asymcute: Compare request message type when matching acknowledgement #18434
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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.
nmeum
requested review from
miri64,
haukepetersen,
PeterKietzmann and
cgundogan
as code owners
benpicco
added
the
Type: bug
maribu
approved these changes
Aug 10, 2022
maribu
added
the
CI: ready for build
FYI: I found this with SymEx-VP so I haven't done any tests with a particular MQTT-SN broker implementation (yet). |
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OK, I guess I should test it prior hitting the merge button just to be sure, then. :) |
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❗ This may cause a semantic merge conflict with #18433, once that is merged: |
miri64
added
the
Process: needs backport
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@nmeum can you please provide a backport to the 2022.07 branch, e.g. by using the |
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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.