1/* $OpenBSD: auth2-pubkey.c,v 1.47 2015/02/17 00:14:05 djm Exp $ */
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
26#include "includes.h"
27
28#include <sys/types.h>
29#include <sys/stat.h>
30#include <sys/wait.h>
31
32#include <errno.h>
33#include <fcntl.h>
34#ifdef HAVE_PATHS_H
35# include <paths.h>
36#endif
37#include <pwd.h>
38#include <signal.h>
39#include <stdio.h>
40#include <stdarg.h>
41#include <string.h>
42#include <time.h>
43#include <unistd.h>
44#include <limits.h>
45
46#include "xmalloc.h"
47#include "ssh.h"
48#include "ssh2.h"
49#include "packet.h"
50#include "buffer.h"
51#include "log.h"
52#include "misc.h"
53#include "servconf.h"
54#include "compat.h"
55#include "key.h"
56#include "hostfile.h"
57#include "auth.h"
58#include "pathnames.h"
59#include "uidswap.h"
60#include "auth-options.h"
61#include "canohost.h"
62#ifdef GSSAPI
63#include "ssh-gss.h"
64#endif
65#include "monitor_wrap.h"
66#include "authfile.h"
67#include "match.h"
68
69/* import */
70extern ServerOptions options;
71extern u_char *session_id2;
72extern u_int session_id2_len;
73
74static int
75userauth_pubkey(Authctxt *authctxt)
76{
77	Buffer b;
78	Key *key = NULL;
79	char *pkalg, *userstyle;
80	u_char *pkblob, *sig;
81	u_int alen, blen, slen;
82	int have_sig, pktype;
83	int authenticated = 0;
84
85	if (!authctxt->valid) {
86		debug2("userauth_pubkey: disabled because of invalid user");
87		return 0;
88	}
89	have_sig = packet_get_char();
90	if (datafellows & SSH_BUG_PKAUTH) {
91		debug2("userauth_pubkey: SSH_BUG_PKAUTH");
92		/* no explicit pkalg given */
93		pkblob = packet_get_string(&blen);
94		buffer_init(&b);
95		buffer_append(&b, pkblob, blen);
96		/* so we have to extract the pkalg from the pkblob */
97		pkalg = buffer_get_string(&b, &alen);
98		buffer_free(&b);
99	} else {
100		pkalg = packet_get_string(&alen);
101		pkblob = packet_get_string(&blen);
102	}
103	pktype = key_type_from_name(pkalg);
104	if (pktype == KEY_UNSPEC) {
105		/* this is perfectly legal */
106		logit("userauth_pubkey: unsupported public key algorithm: %s",
107		    pkalg);
108		goto done;
109	}
110	key = key_from_blob(pkblob, blen);
111	if (key == NULL) {
112		error("userauth_pubkey: cannot decode key: %s", pkalg);
113		goto done;
114	}
115	if (key->type != pktype) {
116		error("userauth_pubkey: type mismatch for decoded key "
117		    "(received %d, expected %d)", key->type, pktype);
118		goto done;
119	}
120	if (key_type_plain(key->type) == KEY_RSA &&
121	    (datafellows & SSH_BUG_RSASIGMD5) != 0) {
122		logit("Refusing RSA key because client uses unsafe "
123		    "signature scheme");
124		goto done;
125	}
126	if (auth2_userkey_already_used(authctxt, key)) {
127		logit("refusing previously-used %s key", key_type(key));
128		goto done;
129	}
130	if (match_pattern_list(sshkey_ssh_name(key), options.pubkey_key_types,
131	    strlen(options.pubkey_key_types), 0) != 1) {
132		logit("%s: key type %s not in PubkeyAcceptedKeyTypes",
133		    __func__, sshkey_ssh_name(key));
134		goto done;
135	}
136
137	if (have_sig) {
138		sig = packet_get_string(&slen);
139		packet_check_eom();
140		buffer_init(&b);
141		if (datafellows & SSH_OLD_SESSIONID) {
142			buffer_append(&b, session_id2, session_id2_len);
143		} else {
144			buffer_put_string(&b, session_id2, session_id2_len);
145		}
146		/* reconstruct packet */
147		buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
148		xasprintf(&userstyle, "%s%s%s", authctxt->user,
149		    authctxt->style ? ":" : "",
150		    authctxt->style ? authctxt->style : "");
151		buffer_put_cstring(&b, userstyle);
152		free(userstyle);
153		buffer_put_cstring(&b,
154		    datafellows & SSH_BUG_PKSERVICE ?
