libroach: ensure correct lifetime for resume_key on reverse iteration#32492
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Fixes cockroachdb#32149. Before this change, it was possible for `DBScanResults.resume_key` to point into memory owned by `mvccScanner`, which went out of scope after `MVCCScan` returned. This allowed for memory corruption when returning the key to Go. This change fixes this corruption by copying the memory to the `DBIterator` before returning, which should have a lifetime which exceeds that of the `DBScanResults`. Release note: None
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Found with lots of help from @benesch! |
petermattis
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c-deps/libroach/mvcc.h, line 141 at r1 (raw file):
// instead of iter_rep_'s underlying storage if iterating in reverse (see // iterPeekPrev), so copy the key onto the DBIterator struct to ensure it // has a lifetime that outlives the DBScanResults.
Wow! Nice find.
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32492: libroach: ensure correct lifetime for resume_key on reverse iteration r=nvanbenschoten a=nvanbenschoten Fixes #32149. Before this change, it was possible for `DBScanResults.resume_key` to point into memory owned by `mvccScanner`, which went out of scope after `MVCCScan` returned. This allowed for memory corruption when returning the key to Go. This change fixes this corruption by copying the memory to the `DBIterator` before returning, which should have a lifetime which exceeds that of the `DBScanResults`. Release note: None Co-authored-by: Nathan VanBenschoten <nvanbenschoten@gmail.com>
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Fixes #32149.
Before this change, it was possible for
DBScanResults.resume_keytopoint into memory owned by
mvccScanner, which went out of scope afterMVCCScanreturned. This allowed for memory corruption when returningthe key to Go.
This change fixes this corruption by copying the memory to the
DBIteratorbefore returning, which should have a lifetime which exceeds that of the
DBScanResults.Release note: None