[PATCH v2] libio: use PTR_MANGLE/PTR_DEMANGLE for FILE vtables

[Florian Weimer]

On 10/03/2015 12:22 AM, Mike Frysinger wrote:
> On 01 Oct 2015 15:27, Kees Cook wrote:
>> Okay, so, since roughly 2007? Should I name the config "--only-v6+" or
>> something?

It's more like 2003, but I need to double-check the dates.

> i wouldn't make it opaque.  just call it something like "libio-file-ptr-mangle".

It should be --disable-libio-compatibility or something like that.  If
we know all the possible vtables, we can do much better in terms of
hardening, and likely even devirtualize some of the function calls.
Pointer mangling is better than nothing, but I don't think the option
should be tied to that.

> then in the documentation, describe the possible limitations.

I plan to put the results of my libio archaeology on the wiki.  It
should make documenting the impact of the new configure option easier.

Florian