[PATCH] randomized mmap

Suleiman Souhlal ssouhlal at FreeBSD.org
Sun May 29 19:47:10 PDT 2005


The patch at http://people.freebsd.org/~ssouhlal/testing/ 
mmap_random-20050528.diff implements random mmap addresses (unless of  
course MAP_FIXED is being used), again from OpenBSD.
This behavior can be disabled setting the vm.mmap_random sysctl to 0.
I think this could greatly increase memory fragmentation, so I'm not  
sure it would be such a good idea to have it on by default. Also, it  
doesn't really make attacks unfeasable, but the implementation is so  
simple that I don't think we really lose anything by letting users  
decide if they want to enable it or not.

Any comment?
Suleiman Souhlal     | ssouhlal at vt.edu
The FreeBSD Project  | ssouhlal at FreeBSD.org

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