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/* authen_s.c - Send authentication request to the 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 "tacplus.h"
#include "libtac.h"
#include "xalloc.h"
#include "md5.h"
/* this function sends a packet do TACACS+ server, asking
* for validation of given username and password
*
* return value:
* 0 : success
* < 0 : error status code, see LIBTAC_STATUS_...
* LIBTAC_STATUS_WRITE_ERR
* LIBTAC_STATUS_WRITE_TIMEOUT
* LIBTAC_STATUS_ASSEMBLY_ERR
*/
int tac_authen_send(int fd, const char *user, char *pass, char *tty,
char *rem_addr) {
HDR *th; /* TACACS+ packet header */
struct authen_start tb; /* message body */
int user_len, port_len, chal_len, mdp_len, token_len, bodylength, w;
int rem_addr_len;
int pkt_len = 0;
int ret = 0;
char *chal = "1234123412341234";
char digest[MD5_LEN];
char *token = NULL;
u_char *pkt = NULL, *mdp = NULL;
MD5_CTX mdcontext;
th=_tac_req_header(TAC_PLUS_AUTHEN, 0);
/* set some header options */
if ((tac_login != NULL) && (strcmp(tac_login,"login") == 0)) {
th->version = TAC_PLUS_VER_0;
} else {
th->version = TAC_PLUS_VER_1;
}
th->encryption = tac_encryption ? TAC_PLUS_ENCRYPTED_FLAG : TAC_PLUS_UNENCRYPTED_FLAG;
TACDEBUG((LOG_DEBUG, "%s: user '%s', tty '%s', rem_addr '%s', encrypt: %s", \
__FUNCTION__, user, tty, rem_addr, \
(tac_encryption) ? "yes" : "no"))
if ((tac_login != NULL) && (strcmp(tac_login,"chap") == 0)) {
chal_len = strlen(chal);
mdp_len = sizeof(u_char) + strlen(pass) + chal_len;
mdp = (u_char *) xcalloc(1, mdp_len);
mdp[0] = 5;
memcpy(&mdp[1], pass, strlen(pass));
memcpy(mdp + strlen(pass) + 1, chal, chal_len);
MD5Init(&mdcontext);
MD5Update(&mdcontext, mdp, mdp_len);
MD5Final((u_char *) digest, &mdcontext);
free(mdp);
token = (char*) xcalloc(1, sizeof(u_char) + 1 + chal_len + MD5_LEN);
token[0] = 5;
memcpy(&token[1], chal, chal_len);
memcpy(token + chal_len + 1, digest, MD5_LEN);
} else {
token = xstrdup(pass);
}
/* get size of submitted data */
user_len = strlen(user);
port_len = strlen(tty);
rem_addr_len = strlen(rem_addr);
token_len = strlen(token);
/* fill the body of message */
tb.action = TAC_PLUS_AUTHEN_LOGIN;
tb.priv_lvl = tac_priv_lvl;
if (tac_login == NULL) {
/* default to PAP */
tb.authen_type = TAC_PLUS_AUTHEN_TYPE_PAP;
} else {
if (strcmp(tac_login,"chap") == 0) {
tb.authen_type = TAC_PLUS_AUTHEN_TYPE_CHAP;
} else if (strcmp(tac_login,"login") == 0) {
tb.authen_type = TAC_PLUS_AUTHEN_TYPE_ASCII;
} else {
tb.authen_type = TAC_PLUS_AUTHEN_TYPE_PAP;
}
}
tb.service = tac_authen_service;
tb.user_len = user_len;
tb.port_len = port_len;
tb.rem_addr_len = rem_addr_len; /* may be e.g Caller-ID in future */
tb.data_len = token_len;
/* fill body length in header */
bodylength = sizeof(tb) + user_len
+ port_len + rem_addr_len + token_len;
th->datalength = htonl(bodylength);
/* we can now write the header */
w = write(fd, th, TAC_PLUS_HDR_SIZE);
if (w < 0 || w < TAC_PLUS_HDR_SIZE) {
TACSYSLOG((LOG_ERR,\
"%s: short write on header, wrote %d of %d: %m",\
__FUNCTION__, w, TAC_PLUS_HDR_SIZE))
free(token);
free(pkt);
free(th);
return LIBTAC_STATUS_WRITE_ERR;
}
/* build the packet */
pkt = (u_char *) xcalloc(1, bodylength+10);
bcopy(&tb, pkt+pkt_len, sizeof(tb)); /* packet body beginning */
pkt_len += sizeof(tb);
bcopy(user, pkt+pkt_len, user_len); /* user */
pkt_len += user_len;
bcopy(tty, pkt+pkt_len, port_len); /* tty */
pkt_len += port_len;
bcopy(rem_addr, pkt+pkt_len, rem_addr_len); /* rem addr */
pkt_len += rem_addr_len;
bcopy(token, pkt+pkt_len, token_len); /* password */
pkt_len += token_len;
/* pkt_len == bodylength ? */
if (pkt_len != bodylength) {
TACSYSLOG((LOG_ERR, "%s: bodylength %d != pkt_len %d",\
__FUNCTION__, bodylength, pkt_len))
free(token);
free(pkt);
free(th);
return LIBTAC_STATUS_ASSEMBLY_ERR;
}
/* encrypt the body */
_tac_crypt(pkt, th, bodylength);
w = write(fd, pkt, pkt_len);
if (w < 0 || w < pkt_len) {
TACSYSLOG((LOG_ERR,\
"%s: short write on body, wrote %d of %d: %m",\
__FUNCTION__, w, pkt_len))
ret = LIBTAC_STATUS_WRITE_ERR;
}
free(token);
free(pkt);
free(th);
TACDEBUG((LOG_DEBUG, "%s: exit status=%d", __FUNCTION__, ret))
return ret;
} /* tac_authen_send */
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