2000-05-15 04:37:24 +00:00
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/*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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2000-09-10 09:35:38 +00:00
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2000-05-15 04:37:24 +00:00
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#include "includes.h"
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2001-05-04 04:14:23 +00:00
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RCSID("$OpenBSD: auth2.c,v 1.56 2001/04/19 00:05:11 markus Exp $");
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2000-09-10 09:35:38 +00:00
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RCSID("$FreeBSD$");
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2000-05-15 04:37:24 +00:00
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#include <openssl/evp.h>
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2001-05-04 04:14:23 +00:00
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#include "ssh2.h"
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2000-05-15 04:37:24 +00:00
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#include "xmalloc.h"
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#include "rsa.h"
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2001-05-04 04:14:23 +00:00
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#include "sshpty.h"
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2000-05-15 04:37:24 +00:00
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#include "packet.h"
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#include "buffer.h"
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2001-05-04 04:14:23 +00:00
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#include "log.h"
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2000-05-15 04:37:24 +00:00
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#include "servconf.h"
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#include "compat.h"
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#include "channels.h"
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#include "bufaux.h"
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#include "auth.h"
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#include "session.h"
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#include "dispatch.h"
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#include "key.h"
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2001-05-04 04:14:23 +00:00
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#include "cipher.h"
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2000-05-15 04:37:24 +00:00
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#include "kex.h"
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2001-05-04 04:14:23 +00:00
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#include "pathnames.h"
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2000-05-15 04:37:24 +00:00
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#include "uidswap.h"
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2000-09-10 09:35:38 +00:00
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#include "auth-options.h"
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2001-05-04 04:14:23 +00:00
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#include "misc.h"
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#include "hostfile.h"
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#include "canohost.h"
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#include "tildexpand.h"
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2000-05-15 04:37:24 +00:00
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2000-11-14 04:35:03 +00:00
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#ifdef HAVE_LOGIN_CAP
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#include <login_cap.h>
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#endif /* HAVE_LOGIN_CAP */
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2000-05-15 04:37:24 +00:00
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/* import */
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extern ServerOptions options;
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2001-05-04 04:14:23 +00:00
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extern u_char *session_id2;
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2000-05-15 04:37:24 +00:00
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extern int session_id2_len;
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2000-12-05 02:55:12 +00:00
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static Authctxt *x_authctxt = NULL;
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static int one = 1;
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typedef struct Authmethod Authmethod;
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struct Authmethod {
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char *name;
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int (*userauth)(Authctxt *authctxt);
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int *enabled;
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};
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2000-05-15 04:37:24 +00:00
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/* protocol */
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2000-12-05 02:55:12 +00:00
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void input_service_request(int type, int plen, void *ctxt);
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void input_userauth_request(int type, int plen, void *ctxt);
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void protocol_error(int type, int plen, void *ctxt);
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2000-05-15 04:37:24 +00:00
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/* helper */
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2000-12-05 02:55:12 +00:00
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Authmethod *authmethod_lookup(const char *name);
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char *authmethods_get(void);
