/*
* upap.c - User/Password Authentication Protocol.
*
* Copyright (c) 1989 Carnegie Mellon University.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by Carnegie Mellon University. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#define RCSID "$Id$"
/*
* TODO:
*/
#include <stdio.h>
#include <string.h>
#include "pppd.h"
#include "upap.h"
static const char rcsid[] = RCSID;
static bool hide_password = 1;
/*
* Command-line options.
*/
static option_t pap_option_list[] = {
{ "hide-password", o_bool, &hide_password,
"Don't output passwords to log", 1 },
{ "show-password", o_bool, &hide_password,
"Show password string in debug log messages", 0 },
{ "pap-restart", o_int, &upap[0].us_timeouttime,
"Set retransmit timeout for PAP" },
{ "pap-max-authreq", o_int, &upap[0].us_maxtransmits,
"Set max number of transmissions for auth-reqs" },
{ "pap-timeout", o_int, &upap[0].us_reqtimeout,
"Set time limit for peer PAP authentication" },
{ NULL }
};
/*
* Protocol entry points.
*/
static void upap_init __P((int));
static void upap_lowerup __P((int));
static void upap_lowerdown __P((int));
static void upap_input __P((int, u_char *, int));
static void upap_protrej __P((int));
static int upap_printpkt __P((u_char *, int,
void (*) __P((void *, char *, ...)), void *));
struct protent pap_protent = {
PPP_PAP,
upap_init,
upap_input,
upap_protrej,
upap_lowerup,
upap_lowerdown,
NULL,
NULL,
upap_printpkt,
NULL,
1,
"PAP",
NULL,
pap_option_list,
NULL,
NULL,
NULL
};
upap_state upap[NUM_PPP]; /* UPAP state; one for each unit */
static void upap_timeout __P((void *));
static void upap_reqtimeout __P((void *));
static void upap_rauthreq __P((upap_state *, u_char *, int, int));
static void upap_rauthack __P((upap_state *, u_char *, int, int));
static void upap_rauthnak __P((upap_state *, u_char *, int, int));
static void upap_sauthreq __P((upap_state *));
static void upap_sresp __P((upap_state *, u_char, u_char, char *, int));
/*
* upap_init - Initialize a UPAP unit.
*/
static void
upap_init(unit)
int unit;
{
upap_state *u = &upap[unit];
u->us_unit = unit;
u->us_user = NULL;
u->us_userlen = 0;
u->us_passwd = NULL;
u->us_passwdlen = 0;
u->us_clientstate = UPAPCS_INITIAL;
u->us_serverstate = UPAPSS_INITIAL;
u->us_id = 0;
u->us_timeouttime = UPAP_DEFTIMEOUT;
u->us_maxtransmits = 10;
u->us_reqtimeout = UPAP_DEFREQTIME;
}
/*
* upap_authwithpeer - Authenticate us with our peer (start client).
*
* Set new state and send authenticate's.
*/
void
upap_authwithpeer(unit, user, password)
int unit;
char *user, *password;
{
upap_state *u = &upap[unit];
/* Save the username and password we're given */
u->us_user = user;
u->us_userlen = strlen(user);
u->us_passwd = password;
u->us_passwdlen = strlen(password);
u->us_transmits = 0;
/* Lower layer up yet? */
if (u->us_clientstate == UPAPCS_INITIAL ||
u->us_clientstate == UPAPCS_PENDING) {
u->us_clientstate = UPAPCS_PENDING;
return;
}
upap_sauthreq(u); /* Start protocol */
}
/*
* upap_authpeer - Authenticate our peer (start server).
*
* Set new state.
*/
void
upap_authpeer(unit)
int unit;
{
upap_state *u = &upap[unit];
/* Lower layer up yet? */
if (u->us_serverstate == UPAPSS_INITIAL ||
u->us_serverstate == UPAPSS_PENDING) {
u->us_serverstate = UPAPSS_PENDING;
return;
}
u->us_serverstate = UPAPSS_LISTEN;
if (u->us_reqtimeout > 0)
TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
}
/*
* upap_timeout - Retransmission timer for sending auth-reqs expired.
