE *f;
492: int found_key = 0;
493:
494: /* Temporarily use the user's uid. */
495: temporarily_use_uid(pw);
496:
497: debug("trying public key file %s", file);
498: if ((f = auth_openkeyfile(file, pw, options.strict_modes)) != NULL) {
499: found_key = check_authkeys_file(f, file, key, pw);
500: fclose(f);
501: }
502:
503: restore_uid();
504: return found_key;
505: }
506:
507: /*
508: * Checks whether key is allowed in output of command.
509: * returns 1 if the key is allowed or 0 otherwise.
510: */
511: static int
512: user_key_command_allowed2(struct passwd *user_pw, Key *key)
513: {
514: FILE *f;
515: int ok, found_key = 0;
516: struct passwd *pw;
517: struct stat st;
518: int status, devnull, p[2], i;
519: pid_t pid;
1.32 djm 520: char *username, errmsg[512];
1.31 djm 521:
522: if (options.authorized_keys_command == NULL ||
523: options.authorized_keys_command[0] != '/')
524: return 0;
525:
1.32 djm 526: if (options.authorized_keys_command_user == NULL) {
527: error("No user for AuthorizedKeysCommand specified, skipping");
528: return 0;
529: }
530:
531: username = percent_expand(options.authorized_keys_command_user,
532: "u", user_pw->pw_name, (char *)NULL);
533: pw = getpwnam(username);
534: if (pw == NULL) {
1.34 djm 535: error("AuthorizedKeysCommandUser \"%s\" not found: %s",
536: username, strerror(errno));
1.32 djm 537: free(username);
538: return 0;
1.31 djm 539: }
1.32 djm 540: free(username);
1.31 djm 541:
542: temporarily_use_uid(pw);
543:
544: if (stat(options.authorized_keys_command, &st) < 0) {
545: error("Could not stat AuthorizedKeysCommand \"%s\": %s",
546: options.authorized_keys_command, strerror(errno));
547: goto out;
548: }
549: if (auth_secure_path(options.authorized_keys_command, &st, NULL, 0,
550: errmsg, sizeof(errmsg)) != 0) {
551: error("Unsafe AuthorizedKeysCommand: %s", errmsg);
552: goto out;
553: }
554:
555: if (pipe(p) != 0) {
556: error("%s: pipe: %s", __func__, strerror(errno));
557: goto out;
558: }
559:
1.33 djm 560: debug3("Running AuthorizedKeysCommand: \"%s %s\" as \"%s\"",
561: options.authorized_keys_command, user_pw->pw_name, pw->pw_name);
1.31 djm 562:
563: /*
564: * Don't want to call this in the child, where it can fatal() and
565: * run cleanup_exit() code.
566: */
567: restore_uid();
568:
569: switch ((pid = fork())) {
570: case -1: /* error */
571: error("%s: fork: %s", __func__, strerror(errno));
572: close(p[0]);
573: close(p[1]);
574: return 0;
575: case 0: /* child */
576: for (i = 0; i < NSIG; i++)
577: signal(i, SIG_DFL);
578:
1.33 djm 579: if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
580: error("%s: open %s: %s", __func__, _PATH_DEVNULL,
581: strerror(errno));
582: _exit(1);
583: }
584: /* Keep stderr around a while longer to catch errors */
585: if (dup2(devnull, STDIN_FILENO) == -1 ||
586: dup2(p[1], STDOUT_FILENO) == -1) {
587: error("%s: dup2: %s", __func__, strerror(errno));
588: _exit(1);
589: }
1.32 djm 590: closefrom(STDERR_FILENO + 1);
1.33 djm 591:
1.31 djm 592: /* Don't use permanently_set_uid() here to avoid fatal() */
593: if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
594: error("setresgid %u: %s", (u_int)pw->pw_gid,
595: strerror(errno));
596: _exit(1);
597: }
598: if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
599: error("setresuid %u: %s", (u_int)pw->pw_uid,
600: strerror(errno));
601: _exit(1);
602: }
1.33 djm 603: /* stdin is pointed to /dev/null at this point */
604: if (dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
1.31 djm 605: error("%s: dup2: %s", __func__, strerror(errno));
