RFC: Cygwin 64 bit?

[Ryan Johnson]

On 18/08/2011 12:31 PM, Peter Rosin wrote:
> Den 2011-08-18 15:58 skrev Ryan Johnson:
>> On 18/08/2011 9:24 AM, Corinna Vinschen wrote:
>>> On Aug 18 15:10, Peter Rosin wrote:
>>>> Den 2011-08-18 11:20 skrev Corinna Vinschen:
>>>>> So, nobody except Earnie is interested in the way dlopen opens shared
>>>>> objects?  Nobody even replied to the idea of the pseudo algorithm below.
>>>>> Does really nobody care?
>>>> I have one little reservation, I don't like it when adding a seemingly
>>>> unrelated file can break old stuff. For example, let's say that I in the
>>>> future have an application that relies on the fact that it can dlopen
>>>> "libfoo.so" and get "cygfoo.dll". Everything works fine. If I then
>>>> install something that brings in a real "libfoo.so" things will break.
>>>> It's even a security problem because a carefully crafted rouge
>>>> libfoo.so can appear to work but do unwanted stuff behind my back.
>>> That's a good point.  I don't know how critical that is.  Maybe it would
>>> help to change the order, along these lines:
>>>
>>>     incoming: libfoo.so
>>>     1. check: cygfoo.dll
>>>     2. check: libfoo.dll
>>>     3. check: libfoo.so
>>>
>>> But, of course, regardless of the order, there's always a chance to
>>> slip something in.
>> In theory it does sound bad, but I'm not sure how much of a hole it
>> leaves in practice: the fact that the adversary has to resort to
>> different names rather than simply replacing the targeted library
>> means they have pretty limited control. They can't just
>> delete/rename their target, nor can they stick a decoy earlier in
>> [LD_LIBRARY_]PATH, so they have to resort to exploiting this name
>> overloading. The only way around it that I can think of right off
>> would be if some directory in the search path has the 't' permission
>> set (like /tmp does), so they can add new files even though they
>> can't mess with other files there. That seems unlikely (or at least,
>> easily fixed).
> That's assuming there is no value for the perp in *not* touching
> the attacked software. Any hashes for the files belonging to the
> attacked software would still be correct, for example.
True, but you can shut that party down by not having +t on any of the 
library paths and by having those paths owned by the same user that owns 
the targeted libraries. Both are probably true by default the vast 
majority of the time.

Ryan