HIGH-003: Missing-data nonce-gap requests are unbounded before proposal validity is established #7693

sstanculeanu · 2026-02-10T12:56:01Z

Reasoning behind the pull request

a huge nonce gap porposed can lead to a higher number of requests

Proposed changes

added validation on both proposal and verification to not allow a higher nonce gap than a configured value

Testing procedure

with feat branch

Pre-requisites

Based on the Contributing Guidelines the PR author and the reviewers must check the following requirements are met:

was the PR targeted to the correct branch?
if this is a larger feature that probably needs more than one PR, is there a feat branch created?
if this is a feat branch merging, do all satellite projects have a proper tag inside go.mod?

…al validity is established

codecov · 2026-02-10T13:04:46Z

Codecov Report

❌ Patch coverage is 94.73684% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.53%. Comparing base (3ce7096) to head (7347a19).
⚠️ Report is 2 commits behind head on ai-audit-findings.

Files with missing lines	Patch %	Lines
process/block/metablock.go	50.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@                  Coverage Diff                  @@
##           ai-audit-findings    #7693      +/-   ##
=====================================================
- Coverage              77.53%   77.53%   -0.01%     
=====================================================
  Files                    878      878              
  Lines                 122173   122211      +38     
=====================================================
+ Hits                   94728    94753      +25     
- Misses                 21135    21143       +8     
- Partials                6310     6315       +5

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AdoAdoAdo · 2026-02-10T13:30:27Z

process/block/metablockProposal.go

 	return execResult, nil
 }

+func (mp *metaProcessor) checkShardInfoProposalNonceGap(metaHeader data.MetaHeaderHandler) error {


the check needs to be enforced not only on shardInfo by metachain, but also for metablock and its last executed result notarization, or on shard chain between the block header and its last executed result notarization.

Copilot

Pull request overview

Adds a configurable upper bound for the shard-info proposal nonce gap to prevent unbounded “nonce-gap” missing-data requests before a metablock proposal is fully validated (HIGH-003).

Changes:

Introduces MaxShardInfoProposalNonceGap config/plumbing (config struct, TOML, factory wiring, test configs).
Adds nonce-gap validation for metablock proposal creation and verification, plus a new ErrNonceGapTooLarge.
Extends unit tests and stubs to cover the new behavior.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
`testscommon/headerHandlerStub.go`	Implements `GetShardInfoHandlers()` for tests via a callback + safe default.
`testscommon/generalConfig.go`	Sets a default `MaxShardInfoProposalNonceGap` in the shared test config.
`testscommon/components/configs.go`	Sets `MaxShardInfoProposalNonceGap` in component test config.
`process/errors.go`	Adds `ErrNonceGapTooLarge` error sentinel.
`process/block/metablock_test.go`	Updates meta processor test args with `MaxShardInfoProposalNonceGap`.
`process/block/metablockProposal_test.go`	Adds coverage for nonce-gap validation on propose/verify paths.
`process/block/metablockProposal.go`	Adds nonce-gap validation calls and implements `checkShardInfoProposalNonceGap`.
`process/block/metablock.go`	Stores max-gap in `metaProcessor` and applies a default when unset.
`process/block/argProcessor.go`	Adds `MaxShardInfoProposalNonceGap` to `ArgMetaProcessor`.
`factory/processing/blockProcessorCreator.go`	Wires config value into `ArgMetaProcessor`.
`config/config.go`	Adds `MaxShardInfoProposalNonceGap` to `GeneralSettingsConfig`.
`cmd/node/config/config.toml`	Documents/exposes `MaxShardInfoProposalNonceGap` in node config.

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Copilot · 2026-02-10T13:33:01Z

process/block/metablockProposal.go

+	err = mp.checkShardInfoProposalNonceGap(metaHeader)
+	if err != nil {
+		return nil, err
+	}
+


The nonce-gap validation is invoked in CreateNewHeaderProposal(), but at this stage the metablock’s ShardInfo/ShardInfoProposal handlers are typically not populated yet (they get set later during CreateBlockProposal). This means the "proposal"-side validation may be ineffective and large nonce gaps could still be produced locally. Consider moving (or additionally adding) this check after shard info/proposals are set on the header in the proposal-building flow, keeping VerifyBlockProposal as the inbound guard.

