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freebsd-skq/usr.sbin/pppd/auth.c
peter efabb9ccb1 $Id$ -> $FreeBSD$
1999-08-28 01:35:59 +00:00

1631 lines
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/*
* auth.c - PPP authentication and phase control.
*
* Copyright (c) 1993 The Australian National 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 the Australian National 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.
*
* 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.
*/
#ifndef lint
static char rcsid[] = "$FreeBSD$";
#endif
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <pwd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <utmp.h>
#include <fcntl.h>
#if defined(_PATH_LASTLOG) && defined(_linux_)
#include <lastlog.h>
#endif
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <utmp.h>
#ifdef USE_PAM
#include <security/pam_appl.h>
#endif
#ifdef HAS_SHADOW
#include <shadow.h>
#ifndef PW_PPP
#define PW_PPP PW_LOGIN
#endif
#endif
#include "pppd.h"
#include "fsm.h"
#include "lcp.h"
#include "ipcp.h"
#include "upap.h"
#include "chap.h"
#ifdef CBCP_SUPPORT
#include "cbcp.h"
#endif
#include "pathnames.h"
/* Used for storing a sequence of words. Usually malloced. */
struct wordlist {
struct wordlist *next;
char word[1];
};
/* Bits in scan_authfile return value */
#define NONWILD_SERVER 1
#define NONWILD_CLIENT 2
#define ISWILD(word) (word[0] == '*' && word[1] == 0)
#define FALSE 0
#define TRUE 1
/* The name by which the peer authenticated itself to us. */
char peer_authname[MAXNAMELEN];
/* Records which authentication operations haven't completed yet. */
static int auth_pending[NUM_PPP];
/* Set if we have successfully called plogin() */
static int logged_in;
/* Set if not wild or blank */
static int non_wildclient;
/* Set if we have run the /etc/ppp/auth-up script. */
static int did_authup;
/* List of addresses which the peer may use. */
static struct wordlist *addresses[NUM_PPP];
/* Number of network protocols which we have opened. */
static int num_np_open;
/* Number of network protocols which have come up. */
static int num_np_up;
/* Set if we got the contents of passwd[] from the pap-secrets file. */
static int passwd_from_file;
/* Bits in auth_pending[] */
#define PAP_WITHPEER 1
#define PAP_PEER 2
#define CHAP_WITHPEER 4
#define CHAP_PEER 8
extern char *crypt __P((const char *, const char *));
/* Prototypes for procedures local to this file. */
static void network_phase __P((int));
static void check_idle __P((void *));
static void connect_time_expired __P((void *));
static int plogin __P((char *, char *, char **, int *));
static void plogout __P((void));
static int null_login __P((int));
static int get_pap_passwd __P((char *));
static int have_pap_secret __P((void));
static int have_chap_secret __P((char *, char *, u_int32_t));
static int ip_addr_check __P((u_int32_t, struct wordlist *));
static int scan_authfile __P((FILE *, char *, char *, u_int32_t, char *,
struct wordlist **, char *));
static void free_wordlist __P((struct wordlist *));
static void auth_set_ip_addr __P((int));
static void auth_script __P((char *));
static void set_allowed_addrs __P((int, struct wordlist *));
/*
* An Open on LCP has requested a change from Dead to Establish phase.
* Do what's necessary to bring the physical layer up.
*/
void
link_required(unit)
int unit;
{
}
/*
* LCP has terminated the link; go to the Dead phase and take the
* physical layer down.
*/
void
link_terminated(unit)
int unit;
{
extern time_t etime, stime;
extern int minutes;
if (phase == PHASE_DEAD)
return;
if (logged_in)
plogout();
phase = PHASE_DEAD;
etime = time((time_t *) NULL);
minutes = (etime-stime)/60;
syslog(LOG_NOTICE, "Connection terminated, connected for %d minutes\n",
minutes > 1 ? minutes : 1);
}
/*
* LCP has gone down; it will either die or try to re-establish.
*/
void
link_down(unit)
int unit;
{
int i;
struct protent *protp;
if (did_authup) {
auth_script(_PATH_AUTHDOWN);
did_authup = 0;
}
for (i = 0; (protp = protocols[i]) != NULL; ++i) {
if (!protp->enabled_flag)
continue;
if (protp->protocol != PPP_LCP && protp->lowerdown != NULL)
(*protp->lowerdown)(unit);
if (protp->protocol < 0xC000 && protp->close != NULL)
(*protp->close)(unit, "LCP down");
}
num_np_open = 0;
num_np_up = 0;
if (phase != PHASE_DEAD)
phase = PHASE_TERMINATE;
}
/*
* The link is established.
* Proceed to the Dead, Authenticate or Network phase as appropriate.
*/
void
link_established(unit)
int unit;
{
int auth;
lcp_options *wo = &lcp_wantoptions[unit];
lcp_options *go = &lcp_gotoptions[unit];
lcp_options *ho = &lcp_hisoptions[unit];
int i;
struct protent *protp;
/*
* Tell higher-level protocols that LCP is up.