*/
static void
upap_timeout(arg)
void *arg;
{
upap_state *u = (upap_state *) arg;
if (u->us_clientstate != UPAPCS_AUTHREQ)
return;
if (u->us_transmits >= u->us_maxtransmits) {
/* give up in disgust */
error("No response to PAP authenticate-requests");
u->us_clientstate = UPAPCS_BADAUTH;
auth_withpeer_fail(u->us_unit, PPP_PAP);
return;
}
upap_sauthreq(u); /* Send Authenticate-Request */
}
/*
* upap_reqtimeout - Give up waiting for the peer to send an auth-req.
*/
static void
upap_reqtimeout(arg)
void *arg;
{
upap_state *u = (upap_state *) arg;
if (u->us_serverstate != UPAPSS_LISTEN)
return; /* huh?? */
auth_peer_fail(u->us_unit, PPP_PAP);
u->us_serverstate = UPAPSS_BADAUTH;
}
/*
* upap_lowerup - The lower layer is up.
*
* Start authenticating if pending.
*/
static void
upap_lowerup(unit)
int unit;
{
upap_state *u = &upap[unit];
if (u->us_clientstate == UPAPCS_INITIAL)
u->us_clientstate = UPAPCS_CLOSED;
else if (u->us_clientstate == UPAPCS_PENDING) {
upap_sauthreq(u); /* send an auth-request */
}
if (u->us_serverstate == UPAPSS_INITIAL)
u->us_serverstate = UPAPSS_CLOSED;
else if (u->us_serverstate == UPAPSS_PENDING) {
u->us_serverstate = UPAPSS_LISTEN;
if (u->us_reqtimeout > 0)
TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
}
}
/*
* upap_lowerdown - The lower layer is down.
*
* Cancel all timeouts.
*/
static void
upap_lowerdown(unit)
int unit;
{
upap_state *u = &upap[unit];
if (u->us_clientstate == UPAPCS_AUTHREQ) /* Timeout pending? */
UNTIMEOUT(upap_timeout, u); /* Cancel timeout */
if (u->us_serverstate == UPAPSS_LISTEN && u->us_reqtimeout > 0)
UNTIMEOUT(upap_reqtimeout, u);
u->us_clientstate = UPAPCS_INITIAL;
u->us_serverstate = UPAPSS_INITIAL;
}
/*
* upap_protrej - Peer doesn't speak this protocol.
*
* This shouldn't happen. In any case, pretend lower layer went down.
*/
static void
upap_protrej(unit)
int unit;
{
upap_state *u = &upap[unit];
if (u->us_clientstate == UPAPCS_AUTHREQ) {
error("PAP authentication failed due to protocol-reject");
auth_withpeer_fail(unit, PPP_PAP);
}
if (u->us_serverstate == UPAPSS_LISTEN) {
error("PAP authentication of peer failed (protocol-reject)");
auth_peer_fail(unit, PPP_PAP);
}
upap_lowerdown(unit);
}
/*
* upap_input - Input UPAP packet.
*/
static void
upap_input(unit, inpacket, l)
int unit;
u_char *inpacket;
int l;
{
upap_state *u = &upap[unit];
u_char *inp;
u_char code, id;
int len;
/*
* Parse header (code, id and length).
* If packet too short, drop it.
*/
inp = inpacket;
if (l < UPAP_HEADERLEN) {
UPAPDEBUG(("pap_input: rcvd short header."));
return;
}
GETCHAR(code, inp);
GETCHAR(id, inp);
GETSHORT(len, inp);
if (len < UPAP_HEADERLEN) {
UPAPDEBUG(("pap_input: rcvd illegal length."));
return;
}
if (len > l) {
UPAPDEBUG(("pap_input: rcvd short packet."));
return;
}
len -= UPAP_HEADERLEN;
/*
* Action depends on code.