Suggested change

err = mp.checkShardInfoProposalNonceGap(metaHeader)

if err != nil {

return nil, err

}

Copilot · 2026-02-10T13:33:02Z

process/block/metablockProposal.go

+			// No finalized data for this shard, skip validation
+			continue
+		}
+


checkShardInfoProposalNonceGap() computes nonceGap := maxProposedNonce - lastFinalizedNonce using uint64. If a block contains a proposed nonce lower than the finalized nonce for the same shard, this will underflow and produce a huge gap value, leading to a confusing error and potentially rejecting cases that should be treated as "no gap" or as a distinct validation error. Add an explicit comparison (e.g., handle maxProposedNonce <= lastFinalizedNonce) before subtracting.

Suggested change

// Handle cases where proposed nonce is not ahead of the finalized nonce

if maxProposedNonce <= lastFinalizedNonce {

if maxProposedNonce < lastFinalizedNonce {

return fmt.Errorf("%w: shard %d has proposed nonce %d lower than finalized nonce %d",

process.ErrNonceGapTooLarge,

shardID,

maxProposedNonce,

lastFinalizedNonce)

}

// maxProposedNonce == lastFinalizedNonce: no gap to check

continue

}

Copilot · 2026-02-10T13:33:02Z

cmd/node/config/config.toml

    # Make sure that this is greater than the unbonding period!
    SetGuardianEpochsDelay = 2 # TODO: for mainnet should be 20, 2 is just for testing

+    # MaxShardInfoProposalNonceGap defines the maximum gap allowed between highest finalized shard nonce and lowest proposed shard nonce


The TOML comment says the gap is measured between the "highest finalized" and the "lowest proposed" shard nonce, but the implementation validates against the highest proposed nonce per shard. Please update this comment to match the actual behavior to avoid operator/config confusion.

Suggested change

# MaxShardInfoProposalNonceGap defines the maximum gap allowed between highest finalized shard nonce and lowest proposed shard nonce

# MaxShardInfoProposalNonceGap defines the maximum gap allowed between the highest finalized shard nonce

# and the highest proposed shard nonce per shard

…chain-go into ai-findings-high-003 # Conflicts: # factory/processing/blockProcessorCreator.go # process/block/argProcessor.go # process/block/baseProcess.go # process/block/baseProcess_test.go # process/block/metablock_test.go # process/errors.go

HIGH-003: Missing-data nonce-gap requests are unbounded before propos…

b32f4dd

…al validity is established

sstanculeanu self-assigned this Feb 10, 2026

sstanculeanu added 2 commits February 10, 2026 15:04

CreateNewHeaderProposal tests

cfe420b

VerifyBlockProposal tests

7347a19

sstanculeanu changed the base branch from feat/supernova-async-exec to ai-audit-findings February 10, 2026 13:15

AdoAdoAdo requested a review from Copilot February 10, 2026 13:25

Copilot started reviewing on behalf of AdoAdoAdo February 10, 2026 13:26 View session

AdoAdoAdo reviewed Feb 10, 2026

View reviewed changes

Copilot AI reviewed Feb 10, 2026

View reviewed changes

sstanculeanu added 6 commits February 10, 2026 16:52

fixes after review - extra check

88ba5d5

fix condition to cover transition header

ecc0a84

move check for shard block proposal

c84dd42

fix after merge + fix after copilot

aea0e58

better error

3ee63ea

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HIGH-003: Missing-data nonce-gap requests are unbounded before proposal validity is established #7693

HIGH-003: Missing-data nonce-gap requests are unbounded before proposal validity is established #7693

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+		// Handle cases where proposed nonce is not ahead of the finalized nonce
+		if maxProposedNonce <= lastFinalizedNonce {
+			if maxProposedNonce < lastFinalizedNonce {
+				return fmt.Errorf("%w: shard %d has proposed nonce %d lower than finalized nonce %d",
+					process.ErrNonceGapTooLarge,
+					shardID,
+					maxProposedNonce,
+					lastFinalizedNonce)
+			}
+			// maxProposedNonce == lastFinalizedNonce: no gap to check
+			continue
+		}

	# MaxShardInfoProposalNonceGap defines the maximum gap allowed between highest finalized shard nonce and lowest proposed shard nonce
	# MaxShardInfoProposalNonceGap defines the maximum gap allowed between the highest finalized shard nonce
	# and the highest proposed shard nonce per shard

HIGH-003: Missing-data nonce-gap requests are unbounded before proposal validity is established #7693

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HIGH-003: Missing-data nonce-gap requests are unbounded before proposal validity is established #7693

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sstanculeanu commented Feb 10, 2026

Reasoning behind the pull request

Proposed changes

Testing procedure

Pre-requisites

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Pull request overview

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