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pam_tacplus.c
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pam_tacplus.c
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/* pam_tacplus.c - PAM interface for TACACS+ protocol.
*
* Copyright (C) 2010, Pawel Krawczyk <[email protected]> and
* Jeroen Nijhof <[email protected]>
*
* 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 - see the file COPYING.
*
* See `CHANGES' file for revision history.
*/
#include "pam_tacplus.h"
#include "support.h"
#include <stdlib.h> /* malloc */
#include <stdio.h>
#include <syslog.h>
#include <netdb.h> /* gethostbyname */
#include <sys/socket.h> /* in_addr */
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdarg.h> /* va_ */
#include <signal.h>
#include <string.h> /* strdup */
#include <ctype.h>
#include <time.h>
#include <unistd.h>
#include <strings.h>
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#if defined(HAVE_OPENSSL_RAND_H) && defined(HAVE_LIBCRYPTO)
# include <openssl/rand.h>
#else
# include "magic.h"
#endif
/* address of server discovered by pam_sm_authenticate */
static tacplus_server_t active_server;
/* accounting task identifier */
static short int task_id = 0;
/* Helper functions */
int _pam_send_account(int tac_fd, int type, const char *user, char *tty,
char *r_addr, char *cmd) {
char buf[64];
struct tac_attrib *attr;
int retval;
attr = (struct tac_attrib *) xcalloc(1, sizeof(struct tac_attrib));
sprintf(buf, "%lu", (unsigned long) time(NULL));
if (type == TAC_PLUS_ACCT_FLAG_START) {
tac_add_attrib(&attr, "start_time", buf);
} else if (type == TAC_PLUS_ACCT_FLAG_STOP) {
tac_add_attrib(&attr, "stop_time", buf);
}
sprintf(buf, "%hu", task_id);
tac_add_attrib(&attr, "task_id", buf);
tac_add_attrib(&attr, "service", tac_service);
if (tac_protocol[0] != '\0')
tac_add_attrib(&attr, "protocol", tac_protocol);
if (cmd != NULL) {
tac_add_attrib(&attr, "cmd", cmd);
}
retval = tac_acct_send(tac_fd, type, user, tty, r_addr, attr);
/* this is no longer needed */
tac_free_attrib(&attr);
if (retval < 0) {
_pam_log(LOG_WARNING, "%s: send %s accounting failed (task %hu)",
__FUNCTION__, tac_acct_flag2str(type), task_id);
close(tac_fd);
return -1;
}
struct areply re;
if (tac_acct_read(tac_fd, &re) != TAC_PLUS_ACCT_STATUS_SUCCESS) {
_pam_log(LOG_WARNING, "%s: accounting %s failed (task %hu)",
__FUNCTION__, tac_acct_flag2str(type), task_id);
if (re.msg != NULL)
free(re.msg);
close(tac_fd);
return -1;
}
if (re.msg != NULL)
free(re.msg);
close(tac_fd);
return 0;
}
int _pam_account(pam_handle_t *pamh, int argc, const char **argv, int type,
char *cmd) {
int retval;
static int ctrl;
char *user = NULL;
char *tty = NULL;
char *r_addr = NULL;
char *typemsg;
int status = PAM_SESSION_ERR;
int srv_i, tac_fd;
typemsg = tac_acct_flag2str(type);
ctrl = _pam_parse(argc, argv);
if (ctrl & PAM_TAC_DEBUG) {
syslog(LOG_DEBUG, "%s: [%s] called (pam_tacplus v%u.%u.%u)",
__FUNCTION__, typemsg, PAM_TAC_VMAJ, PAM_TAC_VMIN,
PAM_TAC_VPAT);
syslog(LOG_DEBUG, "%s: tac_srv_no=%d", __FUNCTION__, tac_srv_no);
}
if ((user = _pam_get_user(pamh)) == NULL)
return PAM_USER_UNKNOWN;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: username [%s] obtained", __FUNCTION__, user);
tty = _pam_get_terminal(pamh);
if (!strncmp(tty, "/dev/", 5))
tty += 5;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: tty [%s] obtained", __FUNCTION__, tty);