155		    "ssh-userauth" :
156		    authctxt->service);
157		if (datafellows & SSH_BUG_PKAUTH) {
158			buffer_put_char(&b, have_sig);
159		} else {
160			buffer_put_cstring(&b, "publickey");
161			buffer_put_char(&b, have_sig);
162			buffer_put_cstring(&b, pkalg);
163		}
164		buffer_put_string(&b, pkblob, blen);
165#ifdef DEBUG_PK
166		buffer_dump(&b);
167#endif
168		pubkey_auth_info(authctxt, key, NULL);
169
170		/* test for correct signature */
171		authenticated = 0;
172		if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
173		    PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
174		    buffer_len(&b))) == 1) {
175			authenticated = 1;
176			/* Record the successful key to prevent reuse */
177			auth2_record_userkey(authctxt, key);
178			key = NULL; /* Don't free below */
179		}
180		buffer_free(&b);
181		free(sig);
182	} else {
183		debug("test whether pkalg/pkblob are acceptable");
184		packet_check_eom();
185
186		/* XXX fake reply and always send PK_OK ? */
187		/*
188		 * XXX this allows testing whether a user is allowed
189		 * to login: if you happen to have a valid pubkey this
190		 * message is sent. the message is NEVER sent at all
191		 * if a user is not allowed to login. is this an
192		 * issue? -markus
193		 */
194		if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
195			packet_start(SSH2_MSG_USERAUTH_PK_OK);
196			packet_put_string(pkalg, alen);
197			packet_put_string(pkblob, blen);
198			packet_send();
199			packet_write_wait();
200			authctxt->postponed = 1;
201		}
202	}
203	if (authenticated != 1)
204		auth_clear_options();
205done:
206	debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
207	if (key != NULL)
208		key_free(key);
209	free(pkalg);
210	free(pkblob);
211	return authenticated;
212}
213
214void
215pubkey_auth_info(Authctxt *authctxt, const Key *key, const char *fmt, ...)
216{
217	char *fp, *extra;
218	va_list ap;
219	int i;
220
221	extra = NULL;
222	if (fmt != NULL) {
223		va_start(ap, fmt);
224		i = vasprintf(&extra, fmt, ap);
225		va_end(ap);
226		if (i < 0 || extra == NULL)
227			fatal("%s: vasprintf failed", __func__);
228	}
229
230	if (key_is_cert(key)) {
231		fp = sshkey_fingerprint(key->cert->signature_key,
232		    options.fingerprint_hash, SSH_FP_DEFAULT);
233		auth_info(authctxt, "%s ID %s (serial %llu) CA %s %s%s%s",
234		    key_type(key), key->cert->key_id,
235		    (unsigned long long)key->cert->serial,
236		    key_type(key->cert->signature_key),
237		    fp == NULL ? "(null)" : fp,
238		    extra == NULL ? "" : ", ", extra == NULL ? "" : extra);
239		free(fp);
240	} else {
241		fp = sshkey_fingerprint(key, options.fingerprint_hash,
242		    SSH_FP_DEFAULT);
243		auth_info(authctxt, "%s %s%s%s", key_type(key),
244		    fp == NULL ? "(null)" : fp,
245		    extra == NULL ? "" : ", ", extra == NULL ? "" : extra);
246		free(fp);
247	}
248	free(extra);
249}
250
251static int
252match_principals_option(const char *principal_list, struct sshkey_cert *cert)
253{
254	char *result;
255	u_int i;
256
257	/* XXX percent_expand() sequences for authorized_principals? */
258
259	for (i = 0; i < cert->nprincipals; i++) {
260		if ((result = match_list(cert->principals[i],
261		    principal_list, NULL)) != NULL) {
262			debug3("matched principal from key options \"%.100s\"",
263			    result);
264			free(result);
265			return 1;
266		}
267	}
268	return 0;
269}
270
271static int
272match_principals_file(char *file, struct passwd *pw, struct sshkey_cert *cert)
273{
274	FILE *f;
275	char line[SSH_MAX_PUBKEY_BYTES], *cp, *ep, *line_opts;
276	u_long linenum = 0;
277	u_int i;
278
279	temporarily_use_uid(pw);
