identity index out of range, requested %v, but identities le

Error message

identity index out of range, requested %v, but identities length is %d

What it means

Thrown by the policy compiler in common/cauthdsl when a *cb.SignaturePolicy_SignedBy rule references an identity index that is negative or beyond the number of identities declared in the SignaturePolicyEnvelope. The compiler protects the subsequent identities[t.SignedBy] lookup from an out-of-range panic.

Source

Thrown at common/cauthdsl/cauthdsl.go:63

			for _, policy := range policies {
				copy(_used, used)
				if policy(signedData, _used) {
					verified++
					copy(used, _used)
				}
			}

			if verified >= t.NOutOf.N {
				cauthdslLogger.Debugf("%p gate %d evaluation succeeds", signedData, grepKey)
			} else {
				cauthdslLogger.Debugf("%p gate %d evaluation fails", signedData, grepKey)
			}

			return verified >= t.NOutOf.N
		}, nil
	case *cb.SignaturePolicy_SignedBy:
		if t.SignedBy < 0 || t.SignedBy >= int32(len(identities)) {
			return nil, fmt.Errorf("identity index out of range, requested %v, but identities length is %d", t.SignedBy, len(identities))
		}
		signedByID := identities[t.SignedBy]
		return func(signedData []msp.Identity, used []bool) bool {
			cauthdslLogger.Debugf("%p signed by %d principal evaluation starts (used %v)", signedData, t.SignedBy, used)
			for i, sd := range signedData {
				if used[i] {
					cauthdslLogger.Debugf("%p skipping identity %d because it has already been used", signedData, i)
					continue
				}
				if cauthdslLogger.IsEnabledFor(zapcore.DebugLevel) {
					// Unlike most places, this is a huge print statement, and worth checking log level before create garbage
					cauthdslLogger.Debugf("%p processing identity %d - %v", signedData, i, sd.GetIdentifier())
				}
				err := sd.SatisfiesPrincipal(signedByID)
				if err != nil {
					cauthdslLogger.Debugf("%p identity %d does not satisfy principal: %s", signedData, i, err)
					continue
				}

View on GitHub (pinned to 2736b63f8f)

Solutions

Ensure every SignedBy index in the rule tree is within [0, len(Identities)-1] of the same envelope
Regenerate the policy from source (e.g. configtxgen / policygen tooling) instead of hand-editing serialized bytes
Log len(sigPolicy.Identities) and walk the rule tree before calling compile to find the offending index

Example fix

// before
env.Rule = &cb.SignaturePolicy{Type: &cb.SignaturePolicy_SignedBy{SignedBy: 3}} // only 2 identities
// after
env.Identities = append(env.Identities, mspPrincipalForPeerOrg3)
env.Rule = &cb.SignaturePolicy{Type: &cb.SignaturePolicy_SignedBy{SignedBy: 2}} // index now valid

Defensive patterns

Strategy: validation

Validate before calling

func validateSignedByIndexes(rule *cb.SignaturePolicy, ids []*msp.MSPPrincipal) error {
    switch t := rule.GetType().(type) {
    case *cb.SignaturePolicy_SignedBy:
        if t.SignedBy < 0 || int(t.SignedBy) >= len(ids) {
            return fmt.Errorf("SignedBy %d out of range for %d identities", t.SignedBy, len(ids))
        }
    case *cb.SignaturePolicy_NOutOf_:
        for _, r := range t.NOutOf.Rules {
            if err := validateSignedByIndexes(r, ids); err != nil {
                return err
            }
        }
    }
    return nil
}

Type guard

func signedByInRange(rule *cb.SignaturePolicy, n int) bool {
    sb, ok := rule.GetType().(*cb.SignaturePolicy_SignedBy)
    return ok && sb.SignedBy >= 0 && int(sb.SignedBy) < n
}

Prevention

Always build rules and the Identities list together from one source of truth
Walk the full nested rule tree, not just the top level, when validating indexes
Round-trip marshal/unmarshal the envelope and re-validate before persisting

When it happens

Trigger: Calling compile (directly or via provider.NewPolicy / EnvelopeBasedPolicyProvider.NewPolicy) with a SignaturePolicyEnvelope whose Rule contains SignedBy: N where N < 0 or N >= len(sigPolicy.Identities), e.g. after editing policy protobufs by hand or deserializing a truncated/corrupt policy.

Common situations: Hand-crafted or tool-generated channel application policies referencing principal indexes that were never added to the Identities list; policies serialized by newer tooling than the reader; byte-level corruption during storage or endorsement.

Related errors

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/e8193e89e4fe1e4e. Report an issue: GitHub.