_secure_path.c revision 84225 
1/*-
2 * Based on code copyright (c) 1995,1997 by
3 * Berkeley Software Design, Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, is permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice immediately at the beginning of the file, without modification,
11 *    this list of conditions, and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. This work was done expressly for inclusion into FreeBSD.  Other use
16 *    is permitted provided this notation is included.
17 * 4. Absolutely no warranty of function or purpose is made by the authors.
18 * 5. Modifications may be freely made to this file providing the above
19 *    conditions are met.
20 */
21
22#include <sys/cdefs.h>
23__FBSDID("$FreeBSD: head/lib/libutil/_secure_path.c 84225 2001-09-30 22:35:07Z dillon $");
24
25#include <sys/types.h>
26#include <sys/stat.h>
27#include <syslog.h>
28#include <errno.h>
29#include <libutil.h>
30
31/*
32 * Check for common security problems on a given path
33 * It must be:
34 * 1. A regular file, and exists
35 * 2. Owned and writaable only by root (or given owner)
36 * 3. Group ownership is given group or is non-group writable
37 *
38 * Returns:	-2 if file does not exist,
39 *		-1 if security test failure
40 *		0  otherwise
41 */
42
43int
44_secure_path(const char *path, uid_t uid, gid_t gid)
45{
46    int		r = -1;
47    struct stat	sb;
48    const char	*msg = NULL;
49
50    if (lstat(path, &sb) < 0) {
51	if (errno == ENOENT) /* special case */
52	    r = -2;  /* if it is just missing, skip the log entry */
53	else
54	    msg = "%s: cannot stat %s: %m";
55    }
56    else if (!S_ISREG(sb.st_mode))
57    	msg = "%s: %s is not a regular file";
58    else if (sb.st_mode & S_IWOTH)
59    	msg = "%s: %s is world writable";
60    else if (uid != -1 && sb.st_uid != uid && sb.st_uid != 0) {
61    	if (uid == 0)
62    		msg = "%s: %s is not owned by root";
63    	else
64    		msg = "%s: %s is not owned by uid %d";
65    } else if (gid != -1 && sb.st_gid != gid && (sb.st_mode & S_IWGRP))
66    	msg = "%s: %s is group writeable by non-authorised groups";
67    else
68    	r = 0;
69    if (msg != NULL)
70	syslog(LOG_ERR, msg, "_secure_path", path, uid);
71    return r;
72}
73