280	debug("trying authorized principals file %s", file);
281	if ((f = auth_openprincipals(file, pw, options.strict_modes)) == NULL) {
282		restore_uid();
283		return 0;
284	}
285	while (read_keyfile_line(f, file, line, sizeof(line), &linenum) != -1) {
286		/* Skip leading whitespace. */
287		for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
288			;
289		/* Skip blank and comment lines. */
290		if ((ep = strchr(cp, '#')) != NULL)
291			*ep = '\0';
292		if (!*cp || *cp == '\n')
293			continue;
294		/* Trim trailing whitespace. */
295		ep = cp + strlen(cp) - 1;
296		while (ep > cp && (*ep == '\n' || *ep == ' ' || *ep == '\t'))
297			*ep-- = '\0';
298		/*
299		 * If the line has internal whitespace then assume it has
300		 * key options.
301		 */
302		line_opts = NULL;
303		if ((ep = strrchr(cp, ' ')) != NULL ||
304		    (ep = strrchr(cp, '\t')) != NULL) {
305			for (; *ep == ' ' || *ep == '\t'; ep++)
306				;
307			line_opts = cp;
308			cp = ep;
309		}
310		for (i = 0; i < cert->nprincipals; i++) {
311			if (strcmp(cp, cert->principals[i]) == 0) {
312				debug3("matched principal \"%.100s\" "
313				    "from file \"%s\" on line %lu",
314				    cert->principals[i], file, linenum);
315				if (auth_parse_options(pw, line_opts,
316				    file, linenum) != 1)
317					continue;
318				fclose(f);
319				restore_uid();
320				return 1;
321			}
322		}
323	}
324	fclose(f);
325	restore_uid();
326	return 0;
327}
328
329/*
330 * Checks whether key is allowed in authorized_keys-format file,
331 * returns 1 if the key is allowed or 0 otherwise.
332 */
333static int
334check_authkeys_file(FILE *f, char *file, Key* key, struct passwd *pw)
335{
336	char line[SSH_MAX_PUBKEY_BYTES];
337	const char *reason;
338	int found_key = 0;
339	u_long linenum = 0;
340	Key *found;
341	char *fp;
342
343	found_key = 0;
344
345	found = NULL;
346	while (read_keyfile_line(f, file, line, sizeof(line), &linenum) != -1) {
347		char *cp, *key_options = NULL;
348		if (found != NULL)
349			key_free(found);
350		found = key_new(key_is_cert(key) ? KEY_UNSPEC : key->type);
351		auth_clear_options();
352
353		/* Skip leading whitespace, empty and comment lines. */
354		for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
355			;
356		if (!*cp || *cp == '\n' || *cp == '#')
357			continue;
358
359		if (key_read(found, &cp) != 1) {
360			/* no key?  check if there are options for this key */
361			int quoted = 0;
362			debug2("user_key_allowed: check options: '%s'", cp);
363			key_options = cp;
364			for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
365				if (*cp == '\\' && cp[1] == '"')
366					cp++;	/* Skip both */
367				else if (*cp == '"')
368					quoted = !quoted;
369			}
370			/* Skip remaining whitespace. */
371			for (; *cp == ' ' || *cp == '\t'; cp++)
372				;
373			if (key_read(found, &cp) != 1) {
374				debug2("user_key_allowed: advance: '%s'", cp);
375				/* still no key?  advance to next line*/
376				continue;
377			}
378		}
379		if (key_is_cert(key)) {
380			if (!key_equal(found, key->cert->signature_key))
381				continue;
382			if (auth_parse_options(pw, key_options, file,
383			    linenum) != 1)
384				continue;
385			if (!key_is_cert_authority)
386				continue;
387			if ((fp = sshkey_fingerprint(found,
388			    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
389				continue;
390			debug("matching CA found: file %s, line %lu, %s %s",
391			    file, linenum, key_type(found), fp);
392			/*
393			 * If the user has specified a list of principals as
394			 * a key option, then prefer that list to matching
395			 * their username in the certificate principals list.
