Google rewarded us for the AMD
Bulldozer ASLR security contribution to the Linux
This problem was identified by AMD in 2012 in a
white paper called "Shared Level-1 instruction-cache performance on
AMD family 15h CPUs" [pdf]. In this paper, they proposed five solutions and
workarounds. Unfortunately, the final patch that they proposed and
implemented in the Linux kernel reduced the entropy of the ASLR (on
AMD 15h family) by 87.5%.
We have been rewarded by the novel bit-slicing
ASLR randomization form which is one of the
new elements of the ASLR-NG for
Linux we are working on.