xref: /dragonfly/lib/libutil/_secure_path.3 (revision 6e278935)
1.\" Copyright (c) 1997 David Nugent <davidn@blaze.net.au>
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, is permitted provided that the following conditions
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10.\" 2. Redistributions in binary form must reproduce the above copyright
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13.\" 3. This work was done expressly for inclusion into FreeBSD.  Other use
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15.\" 4. Absolutely no warranty of function or purpose is made by the author
16.\"    David Nugent.
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20.\" $FreeBSD: src/lib/libutil/_secure_path.3,v 1.7.2.4 2002/03/19 01:49:54 dd Exp $
21.\"
22.Dd May 2, 1997
23.Dt _SECURE_PATH 3
24.Os
25.Sh NAME
26.Nm _secure_path
27.Nd determine if a file appears to be secure
28.Sh LIBRARY
29.Lb libutil
30.Sh SYNOPSIS
31.In sys/types.h
32.In libutil.h
33.Ft int
34.Fn _secure_path "const char *path" "uid_t uid" "gid_t gid"
35.Sh DESCRIPTION
36This function does some basic security checking on a given path.
37It is intended to be used by processes running with root privileges
38in order to decide whether or not to trust the contents of a given
39file.
40It uses a method often used to detect system compromise.
41.Pp
42A file is considered
43.Sq secure
44if it meets the following conditions:
45.Bl -enum
46.It
47The file exists, and is a regular file (not a symlink, device
48special or named pipe, etc.),
49.It
50Is not world writable.
51.It
52Is owned by the given uid or uid 0, if uid is not -1,
53.It
54Is not group writable or it has group ownership by the given
55gid, if gid is not -1.
56.El
57.Sh RETURN VALUES
58This function returns zero if the file exists and may be
59considered secure, -2 if the file does not exist, and
60-1 otherwise to indicate a security failure.
61.Xr syslog 3
62is used to log any failure of this function, including the
63reason, at LOG_ERR priority.
64.Sh SEE ALSO
65.Xr lstat 2 ,
66.Xr syslog 3
67.Sh HISTORY
68Code from which this function was derived was contributed to the
69.Fx
70project by Berkeley Software Design, Inc.
71.Sh BUGS
72The checks carried out are rudimentary and no attempt is made
73to eliminate race conditions between use of this function and
74access to the file referenced.
75