forked from OSchip/llvm-project
df6ba242bf
Summary: It was deemed that the salt in the chunk header didn't improve security significantly (and could actually decrease it). The initial idea was that the same chunk would different headers on different allocations, allowing for less predictability. The issue is that gathering the same chunk header with different salts can give information about the other "secrets" (cookie, pointer), and that if an attacker leaks a header, they can reuse it anyway for that same chunk anyway since we don't enforce the salt value. So we get rid of the salt in the header. This means we also get rid of the thread local Prng, and that we don't need a global Prng anymore as well. This makes everything faster. We reuse those 8 bits to store the `ClassId` of a chunk now (0 for a secondary based allocation). This way, we get some additional speed gains: - `ClassId` is computed outside of the locked block; - `getActuallyAllocatedSize` doesn't need the `GetSizeClass` call; - same for `deallocatePrimary`; We add a sanity check at init for this new field (all sanity checks are moved in their own function, `init` was getting crowded). Reviewers: alekseyshl, flowerhack Reviewed By: alekseyshl Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D40796 llvm-svn: 319791 |
||
|---|---|---|
| .. | ||
| cmake | ||
| docs | ||
| include | ||
| lib | ||
| test | ||
| unittests | ||
| www | ||
| .arcconfig | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| CREDITS.TXT | ||
| LICENSE.TXT | ||
| README.txt | ||
README.txt
Compiler-RT ================================ This directory and its subdirectories contain source code for the compiler support routines. Compiler-RT is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. ================================