diff --git a/README.md b/README.md index 784d663..4caf496 100644 --- a/README.md +++ b/README.md @@ -42,17 +42,17 @@ and can cover the same use cases. This allocator is intended as a successor to a previous implementation based on extending OpenBSD malloc with various additional security features. It's still heavily based on the OpenBSD malloc design, albeit not on the existing code -other than reusing the hash table implementation for the time being. The main -differences in the design are that it is solely focused on hardening rather -than finding bugs, uses finer-grained size classes along with slab sizes going -beyond 4k to reduce internal fragmentation, doesn't rely on the kernel having -fine-grained mmap randomization and only targets 64-bit to make aggressive use -of the large address space. There are lots of smaller differences in the -implementation approach. It incorporates the previous extensions made to -OpenBSD malloc including adding padding to allocations for canaries (distinct -from the current OpenBSD malloc canaries), write-after-free detection tied to -the existing clearing on free, queues alongside the existing randomized arrays -for quarantining allocations and proper double-free detection for quarantined +other than reusing the hash table implementation. The main differences in the +design are that it's solely focused on hardening rather than finding bugs, uses +finer-grained size classes along with slab sizes going beyond 4k to reduce +internal fragmentation, doesn't rely on the kernel having fine-grained mmap +randomization and only targets 64-bit to make aggressive use of the large +address space. There are lots of smaller differences in the implementation +approach. It incorporates the previous extensions made to OpenBSD malloc +including adding padding to allocations for canaries (distinct from the current +OpenBSD malloc canaries), write-after-free detection tied to the existing +clearing on free, queues alongside the existing randomized arrays for +quarantining allocations and proper double-free detection for quarantined allocations. The per-size-class memory regions with their own random bases were loosely inspired by the size and type-based partitioning in PartitionAlloc. The planned changes to OpenBSD malloc ended up being too extensive and invasive so