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/* $OpenBSD: login_fbtab.c,v 1.11 2002/06/25 17:42:29 millert Exp $ */
/************************************************************************
* Copyright 1995 by Wietse Venema. All rights reserved. Some individual
* files may be covered by other copyrights.
*
* This material was originally written and compiled by Wietse Venema at
* Eindhoven University of Technology, The Netherlands, in 1990, 1991,
* 1992, 1993, 1994 and 1995.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that this entire copyright notice
* is duplicated in all such copies.
*
* This software is provided "as is" and without any expressed or implied
* warranties, including, without limitation, the implied warranties of
* merchantibility and fitness for any particular purpose.
************************************************************************/
/*
SYNOPSIS
void login_fbtab(tty, uid, gid)
char *tty;
uid_t uid;
gid_t gid;
DESCRIPTION
This module implements device security as described in the
SunOS 4.1.x fbtab(5) and SunOS 5.x logindevperm(4) manual
pages. The program first looks for /etc/fbtab. If that file
cannot be opened it attempts to process /etc/logindevperm.
We expect entries with the folowing format:
Comments start with a # and extend to the end of the line.
Blank lines or lines with only a comment are ignored.
All other lines consist of three fields delimited by
whitespace: a login device (/dev/console), an octal
permission number (0600), and a ":"-delimited list of
devices (/dev/kbd:/dev/mouse). All device names are
absolute paths. A path that ends in "*" refers to all
directory entries except "." and "..".
If the tty argument (relative path) matches a login device
name (absolute path), the permissions of the devices in the
":"-delimited list are set as specified in the second
field, and their ownership is changed to that of the uid
and gid arguments.
DIAGNOSTICS
Problems are reported via the syslog daemon with severity
LOG_ERR.
AUTHOR
Wietse Venema (wietse@wzv.win.tue.nl)
Eindhoven University of Technology
The Netherlands
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <dirent.h>
#include <limits.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <util.h>
#define _PATH_FBTAB "/etc/fbtab"
static void login_protect(const char *, int, uid_t, gid_t);
#define WSPACE " \t\n"
/*
* login_fbtab - apply protections specified in /etc/fbtab or logindevperm
*/
void
login_fbtab(const char *tty, uid_t uid, gid_t gid)
{
FILE *fp;
char *buf, *toklast, *tbuf, *devname, *cp;
int prot;
size_t len;
if ((fp = fopen(_PATH_FBTAB, "r")) == NULL)
return;
tbuf = NULL;
while ((buf = fgetln(fp, &len)) != NULL) {
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
else {
if ((tbuf = (char *)malloc(len + 1)) == NULL)
break;
memcpy(tbuf, buf, len);
tbuf[len] = '\0';
buf = tbuf;
}
if ((cp = strchr(buf, '#')))
*cp = '\0'; /* strip comment */
if (buf[0] == '\0' ||
(cp = devname = strtok_r(buf, WSPACE, &toklast)) == NULL)
continue; /* empty or comment */
if (strncmp(devname, _PATH_DEV, sizeof(_PATH_DEV) - 1) != 0 ||
(cp = strtok_r(NULL, WSPACE, &toklast)) == NULL ||
*cp != '0' ||
sscanf(cp, "%o", &prot) == 0 ||
prot == 0 ||
(prot & 0777) != prot ||
(cp = strtok_r(NULL, WSPACE, &toklast)) == NULL) {
syslog(LOG_ERR, "%s: bad entry: %s", _PATH_FBTAB,
cp ? cp : "(null)");
continue;
}
if (strcmp(devname + sizeof(_PATH_DEV) - 1, tty) == 0) {
for (cp = strtok_r(cp, ":", &toklast); cp != NULL;
cp = strtok_r(NULL, ":", &toklast))
login_protect(cp, prot, uid, gid);
}
}
if (tbuf != NULL)
free(tbuf);
fclose(fp);
}
/*
* login_protect - protect one device entry
*/
static void
login_protect(const char *path, int mask, uid_t uid, gid_t gid)
{
char buf[PATH_MAX];
size_t pathlen = strlen(path);
DIR *dir;
struct dirent *ent;
if (pathlen >= sizeof(buf)) {
errno = ENAMETOOLONG;
syslog(LOG_ERR, "%s: %s: %m", _PATH_FBTAB, path);
return;
}
if (strcmp("/*", path + pathlen - 2) != 0) {
if (chmod(path, mask) && errno != ENOENT)
syslog(LOG_ERR, "%s: chmod(%s): %m", _PATH_FBTAB, path);
if (chown(path, uid, gid) && errno != ENOENT)
syslog(LOG_ERR, "%s: chown(%s): %m", _PATH_FBTAB, path);
} else {
/*
* This is a wildcard directory (/path/to/whatever/*).
* Make a copy of path without the trailing '*' (but leave
* the trailing '/' so we can append directory entries.)
*/
memcpy(buf, path, pathlen - 1);
buf[pathlen - 1] = '\0';
if ((dir = opendir(buf)) == NULL) {
syslog(LOG_ERR, "%s: opendir(%s): %m", _PATH_FBTAB,
path);
return;
}
while ((ent = readdir(dir)) != NULL) {
if (strcmp(ent->d_name, ".") != 0 &&
strcmp(ent->d_name, "..") != 0) {
buf[pathlen - 1] = '\0';
if (strlcat(buf, ent->d_name, sizeof(buf))
>= sizeof(buf)) {
errno = ENAMETOOLONG;
syslog(LOG_ERR, "%s: %s: %m",
_PATH_FBTAB, path);
} else
login_protect(buf, mask, uid, gid);
}
}
closedir(dir);
}
}
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