[fpc-pascal] Text relocation in x86 binary lib

Jonas Maebe jonas.maebe at elis.ugent.be
Mon May 31 18:18:52 CEST 2010


On 31 May 2010, at 16:26, Matthias Klumpp wrote:

> On Mon, 31 May 2010 14:31:19 +0200, Jonas Maebe <jonas.maebe at elis.ugent.be>
> wrote:
>> It's because we don't generate PIC (position-independent code) by  
>> default on Linux-i386, because
>> a) PIC is fairly inefficient on i386 (it requires an extra register,  
>> and the i386 is already register-starved as it is -- on average, it  
>> results in a 10% performance degradation)
>> b) very few people use SELinux, and on non-SELinux systems dynamic  
>> libraries without PIC work fine (with a small memory usage penalty,  
>> because the code cannot be shared amongst multiple processes)
> According to SELinux, this is a security issue..

I guess that it may prevent some address space randomization features. I very much doubt that it opens up security holes by itself though.


Jonas


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