*/
for (i = 0; (protp = protocols[i]) != NULL; ++i)
if (protp->protocol != PPP_LCP && protp->enabled_flag
&& protp->lowerup != NULL)
(*protp->lowerup)(unit);
if (auth_required && !(go->neg_chap || go->neg_upap)) {
/*
* We wanted the peer to authenticate itself, and it refused:
* treat it as though it authenticated with PAP using a username
* of "" and a password of "". If that's not OK, boot it out.
*/
if (!wo->neg_upap || !null_login(unit)) {
syslog(LOG_WARNING, "peer refused to authenticate");
lcp_close(unit, "peer refused to authenticate");
return;
}
}
phase = PHASE_AUTHENTICATE;
auth = 0;
if (go->neg_chap) {
ChapAuthPeer(unit, our_name, go->chap_mdtype);
auth |= CHAP_PEER;
} else if (go->neg_upap) {
upap_authpeer(unit);
auth |= PAP_PEER;
}
if (ho->neg_chap) {
ChapAuthWithPeer(unit, user, ho->chap_mdtype);
auth |= CHAP_WITHPEER;
} else if (ho->neg_upap) {
if (passwd[0] == 0) {
passwd_from_file = 1;
if (!get_pap_passwd(passwd))
syslog(LOG_ERR, "No secret found for PAP login");
}
upap_authwithpeer(unit, user, passwd);
auth |= PAP_WITHPEER;
}
auth_pending[unit] = auth;
if (!auth)
network_phase(unit);
}
/*
* Proceed to the network phase.
*/
static void
network_phase(unit)
int unit;
{
int i;
struct protent *protp;
lcp_options *go = &lcp_gotoptions[unit];
/*
* If the peer had to authenticate, run the auth-up script now.
*/
if ((go->neg_chap || go->neg_upap) && !did_authup) {
auth_script(_PATH_AUTHUP);
did_authup = 1;
}
#ifdef CBCP_SUPPORT
/*
* If we negotiated callback, do it now.
*/
if (go->neg_cbcp) {
phase = PHASE_CALLBACK;
(*cbcp_protent.open)(unit);
return;
}
#endif
phase = PHASE_NETWORK;
#if 0
if (!demand)
set_filters(&pass_filter, &active_filter);
#endif
for (i = 0; (protp = protocols[i]) != NULL; ++i)
if (protp->protocol < 0xC000 && protp->enabled_flag
&& protp->open != NULL) {
(*protp->open)(unit);
if (protp->protocol != PPP_CCP)
++num_np_open;
}
if (num_np_open == 0)
/* nothing to do */
lcp_close(0, "No network protocols running");
}
/*
* The peer has failed to authenticate himself using `protocol'.
*/
void
auth_peer_fail(unit, protocol)
int unit, protocol;
{
/*
* Authentication failure: take the link down
*/
lcp_close(unit, "Authentication failed");
}
/*
* The peer has been successfully authenticated using `protocol'.
*/
void
auth_peer_success(unit, protocol, name, namelen)
int unit, protocol;
char *name;
int namelen;
{
int bit;
switch (protocol) {
case PPP_CHAP:
bit = CHAP_PEER;
break;
case PPP_PAP:
bit = PAP_PEER;
break;
default:
syslog(LOG_WARNING, "auth_peer_success: unknown protocol %x",
protocol);
return;
}
/*
* Save the authenticated name of the peer for later.
*/
if (namelen > sizeof(peer_authname) - 1)
namelen = sizeof(peer_authname) - 1;
BCOPY(name, peer_authname, namelen);
peer_authname[namelen] = 0;
/*
* If we have overridden addresses based on auth info
* then set that information now before continuing.
*/
auth_set_ip_addr(unit);
script_setenv("PEERNAME", peer_authname);
/*
* If there is no more authentication still to be done,
* proceed to the network (or callback) phase.
*/
if ((auth_pending[unit] &= ~bit) == 0)
network_phase(unit);
}
/*
* We have failed to authenticate ourselves to the peer using `protocol'.
*/
void
auth_withpeer_fail(unit, protocol)
int unit, protocol;
{
if (passwd_from_file)
BZERO(passwd, MAXSECRETLEN);
/*
* We've failed to authenticate ourselves to our peer.
* He'll probably take the link down, and there's not much
* we can do except wait for that.
*/
}
/*
* We have successfully authenticated ourselves with the peer using `protocol'.
*/
void
auth_withpeer_success(unit, protocol)
int unit, protocol;
{
int bit;
switch (protocol) {
case PPP_CHAP:
bit = CHAP_WITHPEER;
break;
case PPP_PAP:
if (passwd_from_file)
BZERO(passwd, MAXSECRETLEN);
bit = PAP_WITHPEER;
break;
default:
syslog(LOG_WARNING, "auth_peer_success: unknown protocol %x",
protocol);
bit = 0;
}
/*
* If we have overridden addresses based on auth info
* then set that information now before continuing.
*/
auth_set_ip_addr(unit);
/*
* If there is no more authentication still being done,
* proceed to the network (or callback) phase.
*/
if ((auth_pending[unit] &= ~bit) == 0)
network_phase(unit);
}
/*
* np_up - a network protocol has come up.
*/
void
np_up(unit, proto)
int unit, proto;
{
if (num_np_up == 0) {
/*
* At this point we consider that the link has come up successfully.
