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skey_fn.c
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C/C++ Source or Header
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2012-06-28
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7KB
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224 lines
/*
* $Id: skey_fn.c,v 1.10 2009-03-17 18:40:20 heas Exp $
*
* Copyright (c) 1995-1998 by Cisco systems, Inc.
*
* Permission to use, copy, modify, and distribute this software for
* any purpose and without fee is hereby granted, provided that this
* copyright and permission notice appear on all copies of the
* software and supporting documentation, the name of Cisco Systems,
* Inc. not be used in advertising or publicity pertaining to
* distribution of the program without specific prior permission, and
* notice be given in supporting documentation that modification,
* copying and distribution is by permission of Cisco Systems, Inc.
*
* Cisco Systems, Inc. makes no representations about the suitability
* of this software for any purpose. THIS SOFTWARE IS PROVIDED ``AS
* IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
* WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE.
*/
#include "tac_plus.h"
#include "expire.h"
/* internal state variables */
#define STATE_AUTHEN_START 0 /* no requests issued */
#define STATE_AUTHEN_GETUSER 1 /* username has been requested */
#define STATE_AUTHEN_GETPASS 2 /* password has been requested */
#include <skey.h>
struct private_data {
struct skey skey;
char password[MAX_PASSWD_LEN + 1];
int state;
};
/*
* Use s/key to verify a supplied password using state set up earlier
* when the username was supplied.
*/
static int
skey_verify(char *passwd, struct authen_data *data)
{
struct private_data *p = data->method_data;
struct skey *skeyp = &p->skey;
data->status = TAC_PLUS_AUTHEN_STATUS_FAIL;
if (skeyverify(skeyp, passwd) == 0) {
/* S/Key authentication succeeded */
data->status = TAC_PLUS_AUTHEN_STATUS_PASS;
if (skeyp->n < 5) {
data->server_msg = tac_strdup("Password will expire soon");
return(1);
}
}
return(0);
}
/*
* Skey tacacs login authentication function. Wants a username
* and a password, and tries to verify them via skey.
*
* Choose_authen will ensure that we already have a username before this
* gets called.
*
* We will query for a password and keep it in the method_data.
*
* Any strings returned via pointers in authen_data must come from the
* heap. They will get freed by the caller.
*
* Return 0 if data->status is valid, otherwise 1
*/
int
skey_fn(struct authen_data *data)
{
char *name, *passwd;
struct private_data *p;
char *prompt;
int pwlen;
p = (struct private_data *) data->method_data;
/* An abort has been received. Clean up and return */
if (data->flags & TAC_PLUS_CONTINUE_FLAG_ABORT) {
if (data->method_data)
free(data->method_data);
data->method_data = NULL;
return(1);
}
/* Initialise method_data if first time through */
if (!p) {
p = (struct private_data *) tac_malloc(sizeof(struct private_data));
memset(p, 0, sizeof(struct private_data));
data->method_data = p;
p->state = STATE_AUTHEN_START;
}
/* Unless we're enabling, we need a username */
if (data->service != TAC_PLUS_AUTHEN_SVC_ENABLE &&
(char)data->NAS_id->username[0] == '\0') {
switch (p->state) {
case STATE_AUTHEN_GETUSER:
/* we have previously asked for a username but none came back.
* This is a gross error */
data->status = TAC_PLUS_AUTHEN_STATUS_ERROR;
report(LOG_ERR, "%s: No username supplied after GETUSER",
session.peer);
return(0);
case STATE_AUTHEN_START:
/* No username. Try requesting one */
data->status = TAC_PLUS_AUTHEN_STATUS_GETUSER;
if (data->service == TAC_PLUS_AUTHEN_SVC_LOGIN) {
prompt = "\nUser Access Verification\n\nUsername: ";
} else {
prompt = "Username: ";
}
data->server_msg = tac_strdup(prompt);
p->state = STATE_AUTHEN_GETUSER;
return(0);
default:
/* something awful has happened. Give up and die */
report(LOG_ERR, "%s: skey_fn bad state %d",
session.peer, p->state);
return(1);
}
}
/* we now have a username if we needed one */
name = data->NAS_id->username;
/* Do we have a password? */
passwd = p->password;
if (!passwd[0]) {
char skeyprompt[80];
/* no password yet. Either we need to ask for one and expect to get
* called again, or we asked but nothing came back, which is fatal */
switch (p->state) {
case STATE_AUTHEN_GETPASS:
/* We already asked for a password. This should be the reply */
if (data->client_msg) {
pwlen = MIN(strlen(data->client_msg), MAX_PASSWD_LEN);
} else {
pwlen = 0;
}
strncpy(passwd, data->client_msg, pwlen);
passwd[pwlen] = '\0';
break;
default:
/* Request a password */
passwd = cfg_get_login_secret(name, TAC_PLUS_RECURSE);
if (!passwd && !STREQ(passwd, "skey")) {
report(LOG_ERR, "Cannot find skey password declaration for %s",
name);
data->status = TAC_PLUS_AUTHEN_STATUS_ERROR;
return(1);
}
if (skeychallenge(&p->skey, name, skeyprompt, 80) == 0) {
char buf[256];
snprintf(buf, sizeof(buf), "%s\nS/Key challenge: ", skeyprompt);
data->server_msg = tac_strdup(buf);
data->status = TAC_PLUS_AUTHEN_STATUS_GETPASS;
p->state = STATE_AUTHEN_GETPASS;
return(0);
}
data->status = TAC_PLUS_AUTHEN_STATUS_ERROR;
report(LOG_ERR, "Cannot generate skey prompt for %s", name);
return(1);
}
}
/* We have a username and password. Try validating */
/* Assume the worst */
data->status = TAC_PLUS_AUTHEN_STATUS_FAIL;
switch (data->service) {
case TAC_PLUS_AUTHEN_SVC_LOGIN:
case TAC_PLUS_AUTHEN_SVC_ENABLE:
skey_verify(passwd, data);
if (debug)
report(LOG_INFO, "login/enable query for '%s' %s from %s %s",
name && name[0] ? name : "unknown",
data->NAS_id->NAS_port && data->NAS_id->NAS_port[0] ?
data->NAS_id->NAS_port : "unknown",
session.peer,
(data->status == TAC_PLUS_AUTHEN_STATUS_PASS) ?
"accepted" : "rejected");
break;
default:
data->status = TAC_PLUS_AUTHEN_STATUS_ERROR;
report(LOG_ERR, "%s: Bogus service value %d from packet",
session.peer, data->service);
break;
}
if (data->method_data)
free(data->method_data);
data->method_data = NULL;
switch (data->status) {
case TAC_PLUS_AUTHEN_STATUS_ERROR:
case TAC_PLUS_AUTHEN_STATUS_FAIL:
case TAC_PLUS_AUTHEN_STATUS_PASS:
return(0);
default:
report(LOG_ERR, "%s: skey_fn couldn't set recognizable status %d",
session.peer, data->status);
data->status = TAC_PLUS_AUTHEN_STATUS_ERROR;
return(1);
}
}