r_addr = _pam_get_rhost(pamh);
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: rhost [%s] obtained", __FUNCTION__, r_addr);
/* checks for specific data required by TACACS+, which should
be supplied in command line */
if (*tac_service == '\0') {
_pam_log(LOG_ERR, "ACC: TACACS+ service type not configured");
return PAM_AUTH_ERR;
}
if (*tac_protocol == '\0') {
_pam_log(LOG_ERR,
"ACC: TACACS+ protocol type not configured (IGNORED)");
}
/* when this module is called from within pppd or other
application dealing with serial lines, it is likely
that we will get hit with signal caused by modem hangup;
this is important only for STOP packets, it's relatively
rare that modem hangs up on accounting start */
if (type == TAC_PLUS_ACCT_FLAG_STOP) {
signal(SIGALRM, SIG_IGN);
signal(SIGCHLD, SIG_IGN);
signal(SIGHUP, SIG_IGN);
}
status = PAM_SESSION_ERR;
for (srv_i = 0; srv_i < tac_srv_no; srv_i++) {
tac_fd = tac_connect_single(tac_srv[srv_i].addr, tac_srv[srv_i].key,
NULL, tac_timeout);
if (tac_fd < 0) {
_pam_log(LOG_WARNING, "%s: error sending %s (fd)", __FUNCTION__,
typemsg);
continue;
}
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: connected with fd=%d (srv %d)", __FUNCTION__,
tac_fd, srv_i);
retval = _pam_send_account(tac_fd, type, user, tty, r_addr, cmd);
if (retval < 0) {
_pam_log(LOG_WARNING, "%s: error sending %s (acct)", __FUNCTION__,
typemsg);
} else {
status = PAM_SUCCESS;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: [%s] for [%s] sent", __FUNCTION__,
typemsg, user);
}
close(tac_fd);
if ((status == PAM_SUCCESS) && !(ctrl & PAM_TAC_ACCT)) {
/* do not send acct start/stop packets to _all_ servers */
break;
}
}
if (type == TAC_PLUS_ACCT_FLAG_STOP) {
signal(SIGALRM, SIG_DFL);
signal(SIGCHLD, SIG_DFL);
signal(SIGHUP, SIG_DFL);
}
return status;
}
/* Main PAM functions */
/* authenticates user on remote TACACS+ server
* returns PAM_SUCCESS if the supplied username and password
* pair is valid
*/
PAM_EXTERN
int pam_sm_authenticate(pam_handle_t * pamh, int flags, int argc,
const char **argv) {
int ctrl, retval;
char *user;
char *pass;
char *tty;
char *r_addr;
int srv_i;
int tac_fd, status, msg, communicating;
user = pass = tty = r_addr = NULL;
ctrl = _pam_parse(argc, argv);
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: called (pam_tacplus v%u.%u.%u)", __FUNCTION__,
PAM_TAC_VMAJ, PAM_TAC_VMIN, PAM_TAC_VPAT);
if ((user = _pam_get_user(pamh)) == NULL)
return PAM_USER_UNKNOWN;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: user [%s] obtained", __FUNCTION__, user);
retval = tacacs_get_password(pamh, flags, ctrl, &pass);
if (retval != PAM_SUCCESS || pass == NULL || *pass == '\0') {
_pam_log(LOG_ERR, "unable to obtain password");
free(pass);
return PAM_CRED_INSUFFICIENT;
}
retval = pam_set_item(pamh, PAM_AUTHTOK, pass);
if (retval != PAM_SUCCESS) {
_pam_log(LOG_ERR, "unable to set password");
free(pass);
return PAM_CRED_INSUFFICIENT;
}
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: password obtained", __FUNCTION__);
tty = _pam_get_terminal(pamh);
if (!strncmp(tty, "/dev/", 5))
tty += 5;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: tty [%s] obtained", __FUNCTION__, tty);
r_addr = _pam_get_rhost(pamh);
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: rhost [%s] obtained", __FUNCTION__, r_addr);
status = PAM_AUTHINFO_UNAVAIL;
for (srv_i = 0; srv_i < tac_srv_no; srv_i++) {