396			 */
397			if (authorized_principals != NULL &&
398			    !match_principals_option(authorized_principals,
399			    key->cert)) {
400				reason = "Certificate does not contain an "
401				    "authorized principal";
402 fail_reason:
403				free(fp);
404				error("%s", reason);
405				auth_debug_add("%s", reason);
406				continue;
407			}
408			if (key_cert_check_authority(key, 0, 0,
409			    authorized_principals == NULL ? pw->pw_name : NULL,
410			    &reason) != 0)
411				goto fail_reason;
412			if (auth_cert_options(key, pw) != 0) {
413				free(fp);
414				continue;
415			}
416			verbose("Accepted certificate ID \"%s\" "
417			    "signed by %s CA %s via %s", key->cert->key_id,
418			    key_type(found), fp, file);
419			free(fp);
420			found_key = 1;
421			break;
422		} else if (key_equal(found, key)) {
423			if (auth_parse_options(pw, key_options, file,
424			    linenum) != 1)
425				continue;
426			if (key_is_cert_authority)
427				continue;
428			if ((fp = sshkey_fingerprint(found,
429			    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
430				continue;
431			debug("matching key found: file %s, line %lu %s %s",
432			    file, linenum, key_type(found), fp);
433			free(fp);
434			found_key = 1;
435			break;
436		}
437	}
438	if (found != NULL)
439		key_free(found);
440	if (!found_key)
441		debug2("key not found");
442	return found_key;
443}
444
445/* Authenticate a certificate key against TrustedUserCAKeys */
446static int
447user_cert_trusted_ca(struct passwd *pw, Key *key)
448{
449	char *ca_fp, *principals_file = NULL;
450	const char *reason;
451	int ret = 0;
452
453	if (!key_is_cert(key) || options.trusted_user_ca_keys == NULL)
454		return 0;
455
456	if ((ca_fp = sshkey_fingerprint(key->cert->signature_key,
457	    options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
458		return 0;
459
460	if (sshkey_in_file(key->cert->signature_key,
461	    options.trusted_user_ca_keys, 1, 0) != 0) {
462		debug2("%s: CA %s %s is not listed in %s", __func__,
463		    key_type(key->cert->signature_key), ca_fp,
464		    options.trusted_user_ca_keys);
465		goto out;
466	}
467	/*
468	 * If AuthorizedPrincipals is in use, then compare the certificate
469	 * principals against the names in that file rather than matching
470	 * against the username.
471	 */
472	if ((principals_file = authorized_principals_file(pw)) != NULL) {
473		if (!match_principals_file(principals_file, pw, key->cert)) {
474			reason = "Certificate does not contain an "
475			    "authorized principal";
476 fail_reason:
477			error("%s", reason);
478			auth_debug_add("%s", reason);
479			goto out;
480		}
481	}
482	if (key_cert_check_authority(key, 0, 1,
483	    principals_file == NULL ? pw->pw_name : NULL, &reason) != 0)
484		goto fail_reason;
485	if (auth_cert_options(key, pw) != 0)
486		goto out;
487
488	verbose("Accepted certificate ID \"%s\" signed by %s CA %s via %s",
489	    key->cert->key_id, key_type(key->cert->signature_key), ca_fp,
490	    options.trusted_user_ca_keys);
491	ret = 1;
492
493 out:
494	free(principals_file);
495	free(ca_fp);
496	return ret;
497}
498
499/*
500 * Checks whether key is allowed in file.