*/
switch (code) {
case UPAP_AUTHREQ:
upap_rauthreq(u, inp, id, len);
break;
case UPAP_AUTHACK:
upap_rauthack(u, inp, id, len);
break;
case UPAP_AUTHNAK:
upap_rauthnak(u, inp, id, len);
break;
default: /* XXX Need code reject */
break;
}
}
/*
* upap_rauth - Receive Authenticate.
*/
static void
upap_rauthreq(u, inp, id, len)
upap_state *u;
u_char *inp;
int id;
int len;
{
u_char ruserlen, rpasswdlen;
char *ruser, *rpasswd;
int retcode;
char *msg;
int msglen;
if (u->us_serverstate < UPAPSS_LISTEN)
return;
/*
* If we receive a duplicate authenticate-request, we are
* supposed to return the same status as for the first request.
*/
if (u->us_serverstate == UPAPSS_OPEN) {
upap_sresp(u, UPAP_AUTHACK, id, "", 0); /* return auth-ack */
return;
}
if (u->us_serverstate == UPAPSS_BADAUTH) {
upap_sresp(u, UPAP_AUTHNAK, id, "", 0); /* return auth-nak */
return;
}
/*
* Parse user/passwd.
*/
if (len < 1) {
UPAPDEBUG(("pap_rauth: rcvd short packet."));
return;
}
GETCHAR(ruserlen, inp);
len -= sizeof (u_char) + ruserlen + sizeof (u_char);
if (len < 0) {
UPAPDEBUG(("pap_rauth: rcvd short packet."));
return;
}
ruser = (char *) inp;
INCPTR(ruserlen, inp);
GETCHAR(rpasswdlen, inp);
if (len < rpasswdlen) {
UPAPDEBUG(("pap_rauth: rcvd short packet."));
return;
}
rpasswd = (char *) inp;
/*
* Check the username and password given.
*/
retcode = check_passwd(u->us_unit, ruser, ruserlen, rpasswd,
rpasswdlen, &msg);
BZERO(rpasswd, rpasswdlen);
msglen = strlen(msg);
if (msglen > 255)
msglen = 255;
upap_sresp(u, retcode, id, msg, msglen);
if (retcode == UPAP_AUTHACK) {
u->us_serverstate = UPAPSS_OPEN;
auth_peer_success(u->us_unit, PPP_PAP, ruser, ruserlen);
} else {
u->us_serverstate = UPAPSS_BADAUTH;
auth_peer_fail(u->us_unit, PPP_PAP);
}
if (u->us_reqtimeout > 0)
UNTIMEOUT(upap_reqtimeout, u);
}
/*
* upap_rauthack - Receive Authenticate-Ack.
*/
static void
upap_rauthack(u, inp, id, len)
upap_state *u;
u_char *inp;
int id;
int len;
{
u_char msglen;
char *msg;
if (u->us_clientstate != UPAPCS_AUTHREQ) /* XXX */
return;
/*
* Parse message.
*/
if (len < 1) {
UPAPDEBUG(("pap_rauthack: ignoring missing msg-length."));
} else {
GETCHAR(msglen, inp);
if (msglen > 0) {
len -= sizeof (u_char);
if (len < msglen) {
UPAPDEBUG(("pap_rauthack: rcvd short packet."));
return;
}
msg = (char *) inp;
PRINTMSG(msg, msglen);
}
}
u->us_clientstate = UPAPCS_OPEN;
auth_withpeer_success(u->us_unit, PPP_PAP);
}
/*
* upap_rauthnak - Receive Authenticate-Nakk.
*/
static void
upap_rauthnak(u, inp, id, len)
upap_state *u;
u_char *inp;
int id;
int len;
{
u_char msglen;
char *msg;
if (u->us_clientstate != UPAPCS_AUTHREQ) /* XXX */
return;
/*
* Parse message.
*/
if (len < 1) {
UPAPDEBUG(("pap_rauthnak: ignoring missing msg-length."));
} else {
GETCHAR(msglen, inp);
if (msglen > 0) {
len -= sizeof (u_char);
if (len < msglen) {
UPAPDEBUG(("pap_rauthnak: rcvd short packet."));
return;
}
msg = (char *) inp;
PRINTMSG(msg, msglen);
}
}
u->us_clientstate = UPAPCS_BADAUTH;
error("PAP authentication failed");
auth_withpeer_fail(u->us_unit, PPP_PAP);
}
/*
* upap_sauthreq - Send an Authenticate-Request.
