freebsd-skq/usr.sbin/ppp/passwdauth.c
imp bf83493bdc Fix many buffer overruns in the code. Specifically, disallow ExpandString
to be used to expand things beyond the size of the buffer passed in.  Also
do a general cleanup of sprintf -> snprintf as well as strcpy and strncat
safety.  Also expand some buffers to allow for the largest possible data
that might be used.

This is a 2.2 candidate.  However, it needs to be vetted on -current
since little testing has been done on this due to my lack of PPP on
this machine.

Reviewed by:	Jordan Hubbard, Peter Wemm, Guido van Rooij
1997-01-10 07:53:28 +00:00

112 lines
2.8 KiB
C

/*
*
* passwdauth.c - pjchilds@imforei.apana.org.au
*
* authenticate user via the password file
*
* 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 Peter Childs. The name of the author 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.
*
*/
#include <sys/types.h>
#include <utmp.h>
#include <time.h>
#include <libutil.h>
#include <pwd.h>
#include "fsm.h"
#include "passwdauth.h"
int
PasswdAuth(name, key)
char *name, *key;
{
static int logged_in = 0;
struct passwd *pwd;
char *salt, *ep;
struct utmp utmp;
#ifdef DEBUG
logprintf( "passwdauth called with name= %s, key= %s\n", name, key );
#endif /* DEBUG */
if(( pwd = getpwnam( name ) ))
salt = pwd->pw_passwd;
else
{
endpwent();
LogPrintf( LOG_LCP, "PasswdAuth - user (%s) not in passwd file\n", name );
return 0; /* false - failed to authenticate (password not in file) */
}
#ifdef LOCALHACK
/*
* All our PPP usernames start with 'P' so i check that here... if you
* don't do this i suggest all your PPP users be members of a group
* and you check the guid
*/
if( name[0] != 'P' )
{
LogPrintf( LOG_LCP, "PasswdAuth - user (%s) not a PPP user\n", name );
endpwent();
return 0;
}
#endif /* LOCALHACK */
ep = crypt( key, salt );
/* strcmp returns 0 if same */
if( strcmp( ep, pwd->pw_passwd ) != 0 )
{
LogPrintf( LOG_LCP, "PasswdAuth - user (%s,%s) authentication failed\n",
name, key );
endpwent();
return 0; /* false - failed to authenticate (didn't match up) */
}
/*
* now we log them in... we have a static login flag so we don't
* do it twice :)
*/
if( ! logged_in )
{
(void)time(&utmp.ut_time);
(void)strncpy(utmp.ut_name, name, sizeof(utmp.ut_name));
/*
* if the first three chacters are "pap" trim them off before doing
* utmp entry (see sample.ppp-pap-dialup
*/
if( strncmp( "pap", dstsystem, 3 ) == 0 )
(void)strncpy(utmp.ut_line, (char *)(dstsystem + 3), sizeof(utmp.ut_line));
else
(void)strncpy(utmp.ut_line, dstsystem, sizeof(utmp.ut_line));
(void)strncpy(utmp.ut_host, "auto-ppp",sizeof(utmp.ut_host));
login(&utmp);
(void)setlogin( pwd->pw_name );
LogPrintf( LOG_LCP, "PasswdAuth has logged in user %s\n", name );
logged_in = 1;
}
endpwent();
return 1;
}