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2001-05-04 04:14:23 +00:00
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int user_key_allowed(struct passwd *pw, Key *key);
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int
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hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
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Key *key);
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2000-05-15 04:37:24 +00:00
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2000-12-05 02:55:12 +00:00
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/* auth */
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2001-05-04 04:14:23 +00:00
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void userauth_banner(void);
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void userauth_reply(Authctxt *authctxt, int authenticated);
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2000-12-05 02:55:12 +00:00
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int userauth_none(Authctxt *authctxt);
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int userauth_passwd(Authctxt *authctxt);
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int userauth_pubkey(Authctxt *authctxt);
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2001-05-04 04:14:23 +00:00
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int userauth_hostbased(Authctxt *authctxt);
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2000-12-05 02:55:12 +00:00
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int userauth_kbdint(Authctxt *authctxt);
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Authmethod authmethods[] = {
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{"none",
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userauth_none,
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&one},
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{"publickey",
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userauth_pubkey,
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2001-05-04 04:14:23 +00:00
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&options.pubkey_authentication},
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2000-12-05 02:55:12 +00:00
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{"password",
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userauth_passwd,
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&options.password_authentication},
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2001-05-04 04:14:23 +00:00
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{"keyboard-interactive",
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userauth_kbdint,
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&options.kbd_interactive_authentication},
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{"hostbased",
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userauth_hostbased,
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&options.hostbased_authentication},
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2000-12-05 02:55:12 +00:00
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{NULL, NULL, NULL}
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2000-05-15 04:37:24 +00:00
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};
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/*
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2000-12-05 02:55:12 +00:00
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* loop until authctxt->success == TRUE
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2000-05-15 04:37:24 +00:00
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*/
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void
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do_authentication2()
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{
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2001-05-04 04:14:23 +00:00
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Authctxt *authctxt = authctxt_new();
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2000-12-05 02:55:12 +00:00
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x_authctxt = authctxt; /*XXX*/
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2001-03-04 02:22:04 +00:00
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#if defined(KRB4) || defined(KRB5)
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2000-12-05 02:55:12 +00:00
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/* turn off kerberos, not supported by SSH2 */
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2001-03-04 02:22:04 +00:00
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options.kerberos_authentication = 0;
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2000-05-15 04:37:24 +00:00
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#endif
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2001-05-04 04:14:23 +00:00
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/* challenge-reponse is implemented via keyboard interactive */
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if (options.challenge_reponse_authentication)
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options.kbd_interactive_authentication = 1;
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2000-05-15 04:37:24 +00:00
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dispatch_init(&protocol_error);
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dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
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2000-12-05 02:55:12 +00:00
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dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
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2001-05-04 04:14:23 +00:00
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do_authenticated(authctxt);
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2000-05-15 04:37:24 +00:00
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}
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void
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2000-12-05 02:55:12 +00:00
