fix(p2p): bound peer-supplied vector sizes in three NOTIFY handlers

[raw391]

Three NOTIFY handlers in cryptonote_protocol_handler.inl iterate a peer-supplied vector without checking its size first:

• handle_notify_new_master_node_vote at line 937 walks arg.votes doing signature verification per element
• handle_notify_new_transactions at line 1081 parses arg.txs under incoming_tx_lock
• handle_request_fluffy_missing_tx at line 980 does per-index dup check + block tx lookup over arg.missing_tx_indices

The codebase already defines CURRENCY_PROTOCOL_MAX_OBJECT_REQUEST_COUNT and CURRENCY_PROTOCOL_MAX_TXS_REQUEST_COUNT at cryptonote_protocol_handler.h:56-57 and uses them in handle_request_get_blocks (line 1190) and handle_notify_request_get_txs (line 1737). This PR adds the same pattern to the three vote/tx/fluffy handlers, plus CURRENCY_PROTOCOL_MAX_FLASHES_COUNT for the flash batch size in handle_notify_new_transactions.

Cap values: 1000 votes (50x current max quorum), 5000 txs and 500 missing-tx indices reuse existing constants, 1000 flashes matches the votes ceiling. LOG_ERROR_CCONTEXT matches the existing sibling pattern at lines 1190 and 1737.

[victor-tucci]

With 30s blocks:
2 hours = 7200 / 30 = 240 blocks
checkpoint every 4 blocks = about 240 / 4 = 60 checkpoint rounds in vote lifetime
each checkpoint round has up to 20 votes

So worst-case checkpoint vote backlog is roughly:
60 * 20 = 1200 votes

That is above:
CURRENCY_PROTOCOL_MAX_VOTES_COUNT = 1000

So with 30s blocks, it is possible to exceed the max limit if enough checkpoint votes accumulate into one P2P relay batch. @raw391

[victor-tucci]

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📥 Commits

Reviewing files that changed from the base of the PR and between c8e54f6 and c96063c.

📒 Files selected for processing (2)

• src/cryptonote_protocol/cryptonote_protocol_handler.h
• src/cryptonote_protocol/cryptonote_protocol_handler.inl

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📝 Walkthrough

Summary by CodeRabbit

• Bug Fixes
  • Strengthened network request validation to reject oversized peer messages earlier.
  • Peers sending excessively large vote, transaction, flash, or missing-item requests may now be disconnected to help keep the network stable and responsive.
  • Added clearer protection against malformed or unusually large incoming data.

Walkthrough

New maximum count constants for votes and flashes are added, and three P2P protocol handlers now validate incoming request sizes against these and existing limits, disconnecting peers whose requests exceed the thresholds.

Changes

Oversized request rejection

Layer / File(s)	Summary
Protocol limit constants and size validation src/cryptonote_protocol/cryptonote_protocol_handler.h, src/cryptonote_protocol/cryptonote_protocol_handler.inl	Adds CURRENCY_PROTOCOL_MAX_VOTES_COUNT and CURRENCY_PROTOCOL_MAX_FLASHES_COUNT constants; handle_notify_new_master_node_vote, handle_request_fluffy_missing_tx, and handle_notify_new_transactions now check list sizes against these and CURRENCY_PROTOCOL_MAX_OBJECT_REQUEST_COUNT/CURRENCY_PROTOCOL_MAX_TXS_REQUEST_COUNT, logging an error and dropping the connection when exceeded.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Peer
  participant ProtocolHandler
  participant Connection

  Peer->>ProtocolHandler: notify_new_master_node_vote / request_fluffy_missing_tx / notify_new_transactions
  ProtocolHandler->>ProtocolHandler: check size against MAX_* limit
  alt size exceeds limit
    ProtocolHandler->>Connection: drop_connection(context, false, false)
    ProtocolHandler-->>Peer: return 1
  else size within limit
    ProtocolHandler->>ProtocolHandler: continue normal processing
  end

Loading

Poem

A rabbit hops the network line,
Counting votes and flashes fine,
Too many? Snip, the link is cut,
No oversized bundle clogs this hutch!
Hop, hop—safe and tidy code. 🐇📦

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: adding bounds checks for peer-supplied vectors in NOTIFY handlers.
Description check	✅ Passed	The description clearly matches the patch and explains the added size checks and limits in the affected handlers.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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