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login.c
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login.c
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#ident "$Id: login.c,v 4.19 2003/12/05 22:28:58 gert Exp $ Copyright (C) 1993 Gert Doering"
/* login.c
*
* handle calling of login program(s) for data calls
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <pwd.h>
#include <ctype.h>
#ifndef EINVAL
#include <errno.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
/* NeXTStep/86 has some byte order problems (Christian Starkjohann) */
#if defined(NeXT) && defined(__LITTLE_ENDIAN__) && !defined(NEXTSGTTY)
# define pw_uid pw_short_pad1
# define pw_gid pw_short_pad2
# define gr_gid gr_short_pad
#endif
#include "mgetty.h"
#include "config.h"
#include "policy.h"
#include "mg_utmp.h"
#ifdef SECUREWARE
extern int setluid();
#endif
extern char * Device; /* mgetty.c */
/* match( user, key )
*
* match "user" against "key"
* key may start or end with "*" (wildcard)
*/
boolean match _P2( (user,key), char * user, char * key )
{
int lk = strlen( key );
int lu = strlen( user );
int i;
lprintf( L_NOISE, "match: user='%s', key='%s'", user, key );
/* empty lines do not match */
if ( lk == 0 ) return FALSE;
#ifdef FIDO
/* special handling for fido logins */
if ( user[0] == '\377' && strcmp( key, "/FIDO/" ) == 0 )
{
return TRUE;
}
#endif
if ( key[0] == '*' ) /* "*bc?" */
{
if ( key[lk-1] == '*' ) /* "*bc*" */
{
if ( lk < 2 ) return TRUE; /* "*" or "**" */
for ( i=0; i <= lu - (lk-2); i++ )
{
if ( strncmp( &user[i], &key[1], lk-2 ) == 0 ) return TRUE;
}
return FALSE;
}
else /* "*bcd" */
{
return ( ( lu >= lk-1 ) &&
( strcmp( &user[ lu-(lk-1) ], &key[1] ) == 0 ) );
}
}
else /* "abc?" */
{
if ( key[lk-1] == '*' ) /* "abc*" */
{
return ( ( lu >= lk-1 ) &&
( strncmp( user, key, lk-1 ) == 0 ) );
}
else
{
return ( ( lu == lk ) &&
( strcmp( user, key ) == 0 ) );
}
}
return FALSE; /*NOTREACHED*/
}
/* execute login
*
* which login program is executed depends on LOGIN_FILE
* default is "/bin/login user"
*
* does *NOT* return
*/
void login_dispatch _P3( (user, is_callback, cfg_file ),
char * user, boolean is_callback, char * cfg_file )
{
#define MAX_LOGIN_ARGS 9
char * argv[MAX_LOGIN_ARGS+2]; /* name + args + NULL */
int argc = 0;
char * cmd = NULL;
int i;
/* read "mgetty.login" config file (if specified) */
FILE * fp = NULL;
int file_version = 1; /* login.config format changed! */
char * line, * key, *p;
struct passwd * pw;
extern struct passwd * getpwnam();
struct stat st;
if ( cfg_file == NULL )
{
lprintf( L_JUNK, "login: no login cfg file defined" );
goto fallthrough;
}
cfg_file = _makepath( cfg_file, CONFDIR );
lprintf( L_JUNK, "login: use login config file %s", cfg_file );
/* first of all, some (somewhat paranoid) checks for file ownership,
* file permissions (0i00), ...
* If something fails, fall through to default ("/bin/login <user>")
*/
if ( stat( cfg_file, &st ) < 0 )
{
lprintf( L_ERROR, "login: stat('%s') failed", cfg_file );
goto fallthrough;
}
/* permission check */
if ( st.st_uid != 0 || ( ( st.st_mode & 0077 ) != 0 ) )
{
errno=EINVAL;
lprintf( L_FATAL, "login: '%s' ignored, wrong permissions. Must be owned by 'root' and have mode '0600'", cfg_file );
goto fallthrough;
}
/* go for it! */
if ( (fp = fopen( cfg_file, "r" )) == NULL )
{
lprintf( L_FATAL, "login: cannot open %s", cfg_file );
}
else
while ( ( line = fgetline( fp ) ) != NULL )
{
norm_line( &line, &key );
/* as the format of login.config has changed over time, we have
* to have "file versions", set by the '!version <n>' keyword
*/
if ( strcmp( key, "!version" ) == 0 )
{
file_version = atoi(line);
if ( file_version < 1 || file_version > 2 )
{
errno = EINVAL;
lprintf( L_ERROR, "login: invalid file version '%s'", line);
file_version = 1;
}
lprintf( L_NOISE, "login: version %d", file_version);
continue;
}
if ( match( user, key ) )
{
char * user_id;
char * utmp_entry;
lputs( L_NOISE, "*** hit!" );
#ifdef FIDO
if ( user[0] == '\377' && strcmp( key, "/FIDO/" ) == 0 )
{
user++;
}
#endif
/* in version 2 files, the next field is used to qualify
* this line for callback only/never/don't care
*/
if ( file_version > 1 )
