mirror of
https://github.com/GrapheneOS/hardened_malloc.git
synced 2024-12-23 14:39:33 -05:00
36 lines
1.8 KiB
Markdown
36 lines
1.8 KiB
Markdown
Very important and should be an easy sell:
|
|
|
|
* improved robustness for high vma count on high memory machines
|
|
* much higher `vm.max_map_count` by default
|
|
* work on improving performance and resource usage with high vma count
|
|
* add a way to disable the brk heap and have mmap grow upwards like it did in
|
|
the past (preserving the same high base entropy)
|
|
|
|
Somewhat important and an easy sell:
|
|
|
|
* alternative to `RLIMIT_AS` for accountable mappings only
|
|
* memory control groups are sometimes a better option but there are still
|
|
users of `RLIMIT_AS` that are problematic for mitigations or simply fast
|
|
garbage collector implementations, etc. mapping lots of `PROT_NONE` memory
|
|
* mremap flag to disable unmapping the source mapping
|
|
* also needed by jemalloc for different reasons
|
|
* not needed if the kernel gets first class support for arbitrarily sized
|
|
guard pages and a virtual memory quarantine feature
|
|
* `MREMAP_DONTUNMAP` is now available but doesn't support expanding the
|
|
mapping which may be an issue due to VMA merging being unreliable
|
|
|
|
Fairly infeasible to land but could reduce overhead and extend coverage of
|
|
security features to other code directly using mmap:
|
|
|
|
* first class support for arbitrarily sized guard pages for mmap and mremap to
|
|
eliminate half of the resulting VMAs and reduce 2 system calls to 1
|
|
* not usable if it doesn't support mremap (shrink, grow, grow via move)
|
|
* not usable if the guard page size is static
|
|
* should support changing guard size for mremap growth via move
|
|
* must be possible to set it up from the process
|
|
* virtual memory quarantine
|
|
* must be possible to set it up from the process
|
|
* first-class support for aligned mappings with mmap and ideally mremap
|
|
* not usable unless guard page support is provided and of course it has to
|
|
work with this too
|