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protocol_error(int type, int plen, void *ctxt)
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2000-05-15 04:37:24 +00:00
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{
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log("auth: protocol error: type %d plen %d", type, plen);
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packet_start(SSH2_MSG_UNIMPLEMENTED);
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packet_put_int(0);
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packet_send();
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packet_write_wait();
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}
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void
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2000-12-05 02:55:12 +00:00
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input_service_request(int type, int plen, void *ctxt)
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2000-05-15 04:37:24 +00:00
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{
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2000-12-05 02:55:12 +00:00
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Authctxt *authctxt = ctxt;
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2001-05-04 04:14:23 +00:00
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u_int len;
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2000-05-15 04:37:24 +00:00
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int accept = 0;
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char *service = packet_get_string(&len);
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packet_done();
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2000-12-05 02:55:12 +00:00
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if (authctxt == NULL)
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fatal("input_service_request: no authctxt");
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2000-05-15 04:37:24 +00:00
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if (strcmp(service, "ssh-userauth") == 0) {
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2000-12-05 02:55:12 +00:00
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if (!authctxt->success) {
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2000-05-15 04:37:24 +00:00
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accept = 1;
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/* now we can handle user-auth requests */
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dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
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}
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}
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/* XXX all other service requests are denied */
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if (accept) {
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packet_start(SSH2_MSG_SERVICE_ACCEPT);
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packet_put_cstring(service);
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packet_send();
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packet_write_wait();
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} else {
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debug("bad service request %s", service);
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packet_disconnect("bad service request %s", service);
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}
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xfree(service);
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}
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void
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2000-12-05 02:55:12 +00:00
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input_userauth_request(int type, int plen, void *ctxt)
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2000-05-15 04:37:24 +00:00
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{
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2000-12-05 02:55:12 +00:00
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Authctxt *authctxt = ctxt;
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Authmethod *m = NULL;
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2001-05-04 04:14:23 +00:00
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char *user, *service, *method, *style = NULL;
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2000-05-15 04:37:24 +00:00
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int authenticated = 0;
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2000-11-14 04:35:03 +00:00
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#ifdef HAVE_LOGIN_CAP
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login_cap_t *lc;
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#endif /* HAVE_LOGIN_CAP */
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#if defined(HAVE_LOGIN_CAP) || defined(LOGIN_ACCESS)
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const char *from_host, *from_ip;
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2001-05-04 04:14:23 +00:00
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from_host = get_canonical_hostname(options.reverse_mapping_check);
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2000-11-14 04:35:03 +00:00
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from_ip = get_remote_ipaddr();
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#endif /* HAVE_LOGIN_CAP || LOGIN_ACCESS */
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2000-05-15 04:37:24 +00:00
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2000-12-05 02:55:12 +00:00
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if (authctxt == NULL)
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fatal("input_userauth_request: no authctxt");
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2000-05-15 04:37:24 +00:00
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2000-12-05 02:55:12 +00:00
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user = packet_get_string(NULL);
