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 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice immediately at the beginning of the file, without modification, 9.\" this list of conditions, and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. This work was done expressly for inclusion into FreeBSD. Other use 14.\" is permitted provided this notation is included. 15.\" 4. Absolutely no warranty of function or purpose is made by the author 16.\" David Nugent. 17.\" 5. Modifications may be freely made to this file providing the above 18.\" conditions are met. 19.\" 20.Dd May 10, 2020 21.Dt _SECURE_PATH 3 22.Os 23.Sh NAME 24.Nm _secure_path 25.Nd determine if a file appears to be secure 26.Sh LIBRARY 27.Lb libutil 28.Sh SYNOPSIS 29.In sys/types.h 30.In libutil.h 31.Ft int 32.Fn _secure_path "const char *path" "uid_t uid" "gid_t gid" 33.Sh DESCRIPTION 34This function does some basic security checking on a given path. 35It is intended to be used by processes running with root privileges 36in order to decide whether or not to trust the contents of a given 37file. 38It uses a method often used to detect system compromise. 39.Pp 40A file is considered 41.Sq secure 42if it meets the following conditions: 43.Bl -enum 44.It 45The file exists, and is a regular file (not a symlink, device 46special or named pipe, etc.), 47.It 48Is not world writable. 49.It 50Is owned by the given uid or uid 0, if uid is not -1, 51.It 52Is not group writable or it has group ownership by the given 53gid, if gid is not -1. 54.El 55.Sh RETURN VALUES 56This function returns zero if the file exists and may be 57considered secure, -2 if the file does not exist, and 58-1 otherwise to indicate a security failure. 59The 60.Xr syslog 3 61function is used to log any failure of this function, including the 62reason, at LOG_ERR priority. 63.Sh SEE ALSO 64.Xr lstat 2 , 65.Xr syslog 3 66.Sh HISTORY 67Code from which this function was derived was contributed to the 68.Fx 69project by Berkeley Software Design, Inc. 70The function 71.Fn _secure_path 72first appeared in 73.Fx 2.2.5 . 74.Sh BUGS 75The checks carried out are rudimentary and no attempt is made 76to eliminate race conditions between use of this function and 77access to the file referenced. 78