501 * returns 1 if the key is allowed or 0 otherwise.
502 */
503static int
504user_key_allowed2(struct passwd *pw, Key *key, char *file)
505{
506	FILE *f;
507	int found_key = 0;
508
509	/* Temporarily use the user's uid. */
510	temporarily_use_uid(pw);
511
512	debug("trying public key file %s", file);
513	if ((f = auth_openkeyfile(file, pw, options.strict_modes)) != NULL) {
514		found_key = check_authkeys_file(f, file, key, pw);
515		fclose(f);
516	}
517
518	restore_uid();
519	return found_key;
520}
521
522/*
523 * Checks whether key is allowed in output of command.
524 * returns 1 if the key is allowed or 0 otherwise.
525 */
526static int
527user_key_command_allowed2(struct passwd *user_pw, Key *key)
528{
529	FILE *f;
530	int ok, found_key = 0;
531	struct passwd *pw;
532	struct stat st;
533	int status, devnull, p[2], i;
534	pid_t pid;
535	char *username, errmsg[512];
536
537	if (options.authorized_keys_command == NULL ||
538	    options.authorized_keys_command[0] != '/')
539		return 0;
540
541	if (options.authorized_keys_command_user == NULL) {
542		error("No user for AuthorizedKeysCommand specified, skipping");
543		return 0;
544	}
545
546	username = percent_expand(options.authorized_keys_command_user,
547	    "u", user_pw->pw_name, (char *)NULL);
548	pw = getpwnam(username);
549	if (pw == NULL) {
550		error("AuthorizedKeysCommandUser \"%s\" not found: %s",
551		    username, strerror(errno));
552		free(username);
553		return 0;
554	}
555	free(username);
556
557	temporarily_use_uid(pw);
558
559	if (stat(options.authorized_keys_command, &st) < 0) {
560		error("Could not stat AuthorizedKeysCommand \"%s\": %s",
561		    options.authorized_keys_command, strerror(errno));
562		goto out;
563	}
564	if (auth_secure_path(options.authorized_keys_command, &st, NULL, 0,
565	    errmsg, sizeof(errmsg)) != 0) {
566		error("Unsafe AuthorizedKeysCommand: %s", errmsg);
567		goto out;
568	}
569
570	if (pipe(p) != 0) {
571		error("%s: pipe: %s", __func__, strerror(errno));
572		goto out;
573	}
574
575	debug3("Running AuthorizedKeysCommand: \"%s %s\" as \"%s\"",
576	    options.authorized_keys_command, user_pw->pw_name, pw->pw_name);
577
578	/*
579	 * Don't want to call this in the child, where it can fatal() and
580	 * run cleanup_exit() code.