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service = packet_get_string(NULL);
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method = packet_get_string(NULL);
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2000-05-15 04:37:24 +00:00
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debug("userauth-request for user %s service %s method %s", user, service, method);
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2001-05-04 04:14:23 +00:00
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debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
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if ((style = strchr(user, ':')) != NULL)
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*style++ = 0;
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2000-12-05 02:55:12 +00:00
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2001-05-04 04:14:23 +00:00
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if (authctxt->attempt++ == 0) {
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2000-12-05 02:55:12 +00:00
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/* setup auth context */
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struct passwd *pw = NULL;
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pw = getpwnam(user);
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if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
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authctxt->pw = pwcopy(pw);
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authctxt->valid = 1;
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debug2("input_userauth_request: setting up authctxt for %s", user);
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#ifdef USE_PAM
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start_pam(pw);
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#endif
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} else {
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log("input_userauth_request: illegal user %s", user);
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2001-03-15 03:15:18 +00:00
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authctxt->pw = NULL;
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2000-12-05 02:55:12 +00:00
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}
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2001-05-04 04:14:23 +00:00
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setproctitle("%s", pw ? user : "unknown");
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2000-12-05 02:55:12 +00:00
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authctxt->user = xstrdup(user);
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authctxt->service = xstrdup(service);
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2001-05-04 04:14:23 +00:00
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authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */
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2000-12-05 02:55:12 +00:00
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} else if (authctxt->valid) {
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if (strcmp(user, authctxt->user) != 0 ||
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strcmp(service, authctxt->service) != 0) {
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2001-05-04 04:14:23 +00:00
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log("input_userauth_request: mismatch: (%s,%s)!=(%s,%s)",
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2000-12-05 02:55:12 +00:00
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user, service, authctxt->user, authctxt->service);
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authctxt->valid = 0;
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2000-05-15 04:37:24 +00:00
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}
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}
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2000-11-14 04:35:03 +00:00
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#ifdef HAVE_LOGIN_CAP
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2000-12-05 02:55:12 +00:00
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if (authctxt->pw != NULL) {
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lc = login_getpwclass(authctxt->pw);
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if (lc == NULL)
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lc = login_getclassbyname(NULL, authctxt->pw);
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if (!auth_hostok(lc, from_host, from_ip)) {
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log("Denied connection for %.200s from %.200s [%.200s].",
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authctxt->pw->pw_name, from_host, from_ip);
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packet_disconnect("Sorry, you are not allowed to connect.");
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}
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if (!auth_timeok(lc, time(NULL))) {
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log("LOGIN %.200s REFUSED (TIME) FROM %.200s",
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authctxt->pw->pw_name, from_host);
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packet_disconnect("Logins not available right now.");
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}
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login_close(lc);
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lc = NULL;
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2000-11-14 04:35:03 +00:00
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}
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#endif /* HAVE_LOGIN_CAP */
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#ifdef LOGIN_ACCESS
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2000-12-05 02:55:12 +00:00
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if (authctxt->pw != NULL &&
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!login_access(authctxt->pw->pw_name, from_host)) {
