mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-26 11:47:31 +00:00
d3951ad162
to Solaris, it is in /usr/libexec) to perform the handing over of tty nodes to the user being granted the pty. Submitted by: Ryan Younce <ryany@pobox.com> Reviewed by: security-officer@, standards@, mike@
104 lines
3.9 KiB
C
104 lines
3.9 KiB
C
/*
|
|
* Copyright (c) 2002 The FreeBSD Project, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This software includes code contributed to the FreeBSD Project
|
|
* by Ryan Younce of North Carolina State University.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the FreeBSD Project nor the names of its
|
|
* contributors may be used to endorse or promote products derived from
|
|
* this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE FREEBSD PROJECT AND CONTRIBUTORS ``AS IS''
|
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE FREEBSD PROJECT OR ITS CONTRIBUTORS
|
|
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
#ifndef lint
|
|
__FBSDID("$FreeBSD$");
|
|
#endif /* not lint */
|
|
|
|
#include <sys/stat.h>
|
|
|
|
#include <grp.h>
|
|
#include <stdlib.h>
|
|
#include <sysexits.h>
|
|
#include <unistd.h>
|
|
|
|
/*
|
|
* pt_chown
|
|
* Utility support routine for grantpt(3).
|
|
*
|
|
* According to IEEE Std 1003.1-2001, grantpt(3) changes ownership and
|
|
* permission bits of a slave pseudo-terminal device associated with a
|
|
* master.
|
|
*
|
|
* Since doing this if we are not the owner of the slave (which would
|
|
* rarely happen) cannot be done by conventional methods, grantpt(3)
|
|
* has to rely on this support program, which is setuid root, to change
|
|
* the slave's owner, group, and permission mode attributes. It's
|
|
* a rather undesirable approach, but Digital Unix and Solaris also seem
|
|
* to rely on this approach to pull this off.
|
|
*
|
|
* This program hangs around long enough to do just these things upon
|
|
* its standard input (which is set up by grantpt(3) to be the master's
|
|
* descriptor, the one passed to it). The rationale behind this
|
|
* approach not allowing somebody to modify ownership of another active
|
|
* pseudo terminal is:
|
|
*
|
|
* 1) This program only operates on its standard input. If STDIN_FILENO
|
|
* is not open or is not a pseudo-terminal master, no action is
|
|
* taken and the program exits (ptsname() is called for a non-NULL
|
|
* return).
|
|
* 2) Only one active file description for a pseudo-terminal master
|
|
* can exist at a time (attempting to open an active PTY returns with
|
|
* EIO - I/O Error). Thus, if the pseudo-terminal is already in
|
|
* use by somebody else, it could not have been opened to begin
|
|
* with, and thus this program would be useless in such situations.
|
|
*/
|
|
int
|
|
main(int argc, char *argv[])
|
|
{
|
|
int retcode;
|
|
char *slave;
|
|
gid_t gid;
|
|
struct group *grp;
|
|
|
|
retcode = EX_OK;
|
|
|
|
if ((slave = ptsname(STDIN_FILENO)) == NULL)
|
|
retcode = EX_USAGE;
|
|
else {
|
|
gid = (grp = getgrnam("tty")) ? grp->gr_gid : -1;
|
|
if (chown(slave, getuid(), gid) == 0 &&
|
|
chmod(slave, S_IRUSR | S_IWUSR | S_IWGRP) == 0)
|
|
retcode = 0;
|
|
else
|
|
retcode = EX_NOPERM;
|
|
}
|
|
|
|
/*
|
|
* grantpt(3) checks the retcode for being either zero or
|
|
* nonzero. Any nonzero return results in errno being set
|
|
* to EACCES.
|
|
*/
|
|
exit(retcode);
|
|
}
|