581	 */
582	restore_uid();
583
584	switch ((pid = fork())) {
585	case -1: /* error */
586		error("%s: fork: %s", __func__, strerror(errno));
587		close(p[0]);
588		close(p[1]);
589		return 0;
590	case 0: /* child */
591		for (i = 0; i < NSIG; i++)
592			signal(i, SIG_DFL);
593
594		if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
595			error("%s: open %s: %s", __func__, _PATH_DEVNULL,
596			    strerror(errno));
597			_exit(1);
598		}
599		/* Keep stderr around a while longer to catch errors */
600		if (dup2(devnull, STDIN_FILENO) == -1 ||
601		    dup2(p[1], STDOUT_FILENO) == -1) {
602			error("%s: dup2: %s", __func__, strerror(errno));
603			_exit(1);
604		}
605		closefrom(STDERR_FILENO + 1);
606
607		/* Don't use permanently_set_uid() here to avoid fatal() */
608		if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
609			error("setresgid %u: %s", (u_int)pw->pw_gid,
610			    strerror(errno));
611			_exit(1);
612		}
613		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
614			error("setresuid %u: %s", (u_int)pw->pw_uid,
615			    strerror(errno));
616			_exit(1);
617		}
618		/* stdin is pointed to /dev/null at this point */
619		if (dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
620			error("%s: dup2: %s", __func__, strerror(errno));
621			_exit(1);
622		}
623
624		execl(options.authorized_keys_command,
625		    options.authorized_keys_command, user_pw->pw_name, NULL);
626
627		error("AuthorizedKeysCommand %s exec failed: %s",
628		    options.authorized_keys_command, strerror(errno));
629		_exit(127);
630	default: /* parent */
631		break;
632	}
633
634	temporarily_use_uid(pw);
635
636	close(p[1]);
637	if ((f = fdopen(p[0], "r")) == NULL) {
638		error("%s: fdopen: %s", __func__, strerror(errno));
639		close(p[0]);
640		/* Don't leave zombie child */
641		kill(pid, SIGTERM);
642		while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
643			;
644		goto out;
645	}
646	ok = check_authkeys_file(f, options.authorized_keys_command, key, pw);
647	fclose(f);
648
649	while (waitpid(pid, &status, 0) == -1) {
650		if (errno != EINTR) {
651			error("%s: waitpid: %s", __func__, strerror(errno));
652			goto out;
653		}
654	}
655	if (WIFSIGNALED(status)) {
656		error("AuthorizedKeysCommand %s exited on signal %d",
657		    options.authorized_keys_command, WTERMSIG(status));
658		goto out;
659	} else if (WEXITSTATUS(status) != 0) {
660		error("AuthorizedKeysCommand %s returned status %d",
661		    options.authorized_keys_command, WEXITSTATUS(status));
662		goto out;
663	}
664	found_key = ok;
665 out:
666	restore_uid();
667	return found_key;
668}
669
670/*
671 * Check whether key authenticates and authorises the user.
672 */
673int
674user_key_allowed(struct passwd *pw, Key *key)
675{
676	u_int success, i;
677	char *file;
678
679	if (auth_key_is_revoked(key))
680		return 0;
681	if (key_is_cert(key) && auth_key_is_revoked(key->cert->signature_key))
682		return 0;
683
684	success = user_cert_trusted_ca(pw, key);
685	if (success)
686		return success;
687
688	success = user_key_command_allowed2(pw, key);
689	if (success > 0)
690		return success;
691
692	for (i = 0; !success && i < options.num_authkeys_files; i++) {
693
694		if (strcasecmp(options.authorized_keys_files[i], "none") == 0)
695			continue;
696		file = expand_authorized_keys(
697		    options.authorized_keys_files[i], pw);
698
699		success = user_key_allowed2(pw, key, file);
700		free(file);
701	}
702
703	return success;
704}
705
706/* Records a public key in the list of previously-successful keys */
707void
708auth2_record_userkey(Authctxt *authctxt, struct sshkey *key)
709{
710	struct sshkey **tmp;
711
712	if (authctxt->nprev_userkeys >= INT_MAX ||
713	    (tmp = reallocarray(authctxt->prev_userkeys,
714	    authctxt->nprev_userkeys + 1, sizeof(*tmp))) == NULL)
715		fatal("%s: reallocarray failed", __func__);
716	authctxt->prev_userkeys = tmp;
717	authctxt->prev_userkeys[authctxt->nprev_userkeys] = key;
718	authctxt->nprev_userkeys++;
719}
720
721/* Checks whether a key has already been used successfully for authentication */
722int
723auth2_userkey_already_used(Authctxt *authctxt, struct sshkey *key)
724{
725	u_int i;
726
727	for (i = 0; i < authctxt->nprev_userkeys; i++) {
728		if (sshkey_equal_public(key, authctxt->prev_userkeys[i])) {
729			return 1;
730		}
731	}
732	return 0;
733}
734
735Authmethod method_pubkey = {
736	"publickey",
737	userauth_pubkey,
738	&options.pubkey_authentication
739};
740