{
char cbq = toupper( *(line++) );
if ( ( cbq == 'Y' && ! is_callback ) ||
( cbq == 'N' && is_callback ) )
{
lprintf( L_NOISE, "-> skipped: %c/%d", cbq, is_callback );
continue;
}
/* skip to next field */
while( *line && !isspace(*line) ) line++;
while( isspace(*line) ) line++;
}
/* get (login) user id */
user_id = strtok( line, " \t" );
/* get utmp entry */
utmp_entry = strtok( NULL, " \t" );
/* get login program */
argv[0] = cmd = strtok( NULL, " \t" );
/* sanity checks - *before* setting anything */
errno = EINVAL;
if ( user_id == NULL )
{
lprintf( L_FATAL, "login: uid field blank, skipping line" );
continue;
}
if ( utmp_entry == NULL )
{
lprintf( L_FATAL, "login: utmp field blank, skipping line" );
continue;
}
if ( cmd == NULL )
{
lprintf( L_FATAL, "login: no login command, skipping line" );
continue;
}
/* OK, all values given. Now write utmp entry */
if ( strcmp( utmp_entry, "-" ) != 0 )
{
if ( strcmp( utmp_entry, "@" ) == 0 ) utmp_entry = user;
lprintf( L_NOISE, "login: utmp entry: %s", utmp_entry );
make_utmp_wtmp( Device, UT_USER, utmp_entry, Connect );
}
/* set UID (+login uid) */
if ( strcmp( user_id, "-" ) != 0 )
{
pw = getpwnam( user_id );
if ( pw == NULL )
{
lprintf( L_ERROR, "getpwnam('%s') failed", user_id );
}
else
{
lprintf( L_NOISE, "login: user id: %s (uid %d, gid %d)",
user_id, pw->pw_uid, pw->pw_gid );
#if SECUREWARE
if ( setluid( pw->pw_uid ) == -1 )
{
lprintf( L_ERROR, "cannot set LUID %d", pw->pw_uid);
}
#endif
if ( setgid( pw->pw_gid ) == -1 )
{
lprintf( L_ERROR, "cannot set gid %d", pw->pw_gid );
}
if ( setuid( pw->pw_uid ) == -1 )
{
lprintf( L_ERROR, "cannot set uid %d", pw->pw_uid );
}
}
} /* end if (uid given) */
/* now build 'login' command line */
/* strip path name off to-be-argv[0] */
p = strrchr( argv[0], '/' );
if ( p != NULL ) argv[0] = p+1;
/* break up line into whitespace-separated command line
arguments, substituting '@' by the user name
*/
argc = 1;
p = strtok( NULL, " \t" );
while ( argc <= MAX_LOGIN_ARGS && p != NULL )
{
if ( strcmp( p, "@" ) == 0 ) /* user name */
{
if ( user != NULL && user[0] != 0 )
{
argv[argc++] = user;
}
}
else if ( strcmp( p, "\\I" ) == 0 ) /* Connect */
{
argv[argc++] = Connect[0]? Connect: "??";
}
else if ( strcmp( p, "\\Y" ) == 0 ) /* CallerID */
{
argv[argc++] = CallerId;
}
else
argv[argc++] = p;
p = strtok( NULL, " \t" );
}
if ( p != NULL ) /* arguments left? */
lprintf( L_WARN, "login.config: max. %d command line arguments possible, truncated at: '%s'", MAX_LOGIN_ARGS, p);
break;
} /* end if (matching line found) */
} /* end while( not end of config file ) */
if ( fp != NULL ) fclose( fp );
fallthrough:
/* default to "/bin/login <user>" */
if ( argc == 0 )
{
lprintf( L_NOISE, "login: fall back to %s", DEFAULT_LOGIN_PROGRAM );
cmd = DEFAULT_LOGIN_PROGRAM;
argv[argc++] = "login";
/* append user name to argument list (if not empty) */
if ( user[0] != 0 )
{
argv[argc++] = user;
}
}
/* terminate list */
argv[argc] = NULL;
/* verbose login message */
lprintf( L_NOISE, "calling login: cmd='%s', argv[]='", cmd );
for ( i=0; i<argc; i++) { lputs( L_NOISE, argv[i] );
lputs( L_NOISE, (i<argc-1)?" ":"'" ); }
/* set a couple of environment variables (mainly useful for "special"
* logins, like Fido and AutoPPP, because /bin/login reconstructs its
* environment from scratch) - not general enough, though.
*/
setup_environment();
/* audit record */
lprintf( L_AUDIT,
"data dev=%s, pid=%d, caller='%s', conn='%s', name='%s', cmd='%s', user='%s'",
Device, getpid(), CallerId, Connect, CallName,
cmd, user );
/* make sure close-on-exec bit is unset
* (BUG in FreeBSD 4.1.1 syslog() - sets c-o-e on FD 0 !!!
*/
if ( fcntl(0, F_GETFD, 0 ) & 1 )
lprintf( L_WARN, "WARNING: close-on-exec bit set on FD 0 - OS BUG?" );
/* execute login */
execv( cmd, argv );
/* FIXME: try via shell call */
lprintf( L_FATAL, "cannot execute '%s'", cmd );
exit(FAIL);
}
void setup_environment _P0(void)
{
if ( *CallerId )
set_env_var( "CALLER_ID", CallerId );
if ( *CallName )
set_env_var( "CALLER_NAME", CallName );
if ( *CalledNr )
set_env_var( "CALLED_ID", CalledNr );
set_env_var( "CONNECT", Connect );
set_env_var( "DEVICE", Device );
}