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/* $OpenBSD: login_fbtab.c,v 1.16 2015/11/27 01:57:59 mmcc Exp $ */
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/************************************************************************
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* Copyright 1995 by Wietse Venema. All rights reserved. Some individual
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* files may be covered by other copyrights.
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*
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* This material was originally written and compiled by Wietse Venema at
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* Eindhoven University of Technology, The Netherlands, in 1990, 1991,
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* 1992, 1993, 1994 and 1995.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that this entire copyright notice
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* is duplicated in all such copies.
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*
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* This software is provided "as is" and without any expressed or implied
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* warranties, including, without limitation, the implied warranties of
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* merchantibility and fitness for any particular purpose.
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************************************************************************/
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/*
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SYNOPSIS
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void login_fbtab(tty, uid, gid)
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char *tty;
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uid_t uid;
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gid_t gid;
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DESCRIPTION
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This module implements device security as described in the
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SunOS 4.1.x fbtab(5) and SunOS 5.x logindevperm(4) manual
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pages. The program first looks for /etc/fbtab. If that file
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cannot be opened it attempts to process /etc/logindevperm.
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We expect entries with the folowing format:
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Comments start with a # and extend to the end of the line.
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Blank lines or lines with only a comment are ignored.
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All other lines consist of three fields delimited by
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whitespace: a login device (/dev/console), an octal
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permission number (0600), and a ":"-delimited list of
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devices (/dev/kbd:/dev/mouse). All device names are
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absolute paths. A path that ends in "*" refers to all
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directory entries except "." and "..".
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If the tty argument (relative path) matches a login device
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name (absolute path), the permissions of the devices in the
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":"-delimited list are set as specified in the second
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field, and their ownership is changed to that of the uid
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and gid arguments.
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DIAGNOSTICS
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Problems are reported via the syslog daemon with severity
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LOG_ERR.
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AUTHOR
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Wietse Venema (wietse@wzv.win.tue.nl)
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Eindhoven University of Technology
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The Netherlands
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <dirent.h>
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#include <limits.h>
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#include <paths.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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#include <util.h>
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#define _PATH_FBTAB "/etc/fbtab"
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static void login_protect(const char *, mode_t, uid_t, gid_t);
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#define WSPACE " \t\n"
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/*
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* login_fbtab - apply protections specified in /etc/fbtab or logindevperm
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*/
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void
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login_fbtab(const char *tty, uid_t uid, gid_t gid)
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{
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FILE *fp;
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char *buf, *toklast, *tbuf, *devnam, *cp;
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mode_t prot;
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size_t len;
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if ((fp = fopen(_PATH_FBTAB, "r")) == NULL)
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return;
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tbuf = NULL;
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while ((buf = fgetln(fp, &len)) != NULL) {
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if (buf[len - 1] == '\n')
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buf[len - 1] = '\0';
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else {
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if ((tbuf = malloc(len + 1)) == NULL)
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break;
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memcpy(tbuf, buf, len);
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tbuf[len] = '\0';
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buf = tbuf;
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}
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if ((cp = strchr(buf, '#')))
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*cp = '\0'; /* strip comment */
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if (buf[0] == '\0' ||
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(cp = devnam = strtok_r(buf, WSPACE, &toklast)) == NULL)
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continue; /* empty or comment */
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if (strncmp(devnam, _PATH_DEV, sizeof(_PATH_DEV) - 1) != 0 ||
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(cp = strtok_r(NULL, WSPACE, &toklast)) == NULL ||
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*cp != '0' ||
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sscanf(cp, "%o", &prot) == 0 ||
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prot == 0 ||
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(prot & 0777) != prot ||
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(cp = strtok_r(NULL, WSPACE, &toklast)) == NULL) {
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syslog(LOG_ERR, "%s: bad entry: %s", _PATH_FBTAB,
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cp ? cp : "(null)");
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continue;
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}
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if (strcmp(devnam + sizeof(_PATH_DEV) - 1, tty) == 0) {
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for (cp = strtok_r(cp, ":", &toklast); cp != NULL;
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cp = strtok_r(NULL, ":", &toklast))
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login_protect(cp, prot, uid, gid);
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}
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}
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free(tbuf);
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fclose(fp);
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}
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/*
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* login_protect - protect one device entry
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*/
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static void
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login_protect(const char *path, mode_t mask, uid_t uid, gid_t gid)
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{
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char buf[PATH_MAX];
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size_t pathlen = strlen(path);
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DIR *dir;
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struct dirent *ent;
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if (pathlen >= sizeof(buf)) {
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errno = ENAMETOOLONG;
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syslog(LOG_ERR, "%s: %s: %m", _PATH_FBTAB, path);
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return;
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}
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if (strcmp("/*", path + pathlen - 2) != 0) {
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if (chmod(path, mask) && errno != ENOENT)
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syslog(LOG_ERR, "%s: chmod(%s): %m", _PATH_FBTAB, path);
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if (chown(path, uid, gid) && errno != ENOENT)
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syslog(LOG_ERR, "%s: chown(%s): %m", _PATH_FBTAB, path);
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} else {
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/*
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* This is a wildcard directory (/path/to/whatever/ * ).
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* Make a copy of path without the trailing '*' (but leave
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* the trailing '/' so we can append directory entries.)
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*/
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memcpy(buf, path, pathlen - 1);
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buf[pathlen - 1] = '\0';
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if ((dir = opendir(buf)) == NULL) {
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syslog(LOG_ERR, "%s: opendir(%s): %m", _PATH_FBTAB,
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path);
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return;
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}
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while ((ent = readdir(dir)) != NULL) {
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if (strcmp(ent->d_name, ".") != 0 &&
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strcmp(ent->d_name, "..") != 0) {
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buf[pathlen - 1] = '\0';
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if (strlcat(buf, ent->d_name, sizeof(buf))
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>= sizeof(buf)) {
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errno = ENAMETOOLONG;
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syslog(LOG_ERR, "%s: %s: %m",
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_PATH_FBTAB, path);
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} else
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login_protect(buf, mask, uid, gid);
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}
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}
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closedir(dir);
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}
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}
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