mmap zero mapping disallowed (Re: svn commit: r197537 -
julian at elischer.org
Sun Sep 27 18:58:23 UTC 2009
Robert Watson wrote:
> On Sun, 27 Sep 2009, Simon L. Nielsen wrote:
>> As mentioned in the commit message FreeBSD 9 / head now does not allow
>> mmap'ing at zero by default, and this may break some apps.
>> If anyone encounters applications which break because of this change,
>> please let report it so we can see if it can be fixed. It might not
>> be possible to fix some applications, but we at least would know which
>> applications might need a special note in the documentation.
> There are probably some other ways to arrange mappings at 0x0, so we'll
> need to dig through the system to identify them. To mind, the various
> executable image activators are interesting (elf, a.out, etc), but we
> should check other things that call VM insertion routines -- things like
> the more interesting 3D device drivers. At the end of the day, this is
> a mitigation technique, so if there are edge case non-default compiled
> copmonents, etc, that's fine, but it would be nice to be thorough where
> we can.
> While our automatic address selection code ever pick 0x0 as a mapping
> address, btw?
> Robert N M Watson
> Computer Laboratory
> University of Cambridge
What they need to do now is find a fault where the offset is > 4096..
I wouldn't bet against it..
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