memtx: fix use-after-free of successor in tree_iterator_start
#7759
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
CuriousGeorgiy
force-pushed
the
gh-77{5,6}-memtx-tree-successor-use-after-free
branch
2 times, most recently
from
1344779
to
a92f029
Compare
CuriousGeorgiy
force-pushed
the
gh-77{5,6}-memtx-tree-successor-use-after-free
branch
from
a92f029
to
d72d7c5
Compare
drewdzzz
requested changes
Oct 31, 2022
There was a problem hiding this comment.
The patch solves the set problems, but I am concerned about the current development vector - some methods categorically cannot call GC, and some methods on the contrary can do it implicitly (for example, gap trackers now should not call GC, but all other trackers can), and most importantly - during the process of development and support of transaction manager we must ensure that methods without GC do not call methods with it. I believe we need to redesign the transaction manager garbage collection system. The easiest option is to make ALL GC calls explicit.
CuriousGeorgiy
force-pushed
the
gh-77{5,6}-memtx-tree-successor-use-after-free
branch
from
d72d7c5
to
a81a8b0
Compare
We assumed that the successor tuple's story could not get garbage collected on clarify of result tuple in `tree_iterator_start`, since they coincide in case of regular iterators. But this is not the case for reverse iterators: the result tuple is of-by-one from the successor, which means the successor's story can get garbage collected along with the tuple itself getting deleted, leading to use-after-free of successor: remove garbage collection from `memtx_tx_tuple_clarify` and call it manually. The crash in tarantool#7756 revealed that the `put` in transaction manager's story hash table was performed incorrectly: fix it and add an assertion that nothing was replaced. Closes tarantool#7755 Closes tarantool#7756 NO_DOC=bugfix
CuriousGeorgiy
force-pushed
the
gh-77{5,6}-memtx-tree-successor-use-after-free
branch
from
a81a8b0
to
8d3f75b
Compare
alyapunov
approved these changes
Nov 29, 2022
|
Backported to 2.10. |
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.
We assumed that the successor tuple's story could not get garbage collected on clarify of result tuple in
tree_iterator_start, since they coincide in case of regular iterators. But this is not the case for reverse iterators: the result tuple is of-by-one from the successor, which means the successor's story can get garbage collected along with the tuple itself getting deleted, leading to use-after-free of successor: remove garbage collection frommemtx_tx_tuple_clarifyand call it manually.The crash in #7756 revealed that the
putin transaction manager's story hash table was performed incorrectly: fix it and add an assertion that nothing was replaced.Closes #7755
Closes #7756