*/
need_holdoff = 0;
if (idle_time_limit > 0)
TIMEOUT(check_idle, NULL, idle_time_limit);
/*
* Set a timeout to close the connection once the maximum
* connect time has expired.
*/
if (maxconnect > 0)
TIMEOUT(connect_time_expired, 0, maxconnect);
/*
* Detach now, if the updetach option was given.
*/
if (nodetach == -1)
detach();
}
++num_np_up;
}
/*
* np_down - a network protocol has gone down.
*/
void
np_down(unit, proto)
int unit, proto;
{
if (--num_np_up == 0 && idle_time_limit > 0) {
UNTIMEOUT(check_idle, NULL);
}
}
/*
* np_finished - a network protocol has finished using the link.
*/
void
np_finished(unit, proto)
int unit, proto;
{
if (--num_np_open <= 0) {
/* no further use for the link: shut up shop. */
lcp_close(0, "No network protocols running");
}
}
/*
* check_idle - check whether the link has been idle for long
* enough that we can shut it down.
*/
static void
check_idle(arg)
void *arg;
{
struct ppp_idle idle;
time_t itime;
if (!get_idle_time(0, &idle))
return;
itime = MIN(idle.xmit_idle, idle.recv_idle);
if (itime >= idle_time_limit) {
/* link is idle: shut it down. */
syslog(LOG_INFO, "Terminating connection due to lack of activity.");
lcp_close(0, "Link inactive");
} else {
TIMEOUT(check_idle, NULL, idle_time_limit - itime);
}
}
/*
* connect_time_expired - log a message and close the connection.
*/
static void
connect_time_expired(arg)
void *arg;
{
syslog(LOG_INFO, "Connect time expired");
lcp_close(0, "Connect time expired"); /* Close connection */
}
/*
* auth_check_options - called to check authentication options.
*/
void
auth_check_options()
{
lcp_options *wo = &lcp_wantoptions[0];
int can_auth;
ipcp_options *ipwo = &ipcp_wantoptions[0];
u_int32_t remote;
/* Default our_name to hostname, and user to our_name */
if (our_name[0] == 0 || usehostname)
strcpy(our_name, hostname);
if (user[0] == 0)
strcpy(user, our_name);
/* If authentication is required, ask peer for CHAP or PAP. */
if (auth_required && !wo->neg_chap && !wo->neg_upap) {
wo->neg_chap = 1;
wo->neg_upap = 1;
}
/*
* Check whether we have appropriate secrets to use
* to authenticate the peer.
*/
can_auth = wo->neg_upap && (uselogin || have_pap_secret());
if (!can_auth && wo->neg_chap) {
remote = ipwo->accept_remote? 0: ipwo->hisaddr;
can_auth = have_chap_secret(remote_name, our_name, remote);
}
if (auth_required && !can_auth) {
option_error("peer authentication required but no suitable secret(s) found\n");
if (remote_name[0] == 0)
option_error("for authenticating any peer to us (%s)\n", our_name);
else
option_error("for authenticating peer %s to us (%s)\n",
remote_name, our_name);
exit(1);
}
/*
* Check whether the user tried to override certain values
* set by root.
*/
if (!auth_required && auth_req_info.priv > 0) {
if (!default_device && devnam_info.priv == 0) {
option_error("can't override device name when noauth option used");
exit(1);
}
if ((connector != NULL && connector_info.priv == 0)
|| (disconnector != NULL && disconnector_info.priv == 0)
|| (welcomer != NULL && welcomer_info.priv == 0)) {
option_error("can't override connect, disconnect or welcome");
option_error("option values when noauth option used");
exit(1);
}
}
}
/*
* auth_reset - called when LCP is starting negotiations to recheck
* authentication options, i.e. whether we have appropriate secrets
* to use for authenticating ourselves and/or the peer.
*/
void
auth_reset(unit)
int unit;
{
lcp_options *go = &lcp_gotoptions[unit];
lcp_options *ao = &lcp_allowoptions[0];
ipcp_options *ipwo = &ipcp_wantoptions[0];
u_int32_t remote;
ao->neg_upap = !refuse_pap && (passwd[0] != 0 || get_pap_passwd(NULL));
ao->neg_chap = !refuse_chap
&& have_chap_secret(user, remote_name, (u_int32_t)0);
if (go->neg_upap && !uselogin && !have_pap_secret())
go->neg_upap = 0;
if (go->neg_chap) {
remote = ipwo->accept_remote? 0: ipwo->hisaddr;
if (!have_chap_secret(remote_name, our_name, remote))
go->neg_chap = 0;
}
}
/*
* check_passwd - Check the user name and passwd against the PAP secrets
* file. If requested, also check against the system password database,
* and login the user if OK.
*
* returns:
* UPAP_AUTHNAK: Authentication failed.
* UPAP_AUTHACK: Authentication succeeded.
* In either case, msg points to an appropriate message.
*/
int
check_passwd(unit, auser, userlen, apasswd, passwdlen, msg, msglen)
int unit;
char *auser;
int userlen;
char *apasswd;
int passwdlen;
char **msg;
int *msglen;
{
int ret;
char *filename;
FILE *f;
struct wordlist *addrs;
u_int32_t remote;
ipcp_options *ipwo = &ipcp_wantoptions[unit];
char passwd[256], user[256];
char secret[MAXWORDLEN];
static int attempts = 0;
int len;
/*
* Make copies of apasswd and auser, then null-terminate them.
