shadow/libmisc/chowntty.c

80 lines
1.9 KiB
C

/*
* SPDX-FileCopyrightText: 1989 - 1994, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 2001, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
* SPDX-FileCopyrightText: 2007 - 2009, Nicolas François
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#ident "$Id$"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <errno.h>
#include <grp.h>
#include "prototypes.h"
#include "defines.h"
#include <pwd.h>
#include "getdef.h"
#include "shadowlog.h"
/*
* chown_tty() sets the login tty to be owned by the new user ID
* with TTYPERM modes
*/
void chown_tty (const struct passwd *info)
{
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.
*/
grent = getgr_nam_gid (getdef_str ("TTYGROUP"));
if (NULL != grent) {
gid = grent->gr_gid;
gr_free (grent);
} else {
gid = info->pw_gid;
}
/*
* Change the permissions on the TTY to be owned by the user with
* the group as determined above.
*/
if ( (fchown (STDIN_FILENO, info->pw_uid, gid) != 0)
|| (fchmod (STDIN_FILENO, (mode_t)getdef_num ("TTYPERM", 0600)) != 0)) {
int err = errno;
FILE *shadow_logfd = log_get_logfd();
fprintf (shadow_logfd,
_("Unable to change owner or mode of tty stdin: %s"),
strerror (err));
SYSLOG ((LOG_WARN,
"unable to change owner or mode of tty stdin for user `%s': %s\n",
info->pw_name, strerror (err)));
if (EROFS != err) {
closelog ();
exit (EXIT_FAILURE);
}
}
#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
}