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: trying srv %d", __FUNCTION__, srv_i);
tac_fd = tac_connect_single(tac_srv[srv_i].addr, tac_srv[srv_i].key,
NULL, tac_timeout);
if (tac_fd < 0) {
_pam_log(LOG_ERR, "connection failed srv %d: %m", srv_i);
continue;
}
if (tac_authen_send(tac_fd, user, pass, tty, r_addr,
TAC_PLUS_AUTHEN_LOGIN) < 0) {
close(tac_fd);
_pam_log(LOG_ERR, "error sending auth req to TACACS+ server");
continue;
}
communicating = 1;
while (communicating) {
struct areply re = { .attr = NULL, .msg = NULL, .status = 0,
.flags = 0 };
struct pam_message conv_msg = { .msg_style = 0, .msg = NULL };
struct pam_response *resp = NULL;
msg = tac_authen_read(tac_fd, &re);
if (NULL != re.msg) {
conv_msg.msg = re.msg;
}
/* talk the protocol */
switch (msg) {
case TAC_PLUS_AUTHEN_STATUS_PASS:
/* success */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_PASS");
if (NULL != conv_msg.msg) {
conv_msg.msg_style = PAM_TEXT_INFO;
retval = converse(pamh, 1, &conv_msg, &resp);
if (PAM_SUCCESS == retval) {
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "send msg=\"%s\"", conv_msg.msg);
} else {
_pam_log(LOG_WARNING,
"%s: error sending msg=\"%s\", retval=%d",
__FUNCTION__, conv_msg.msg, retval);
}
}
status = PAM_SUCCESS;
communicating = 0;
active_server.addr = tac_srv[srv_i].addr;
active_server.key = tac_srv[srv_i].key;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: active srv %d", __FUNCTION__, srv_i);
break;
case TAC_PLUS_AUTHEN_STATUS_FAIL:
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_FAIL");
if (NULL != conv_msg.msg) {
conv_msg.msg_style = PAM_ERROR_MSG;
retval = converse(pamh, 1, &conv_msg, &resp);
if (PAM_SUCCESS == retval) {
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "send msg=\"%s\"", conv_msg.msg);
} else {
_pam_log(LOG_WARNING,
"%s: error sending msg=\"%s\", retval=%d",
__FUNCTION__, conv_msg.msg, retval);
}
}
status = PAM_AUTH_ERR;
communicating = 0;
_pam_log(LOG_ERR, "auth failed: %d", msg);
break;
case TAC_PLUS_AUTHEN_STATUS_GETDATA:
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_GETDATA");
if (NULL != conv_msg.msg) {
int echo_off = (0x1 == (re.flags & 0x1));
conv_msg.msg_style =
echo_off ? PAM_PROMPT_ECHO_OFF : PAM_PROMPT_ECHO_ON;
retval = converse(pamh, 1, &conv_msg, &resp);
if (PAM_SUCCESS == retval) {
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "sent msg=\"%s\", resp=\"%s\"",
conv_msg.msg, resp->resp);
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "%s: calling tac_cont_send",
__FUNCTION__);
if (0
> tac_cont_send_seq(tac_fd, resp->resp,
re.seq_no + 1)) {
_pam_log(LOG_ERR,
"error sending continue req to TACACS+ server");
status = PAM_AUTH_ERR;
communicating = 0;
}
} else {
_pam_log(LOG_WARNING,
"%s: error sending msg=\"%s\", retval=%d (%s)",
__FUNCTION__, conv_msg.msg, retval,
pam_strerror(pamh, retval));
status = PAM_AUTH_ERR;
communicating = 0;
}
} else {
syslog(LOG_ERR,
"GETDATA response with no message, returning PAM_AUTH_ERR");
status = PAM_AUTH_ERR;
communicating = 0;
}
break;
case TAC_PLUS_AUTHEN_STATUS_GETUSER:
/* not implemented */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_GETUSER");
communicating = 0;
break;
case TAC_PLUS_AUTHEN_STATUS_GETPASS:
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_GETPASS");
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: tac_cont_send called", __FUNCTION__);
if (tac_cont_send(tac_fd, pass) < 0) {
_pam_log(LOG_ERR,
