libroach: ensure correct lifetime for resume_key on reverse iteration #32492
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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
|
This change is |
|
Found with lots of help from @benesch! |
petermattis
approved these changes
Nov 20, 2018
There was a problem hiding this comment.
Reviewable status:
complete! 1 of 0 LGTMs obtained
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.
|
bors r+ |
craig bot
pushed a commit
that referenced
this pull request
Nov 20, 2018
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 <[email protected]>
Build succeeded |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
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