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2000-11-14 04:35:03 +00:00
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log("Denied connection for %.200s from %.200s [%.200s].",
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2000-12-05 02:55:12 +00:00
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authctxt->pw->pw_name, from_host, from_ip);
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2000-11-14 04:35:03 +00:00
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packet_disconnect("Sorry, you are not allowed to connect.");
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}
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#endif /* LOGIN_ACCESS */
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2001-05-04 04:14:23 +00:00
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/* reset state */
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dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error);
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authctxt->postponed = 0;
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#ifdef BSD_AUTH
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if (authctxt->as) {
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auth_close(authctxt->as);
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authctxt->as = NULL;
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}
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#endif
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2000-11-14 04:35:03 +00:00
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2001-05-04 04:14:23 +00:00
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/* try to authenticate user */
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2000-12-05 02:55:12 +00:00
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m = authmethod_lookup(method);
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if (m != NULL) {
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debug2("input_userauth_request: try method %s", method);
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authenticated = m->userauth(authctxt);
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}
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#ifdef USE_PAM
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if (authenticated && authctxt->user && !do_pam_account(authctxt->user, NULL))
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authenticated = 0;
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#endif /* USE_PAM */
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2001-05-04 04:14:23 +00:00
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userauth_finish(authctxt, authenticated, method);
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2000-12-05 02:55:12 +00:00
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xfree(service);
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xfree(user);
|
|
|
|
xfree(method);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
2001-05-04 04:14:23 +00:00
|
|
|
userauth_finish(Authctxt *authctxt, int authenticated, char *method)
|
2000-12-05 02:55:12 +00:00
|
|
|
{
|
2001-05-04 04:14:23 +00:00
|
|
|
if (!authctxt->valid && authenticated)
|
|
|
|
fatal("INTERNAL ERROR: authenticated invalid user %s",
|
|
|
|
authctxt->user);
|
2000-12-05 02:55:12 +00:00
|
|
|
|
2001-05-04 04:14:23 +00:00
|
|
|
/* Special handling for root */
|
|
|
|
if (authenticated && authctxt->pw->pw_uid == 0 &&
|
|
|
|
!auth_root_allowed(method))
|
|
|
|
authenticated = 0;
|
2000-05-15 04:37:24 +00:00
|
|
|
|
2001-05-04 04:14:23 +00:00
|
|
|
/* Log before sending the reply */
|
|
|
|
auth_log(authctxt, authenticated, method, " ssh2");
|
2000-12-05 02:55:12 +00:00
|
|
|
|
2001-05-04 04:14:23 +00:00
|
|
|
if (!authctxt->postponed)
|
|
|
|
userauth_reply(authctxt, authenticated);
|
|
|
|
}
|
2000-12-05 02:55:12 +00:00
|
|
|
|
2001-05-04 04:14:23 +00:00
|
|
|
void
|
|
|
|
userauth_banner(void)
|
|
|
|
{
|
|
|
|
struct stat st;
|
|
|
|
char *banner = NULL;
|
|
|
|
off_t len, n;
|
|
|
|
int fd;
|
|
|
|
|
|
|
|
if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
|
|
|
|
return;
|
|
|
|
if ((fd = open(options.banner, O_RDONLY)) < 0)
|
|
|
|
return;
|
|
|
|
if (fstat(fd, &st) < 0)
|
|
|
|
goto done;
|
|
|
|
len = st.st_size;
|
|
|
|
banner = xmalloc(len + 1);
|
|
|
|
if ((n = read(fd, banner, len)) < 0)
|
|
|
|
goto done;
|
|
|
|
banner[n] = '\0';
|
|
|
|
packet_start(SSH2_MSG_USERAUTH_BANNER);
|
|
|
|
packet_put_cstring(banner);
|
|
|
|
packet_put_cstring(""); /* language, unused */
|
|
|
|
packet_send();
|
|
|
|
debug("userauth_banner: sent");
|
|
|
|
done:
|
|
|
|
if (banner)
|
|
|
|
xfree(banner);
|
|
|
|
close(fd);
|
|
|
|
return;
|
2000-12-05 02:55:12 +00:00
|
|
|
}
|
2000-05-15 04:37:24 +00:00
|
|
|
|
2001-05-04 04:14:23 +00:00
|
|
|
void
|
2000-12-05 02:55:12 +00:00
|
|
|
userauth_reply(Authctxt *authctxt, int authenticated)
|
|
|
|
{
|
2001-05-04 04:14:23 +00:00
|
|
|
char *methods;
|
|
|
|
|
2000-05-15 04:37:24 +00:00
|
|
|
/* XXX todo: check if multiple auth methods are needed */
|
|
|
|
if (authenticated == 1) {
|
|
|
|
/* turn off userauth */
|
|
|
|
dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
|
|
|
|
packet_start(SSH2_MSG_USERAUTH_SUCCESS);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
/* now we can break out */
|
2000-12-05 02:55:12 +00:00
|
|
|
authctxt->success = 1;
|
2001-05-04 04:14:23 +00:00
|
|
|
} else {
|
|
|
|
if (authctxt->failures++ > AUTH_FAIL_MAX)
|
|
|
|
packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
|
|
|
|
methods = authmethods_get();
|
2000-05-15 04:37:24 +00:00
|
|
|
packet_start(SSH2_MSG_USERAUTH_FAILURE);
|
2000-12-05 02:55:12 +00:00
|
|
|
packet_put_cstring(methods);
|
|
|
|
packet_put_char(0); /* XXX partial success, unused */
|
2000-05-15 04:37:24 +00:00
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
2000-12-05 02:55:12 +00:00
|
|
|
xfree(methods);
|
2000-05-15 04:37:24 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
int
|
2000-12-05 02:55:12 +00:00
|
|
|
userauth_none(Authctxt *authctxt)
|
2000-05-15 04:37:24 +00:00
|
|
|
{
|
2000-12-05 02:55:12 +00:00
|
|
|
/* disable method "none", only allowed one time */
|
|
|
|
