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/* authen_r.c - Read authentication reply from server.
*
* Copyright (C) 2010, Pawel Krawczyk <pawel.krawczyk@hush.com> and
* Jeroen Nijhof <jeroen@jeroennijhof.nl>
*
* 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 "libtac.h"
#include "messages.h"
/* reads packet from TACACS+ server; returns:
* TAC_PLUS_AUTHEN_STATUS_PASS if the authentication succeded
* an other integer if failed. Check tacplus.h for all possible values
*
* return value:
* < 0 : error status code, see LIBTAC_STATUS_...
* LIBTAC_STATUS_READ_TIMEOUT
* LIBTAC_STATUS_SHORT_HDR
* LIBTAC_STATUS_SHORT_BODY
* LIBTAC_STATUS_PROTOCOL_ERR
* >= 0 : server response, see TAC_PLUS_AUTHEN_STATUS_...
*/
int tac_authen_read(int fd) {
HDR th;
struct authen_reply *tb = NULL;
int len_from_header, r, len_from_body;
char *msg = NULL;
int timeleft;
int status;
/* read the reply header */
if (tac_readtimeout_enable &&
tac_read_wait(fd,tac_timeout*1000,TAC_PLUS_HDR_SIZE,&timeleft) < 0 ) {
TACSYSLOG((LOG_ERR,\
"%s: reply timeout after %d secs", __FUNCTION__, tac_timeout))
status=LIBTAC_STATUS_READ_TIMEOUT;
free(tb);
return status;
}
r = read(fd, &th, TAC_PLUS_HDR_SIZE);
if (r < TAC_PLUS_HDR_SIZE) {
TACSYSLOG((LOG_ERR,\
"%s: short reply header, read %d of %d: %m",\
__FUNCTION__,\
r, TAC_PLUS_HDR_SIZE))
status=LIBTAC_STATUS_SHORT_HDR;
free(tb);
return status;
}
/* check the reply fields in header */
msg = _tac_check_header(&th, TAC_PLUS_AUTHEN);
if(msg != NULL) {
status = LIBTAC_STATUS_PROTOCOL_ERR;
free(tb);
return status;
}
len_from_header = ntohl(th.datalength);
tb = (struct authen_reply *) xcalloc(1, len_from_header);
/* read reply packet body */
if (tac_readtimeout_enable &&
tac_read_wait(fd,timeleft,len_from_header,NULL) < 0 ) {
TACSYSLOG((LOG_ERR,\
"%s: reply timeout after %d secs", __FUNCTION__, tac_timeout))
status=LIBTAC_STATUS_READ_TIMEOUT;
}
r = read(fd, tb, len_from_header);
if (r < len_from_header) {
TACSYSLOG((LOG_ERR,\
"%s: short reply body, read %d of %d: %m",\
__FUNCTION__,\
r, len_from_header))
status = LIBTAC_STATUS_SHORT_BODY;
free(tb);
return status;
}
/* decrypt the body */
_tac_crypt((u_char *) tb, &th, len_from_header);
/* Convert network byte order to host byte order */
tb->msg_len = ntohs(tb->msg_len);
tb->data_len = ntohs(tb->data_len);
/* check the length fields */
len_from_body = sizeof(tb->status) + sizeof(tb->flags) +
sizeof(tb->msg_len) + sizeof(tb->data_len) +
tb->msg_len + tb->data_len;
if(len_from_header != len_from_body) {
TACSYSLOG((LOG_ERR,\
"%s: inconsistent reply body, incorrect key?",\
__FUNCTION__))
status = LIBTAC_STATUS_PROTOCOL_ERR;
free(tb);
return status;
}
/* save status and clean up */
r = tb->status;
status = r;
/* server authenticated username and password successfully */
if (r == TAC_PLUS_AUTHEN_STATUS_PASS) {
TACDEBUG((LOG_DEBUG, "%s: authentication ok", __FUNCTION__))
free(tb);
return status;
}
/* server ask for continue packet with password */
if (r == TAC_PLUS_AUTHEN_STATUS_GETPASS) {
TACDEBUG((LOG_DEBUG, "%s: continue packet with password needed", __FUNCTION__))
free(tb);
return status;
}
TACDEBUG((LOG_DEBUG, "%s: authentication failed, server reply status=%d",\
__FUNCTION__, r))
free(tb);
return status;
} /* tac_authen_read */
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