"error sending continue req to TACACS+ server");
communicating = 0;
}
/* continue the while loop; go read tac response */
break;
case TAC_PLUS_AUTHEN_STATUS_RESTART:
/* try it again */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_RESTART");
/*
* not implemented
* WdJ: I *think* you can just do tac_authen_send(user, pass) again
* but I'm not sure
*/
communicating = 0;
break;
case TAC_PLUS_AUTHEN_STATUS_ERROR:
/* server has problems */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_ERROR");
communicating = 0;
break;
case TAC_PLUS_AUTHEN_STATUS_FOLLOW:
/* server tells to try a different server address */
/* not implemented */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_FOLLOW");
communicating = 0;
break;
default:
if (msg < 0) {
/* connection error */
communicating = 0;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"error communicating with tacacs server");
break;
}
/* unknown response code */
communicating = 0;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "tacacs status: unknown response 0x%02x",
msg);
}
if (NULL != resp) {
free(resp->resp);
free(resp);
}
free(re.msg);
} /* end while(communicating) */
close(tac_fd);
if (status == PAM_SUCCESS || status == PAM_AUTH_ERR)
break;
}
if (status != PAM_SUCCESS && status != PAM_AUTH_ERR)
_pam_log(LOG_ERR, "no more servers to connect");
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: exit with pam status: %d", __FUNCTION__, status);
if (NULL != pass) {
bzero(pass, strlen(pass));
free(pass);
pass = NULL;
}
return status;
} /* pam_sm_authenticate */
/* no-op function to satisfy PAM authentication module */
PAM_EXTERN
int pam_sm_setcred(pam_handle_t * pamh, int flags, int argc, const char **argv) {
int ctrl = _pam_parse(argc, argv);
pamh = pamh;
flags = flags; /* unused */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: called (pam_tacplus v%u.%u.%u)", __FUNCTION__,
PAM_TAC_VMAJ, PAM_TAC_VMIN, PAM_TAC_VPAT);
return PAM_SUCCESS;
} /* pam_sm_setcred */
/* authorizes user on remote TACACS+ server, i.e. checks
* his permission to access requested service
* returns PAM_SUCCESS if the service is allowed
*/
PAM_EXTERN
int pam_sm_acct_mgmt(pam_handle_t * pamh, int flags, int argc,
const char **argv) {
int retval, ctrl, status = PAM_AUTH_ERR;
char *user;
char *tty;
char *r_addr;
struct areply arep;
struct tac_attrib *attr = NULL;
int tac_fd;
flags = flags; /* unused */
user = tty = r_addr = NULL;
memset(&arep, 0, sizeof(arep));
/* this also obtains service name for authorization
this should be normally performed by pam_get_item(PAM_SERVICE)
but since PAM service names are incompatible TACACS+
we have to pass it via command line argument until a better
solution is found ;) */
ctrl = _pam_parse(argc, argv);
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: called (pam_tacplus v%u.%u.%u)", __FUNCTION__,
PAM_TAC_VMAJ, PAM_TAC_VMIN, PAM_TAC_VPAT);
if ((user = _pam_get_user(pamh)) == NULL)
return PAM_USER_UNKNOWN;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: username obtained [%s]", __FUNCTION__, user);
tty = _pam_get_terminal(pamh);
if (!strncmp(tty, "/dev/", 5))
tty += 5;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: tty obtained [%s]", __FUNCTION__, tty);
r_addr = _pam_get_rhost(pamh);
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: rhost obtained [%s]", __FUNCTION__, r_addr);
/* checks if user has been successfully authenticated
