Memory allocated with kmem_* is unmapped upon free, so KASAN doesn't
provide a ton of benefit, but since allocations are always a multiple of
the page size we can create a redzone.
Details
Details
- Reviewers
- None
- Commits
- rG2b914b85ddf4: kmem: Add KASAN state transitions
Diff Detail
Diff Detail
- Repository
- rG FreeBSD src repository
- Lint
Lint Not Applicable - Unit
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Event Timeline
| sys/vm/vm_kern.c | ||
|---|---|---|
| 422–423 | Does this mean we don't get buffer overflow checks when size is a multiple of PAGE_SIZE? | |
| sys/vm/vm_kern.c | ||
|---|---|---|
| 422–423 | That's correct. I thought about padding it by one page but was a bit wary about doing so for contig allocs, since that could conceivably result in an impossible allocation request. For instance, suppose that high - low == size, we wouldn't be able to add padding. And we have to either pad all allocations or none. One thing we could do is add a guard page instead, so that overflows result in a page fault. That's not KASAN-specific, of course, but it'd make sense to enable that when KASAN is enabled. Any thoughts? | |