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clarify write-after-free detection feature

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Daniel Micay 2018-11-16 03:26:07 -05:00
parent a617f7604d
commit 315415acf2
1 changed files with 2 additions and 1 deletions
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@ -195,6 +195,8 @@ was a bit less important and if a core goal was finding latent bugs.
* [in-progress] Randomized choice of slabs
* [in-progress] Randomized allocation of slabs
* Slab allocations are zeroed on free
* Detection of write-after-free for slab allocations by verifying zero filling
is intact at allocation time
* 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 primarily based on a FIFO ring buffer, with the oldest
@ -203,7 +205,6 @@ was a bit less important and if a core goal was finding latent bugs.
* Another layer of the quarantine swaps with a random slot in an array to
randomize the number of large deallocations required to push mappings out
of the quarantine
* 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
* Delayed free via a combination of FIFO and randomization for slab allocations