*/
static void
upap_sauthreq(u)
upap_state *u;
{
u_char *outp;
int outlen;
outlen = UPAP_HEADERLEN + 2 * sizeof (u_char) +
u->us_userlen + u->us_passwdlen;
outp = outpacket_buf;
MAKEHEADER(outp, PPP_PAP);
PUTCHAR(UPAP_AUTHREQ, outp);
PUTCHAR(++u->us_id, outp);
PUTSHORT(outlen, outp);
PUTCHAR(u->us_userlen, outp);
BCOPY(u->us_user, outp, u->us_userlen);
INCPTR(u->us_userlen, outp);
PUTCHAR(u->us_passwdlen, outp);
BCOPY(u->us_passwd, outp, u->us_passwdlen);
output(u->us_unit, outpacket_buf, outlen + PPP_HDRLEN);
TIMEOUT(upap_timeout, u, u->us_timeouttime);
++u->us_transmits;
u->us_clientstate = UPAPCS_AUTHREQ;
}
/*
* upap_sresp - Send a response (ack or nak).
*/
static void
upap_sresp(u, code, id, msg, msglen)
upap_state *u;
u_char code, id;
char *msg;
int msglen;
{
u_char *outp;
int outlen;
outlen = UPAP_HEADERLEN + sizeof (u_char) + msglen;
outp = outpacket_buf;
MAKEHEADER(outp, PPP_PAP);
PUTCHAR(code, outp);
PUTCHAR(id, outp);
PUTSHORT(outlen, outp);
PUTCHAR(msglen, outp);
BCOPY(msg, outp, msglen);
output(u->us_unit, outpacket_buf, outlen + PPP_HDRLEN);
}
/*
* upap_printpkt - print the contents of a PAP packet.
*/
static char *upap_codenames[] = {
"AuthReq", "AuthAck", "AuthNak"
};
static int
upap_printpkt(p, plen, printer, arg)
u_char *p;
int plen;
void (*printer) __P((void *, char *, ...));
void *arg;
{
int code, id, len;
int mlen, ulen, wlen;
char *user, *pwd, *msg;
u_char *pstart;
if (plen < UPAP_HEADERLEN)
return 0;
pstart = p;
GETCHAR(code, p);
GETCHAR(id, p);
GETSHORT(len, p);
if (len < UPAP_HEADERLEN || len > plen)
return 0;
if (code >= 1 && code <= sizeof(upap_codenames) / sizeof(char *))
printer(arg, " %s", upap_codenames[code-1]);
else
printer(arg, " code=0x%x", code);
printer(arg, " id=0x%x", id);
len -= UPAP_HEADERLEN;
switch (code) {
case UPAP_AUTHREQ:
if (len < 1)
break;
ulen = p[0];
if (len < ulen + 2)
break;
wlen = p[ulen + 1];
if (len < ulen + wlen + 2)
break;
user = (char *) (p + 1);
pwd = (char *) (p + ulen + 2);
p += ulen + wlen + 2;
len -= ulen + wlen + 2;
printer(arg, " user=");
print_string(user, ulen, printer, arg);
printer(arg, " password=");
if (!hide_password)
print_string(pwd, wlen, printer, arg);
else
printer(arg, "<hidden>");
break;
case UPAP_AUTHACK:
case UPAP_AUTHNAK:
if (len < 1)
break;
mlen = p[0];
if (len < mlen + 1)
break;
msg = (char *) (p + 1);
p += mlen + 1;
len -= mlen + 1;
printer(arg, " ");
print_string(msg, mlen, printer, arg);
break;
}
/* print the rest of the bytes in the packet */
for (; len > 0; --len) {
GETCHAR(code, p);
printer(arg, " %.2x", code);
}
return p - pstart;
}
