[PATCH] D63360: hwasan: Use the lower 8 bits of the ring buffer entry address as the base stack tag.
Evgenii Stepanov via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 14 13:54:46 PDT 2019
eugenis added inline comments.
================
Comment at: llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp:1007
+ // The base tag will be a multiple of 8, so we should avoid using tags with
+ // lower bits clear so that we don't end up with a final tag of 0.
+ ++TagOffset;
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We are losing a lot of entropy by allowing these zero bits in the base tag. Single-alloca functions, for example, will only have 32 different tags.
How about using bits 3 .. 11 ?
Repository:
rG LLVM Github Monorepo
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https://reviews.llvm.org/D63360/new/
https://reviews.llvm.org/D63360
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