by TACACS+; we cannot solely authorize user if it hasn't
been authenticated or has been authenticated by method other
than TACACS+ */
if (active_server.addr == NULL) {
_pam_log(LOG_ERR, "user not authenticated by TACACS+");
return PAM_AUTH_ERR;
}
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: active server is [%s]", __FUNCTION__,
tac_ntop(active_server.addr->ai_addr));
/* checks for specific data required by TACACS+, which should
be supplied in command line */
if (!*tac_service) {
_pam_log(LOG_ERR, "SM: TACACS+ service type not configured");
return PAM_AUTH_ERR;
}
if (!*tac_protocol) {
_pam_log(LOG_ERR, "SM: TACACS+ protocol type not configured (IGNORED)");
}
tac_add_attrib(&attr, "service", tac_service);
if (tac_protocol[0] != '\0')
tac_add_attrib(&attr, "protocol", tac_protocol);
tac_fd = tac_connect_single(active_server.addr, active_server.key, NULL,
tac_timeout);
if (tac_fd < 0) {
_pam_log(LOG_ERR, "TACACS+ server unavailable");
if (arep.msg != NULL)
free(arep.msg);
return PAM_AUTH_ERR;
}
retval = tac_author_send(tac_fd, user, tty, r_addr, attr);
tac_free_attrib(&attr);
if (retval < 0) {
_pam_log(LOG_ERR, "error getting authorization");
if (arep.msg != NULL)
free(arep.msg);
close(tac_fd);
return PAM_AUTH_ERR;
}
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: sent authorization request", __FUNCTION__);
tac_author_read(tac_fd, &arep);
if (arep.status != AUTHOR_STATUS_PASS_ADD
&& arep.status != AUTHOR_STATUS_PASS_REPL) {
_pam_log(LOG_ERR, "TACACS+ authorisation failed for [%s]", user);
if (arep.msg != NULL)
free(arep.msg);
close(tac_fd);
return PAM_PERM_DENIED;
}
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: user [%s] successfully authorized", __FUNCTION__,
user);
status = PAM_SUCCESS;
attr = arep.attr;
while (attr != NULL) {
char attribute[attr->attr_len];
char value[attr->attr_len];
char *sep;
sep = index(attr->attr, '=');
if (sep == NULL)
sep = index(attr->attr, '*');
if (sep != NULL) {
bcopy(attr->attr, attribute, attr->attr_len - strlen(sep));
attribute[attr->attr_len - strlen(sep)] = '\0';
bcopy(sep, value, strlen(sep));
value[strlen(sep)] = '\0';
size_t i;
for (i = 0; attribute[i] != '\0'; i++) {
attribute[i] = toupper(attribute[i]);
if (attribute[i] == '-')
attribute[i] = '_';
}
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: returned attribute `%s%s' from server",
__FUNCTION__, attribute, value);
/* make returned attributes available for other PAM modules via PAM environment */
if (pam_putenv(pamh,
strncat(attribute, value, strlen(value))) != PAM_SUCCESS)
syslog(LOG_WARNING, "%s: unable to set PAM environment",
__FUNCTION__);
} else {
syslog(LOG_WARNING, "%s: invalid attribute `%s', no separator",
__FUNCTION__, attr->attr);
}
attr = attr->next;
}
/* free returned attributes */
if (arep.attr != NULL)
tac_free_attrib(&arep.attr);
if (arep.msg != NULL)
free(arep.msg);
close(tac_fd);
return status;
} /* pam_sm_acct_mgmt */
/* sends START accounting request to the remote TACACS+ server
* returns PAM error only if the request was refused or there
* were problems connection to the server
*/
/* accounting packets may be directed to any TACACS+ server,
* independent from those used for authentication and authorization;
* it may be also directed to all specified servers
*/
PAM_EXTERN
int pam_sm_open_session(pam_handle_t * pamh, int flags, int argc,
const char **argv) {
