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/*
* ProFTPD - mod_sftp 'keyboard-interactive' user authentication
* Copyright (c) 2008-2011 TJ Saunders
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.
*
* As a special exemption, TJ Saunders and other respective copyright holders
* give permission to link this program with OpenSSL, and distribute the
* resulting executable, without including the source code for OpenSSL in the
* source distribution.
*
* $Id: auth-kbdint.c,v 1.6 2011/08/04 21:15:19 castaglia Exp $
*/
#include "mod_sftp.h"
#include "ssh2.h"
#include "packet.h"
#include "auth.h"
#include "msg.h"
#include "cipher.h"
#include "mac.h"
#include "utf8.h"
#include "kbdint.h"
static const char *trace_channel = "ssh2";
int sftp_auth_kbdint(struct ssh2_packet *pkt, cmd_rec *pass_cmd,
const char *orig_user, const char *user, const char *service, char **buf,
uint32_t *buflen, int *send_userauth_fail) {
const char *cipher_algo, *mac_algo;
struct passwd *pw;
char *submethods;
sftp_kbdint_driver_t *driver;
int res = -1;
if (sftp_kbdint_have_drivers() == 0) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"no 'keyboard-interactive' drivers currently registered, unable to "
"authenticate user '%s' via 'keyboard-interactive' method", user);
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
if (pr_cmd_dispatch_phase(pass_cmd, PRE_CMD, 0) < 0) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"authentication request for user '%s' blocked by '%s' handler",
orig_user, pass_cmd->argv[0]);
pr_cmd_dispatch_phase(pass_cmd, POST_CMD_ERR, 0);
pr_cmd_dispatch_phase(pass_cmd, LOG_CMD_ERR, 0);
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
pw = pr_auth_getpwnam(pkt->pool, user);
if (pw == NULL) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"no account for user '%s' found", user);
pr_log_auth(PR_LOG_NOTICE,
"USER %s: no such user found from %s [%s] to %s:%d", user,
session.c->remote_name, pr_netaddr_get_ipstr(session.c->remote_addr),
pr_netaddr_get_ipstr(session.c->local_addr), session.c->local_port);
*send_userauth_fail = TRUE;
errno = ENOENT;
return 0;
}
cipher_algo = sftp_cipher_get_read_algo();
mac_algo = sftp_mac_get_read_algo();
/* XXX Is this too strict? For PAM authentication, no -- but for S/Key or
* one-time password authencation, maybe yes.
*/
if (strncmp(cipher_algo, "none", 5) == 0 ||
strncmp(mac_algo, "none", 5) == 0) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"cipher algorithm '%s' or MAC algorithm '%s' unacceptable for "
"keyboard-interactive authentication, denying authentication request",
cipher_algo, mac_algo);
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
/* XXX Read off the deprecated language string. */
sftp_msg_read_string(pkt->pool, buf, buflen);
submethods = sftp_msg_read_string(pkt->pool, buf, buflen);
if (strlen(submethods) > 0) {
pr_trace_msg(trace_channel, 8, "client suggested 'keyboard-interactive' "
"methods: %s", submethods);
}
/* XXX get our own get_shared_name() function (see kex.c), to see if
* any of the "hints" sent by the client match any of the registered
* kbdint drivers.
*/
driver = sftp_kbdint_first_driver();
while (driver) {
pr_signals_handle();
pr_trace_msg(trace_channel, 3, "trying kbdint driver '%s' for user '%s'",
driver->driver_name, user);
res = driver->open(driver, user);
if (res < 0) {
driver = sftp_kbdint_next_driver();
continue;
}
res = driver->authenticate(driver, user);
driver->close(driver);
if (res == 0)
break;
driver = sftp_kbdint_next_driver();
}
if (res < 0) {
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
return 1;
}
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