fix: MessageQueueShm head index boundary check

[yinggeh]

What does the PR do?

When attacker registers the same shm created by python backend, they can overwrite MessageQueueShm::head data with a very large index and inject malicious code to the memory space.

Checklist

• PR title reflects the change and is of format <commit_type>: <Title>
• Changes are described in the pull request.
• Related issues are referenced.
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• Added test plan and verified test passes.
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Commit Type:

• fix

Related PRs:

Where should the reviewer start?

The index boundary check is in src/message_queue.h

Test plan:

• CI Pipeline ID:
  30975011

Caveats:

Background

Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)

• closes GitHub issue: #xxx

[yinggeh]

No unit test because triton-inference-server/server#8273 makes the exploitation impossible.

[pskiran1]

LGTM! Will wait for other expert review.

[statiraju]

@tanmayv25 can you help approve.

[tanmayv25]

LGTM