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clarify wording

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Daniel Micay 2018-11-19 08:04:37 -05:00
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@ -17,16 +17,16 @@ This allocator is intended as a successor to a previous implementation based on
extending OpenBSD malloc with various additional security features. It's still extending OpenBSD malloc with various additional security features. It's still
heavily based on the OpenBSD malloc design, albeit not on the existing code 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 other than reusing the hash table implementation for the time being. The main
differences in the design are that it's solely focused on hardening rather than differences in the design are that it is solely focused on hardening rather
finding bugs, uses finer-grained size classes based on jemalloc with slab sizes than finding bugs, uses finer-grained size classes along with slab sizes going
going beyond 4k, it doesn't rely on the kernel having fine-grained mmap beyond 4k to reduce internal fragmentation, doesn't rely on the kernel having
randomization and it only targets 64-bit to make aggressive use of the large fine-grained mmap randomization and only targets 64-bit to make aggressive use
address space. There are lots of smaller differences in the implementation of the large address space. There are lots of smaller differences in the
approach. It incorporates the previous extensions made to OpenBSD malloc implementation approach. It incorporates the previous extensions made to
including adding padding to allocations for canaries (distinct from the current OpenBSD malloc including adding padding to allocations for canaries (distinct
OpenBSD malloc canaries), write-after-free detection tied to the existing from the current OpenBSD malloc canaries), write-after-free detection tied to
clearing on free, queues alongside the existing randomized arrays for the existing clearing on free, queues alongside the existing randomized arrays
quarantining allocations and proper double-free detection for quarantined for quarantining allocations and proper double-free detection for quarantined
allocations. The per-size-class memory regions with their own random bases were 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 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 planned changes to OpenBSD malloc ended up being too extensive and invasive so