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document the randomized array in the quarantine

pull/50/merge
Daniel Micay 2018-10-12 15:10:35 -04:00
parent 6669166fe9
commit 0a64c7d6a1
1 changed files with 6 additions and 3 deletions
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@ -135,9 +135,12 @@ allocation and then unmapped on free.
* Slab allocations are zeroed on free * Slab allocations are zeroed on free
* Large allocations are purged and memory protected on free with the memory * Large allocations are purged and memory protected on free with the memory
mapping kept reserved in a quarantine to detect use-after-free mapping kept reserved in a quarantine to detect use-after-free
* The quarantine is a FIFO ring buffer, with the oldest mapping in the * The quarantine is primarily based on a FIFO ring buffer, with the oldest
quarantine being unmapped to make room for the most recently freed mapping in the quarantine being unmapped to make room for the most
mapping recently freed mapping
* 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 * Detection of write-after-free by verifying zero filling is intact
* Memory in fresh allocations is consistently zeroed due to it either being * Memory in fresh allocations is consistently zeroed due to it either being
fresh pages or zeroed on free after previous usage fresh pages or zeroed on free after previous usage