*/
len = MIN(passwdlen, sizeof(passwd) - 1);
BCOPY(apasswd, passwd, len);
passwd[len] = '\0';
len = MIN(userlen, sizeof(user) - 1);
BCOPY(auser, user, len);
user[len] = '\0';
*msg = (char *) 0;
/*
* Open the file of pap secrets and scan for a suitable secret
* for authenticating this user.
*/
filename = _PATH_UPAPFILE;
addrs = NULL;
ret = UPAP_AUTHACK;
f = fopen(filename, "r");
if (f == NULL) {
syslog(LOG_ERR, "Can't open PAP password file %s: %m", filename);
ret = UPAP_AUTHNAK;
} else {
check_access(f, filename);
remote = ipwo->accept_remote? 0: ipwo->hisaddr;
if (scan_authfile(f, user, our_name, remote,
secret, &addrs, filename) < 0
|| (secret[0] != 0 && (cryptpap || strcmp(passwd, secret) != 0)
&& strcmp(crypt(passwd, secret), secret) != 0)) {
syslog(LOG_WARNING, "PAP authentication failure for %s", user);
ret = UPAP_AUTHNAK;
}
fclose(f);
}
if (uselogin && ret == UPAP_AUTHACK) {
ret = plogin(user, passwd, msg, msglen);
if (ret == UPAP_AUTHNAK) {
syslog(LOG_WARNING, "PAP login failure for %s", user);
}
}
if (ret == UPAP_AUTHNAK) {
if (*msg == (char *) 0)
*msg = "Login incorrect";
*msglen = strlen(*msg);
/*
* Frustrate passwd stealer programs.
* Allow 10 tries, but start backing off after 3 (stolen from login).
* On 10'th, drop the connection.
*/
if (attempts++ >= 10) {
syslog(LOG_WARNING, "%d LOGIN FAILURES ON %s, %s",
attempts, devnam, user);
quit();
}
if (attempts > 3)
sleep((u_int) (attempts - 3) * 5);
if (addrs != NULL)
free_wordlist(addrs);
} else {
attempts = 0; /* Reset count */
if (*msg == (char *) 0)
*msg = "Login ok";
*msglen = strlen(*msg);
set_allowed_addrs(unit, addrs);
}
BZERO(passwd, sizeof(passwd));
BZERO(secret, sizeof(secret));
return ret;
}
/*
* Check if an "entry" is in the file "fname" - used by ppplogin.
* Taken from libexec/ftpd/ftpd.c
* Returns: 0 if not found, 1 if found, 2 if file can't be opened for reading.
*/
static int
checkfile(fname, name)
char *fname;
char *name;
{
FILE *fd;
int found = 0;
char *p, line[BUFSIZ];
if ((fd = fopen(fname, "r")) != NULL) {
while (fgets(line, sizeof(line), fd) != NULL)
if ((p = strchr(line, '\n')) != NULL) {
*p = '\0';
if (line[0] == '#')
continue;
if (strcmp(line, name) == 0) {
found = 1;
break;
}
}
(void) fclose(fd);
} else {
return(2);
}
return (found);
}
/*
* This function is needed for PAM.
*/
#ifdef USE_PAM
static char *PAM_username = "";
static char *PAM_password = "";
#ifdef PAM_ESTABLISH_CRED /* new PAM defines :(^ */
#define MY_PAM_STRERROR(err_code) (char *) pam_strerror(pamh,err_code)
#else
#define MY_PAM_STRERROR(err_code) (char *) pam_strerror(err_code)
#endif
static int pam_conv (int num_msg,
const struct pam_message **msg,
struct pam_response **resp,
void *appdata_ptr)
{
int count = 0, replies = 0;
struct pam_response *reply = NULL;
int size = 0;
for (count = 0; count < num_msg; count++)
{
size += sizeof (struct pam_response);
reply = realloc (reply, size); /* ANSI: is malloc() if reply==NULL */
if (!reply)
return PAM_CONV_ERR;
switch (msg[count]->msg_style)
{
case PAM_PROMPT_ECHO_ON:
reply[replies].resp_retcode = PAM_SUCCESS;
reply[replies++].resp = strdup(PAM_username); /* never NULL */
break;
case PAM_PROMPT_ECHO_OFF:
reply[replies].resp_retcode = PAM_SUCCESS;
reply[replies++].resp = strdup(PAM_password); /* never NULL */
break;
case PAM_TEXT_INFO:
reply[replies].resp_retcode = PAM_SUCCESS;
reply[replies++].resp = NULL;
break;
case PAM_ERROR_MSG:
default:
free (reply);
return PAM_CONV_ERR;
}
}
if (resp)
*resp = reply;
else
free (reply);
return PAM_SUCCESS;
}
#endif
/*
* plogin - Check the user name and password against the system
* password database, and login the user if OK.
*
* returns:
* UPAP_AUTHNAK: Login failed.
* UPAP_AUTHACK: Login succeeded.
