_secure_path -- determine if a file appears to be secure
System Utilities Library (libutil, -lutil)
#include <sys/types.h>
#include <libutil.h>
int
_secure_path(const char *path, uid_t uid, gid_t gid);
This function does some basic security checking on a given path. It is
intended to be used by processes running with root privileges in order to
decide whether or not to trust the contents of a given file. It uses a
method often used to detect system compromise.
A file is considered `secure' if it meets the following conditions:
1. The file exists, and is a regular file (not a symlink, device special
or named pipe, etc.),
2. Is not world writable.
3. Is owned by the given uid or uid 0, if uid is not -1,
4. Is not group writable or it has group ownership by the given gid, if
gid is not -1.
This function returns zero if the file exists and may be considered
secure, -2 if the file does not exist, and -1 otherwise to indicate a
security failure. The syslog(3) function is used to log any failure of
this function, including the reason, at LOG_ERR priority.
The checks carried out are rudimentary and no attempt is made to eliminate
race conditions between use of this function and access to the file
referenced.
lstat(2), syslog(3)
Code from which this function was derived was contributed to the FreeBSD
project by Berkeley Software Design, Inc.
FreeBSD 5.2.1 May 2, 1997 FreeBSD 5.2.1 [ Back ] |