#if defined(HAVE_OPENSSL_RAND_H) && defined(HAVE_LIBCRYPTO)
RAND_pseudo_bytes((unsigned char *) &task_id, sizeof(task_id));
#else
task_id=(short int) magic();
#endif
flags = flags; /* unused */
return _pam_account(pamh, argc, argv, TAC_PLUS_ACCT_FLAG_START, NULL);
} /* pam_sm_open_session */
/* sends STOP accounting request to the remote TACACS+ server
* returns PAM error only if the request was refused or there
* were problems connection to the server
*/
PAM_EXTERN
int pam_sm_close_session(pam_handle_t * pamh, int flags, int argc,
const char **argv) {
flags = flags; /* unused */
return _pam_account(pamh, argc, argv, TAC_PLUS_ACCT_FLAG_STOP, NULL);
} /* pam_sm_close_session */
#ifdef PAM_SM_PASSWORD
/* no-op function for future use */
PAM_EXTERN
int pam_sm_chauthtok(pam_handle_t * pamh, int flags, int argc,
const char **argv) {
int ctrl, retval;
char *user;
char *pass;
char *tty;
char *r_addr;
const void *pam_pass = NULL;
int srv_i;
int tac_fd, status, msg, communicating;
user = pass = tty = r_addr = NULL;
ctrl = _pam_parse(argc, argv);
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: called (pam_tacplus v%u.%u.%u)", __FUNCTION__,
PAM_TAC_VMAJ, PAM_TAC_VMIN, PAM_TAC_VPAT);
syslog(LOG_DEBUG, "%s(flags=%d, argc=%d)", __func__, flags, argc);
if ((pam_get_item(pamh, PAM_OLDAUTHTOK, &pam_pass) == PAM_SUCCESS)
&& (pam_pass != NULL)) {
if ((pass = strdup(pam_pass)) == NULL)
return PAM_BUF_ERR;
} else {
pass = strdup("");
}
if ((user = _pam_get_user(pamh)) == NULL) {
if (pass) {
free(pass);
}
return PAM_USER_UNKNOWN;
}
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: user [%s] obtained", __FUNCTION__, user);
tty = _pam_get_terminal(pamh);
if (!strncmp(tty, "/dev/", 5))
tty += 5;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: tty [%s] obtained", __FUNCTION__, tty);
r_addr = _pam_get_rhost(pamh);
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: rhost [%s] obtained", __FUNCTION__, r_addr);
if (PAM_SILENT == (flags & PAM_SILENT)) {
status = PAM_AUTHTOK_ERR;
goto finish;
}
status = PAM_TRY_AGAIN;
for (srv_i = 0; srv_i < tac_srv_no; srv_i++) {
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: trying srv %d", __FUNCTION__, srv_i);
tac_fd = tac_connect_single(tac_srv[srv_i].addr, tac_srv[srv_i].key,
NULL, tac_timeout);
if (tac_fd < 0) {
_pam_log(LOG_ERR, "connection failed srv %d: %m", srv_i);
continue;
}
if (PAM_PRELIM_CHECK == (flags & PAM_PRELIM_CHECK)) {
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "%s: finishing PAM_PRELIM_CHECK with srv %d",
__FUNCTION__, srv_i);
close(tac_fd);
status = PAM_SUCCESS;
goto finish;
}
if (tac_authen_send(tac_fd, user, "", tty, r_addr,
TAC_PLUS_AUTHEN_CHPASS) < 0) {
close(tac_fd);
_pam_log(LOG_ERR, "error sending auth req to TACACS+ server");
continue;
}
communicating = 1;
while (communicating) {
struct areply re = { .attr = NULL, .msg = NULL, .status = 0,
.flags = 0 };
struct pam_message conv_msg = { .msg_style = 0, .msg = NULL };
struct pam_response *resp = NULL;
msg = tac_authen_read(tac_fd, &re);
if (NULL != re.msg) {
conv_msg.msg = re.msg;
}
/* talk the protocol */
switch (msg) {
case TAC_PLUS_AUTHEN_STATUS_PASS:
/* success */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_PASS");
if (NULL != conv_msg.msg) {
conv_msg.msg_style = PAM_TEXT_INFO;
retval = converse(pamh, 1, &conv_msg, &resp);
if (PAM_SUCCESS == retval) {
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "send msg=\"%s\"", conv_msg.msg);
