5.4 I/O Restrictions
I/O Restrictions are feature introduced in POV-Ray for Unix 3.5. The purpose of this feature is to attempt to at
least partially protect a machine running POV-Ray from having files read or written outside of a given set of
The need for this is related to the fact that the POV-Ray scene language has, over the years, become something more
akin to a scripting language combined with a scene-description model. It is now possible to write obfuscated POV-Ray
code, and to open, create, read and write arbitrary files anywhere on the target system's hard disk (subject to
operating system permission).
The basic idea of I/O Restrictions is to attempt to protect the user from a script that may have been downloaded
from an untrusted source, and which may attempt to create or modify files that it should not.
The I/O Restriction facility hooks the file open and creation functions in the core POV-Ray renderer code, and
allows the Unix version to allow or deny any particular file operation.
Note: We do not guarantee that the I/O Restriction facility will actually stop
anything from happening. There is always the chance that, like almost all software, it could have a bug in it that
causes it to malfunction. Therefore, the onus is on the person who chooses to load an INI or scene file into POV-Ray
to ensure that it does not do anything that it should not do. Please consider I/O Restrictions just a
sometimes-helpful backup for manual checks.
Please read this section in full so that you understand the caveats and conditions of the facility (such as the
fact that some directories are allowed by default).