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deb-mbse/unix/chowntty.c

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2009-05-15 20:01:56 +00:00
/*****************************************************************************
*
* $Id: chowntty.c,v 1.2 2003/08/15 20:05:36 mbroek Exp $
* Purpose ...............: MBSE BBS Shadow Password Suite
* Original Source .......: Shadow Password Suite
* Original Copyright ....: Julianne Frances Haugh and others.
*
*****************************************************************************
* Copyright (C) 1997-2001
*
* Michiel Broek FIDO: 2:280/2802
* Beekmansbos 10
* 1971 BV IJmuiden
* the Netherlands
*
* This file is part of MBSE BBS.
*
* This BBS is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* MBSE BBS is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with MBSE BBS; see the file COPYING. If not, write to the Free
* Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*****************************************************************************/
#include "../config.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <syslog.h>
#include <stdio.h>
#include <grp.h>
#include "mblogin.h"
#include <pwd.h>
#include "getdef.h"
#include "chowntty.h"
/*
* is_my_tty -- determine if "tty" is the same as TTY stdin is using
*/
int is_my_tty(const char *tty)
{
struct stat by_name, by_fd;
if (stat (tty, &by_name) || fstat (0, &by_fd))
return 0;
if (by_name.st_rdev != by_fd.st_rdev)
return 0;
else
return 1;
}
/*
* chown_tty() sets the login tty to be owned by the new user ID
* with TTYPERM modes
*/
void chown_tty(const char *tty, const struct passwd *info)
{
char buf[200], full_tty[200];
char *group; /* TTY group name or number */
struct group *grent;
gid_t gid;
/*
* * See if login.defs has some value configured for the port group
* * ID. Otherwise, use the user's primary group ID.
* */
if (! (group = getdef_str ("TTYGROUP")))
gid = info->pw_gid;
else if (group[0] >= '0' && group[0] <= '9')
gid = atoi (group);
else if ((grent = getgrnam (group)))
gid = grent->gr_gid;
else
gid = info->pw_gid;
/*
* Change the permissions on the TTY to be owned by the user with
* the group as determined above.
*/
if (*tty != '/') {
snprintf(full_tty, sizeof full_tty, "/dev/%s", tty);
tty = full_tty;
}
if (! is_my_tty (tty)) {
syslog(LOG_WARNING, "unable to determine TTY name, got %s\n", tty);
closelog();
exit (1);
}
if (chown(tty, info->pw_uid, gid) || chmod(tty, 0600)) {
snprintf(buf, sizeof buf, "Unable to change tty %s", tty);
syslog(LOG_WARNING, "unable to change tty `%s' for user `%s'\n", tty, info->pw_name);
closelog();
perror (buf);
exit(1);
}
#ifdef __linux__
/*
* Please don't add code to chown /dev/vcs* to the user logging in -
* it's a potential security hole. I wouldn't like the previous user
* to hold the file descriptor open and watch my screen. We don't
* have the *BSD revoke() system call yet, and vhangup() only works
* for tty devices (which vcs* is not). --marekm
*/
#endif
}