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add quarantine for large allocations

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Daniel Micay 2018-10-08 15:50:31 -04:00
parent cc9699f1b4
commit 1a10c17e8b
3 changed files with 38 additions and 5 deletions
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README.md
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@ -75,6 +75,8 @@ features with a significant performance or memory usage cost.
#define SLAB_CANARY true
#define GUARD_SLABS_INTERVAL 1
#define GUARD_SIZE_DIVISOR 2
#define REGION_QUARANTINE_SIZE 1024
#define REGION_QUARANTINE_SKIP_THRESHOLD (32 * 1024 * 1024)
```
There will be more control over enabled features in the future along with
@ -127,7 +129,12 @@ allocation and then unmapped on free.
* [in-progress] Randomized delayed free for slab allocations
* [in-progress] Randomized allocation of slabs
* [more randomization coming as the implementation is matured]
* Slab allocations are zeroed on free and large allocations are unmapped
* Slab allocations are zeroed on free
* Large allocations are purged and memory protected on free with the memory
mapping kept reserved in a quarantine to detect use-after-free
* The quarantine is a FIFO ring buffer, with the oldest mapping in the
quarantine being unmapped to make room for the most recently freed
mapping
* Detection of write-after-free by verifying zero filling is intact
* Memory in fresh allocations is consistently zeroed due to it either being
fresh pages or zeroed on free after previous usage