* In either case, msg points to an appropriate message.
*
* UPAP_AUTHACK should only be returned *after* wtmp and utmp are updated.
*/
static int
plogin(user, passwd, msg, msglen)
char *user;
char *passwd;
char **msg;
int *msglen;
{
#ifdef USE_PAM
struct pam_conv pam_conversation;
pam_handle_t *pamh;
int pam_error;
/*
* Fill the pam_conversion structure
*/
memset (&pam_conversation, '\0', sizeof (struct pam_conv));
pam_conversation.conv = &pam_conv;
pam_error = pam_start ("ppp", user, &pam_conversation, &pamh);
if (pam_error != PAM_SUCCESS) {
*msg = MY_PAM_STRERROR (pam_error);
return UPAP_AUTHNAK;
}
/*
* Define the fields for the credintial validation
*/
(void) pam_set_item (pamh, PAM_TTY, devnam);
PAM_username = user;
PAM_password = passwd;
/*
* Validate the user
*/
pam_error = pam_authenticate (pamh, PAM_SILENT);
if (pam_error == PAM_SUCCESS) {
pam_error = pam_acct_mgmt (pamh, PAM_SILENT);
/* start a session for this user. Session closed when link ends. */
if (pam_error == PAM_SUCCESS)
(void) pam_open_session (pamh, PAM_SILENT);
}
*msg = MY_PAM_STRERROR (pam_error);
PAM_username =
PAM_password = "";
/*
* Clean up the mess
*/
(void) pam_end (pamh, pam_error);
if (pam_error != PAM_SUCCESS)
return UPAP_AUTHNAK;
/*
* Use the non-PAM methods directly
*/
#else /* #ifdef USE_PAM */
struct passwd *pw;
struct utmp utmp;
struct timeval tp;
char *tty;
#ifdef HAS_SHADOW
struct spwd *spwd;
struct spwd *getspnam();
#endif
pw = getpwnam(user);
endpwent();
if (pw == NULL) {
return (UPAP_AUTHNAK);
}
/*
* Check that the user is not listed in /etc/ppp/ppp.deny
* and that the user's shell is listed in /etc/ppp/ppp.shells
* if /etc/ppp/ppp.shells exists.
*/
if (checkfile(_PATH_PPPDENY, user) == 1) {
syslog(LOG_WARNING, "upap user %s: login denied in %s",
user, _PATH_PPPDENY);
return (UPAP_AUTHNAK);
}
if (checkfile(_PATH_PPPSHELLS, pw->pw_shell) == 0) {
syslog(LOG_WARNING, "upap user %s: shell %s not in %s",
user, pw->pw_shell, _PATH_PPPSHELLS);
return (UPAP_AUTHNAK);
}
#ifdef HAS_SHADOW
spwd = getspnam(user);
endspent();
if (spwd) {
/* check the age of the password entry */
long now = time(NULL) / 86400L;
if ((spwd->sp_expire > 0 && now >= spwd->sp_expire)
|| ((spwd->sp_max >= 0 && spwd->sp_max < 10000)
&& spwd->sp_lstchg >= 0
&& now >= spwd->sp_lstchg + spwd->sp_max)) {
syslog(LOG_WARNING, "Password for %s has expired", user);
return (UPAP_AUTHNAK);
}
pw->pw_passwd = spwd->sp_pwdp;
}
#endif
/*
* If no passwd, don't let them login.
*/
if (pw->pw_passwd == NULL || *pw->pw_passwd == '\0'
|| strcmp(crypt(passwd, pw->pw_passwd), pw->pw_passwd) != 0)
return (UPAP_AUTHNAK);
if (pw->pw_expire) {
(void)gettimeofday(&tp, (struct timezone *)NULL);
if (tp.tv_sec >= pw->pw_expire) {
syslog(LOG_INFO, "pap user %s account expired", user);
return (UPAP_AUTHNAK);
}
}
/* These functions are not enabled for PAM. The reason for this is that */
/* there is not necessarily a "passwd" entry for this user. That is */
/* real purpose of 'PAM' -- to virtualize the account data from the */
/* application. If you want to do the same thing, write the entry in */
/* the 'session' hook. */
/* Log in wtmp and utmp using login() */
tty = devnam;
if (strncmp(tty, "/dev/", 5) == 0)
tty += 5;
if (logout(tty)) /* Already entered (by login?) */
logwtmp(tty, "", "");
#if defined(_PATH_LASTLOG)
{
struct lastlog ll;
int fd;
if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) {
(void)lseek(fd, (off_t)(pw->pw_uid * sizeof(ll)), SEEK_SET);
memset((void *)&ll, 0, sizeof(ll));
(void)time(&ll.ll_time);
(void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
(void)write(fd, (char *)&ll, sizeof(ll));
(void)close(fd);
}
}
#endif
memset((void *)&utmp, 0, sizeof(utmp));
(void)time(&utmp.ut_time);
(void)strncpy(utmp.ut_name, user, sizeof(utmp.ut_name));
(void)strncpy(utmp.ut_host, ":PPP", sizeof(utmp.ut_host));
(void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
login(&utmp); /* This logs us in wtmp too */
#endif /* #ifdef USE_PAM */
syslog(LOG_INFO, "user %s logged in", user);
logged_in = TRUE;
return (UPAP_AUTHACK);
}
/*
* plogout - Logout the user.