Authmethod *m = authmethod_lookup("none");
|
|
|
|
if (m != NULL)
|
|
|
|
m->enabled = NULL;
|
2000-05-15 04:37:24 +00:00
|
|
|
packet_done();
|
2001-05-04 04:14:23 +00:00
|
|
|
userauth_banner();
|
2000-12-05 02:55:12 +00:00
|
|
|
#ifdef USE_PAM
|
2001-05-04 04:14:23 +00:00
|
|
|
return authctxt->valid ? auth_pam_password(authctxt, "") : 0;
|
2000-12-05 02:55:12 +00:00
|
|
|
#else /* !USE_PAM */
|
2001-05-04 04:14:23 +00:00
|
|
|
return authctxt->valid ? auth_password(authctxt, "") : 0;
|
2000-12-05 02:55:12 +00:00
|
|
|
#endif /* USE_PAM */
|
2000-05-15 04:37:24 +00:00
|
|
|
}
|
2000-12-05 02:55:12 +00:00
|
|
|
|
2000-05-15 04:37:24 +00:00
|
|
|
int
|
2000-12-05 02:55:12 +00:00
|
|
|
userauth_passwd(Authctxt *authctxt)
|
2000-05-15 04:37:24 +00:00
|
|
|
{
|
|
|
|
char *password;
|
|
|
|
int authenticated = 0;
|
|
|
|
int change;
|
2001-05-04 04:14:23 +00:00
|
|
|
u_int len;
|
2000-05-15 04:37:24 +00:00
|
|
|
change = packet_get_char();
|
|
|
|
if (change)
|
|
|
|
log("password change not supported");
|
|
|
|
password = packet_get_string(&len);
|
|
|
|
packet_done();
|
2000-12-05 02:55:12 +00:00
|
|
|
if (authctxt->valid &&
|
|
|
|
#ifdef USE_PAM
|
2002-03-16 08:03:48 +00:00
|
|
|
auth_password(authctxt, password) == 1)
|
2000-12-05 02:55:12 +00:00
|
|
|
#else
|
2002-03-16 08:03:48 +00:00
|
|
|
auth_password(authctxt, password) == 1)
|
2000-12-05 02:55:12 +00:00
|
|
|
#endif
|
2000-05-15 04:37:24 +00:00
|
|
|
authenticated = 1;
|
|
|
|
memset(password, 0, len);
|
|
|
|
xfree(password);
|
|
|
|
return authenticated;
|
|
|
|
}
|
2000-12-05 02:55:12 +00:00
|
|
|
|
|
|
|
int
|
|
|
|
userauth_kbdint(Authctxt *authctxt)
|
|
|
|
{
|
|
|
|
int authenticated = 0;
|
|
|
|
char *lang = NULL;
|
|
|
|
char *devs = NULL;
|
|
|
|
|
|
|
|
lang = packet_get_string(NULL);
|
|
|
|
devs = packet_get_string(NULL);
|
|
|
|
packet_done();
|
|
|
|
|
|
|
|
debug("keyboard-interactive language %s devs %s", lang, devs);
|
2001-05-04 04:14:23 +00:00
|
|
|
|
|
|
|
if (options.challenge_reponse_authentication)
|
|
|
|
authenticated = auth2_challenge(authctxt, devs);
|
|
|
|
|
2000-12-05 02:55:12 +00:00
|
|
|
xfree(lang);
|
|
|
|
xfree(devs);
|
|
|
|
return authenticated;
|
|
|
|
}
|
|
|
|
|
2000-05-15 04:37:24 +00:00
|
|
|
int
|
2000-12-05 02:55:12 +00:00
|
|
|
userauth_pubkey(Authctxt *authctxt)
|
2000-05-15 04:37:24 +00:00
|
|
|
{
|
|
|
|
Buffer b;
|
|
|
|
Key *key;
|
|
|
|
char *pkalg, *pkblob, *sig;
|
2001-05-04 04:14:23 +00:00
|
|
|
u_int alen, blen, slen;
|
|
|
|
int have_sig, pktype;
|
2000-05-15 04:37:24 +00:00
|
|
|
int authenticated = 0;
|
|
|
|
|
2000-12-05 02:55:12 +00:00
|
|
|
if (!authctxt->valid) {
|
|
|
|
debug2("userauth_pubkey: disabled because of invalid user");
|
2000-05-15 04:37:24 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
have_sig = packet_get_char();
|
2001-05-04 04:14:23 +00:00
|
|
|
if (datafellows & SSH_BUG_PKAUTH) {
|
|
|
|
debug2("userauth_pubkey: SSH_BUG_PKAUTH");
|
|
|
|
/* no explicit pkalg given */
|
|
|
|
pkblob = packet_get_string(&blen);
|
|
|
|
buffer_init(&b);
|
|
|
|
buffer_append(&b, pkblob, blen);
|
|
|
|
/* so we have to extract the pkalg from the pkblob */
|
|
|
|
pkalg = buffer_get_string(&b, &alen);
|
|
|
|
buffer_free(&b);
|
|
|
|
} else {
|
|
|
|
pkalg = packet_get_string(&alen);
|
|
|
|
pkblob = packet_get_string(&blen);
|
|
|
|
}
|
|
|
|
pktype = key_type_from_name(pkalg);
|
|
|
|
if (pktype == KEY_UNSPEC) {
|
|
|
|
/* this is perfectly legal */
|
|
|
|
log("userauth_pubkey: unsupported public key algorithm: %s", pkalg);
|
2000-12-05 02:55:12 +00:00
|
|
|
xfree(pkalg);
|
2001-05-04 04:14:23 +00:00
|
|
|
xfree(pkblob);
|
2000-05-15 04:37:24 +00:00
|
|
|
return 0;
|
|
|
|
}
|
2001-05-04 04:14:23 +00:00
|
|
|
key = key_from_blob(pkblob, blen);
|
2000-05-15 04:37:24 +00:00
|
|
|
if (key != NULL) {
|
|
|
|
if (have_sig) {
|
|
|
|
sig = packet_get_string(&slen);
|
|
|
|
packet_done();
|
|
|
|
buffer_init(&b);
|
2000-12-05 02:55:12 +00:00
|
|
|
if (datafellows & SSH_OLD_SESSIONID) {
|
2000-09-10 09:35:38 +00:00
|
|
|
buffer_append(&b, session_id2, session_id2_len);
|
2000-12-05 02:55:12 +00:00
|
|
|
} else {
|
|
|
|
buffer_put_string(&b, session_id2, session_id2_len);
|
2000-09-10 09:35:38 +00:00
|
|
|
}
|
|
|
|
/* reconstruct packet */
|
2000-05-15 04:37:24 +00:00
|
|
|
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
|
2000-12-05 02:55:12 +00:00
|
|
|
buffer_put_cstring(&b, authctxt->user);
|
2000-09-10 09:35:38 +00:00
|
|
|
buffer_put_cstring(&b,
|
2001-05-04 04:14:23 +00:00
|
|
|
datafellows & SSH_BUG_PKSERVICE ?
|
2000-09-10 09:35:38 +00:00
|
|
|
"ssh-userauth" :
|
2000-12-05 02:55:12 +00:00
|
|
|
authctxt->service);
|
2001-05-04 04:14:23 +00:00
|
|
|
if (datafellows & SSH_BUG_PKAUTH) {
|
|
|
|
buffer_put_char(&b, have_sig);
|
|
|
|
} else {
|
|
|
|
buffer_put_cstring(&b, "publickey");
|
|
|
|
buffer_put_char(&b, have_sig);
|
|
|
|
buffer_put_cstring(&b, pkalg);
|
|
|
|
}
|
2000-09-10 09:35:38 +00:00
|
|
|
buffer_put_string(&b, pkblob, blen);
|
2001-05-04 04:14:23 +00:00
|
|
|
#ifdef DEBUG_PK
|
2000-05-15 04:37:24 +00:00
|
|
|
buffer_dump(&b);
|
|
|
|
#endif
|
|
|
|
/* test for correct signature */
|
2001-05-04 04:14:23 +00:00
|
|
|
if (user_key_allowed(authctxt->pw, key) &&
|
|
|
|
key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
|
2000-05-15 04:37:24 +00:00
|
|
|
authenticated = 1;
|
|
|
|
buffer_clear(&b);
|
|
|
|
xfree(sig);
|
|
|
|
} else {
|
2000-12-05 02:55:12 +00:00
|
|
|
debug("test whether pkalg/pkblob are acceptable");
|
2000-05-15 04:37:24 +00:00
|
|
|
packet_done();
|
2000-12-05 02:55:12 +00:00
|
|
|
|
2000-05-15 04:37:24 +00:00
|
|
|
/* XXX fake reply and always send PK_OK ? */
|
|
|
|
/*
|
|
|
|
* XXX this allows testing whether a user is allowed
|
|
|
|
* to login: if you happen to have a valid pubkey this
|
|
|
|
* message is sent. the message is NEVER sent at all
|
|
|
|
* if a user is not allowed to login. is this an
|
|
|
|
* issue? -markus
|
|
|
|
*/
|
2001-05-04 04:14:23 +00:00
|
|
|
if (user_key_allowed(authctxt->pw, key)) {
|
2000-05-15 04:37:24 +00:00
|
|
|
packet_start(SSH2_MSG_USERAUTH_PK_OK);
|
|
|
|
packet_put_string(pkalg, alen);
|
|
|
|
packet_put_string(pkblob, blen);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
