asymcute: Compare request message type when matching acknowledgement #18434
Conversation
This file contains hidden or 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
Currently, asymcute only matches an MQTT-SN request to its acknowledgement using the MsgId header. However, I strongly believe this to be insufficient as asymcute would thus also match a SUBACK to a prior PUBLISH message (for example) as long as the message ID matches. To address this issue, this commit modifies _req_preprocess to also compare the request message type in addition to the message id.
maribu
approved these changes
Aug 10, 2022
FYI: I found this with SymEx-VP so I haven't done any tests with a particular MQTT-SN broker implementation (yet). |
|
OK, I guess I should test it prior hitting the merge button just to be sure, then. :) |
|
❗ This may cause a semantic merge conflict with #18433, once that is merged: |
|
@nmeum can you please provide a backport to the 2022.07 branch, e.g. by using the |
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Outdated suggestions cannot be applied.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.
Contribution description
Currently, asymcute matches an MQTT-SN request to its acknowledgement using only the MsgId header. However, I strongly believe this to be insufficient as asymcute would thus also match a SUBACK to a prior PUBLISH request (for example) as long as the message ID matches. If this happens (e.g. because of a malicious MQTT-SN broker) then this can trigger various bugs in asymcute, e.g. due to incorrect casts of the
req->argvoid*pointer. To address this issue, this commit modifies_req_preprocessto also compare the request message type in addition to the message id.Testing procedure
I haven't tested my fix extensively yet but existing tests should continue to work. Unfortunately, it also a bit difficult to provide a simple test setup for triggering this edge case.
Issues/PRs references
None.