hyperledger/fabric · error

Failing extracting header during check policy on channel [%s

Error message

Failing extracting header during check policy on channel [%s] with policy [%s]: [%s]

What it means

After the Proposal is successfully extracted, CheckPolicy unmarshals proposal.Header with protoutil.UnmarshalHeader. If the Header bytes inside the proposal are invalid (empty or not a serialized Header protobuf), policy evaluation cannot identify the channel/creator and fails with this wrapped error naming the channel, policy, and underlying cause.

Source

Thrown at core/policy/policy.go:88

	if signedProp == nil {
		return fmt.Errorf("Invalid signed proposal during check policy on channel [%s] with policy [%s]", channelID, policyName)
	}

	// Get Policy
	policyManager := p.channelPolicyManagerGetter.Manager(channelID)
	if policyManager == nil {
		return fmt.Errorf("Failed to get policy manager for channel [%s]", channelID)
	}

	// Prepare SignedData
	proposal, err := protoutil.UnmarshalProposal(signedProp.ProposalBytes)
	if err != nil {
		return fmt.Errorf("Failing extracting proposal during check policy on channel [%s] with policy [%s]: [%s]", channelID, policyName, err)
	}

	header, err := protoutil.UnmarshalHeader(proposal.Header)
	if err != nil {
		return fmt.Errorf("Failing extracting header during check policy on channel [%s] with policy [%s]: [%s]", channelID, policyName, err)
	}

	shdr, err := protoutil.UnmarshalSignatureHeader(header.SignatureHeader)
	if err != nil {
		return fmt.Errorf("Invalid Proposal's SignatureHeader during check policy on channel [%s] with policy [%s]: [%s]", channelID, policyName, err)
	}

	sd := []*protoutil.SignedData{{
		Data:      signedProp.ProposalBytes,
		Identity:  shdr.Creator,
		Signature: signedProp.Signature,
	}}

	return p.CheckPolicyBySignedData(channelID, policyName, sd)
}

// CheckPolicyNoChannel checks that the passed signed proposal is valid with the respect to
// passed policy on the local MSP.

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Regenerate the proposal with the SDK so Header is populated via protoutil/proposal factory
2. Check the embedded error text to confirm whether Header bytes are empty or a type mismatch
3. Align fabric-protos / SDK versions between client and peer
4. Reject such proposals at the client before submission by validating proposal.Header is set

Example fix

// before
prop := &pb.Proposal{ PayloadBytes: payload } // Header never set
// after
hdr, _ := protoutil.Marshal(header)
prop := &pb.Proposal{ Header: hdr, PayloadBytes: payload }

// Ensure Header is marshalled into the proposal before sending
if len(proposal.Header) == 0 {
    return errors.New("proposal.Header must be set")
}

function hasHeaderBytes(p) { return p && p.header && p.header.length > 0; }

err := checker.CheckPolicy(policyName, signedProp)
if err != nil {
    if strings.Contains(err.Error(), "Failing extracting header") {
        // Header bytes malformed: reject or re-request a valid proposal
    }
    return err
}

When it happens

Trigger: A proposal whose Header field is nil, empty, or contains bytes from a different message type; proposals crafted by hand or decoded/re-encoded incorrectly by middleware.

Common situations: Custom client code marshaling the wrong struct into proposal.Header; clients built against a different fabric-protos version where Header layout changed; tampered or truncated proposals received through a proxy.

Understand the failure class

Background: "cannot parse invalid wire-format data", "cannot unmarshal", "failed unmarshalling": protobuf unmarshal errors explained — this error's family across 10 libraries.

Related errors

• failed to unmarshal ApplicationPolicy bytes
• Failing extracting proposal during check policy on channel [
• could not unmarshal MSPRole from principal
• invalid MSP role type %d
• malformed org definition for org: %s

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/03aba12359f5dfc6. Report an issue: GitHub.