*/
static void
plogout()
{
#ifdef USE_PAM
struct pam_conv pam_conversation;
pam_handle_t *pamh;
int pam_error;
/*
* Fill the pam_conversion structure. The PAM specification states that the
* session must be able to be closed by a totally different handle from which
* it was created. Hold the PAM group to their own specification!
*/
memset (&pam_conversation, '\0', sizeof (struct pam_conv));
pam_conversation.conv = &pam_conv;
pam_error = pam_start ("ppp", user, &pam_conversation, &pamh);
if (pam_error == PAM_SUCCESS) {
(void) pam_set_item (pamh, PAM_TTY, devnam);
(void) pam_close_session (pamh, PAM_SILENT);
(void) pam_end (pamh, PAM_SUCCESS);
}
#else
char *tty;
tty = devnam;
if (strncmp(tty, "/dev/", 5) == 0)
tty += 5;
logwtmp(tty, "", ""); /* Wipe out wtmp logout entry */
logout(tty); /* Wipe out utmp */
#endif
logged_in = FALSE;
}
/*
* null_login - Check if a username of "" and a password of "" are
* acceptable, and iff so, set the list of acceptable IP addresses
* and return 1.
*/
static int
null_login(unit)
int unit;
{
char *filename;
FILE *f;
int i, ret;
struct wordlist *addrs;
char secret[MAXWORDLEN];
/*
* Open the file of pap secrets and scan for a suitable secret.
* We don't accept a wildcard client.
*/
filename = _PATH_UPAPFILE;
addrs = NULL;
f = fopen(filename, "r");
if (f == NULL)
return 0;
check_access(f, filename);
i = scan_authfile(f, "", our_name, (u_int32_t)0, secret, &addrs, filename);
ret = i >= 0 && (i & NONWILD_CLIENT) != 0 && secret[0] == 0;
BZERO(secret, sizeof(secret));
if (ret)
set_allowed_addrs(unit, addrs);
else
free_wordlist(addrs);
fclose(f);
return ret;
}
/*
* get_pap_passwd - get a password for authenticating ourselves with
* our peer using PAP. Returns 1 on success, 0 if no suitable password
* could be found.
*/
static int
get_pap_passwd(passwd)
char *passwd;
{
char *filename;
FILE *f;
int ret;
struct wordlist *addrs;
char secret[MAXWORDLEN];
filename = _PATH_UPAPFILE;
addrs = NULL;
f = fopen(filename, "r");
if (f == NULL)
return 0;
check_access(f, filename);
ret = scan_authfile(f, user,
remote_name[0]? remote_name: NULL,
(u_int32_t)0, secret, NULL, filename);
fclose(f);
if (ret < 0)
return 0;
if (passwd != NULL) {
strncpy(passwd, secret, MAXSECRETLEN);
passwd[MAXSECRETLEN-1] = 0;
}
BZERO(secret, sizeof(secret));
return 1;
}
/*
* have_pap_secret - check whether we have a PAP file with any
* secrets that we could possibly use for authenticating the peer.
*/
static int
have_pap_secret()
{
FILE *f;
int ret;
char *filename;
ipcp_options *ipwo = &ipcp_wantoptions[0];
u_int32_t remote;
filename = _PATH_UPAPFILE;
f = fopen(filename, "r");
if (f == NULL)
return 0;
remote = ipwo->accept_remote? 0: ipwo->hisaddr;
ret = scan_authfile(f, NULL, our_name, remote, NULL, NULL, filename);
fclose(f);
if (ret < 0)
return 0;
return 1;
}
/*
* have_chap_secret - check whether we have a CHAP file with a
* secret that we could possibly use for authenticating `client'
* on `server'. Either can be the null string, meaning we don't
* know the identity yet.
*/
static int
have_chap_secret(client, server, remote)
char *client;
char *server;
u_int32_t remote;
{
FILE *f;
int ret;
char *filename;
filename = _PATH_CHAPFILE;
f = fopen(filename, "r");
if (f == NULL)
return 0;
if (client[0] == 0)
client = NULL;
else if (server[0] == 0)
server = NULL;
ret = scan_authfile(f, client, server, remote, NULL, NULL, filename);
fclose(f);
if (ret < 0)
return 0;
return 1;
}
/*
* get_secret - open the CHAP secret file and return the secret
* for authenticating the given client on the given server.
* (We could be either client or server).
*/
int
get_secret(unit, client, server, secret, secret_len, save_addrs)
int unit;
char *client;
char *server;
char *secret;
int *secret_len;
int save_addrs;
{
FILE *f;
int ret, len;
char *filename;
struct wordlist *addrs;
char secbuf[MAXWORDLEN];
filename = _PATH_CHAPFILE;
addrs = NULL;
secbuf[0] = 0;
f = fopen(filename, "r");
if (f == NULL) {
syslog(LOG_ERR, "Can't open chap secret file %s: %m", filename);
return 0;
}
check_access(f, filename);
ret = scan_authfile(f, client, server, (u_int32_t)0,
secbuf, &addrs, filename);
fclose(f);
if (ret < 0)
return 0;
if (save_addrs)
set_allowed_addrs(unit, addrs);
len = strlen(secbuf);
if (len > MAXSECRETLEN) {
syslog(LOG_ERR, "Secret for %s on %s is too long", client, server);
len = MAXSECRETLEN;
}
BCOPY(secbuf, secret, len);
BZERO(secbuf, sizeof(secbuf));
*secret_len = len;
return 1;
}
/*
* set_allowed_addrs() - set the list of allowed addresses.
