shadow/libmisc/chowntty.c

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/*
* Copyright (c) 1989 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 2001, Marek Michałkiewicz
* Copyright (c) 2003 - 2005, Tomasz Kłoczko
* Copyright (c) 2007 , Nicolas François
* All rights reserved.
*
* 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. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
* HOLDERS OR 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 <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"
/*
* is_my_tty -- determine if "tty" is the same as TTY stdin is using
*/
static bool is_my_tty (const char *tty)
{
struct stat by_name, by_fd;
if ((stat (tty, &by_name) != 0) || (fstat (0, &by_fd) != 0)) {
return false;
}
if (by_name.st_rdev != by_fd.st_rdev) {
return false;
} else {
return true;
}
}
/*
* 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);
* lib/prototypes.h, configure.in, libmisc/Makefile.am, libmisc/xgetXXbyYY.c, libmisc/xgetpwnam.c, libmisc/xgetpwuid.c, libmisc/xgetgrnam.c, libmisc/xgetgrgid.c, libmisc/xgetspnam.c: Added functions xgetpwnam(), xgetpwuid(), xgetgrnam(), xgetgrgid(), and xgetspnam(). They allocate memory for the returned structure and are more robust to successive calls. They are implemented with the libc's getxxyyy_r() functions if available. * libmisc/limits.c, libmisc/entry.c, libmisc/chowntty.c, libmisc/addgrps.c, libmisc/myname.c, libmisc/rlogin.c, libmisc/pwdcheck.c, src/newgrp.c, src/login_nopam.c, src/userdel.c, src/lastlog.c, src/grpck.c, src/gpasswd.c, src/newusers.c, src/chpasswd.c, src/chfn.c, src/groupmems.c, src/usermod.c, src/expiry.c, src/groupdel.c, src/chgpasswd.c, src/su.c, src/useradd.c, src/groupmod.c, src/passwd.c, src/pwck.c, src/groupadd.c, src/chage.c, src/login.c, src/suauth.c, src/faillog.c, src/groups.c, src/chsh.c, src/id.c: Review all the usage of one of the getpwnam(), getpwuid(), getgrnam(), getgrgid(), and getspnam() functions. It was noticed on http://bugs.debian.org/341230 that chfn and chsh use a passwd structure after calling a pam function, which result in using information from the passwd structure requested by pam, not the original one. It is much easier to use the new xget... functions to avoid these issues. I've checked which call to the original get... functions could be left (reducing the scope of the structure if possible), and I've left comments to ease future reviews (e.g. /* local, no need for xgetpwnam */). Note: the getpwent/getgrent calls should probably be checked also. * src/groupdel.c, src/expiry.c: Fix typos in comments. * src/groupmod.c: Re-indent. * libmisc/Makefile.am, lib/groupmem.c, lib/groupio.c, lib/pwmem.c, lib/pwio.c, lib/shadowmem.c, lib/shadowio.c: Move the __<xx>_dup functions (used by the xget... functions) from the <xx>io.c files to the new <xx>mem.c files. This avoid linking some utils against the SELinux library.
2007-11-19 04:45:26 +05:30
else if ((grent = getgrnam (group))) /* local, no need for xgetgrnam */
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_WARN,
"unable to determine TTY name, got %s\n", tty));
closelog ();
exit (1);
}
if ((chown (tty, info->pw_uid, gid) != 0)||
(chmod (tty, getdef_num ("TTYPERM", 0600)) != 0)) {
int err = errno;
snprintf (buf, sizeof buf, _("Unable to change tty %s"), tty);
perror (buf);
SYSLOG ((LOG_WARN,
"unable to change tty `%s' for user `%s'\n", tty,
info->pw_name));
closelog ();
if (err != EROFS)
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
}