606: _exit(1);
607: }
608:
609: execl(options.authorized_keys_command,
1.33 djm 610: options.authorized_keys_command, user_pw->pw_name, NULL);
1.31 djm 611:
612: error("AuthorizedKeysCommand %s exec failed: %s",
613: options.authorized_keys_command, strerror(errno));
614: _exit(127);
615: default: /* parent */
616: break;
617: }
618:
619: temporarily_use_uid(pw);
620:
621: close(p[1]);
622: if ((f = fdopen(p[0], "r")) == NULL) {
623: error("%s: fdopen: %s", __func__, strerror(errno));
624: close(p[0]);
625: /* Don't leave zombie child */
626: kill(pid, SIGTERM);
627: while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
628: ;
629: goto out;
630: }
631: ok = check_authkeys_file(f, options.authorized_keys_command, key, pw);
632: fclose(f);
633:
634: while (waitpid(pid, &status, 0) == -1) {
635: if (errno != EINTR) {
636: error("%s: waitpid: %s", __func__, strerror(errno));
637: goto out;
638: }
639: }
640: if (WIFSIGNALED(status)) {
641: error("AuthorizedKeysCommand %s exited on signal %d",
642: options.authorized_keys_command, WTERMSIG(status));
643: goto out;
644: } else if (WEXITSTATUS(status) != 0) {
645: error("AuthorizedKeysCommand %s returned status %d",
646: options.authorized_keys_command, WEXITSTATUS(status));
647: goto out;
648: }
649: found_key = ok;
650: out:
651: restore_uid();
652: return found_key;
653: }
654:
655: /*
656: * Check whether key authenticates and authorises the user.
657: */
1.1 markus 658: int
659: user_key_allowed(struct passwd *pw, Key *key)
660: {
1.29 djm 661: u_int success, i;
1.1 markus 662: char *file;
1.21 djm 663:
664: if (auth_key_is_revoked(key))
665: return 0;
666: if (key_is_cert(key) && auth_key_is_revoked(key->cert->signature_key))
667: return 0;
668:
669: success = user_cert_trusted_ca(pw, key);
670: if (success)
671: return success;
1.1 markus 672:
1.31 djm 673: success = user_key_command_allowed2(pw, key);
674: if (success > 0)
675: return success;
676:
1.29 djm 677: for (i = 0; !success && i < options.num_authkeys_files; i++) {
1.31 djm 678:
679: if (strcasecmp(options.authorized_keys_files[i], "none") == 0)
680: continue;
1.29 djm 681: file = expand_authorized_keys(
682: options.authorized_keys_files[i], pw);
1.31 djm 683:
1.29 djm 684: success = user_key_allowed2(pw, key, file);
1.36 djm 685: free(file);
1.29 djm 686: }
1.1 markus 687:
688: return success;
1.44 ! djm 689: }
! 690:
! 691: /* Records a public key in the list of previously-successful keys */
! 692: void
! 693: auth2_record_userkey(Authctxt *authctxt, struct sshkey *key)
! 694: {
! 695: struct sshkey **tmp;
! 696:
! 697: if (authctxt->nprev_userkeys >= INT_MAX ||
! 698: (tmp = reallocarray(authctxt->prev_userkeys,
! 699: authctxt->nprev_userkeys + 1, sizeof(*tmp))) == NULL)
! 700: fatal("%s: reallocarray failed", __func__);
! 701: authctxt->prev_userkeys = tmp;
! 702: authctxt->prev_userkeys[authctxt->nprev_userkeys] = key;
! 703: authctxt->nprev_userkeys++;
! 704: }
! 705:
! 706: /* Checks whether a key has already been used successfully for authentication */
! 707: int
! 708: auth2_userkey_already_used(Authctxt *authctxt, struct sshkey *key)
! 709: {
! 710: u_int i;
! 711:
! 712: for (i = 0; i < authctxt->nprev_userkeys; i++) {
! 713: if (sshkey_equal_public(key, authctxt->prev_userkeys[i])) {
! 714: return 1;
! 715: }
! 716: }
! 717: return 0;
1.1 markus 718: }
1.2 markus 719:
720: Authmethod method_pubkey = {
721: "publickey",
722: userauth_pubkey,
723: &options.pubkey_authentication
724: };
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