*/
static void
set_allowed_addrs(unit, addrs)
int unit;
struct wordlist *addrs;
{
if (addresses[unit] != NULL)
free_wordlist(addresses[unit]);
addresses[unit] = addrs;
/*
* If there's only one authorized address we might as well
* ask our peer for that one right away
*/
if (addrs != NULL && addrs->next == NULL) {
char *p = addrs->word;
struct ipcp_options *wo = &ipcp_wantoptions[unit];
u_int32_t a;
struct hostent *hp;
if (*p != '!' && *p != '-' && strchr(p, '/') == NULL) {
hp = gethostbyname(p);
if (hp != NULL && hp->h_addrtype == AF_INET)
a = *(u_int32_t *)hp->h_addr;
else
a = inet_addr(p);
if (a != (u_int32_t) -1)
wo->hisaddr = a;
}
}
}
static void
auth_set_ip_addr(unit)
int unit;
{
struct wordlist *addrs;
if (non_wildclient && (addrs = addresses[unit]) != NULL) {
for (; addrs != NULL; addrs = addrs->next) {
/* Look for address overrides, and set them if we have any */
if (strchr(addrs->word, ':') != NULL) {
if (setipaddr(addrs->word))
break;
}
}
}
}
/*
* auth_ip_addr - check whether the peer is authorized to use
* a given IP address. Returns 1 if authorized, 0 otherwise.
*/
int
auth_ip_addr(unit, addr)
int unit;
u_int32_t addr;
{
return ip_addr_check(addr, addresses[unit]);
}
static int
ip_addr_check(addr, addrs)
u_int32_t addr;
struct wordlist *addrs;
{
int x, y;
u_int32_t a, mask, ah;
int accept;
char *ptr_word, *ptr_mask;
struct hostent *hp;
struct netent *np;
/* don't allow loopback or multicast address */
if (bad_ip_adrs(addr))
return 0;
if (addrs == NULL)
return !auth_required; /* no addresses authorized */
x = y = 0;
for (; addrs != NULL; addrs = addrs->next) {
y++;
/* "-" means no addresses authorized, "*" means any address allowed */
ptr_word = addrs->word;
if (strcmp(ptr_word, "-") == 0)
break;
if (strcmp(ptr_word, "*") == 0)
return 1;
/*
* A colon in the string means that we wish to force a specific
* local:remote address, but we ignore these for now.
*/
if (strchr(addrs->word, ':') != NULL)
x++;
else {
accept = 1;
if (*ptr_word == '!') {
accept = 0;
++ptr_word;
}
mask = ~ (u_int32_t) 0;
ptr_mask = strchr (ptr_word, '/');
if (ptr_mask != NULL) {
int bit_count;
bit_count = (int) strtol (ptr_mask+1, (char **) 0, 10);
if (bit_count <= 0 || bit_count > 32) {
syslog (LOG_WARNING,
"invalid address length %s in auth. address list",
ptr_mask);
continue;
}
*ptr_mask = '\0';
mask <<= 32 - bit_count;
}
hp = gethostbyname(ptr_word);
if (hp != NULL && hp->h_addrtype == AF_INET) {
a = *(u_int32_t *)hp->h_addr;
} else {
np = getnetbyname (ptr_word);
if (np != NULL && np->n_addrtype == AF_INET) {
a = htonl (*(u_int32_t *)np->n_net);
if (ptr_mask == NULL) {
/* calculate appropriate mask for net */
ah = ntohl(a);
if (IN_CLASSA(ah))
mask = IN_CLASSA_NET;
else if (IN_CLASSB(ah))
mask = IN_CLASSB_NET;
else if (IN_CLASSC(ah))
mask = IN_CLASSC_NET;
}
} else {
a = inet_addr (ptr_word);
}
}
if (ptr_mask != NULL)
*ptr_mask = '/';
if (a == (u_int32_t)-1L)
syslog (LOG_WARNING,
"unknown host %s in auth. address list",
addrs->word);
else
/* Here a and addr are in network byte order,
and mask is in host order. */
if (((addr ^ a) & htonl(mask)) == 0)
return accept;
} /* else */
}
return x == y; /* not in list => can't have it */
}
/*
* bad_ip_adrs - return 1 if the IP address is one we don't want
* to use, such as an address in the loopback net or a multicast address.
* addr is in network byte order.
*/
int
bad_ip_adrs(addr)
u_int32_t addr;
{
addr = ntohl(addr);
return (addr >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET
|| IN_MULTICAST(addr) || IN_BADCLASS(addr);
}
/*
* check_access - complain if a secret file has too-liberal permissions.