2001-05-04 04:14:23 +00:00
|
|
|
authctxt->postponed = 1;
|
2000-05-15 04:37:24 +00:00
|
|
|
}
|
|
|
|
}
|
2000-12-05 02:55:12 +00:00
|
|
|
if (authenticated != 1)
|
|
|
|
auth_clear_options();
|
2000-05-15 04:37:24 +00:00
|
|
|
key_free(key);
|
|
|
|
}
|
2001-05-04 04:14:23 +00:00
|
|
|
debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
|
|
|
|
xfree(pkalg);
|
|
|
|
xfree(pkblob);
|
|
|
|
return authenticated;
|
|
|
|
}
|
|
|
|
|
|
|
|
int
|
|
|
|
userauth_hostbased(Authctxt *authctxt)
|
|
|
|
{
|
|
|
|
Buffer b;
|
|
|
|
Key *key;
|
|
|
|
char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
|
|
|
|
u_int alen, blen, slen;
|
|
|
|
int pktype;
|
|
|
|
int authenticated = 0;
|
|
|
|
|
|
|
|
if (!authctxt->valid) {
|
|
|
|
debug2("userauth_hostbased: disabled because of invalid user");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
pkalg = packet_get_string(&alen);
|
|
|
|
pkblob = packet_get_string(&blen);
|
|
|
|
chost = packet_get_string(NULL);
|
|
|
|
cuser = packet_get_string(NULL);
|
|
|
|
sig = packet_get_string(&slen);
|
|
|
|
|
|
|
|
debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
|
|
|
|
cuser, chost, pkalg, slen);
|
|
|
|
#ifdef DEBUG_PK
|
|
|
|
debug("signature:");
|
|
|
|
buffer_init(&b);
|
|
|
|
buffer_append(&b, sig, slen);
|
|
|
|
buffer_dump(&b);
|
|
|
|
buffer_free(&b);
|
|
|
|
#endif
|
|
|
|
pktype = key_type_from_name(pkalg);
|
|
|
|
if (pktype == KEY_UNSPEC) {
|
|
|
|
/* this is perfectly legal */
|
|
|
|
log("userauth_hostbased: unsupported "
|
|
|
|
"public key algorithm: %s", pkalg);
|
|
|
|
goto done;
|
|
|
|
}
|
|
|
|
key = key_from_blob(pkblob, blen);
|
|
|
|
if (key == NULL) {
|
|
|
|
debug("userauth_hostbased: cannot decode key: %s", pkalg);
|
|
|
|
goto done;
|
|
|
|
}
|
|
|
|
service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
|
|
|
|
authctxt->service;
|
|
|
|
buffer_init(&b);
|
|
|
|
buffer_put_string(&b, session_id2, session_id2_len);
|
|
|
|
/* reconstruct packet */
|
|
|
|
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
|
|
|
|
buffer_put_cstring(&b, authctxt->user);
|
|
|
|
buffer_put_cstring(&b, service);
|
|
|
|
buffer_put_cstring(&b, "hostbased");
|
|
|
|
buffer_put_string(&b, pkalg, alen);
|
|
|
|
buffer_put_string(&b, pkblob, blen);
|
|
|
|
buffer_put_cstring(&b, chost);
|
|
|
|
buffer_put_cstring(&b, cuser);
|
|
|
|
#ifdef DEBUG_PK
|
|
|
|
buffer_dump(&b);
|
|
|
|
#endif
|
|
|
|
/* test for allowed key and correct signature */
|
|
|
|
if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
|
|
|
|
key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
|
|
|
|
authenticated = 1;
|
|
|
|
|
|
|
|
buffer_clear(&b);
|
|
|
|
key_free(key);
|
|
|
|
|
|
|
|
done:
|
|
|
|
debug2("userauth_hostbased: authenticated %d", authenticated);
|
2000-05-15 04:37:24 +00:00
|
|
|
xfree(pkalg);
|
|
|
|
xfree(pkblob);
|
2001-05-04 04:14:23 +00:00
|
|
|
xfree(cuser);
|
|
|
|
xfree(chost);
|
|
|
|
xfree(sig);
|
2000-05-15 04:37:24 +00:00
|
|
|
return authenticated;
|
|
|
|
}
|
|
|
|
|
2000-12-05 02:55:12 +00:00
|
|
|
/* get current user */
|
2000-05-15 04:37:24 +00:00
|
|
|
|
|
|
|
struct passwd*
|
|
|
|
auth_get_user(void)
|
|
|
|
{
|
2000-12-05 02:55:12 +00:00
|
|
|
return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
|
2000-05-15 04:37:24 +00:00
|
|
|
}
|
|
|
|
|
2000-12-05 02:55:12 +00:00
|
|
|
#define DELIM ","
|
|
|
|
|
|
|
|
char *
|
|
|
|
authmethods_get(void)
|
2000-05-15 04:37:24 +00:00
|
|
|
{
|
2000-12-05 02:55:12 +00:00
|
|
|
Authmethod *method = NULL;
|
2001-05-04 04:14:23 +00:00
|
|
|
u_int size = 0;
|
2000-12-05 02:55:12 +00:00
|
|
|
char *list;
|
|
|
|
|
|
|
|
for (method = authmethods; method->name != NULL; method++) {
|
|
|
|
if (strcmp(method->name, "none") == 0)
|
|
|
|
continue;
|
|
|
|
if (method->enabled != NULL && *(method->enabled) != 0) {
|
|
|
|
if (size != 0)
|
|
|
|
size += strlen(DELIM);
|
|
|
|
size += strlen(method->name);
|
2000-05-15 04:37:24 +00:00
|
|
|
}
|
2000-12-05 02:55:12 +00:00
|
|
|
}
|
|
|
|
size++; /* trailing '\0' */
|
|
|
|
list = xmalloc(size);
|
|
|
|
list[0] = '\0';
|
|
|
|
|
|
|
|
for (method = authmethods; method->name != NULL; method++) {
|
|
|
|
if (strcmp(method->name, "none") == 0)
|
|
|
|
continue;
|
|
|
|
if (method->enabled != NULL && *(method->enabled) != 0) {
|
|
|
|
if (list[0] != '\0')
|
|
|
|
strlcat(list, DELIM, size);
|
|
|
|
strlcat(list, method->name, size);
|
2000-05-15 04:37:24 +00:00
|
|
|
}
|
|
|
|
}
|
2000-12-05 02:55:12 +00:00
|
|
|
return list;
|
|
|
|
}
|
|
|
|
|
|
|
|
Authmethod *
|
|
|
|
authmethod_lookup(const char *name)
|
|
|
|
{
|
|
|
|
Authmethod *method = NULL;
|
|
|
|
if (name != NULL)
|
|
|
|
for (method = authmethods; method->name != NULL; method++)
|
|
|
|
if (method->enabled != NULL &&
|
|
|
|
*(method->enabled) != 0 &&
|
|
|
|
strcmp(name, method->name) == 0)
|
|
|
|
return method;
|
|
|
|
debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
|
|
|
|
return NULL;
|
2000-05-15 04:37:24 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* return 1 if user allows given key */
|
|
|
|
int
|
2001-05-04 04:14:23 +00:00
|
|
|
user_key_allowed(struct passwd *pw, Key *key)
|
2000-05-15 04:37:24 +00:00
|
|
|
{
|
2001-05-04 04:14:23 +00:00
|
|
|
char line[8192], file[MAXPATHLEN];
|
2000-05-15 04:37:24 +00:00
|
|
|
int found_key = 0;
|
|
|
|
FILE *f;
|
2001-05-04 04:14:23 +00:00
|
|
|
u_long linenum = 0;
|
2000-05-15 04:37:24 +00:00
|
|
|
struct stat st;
|
|
|
|
Key *found;
|
|
|
|
|
2000-12-05 02:55:12 +00:00
|
|
|
if (pw == NULL)
|
|
|
|
return 0;
|
|
|
|
|
2000-05-15 04:37:24 +00:00
|
|
|
/* Temporarily use the user's uid. */
|
2001-05-04 04:14:23 +00:00
|
|
|
temporarily_use_uid(pw);
|
2000-05-15 04:37:24 +00:00
|
|
|
|
|
|
|
/* The authorized keys. */
|
|
|
|
snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir,
|
2001-05-04 04:14:23 +00:00
|
|
|
_PATH_SSH_USER_PERMITTED_KEYS2);
|
2000-05-15 04:37:24 +00:00
|
|
|
|
|
|
|
/* Fail quietly if file does not exist */
|
|
|
|
if (stat(file, &st) < 0) {
|
|
|
|
/* Restore the privileged uid. */
|
|
|
|
restore_uid();
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
/* Open the file containing the authorized keys. */
|
|
|
|