} else {
_pam_log(LOG_WARNING,
"%s: error sending msg=\"%s\", retval=%d",
__FUNCTION__, conv_msg.msg, retval);
}
}
status = PAM_SUCCESS;
communicating = 0;
active_server.addr = tac_srv[srv_i].addr;
active_server.key = tac_srv[srv_i].key;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: active srv %d", __FUNCTION__, srv_i);
break;
case TAC_PLUS_AUTHEN_STATUS_FAIL:
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_FAIL");
if (NULL != conv_msg.msg) {
conv_msg.msg_style = PAM_ERROR_MSG;
retval = converse(pamh, 1, &conv_msg, &resp);
if (PAM_SUCCESS == retval) {
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "send msg=\"%s\"", conv_msg.msg);
} else {
_pam_log(LOG_WARNING,
"%s: error sending msg=\"%s\", retval=%d",
__FUNCTION__, conv_msg.msg, retval);
}
}
status = PAM_AUTHTOK_ERR;
communicating = 0;
_pam_log(LOG_ERR, "chauthtok failed: %d", msg);
break;
case TAC_PLUS_AUTHEN_STATUS_GETDATA:
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_GETDATA");
if (NULL != conv_msg.msg) {
int echo_off = (0x1 == (re.flags & 0x1));
conv_msg.msg_style =
echo_off ? PAM_PROMPT_ECHO_OFF : PAM_PROMPT_ECHO_ON;
retval = converse(pamh, 1, &conv_msg, &resp);
if (PAM_SUCCESS == retval) {
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "sent msg=\"%s\", resp=\"%s\"",
conv_msg.msg, resp->resp);
if (PAM_TAC_DEBUG == (ctrl & PAM_TAC_DEBUG))
syslog(LOG_DEBUG, "%s: calling tac_cont_send",
__FUNCTION__);
if (0
> tac_cont_send_seq(tac_fd, resp->resp,
re.seq_no + 1)) {
_pam_log(LOG_ERR,
"error sending continue req to TACACS+ server");
communicating = 0;
}
} else {
_pam_log(LOG_WARNING,
"%s: error sending msg=\"%s\", retval=%d",
__FUNCTION__, conv_msg.msg, retval);
communicating = 0;
}
} else {
syslog(LOG_ERR,
"GETDATA response with no message, returning PAM_TRY_AGAIN");
communicating = 0;
}
break;
case TAC_PLUS_AUTHEN_STATUS_GETUSER:
/* not implemented */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_GETUSER");
communicating = 0;
break;
case TAC_PLUS_AUTHEN_STATUS_GETPASS:
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_GETPASS");
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "%s: calling tac_cont_send",
__FUNCTION__);
if (tac_cont_send(tac_fd, pass) < 0) {
_pam_log(LOG_ERR,
"error sending continue req to TACACS+ server");
communicating = 0;
break;
}
/* continue the while loop; go read tac response */
break;
case TAC_PLUS_AUTHEN_STATUS_RESTART:
/* try it again */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_RESTART");
/*
* not implemented
* WdJ: I *think* you can just do tac_authen_send(user, pass) again
* but I'm not sure
*/
communicating = 0;
break;
case TAC_PLUS_AUTHEN_STATUS_ERROR:
/* server has problems */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_ERROR");
communicating = 0;
break;
case TAC_PLUS_AUTHEN_STATUS_FOLLOW:
/* server tells to try a different server address */
/* not implemented */
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"tacacs status: TAC_PLUS_AUTHEN_STATUS_FOLLOW");
communicating = 0;
break;
default:
if (msg < 0) {
/* connection error */
communicating = 0;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG,
"error communicating with tacacs server");
break;
}
/* unknown response code */
communicating = 0;
if (ctrl & PAM_TAC_DEBUG)
syslog(LOG_DEBUG, "tacacs status: unknown response 0x%02x",
msg);
}
if (NULL != resp) {
free(resp->resp);
free(resp);