*/
void
check_access(f, filename)
FILE *f;
char *filename;
{
struct stat sbuf;
if (fstat(fileno(f), &sbuf) < 0) {
syslog(LOG_WARNING, "cannot stat secret file %s: %m", filename);
} else if ((sbuf.st_mode & (S_IRWXG | S_IRWXO)) != 0) {
syslog(LOG_WARNING, "Warning - secret file %s has world and/or group access", filename);
}
}
/*
* scan_authfile - Scan an authorization file for a secret suitable
* for authenticating `client' on `server'. The return value is -1
* if no secret is found, otherwise >= 0. The return value has
* NONWILD_CLIENT set if the secret didn't have "*" for the client, and
* NONWILD_SERVER set if the secret didn't have "*" for the server.
* Any following words on the line (i.e. address authorization
* info) are placed in a wordlist and returned in *addrs.
*/
static int
scan_authfile(f, client, server, ipaddr, secret, addrs, filename)
FILE *f;
char *client;
char *server;
u_int32_t ipaddr;
char *secret;
struct wordlist **addrs;
char *filename;
{
int newline, xxx;
int got_flag, best_flag;
FILE *sf;
struct wordlist *ap, *addr_list, *alist, *alast;
char word[MAXWORDLEN];
char atfile[MAXWORDLEN];
char lsecret[MAXWORDLEN];
if (addrs != NULL)
*addrs = NULL;
addr_list = NULL;
if (!getword(f, word, &newline, filename))
return -1; /* file is empty??? */
newline = 1;
best_flag = -1;
for (;;) {
/*
* Skip until we find a word at the start of a line.
*/
while (!newline && getword(f, word, &newline, filename))
;
if (!newline)
break; /* got to end of file */
/*
* Got a client - check if it's a match or a wildcard.
*/
got_flag = 0;
if (client != NULL && strcmp(word, client) != 0 && !ISWILD(word)) {
newline = 0;
continue;
}
if (!ISWILD(word))
got_flag = NONWILD_CLIENT;
/*
* Now get a server and check if it matches.
*/
if (!getword(f, word, &newline, filename))
break;
if (newline)
continue;
if (server != NULL && strcmp(word, server) != 0 && !ISWILD(word))
continue;
if (!ISWILD(word))
got_flag |= NONWILD_SERVER;
/*
* Got some sort of a match - see if it's better than what
* we have already.
*/
if (got_flag <= best_flag)
continue;
/*
* Get the secret.
*/
if (!getword(f, word, &newline, filename))
break;
if (newline)
continue;
/*
* Special syntax: @filename means read secret from file.
*/
if (word[0] == '@') {
strcpy(atfile, word+1);
if ((sf = fopen(atfile, "r")) == NULL) {
syslog(LOG_WARNING, "can't open indirect secret file %s",
atfile);
continue;
}
check_access(sf, atfile);
if (!getword(sf, word, &xxx, atfile)) {
syslog(LOG_WARNING, "no secret in indirect secret file %s",
atfile);
fclose(sf);
continue;
}
fclose(sf);
}
if (secret != NULL)
strcpy(lsecret, word);
/*
* Now read address authorization info and make a wordlist.
*/
alist = alast = NULL;
for (;;) {
if (!getword(f, word, &newline, filename) || newline)
break;
ap = (struct wordlist *) malloc(sizeof(struct wordlist)
+ strlen(word));
if (ap == NULL)
novm("authorized addresses");
ap->next = NULL;
strcpy(ap->word, word);
if (alist == NULL)
alist = ap;
else
alast->next = ap;
alast = ap;
}
/*
* Check if the given IP address is allowed by the wordlist.
*/
if (ipaddr != 0 && !ip_addr_check(ipaddr, alist)) {
free_wordlist(alist);
continue;
}
/*
* This is the best so far; remember it.
*/
best_flag = got_flag;
if (addr_list)
free_wordlist(addr_list);
addr_list = alist;
if (secret != NULL)
strcpy(secret, lsecret);
if (!newline)
break;
}
if (addrs != NULL)
*addrs = addr_list;
else if (addr_list != NULL)
free_wordlist(addr_list);
non_wildclient = (best_flag & NONWILD_CLIENT) && client != NULL &&
*client != '\0';
return best_flag;
}
/*
* free_wordlist - release memory allocated for a wordlist.
*/
static void
free_wordlist(wp)
struct wordlist *wp;
{
struct wordlist *next;
while (wp != NULL) {
next = wp->next;
free(wp);
wp = next;
}
}
/*
* auth_script - execute a script with arguments
* interface-name peer-name real-user tty speed
*/
static void
auth_script(script)
char *script;
{
char strspeed[32];
struct passwd *pw;
char struid[32];
char *user_name;
char *argv[8];
if ((pw = getpwuid(getuid())) != NULL && pw->pw_name != NULL)
user_name = pw->pw_name;
else {
sprintf(struid, "%d", getuid());
user_name = struid;
}
sprintf(strspeed, "%d", baud_rate);
argv[0] = script;
argv[1] = ifname;
argv[2] = peer_authname;
argv[3] = user_name;
argv[4] = devnam;
argv[5] = strspeed;
argv[6] = NULL;
run_program(script, argv, 0);
}
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