f = fopen(file, "r");
|
|
|
|
if (!f) {
|
|
|
|
/* Restore the privileged uid. */
|
|
|
|
restore_uid();
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
if (options.strict_modes) {
|
|
|
|
int fail = 0;
|
|
|
|
char buf[1024];
|
|
|
|
/* Check open file in order to avoid open/stat races */
|
|
|
|
if (fstat(fileno(f), &st) < 0 ||
|
|
|
|
(st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
|
|
|
|
(st.st_mode & 022) != 0) {
|
2000-12-05 02:55:12 +00:00
|
|
|
snprintf(buf, sizeof buf,
|
|
|
|
"%s authentication refused for %.100s: "
|
|
|
|
"bad ownership or modes for '%s'.",
|
|
|
|
key_type(key), pw->pw_name, file);
|
2000-05-15 04:37:24 +00:00
|
|
|
fail = 1;
|
|
|
|
} else {
|
2001-05-04 04:14:23 +00:00
|
|
|
/* Check path to _PATH_SSH_USER_PERMITTED_KEYS */
|
2000-05-15 04:37:24 +00:00
|
|
|
int i;
|
|
|
|
static const char *check[] = {
|
2001-05-04 04:14:23 +00:00
|
|
|
"", _PATH_SSH_USER_DIR, NULL
|
2000-05-15 04:37:24 +00:00
|
|
|
};
|
|
|
|
for (i = 0; check[i]; i++) {
|
|
|
|
snprintf(line, sizeof line, "%.500s/%.100s",
|
|
|
|
pw->pw_dir, check[i]);
|
|
|
|
if (stat(line, &st) < 0 ||
|
|
|
|
(st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
|
|
|
|
(st.st_mode & 022) != 0) {
|
|
|
|
snprintf(buf, sizeof buf,
|
2000-12-05 02:55:12 +00:00
|
|
|
"%s authentication refused for %.100s: "
|
2000-05-15 04:37:24 +00:00
|
|
|
"bad ownership or modes for '%s'.",
|
2000-12-05 02:55:12 +00:00
|
|
|
key_type(key), pw->pw_name, line);
|
2000-05-15 04:37:24 +00:00
|
|
|
fail = 1;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (fail) {
|
|
|
|
fclose(f);
|
2001-05-04 04:14:23 +00:00
|
|
|
log("%s", buf);
|
2000-05-15 04:37:24 +00:00
|
|
|
restore_uid();
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
found_key = 0;
|
2000-12-05 02:55:12 +00:00
|
|
|
found = key_new(key->type);
|
2000-05-15 04:37:24 +00:00
|
|
|
|
|
|
|
while (fgets(line, sizeof(line), f)) {
|
2000-09-10 09:35:38 +00:00
|
|
|
char *cp, *options = NULL;
|
2000-05-15 04:37:24 +00:00
|
|
|
linenum++;
|
|
|
|
/* Skip leading whitespace, empty and comment lines. */
|
|
|
|
for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
|
|
|
|
;
|
|
|
|
if (!*cp || *cp == '\n' || *cp == '#')
|
|
|
|
continue;
|
2000-09-10 09:35:38 +00:00
|
|
|
|
2001-05-04 04:14:23 +00:00
|
|
|
if (key_read(found, &cp) == -1) {
|
2000-09-10 09:35:38 +00:00
|
|
|
/* no key? check if there are options for this key */
|
|
|
|
int quoted = 0;
|
2001-05-04 04:14:23 +00:00
|
|
|
debug2("user_key_allowed: check options: '%s'", cp);
|
2000-09-10 09:35:38 +00:00
|
|
|
options = cp;
|
|
|
|
for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
|
|
|
|
if (*cp == '\\' && cp[1] == '"')
|
|
|
|
cp++; /* Skip both */
|
|
|
|
else if (*cp == '"')
|
|
|
|
quoted = !quoted;
|
|
|
|
}
|
|
|
|
/* Skip remaining whitespace. */
|
|
|
|
for (; *cp == ' ' || *cp == '\t'; cp++)
|
|
|
|
;
|
2001-05-04 04:14:23 +00:00
|
|
|
if (key_read(found, &cp) == -1) {
|
|
|
|
debug2("user_key_allowed: advance: '%s'", cp);
|
2000-09-10 09:35:38 +00:00
|
|
|
/* still no key? advance to next line*/
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (key_equal(found, key) &&
|
2001-05-04 04:14:23 +00:00
|
|
|
auth_parse_options(pw, options, file, linenum) == 1) {
|
2000-05-15 04:37:24 +00:00
|
|
|
found_key = 1;
|
|
|
|
debug("matching key found: file %s, line %ld",
|
|
|
|
file, linenum);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
restore_uid();
|
|
|
|
fclose(f);
|
|
|
|
key_free(found);
|
2001-05-04 04:14:23 +00:00
|
|
|
if (!found_key)
|
|
|
|
debug2("key not found");
|
2000-05-15 04:37:24 +00:00
|
|
|
return found_key;
|
|
|
|
}
|
2000-12-05 02:55:12 +00:00
|
|
|
|
2001-05-04 04:14:23 +00:00
|
|
|
/* return 1 if given hostkey is allowed */
|
|
|
|
int
|
|
|
|
hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
|
|
|
|
Key *key)
|
2000-12-05 02:55:12 +00:00
|
|
|
{
|
2001-05-04 04:14:23 +00:00
|
|
|
Key *found;
|
|
|
|
const char *resolvedname, *ipaddr, *lookup;
|
|
|
|
struct stat st;
|
|
|
|
char *user_hostfile;
|
|
|
|
int host_status, len;
|
|
|
|
|
|
|
|
resolvedname = get_canonical_hostname(options.reverse_mapping_check);
|
|
|
|
ipaddr = get_remote_ipaddr();
|
|
|
|
|
|
|
|
debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
|
|
|
|
chost, resolvedname, ipaddr);
|
|
|
|
|
|
|
|
if (options.hostbased_uses_name_from_packet_only) {
|
|
|
|
if (auth_rhosts2(pw, cuser, chost, chost) == 0)
|
|
|
|
return 0;
|
|
|
|
lookup = chost;
|
|
|
|
} else {
|
|
|
|
if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
|
|
|
|
debug2("stripping trailing dot from chost %s", chost);
|
|
|
|
chost[len - 1] = '\0';
|
|
|
|
}
|
|
|
|
if (strcasecmp(resolvedname, chost) != 0)
|
|
|
|
log("userauth_hostbased mismatch: "
|
|
|
|
"client sends %s, but we resolve %s to %s",
|
|
|
|
chost, ipaddr, resolvedname);
|
|
|
|
if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
|
|
|
|
return 0;
|
|
|
|
lookup = resolvedname;
|
|
|
|
}
|
|
|
|
debug2("userauth_hostbased: access allowed by auth_rhosts2");
|
|
|
|
|
|
|
|
/* XXX this is copied from auth-rh-rsa.c and should be shared */
|
|
|
|
found = key_new(key->type);
|
|
|
|
host_status = check_host_in_hostfile(_PATH_SSH_SYSTEM_HOSTFILE2, lookup,
|
|
|
|
key, found, NULL);
|
|
|
|
|
|
|
|
if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
|
|
|
|
user_hostfile = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE2,
|
|
|
|
pw->pw_uid);
|
|
|
|
if (options.strict_modes &&
|
|
|
|
(stat(user_hostfile, &st) == 0) &&
|
|
|
|
((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
|
|
|
|
(st.st_mode & 022) != 0)) {
|
|
|
|
log("Hostbased authentication refused for %.100s: "
|
|
|
|
"bad owner or modes for %.200s",
|
|
|
|
pw->pw_name, user_hostfile);
|
|
|
|
} else {
|
|
|
|
temporarily_use_uid(pw);
|
|
|
|
host_status = check_host_in_hostfile(user_hostfile,
|
|
|
|
lookup, key, found, NULL);
|
|
|
|
restore_uid();
|
|
|
|
}
|
|
|
|
xfree(user_hostfile);
|
|
|
|
}
|
|
|
|
key_free(found);
|
|
|
|
|
|
|
|
debug2("userauth_hostbased: key %s for %s", host_status == HOST_OK ?
|
|
|
|
"ok" : "not found", lookup);
|
|
|
|
return (host_status == HOST_OK);
|
2000-12-05 02:55:12 +00:00
|
|
|
}
|