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messagevalidation.go
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messagevalidation.go
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package hare
import (
"context"
"errors"
"fmt"
"time"
"github.com/spacemeshos/go-spacemesh/common/types"
"github.com/spacemeshos/go-spacemesh/log"
"github.com/spacemeshos/go-spacemesh/signing"
)
type messageValidator interface {
SyntacticallyValidateMessage(ctx context.Context, m *Message) bool
ContextuallyValidateMessage(ctx context.Context, m *Message, expectedK uint32) error
}
type eligibilityValidator struct {
oracle Rolacle
maxExpActives int // the maximal expected committee size
expLeaders int // the expected number of leaders
log.Log
}
func newEligibilityValidator(oracle Rolacle, maxExpActives, expLeaders int, logger log.Log) *eligibilityValidator {
return &eligibilityValidator{oracle, maxExpActives, expLeaders, logger}
}
func (ev *eligibilityValidator) validateRole(ctx context.Context, nodeID types.NodeID, layer types.LayerID, round uint32, proof types.VrfSignature, eligibilityCount uint16) (bool, error) {
return ev.oracle.Validate(ctx, layer, round, expectedCommitteeSize(round, ev.maxExpActives, ev.expLeaders), nodeID, proof, eligibilityCount)
}
func (ev *eligibilityValidator) ValidateEligibilityGossip(ctx context.Context, em *types.HareEligibilityGossip) bool {
res, err := ev.validateRole(ctx, em.NodeID, em.Layer, em.Round, em.Eligibility.Proof, em.Eligibility.Count)
if err != nil {
ev.WithContext(ctx).With().Error("failed to validate role",
em.Layer,
log.Uint32("round", em.Round),
log.Stringer("smesher", em.NodeID),
)
return false
}
return res
}
// Validate the eligibility of the provided message.
func (ev *eligibilityValidator) Validate(ctx context.Context, m *Message) bool {
if m == nil || m.InnerMessage == nil {
ev.Log.Fatal("invalid Msg")
}
res, err := ev.validateRole(ctx, m.SmesherID, m.Layer, m.Round, m.Eligibility.Proof, m.Eligibility.Count)
if err != nil {
ev.WithContext(ctx).With().Error("failed to validate role",
log.Err(err),
log.Stringer("smesher", m.SmesherID),
m.Layer,
log.String("msg_type", m.Type.String()),
)
return false
}
if !res {
ev.WithContext(ctx).With().Warning("validate message failed: role is invalid",
log.Stringer("smesher", m.SmesherID),
m.Layer,
log.String("msg_type", m.Type.String()),
)
return false
}
return true
}
type roleValidator interface {
Validate(context.Context, *Message) bool
}
type pubKeyGetter interface {
Track(*Message)
NodeID(*Message) types.NodeID
}
type syntaxContextValidator struct {
signing *signing.EdSigner
edVerifier *signing.EdVerifier
threshold int
statusValidator func(m *Message) bool // used to validate status Messages in SVP
stateQuerier stateQuerier
roleValidator roleValidator
validMsgsTracker pubKeyGetter // used to check for public keys in the valid messages tracker
eTracker *EligibilityTracker
log.Log
}
func newSyntaxContextValidator(
sgr *signing.EdSigner,
edVerifier *signing.EdVerifier,
threshold int,
validator func(m *Message) bool,
stateQuerier stateQuerier,
ev roleValidator,
validMsgsTracker pubKeyGetter,
et *EligibilityTracker,
logger log.Log,
) *syntaxContextValidator {
return &syntaxContextValidator{
signing: sgr,
edVerifier: edVerifier,
threshold: threshold,
statusValidator: validator,
stateQuerier: stateQuerier,
roleValidator: ev,
validMsgsTracker: validMsgsTracker,
eTracker: et,
Log: logger,
}
}
// contextual validation errors.
var (
errNilMsg = errors.New("nil message")
errNilInner = errors.New("nil inner message")
errEarlyMsg = errors.New("early message")
errInvalidIter = errors.New("incorrect iteration number")
errInvalidRound = errors.New("incorrect round")
errUnexpectedType = errors.New("unexpected message type")
)
// ContextuallyValidateMessage checks if the message is contextually valid.
// Returns nil if the message is contextually valid or a suitable error otherwise.
func (v *syntaxContextValidator) ContextuallyValidateMessage(ctx context.Context, m *Message, currentK uint32) error {
if m == nil {
return errNilMsg
}
if m.InnerMessage == nil {
return errNilInner
}
currentRound := currentK % RoundsPerIteration
// the message must match the current iteration unless it is a notify or pre-round message
currentIteration := currentK / RoundsPerIteration
msgIteration := m.Round / RoundsPerIteration
sameIter := currentIteration == msgIteration
// first validate pre-round and notify
switch m.Type {
case pre:
return nil
case notify:
if currentK == preRound && msgIteration != 0 {
return errInvalidIter
} else if currentK == preRound {
return errInvalidRound
}
// notify before notify could be created for this iteration
if currentRound < commitRound && sameIter {
return errInvalidRound
}
// old notify is accepted
if m.Round <= currentK {
return nil
}
// early notify detected
if m.Round == currentK+1 && currentRound == commitRound {
return errEarlyMsg
}
// future notify is rejected
return errInvalidIter
}
// check status, proposal & commit types
switch m.Type {
case status:
if currentK == preRound && msgIteration != 0 {
return errInvalidIter
} else if currentK == preRound {
return errEarlyMsg
}
if currentRound == notifyRound && currentIteration+1 == msgIteration {
return errEarlyMsg
}
if currentRound == statusRound && sameIter {
return nil
}
if !sameIter {
return errInvalidIter
}
return errInvalidRound
case proposal:
if currentK == preRound && msgIteration != 0 {
return errInvalidIter
} else if currentK == preRound {
return errInvalidRound
}
if currentRound == statusRound && sameIter {
return errEarlyMsg
}
// a late proposal is also contextually valid
if (currentRound == proposalRound || currentRound == commitRound) && sameIter {
return nil
}
if !sameIter {
return errInvalidIter
}
return errInvalidRound
case commit:
if currentK == preRound && msgIteration != 0 {
return errInvalidIter
} else if currentK == preRound {
return errInvalidRound
}
if currentRound == proposalRound && sameIter {
return errEarlyMsg
}
if currentRound == commitRound && sameIter {
return nil
}
if !sameIter {
return errInvalidIter
}
return errInvalidRound
}
return errUnexpectedType
}
// SyntacticallyValidateMessage the syntax of the provided message.
func (v *syntaxContextValidator) SyntacticallyValidateMessage(ctx context.Context, m *Message) bool {
logger := v.WithContext(ctx)
if m == nil {
logger.Warning("syntax validation failed: m is nil")
return false
}
if m.SmesherID == types.EmptyNodeID {
logger.Warning("syntax validation failed: missing public key")
return false
}
if m.InnerMessage == nil {
logger.With().Warning("syntax validation failed: inner message is nil",
log.Stringer("smesher", m.SmesherID),
)
return false
}
claimedRound := m.Round % RoundsPerIteration
switch m.Type {
case pre:
return true
case status:
return claimedRound == statusRound
case proposal:
return claimedRound == proposalRound && v.validateSVP(ctx, m)
case commit:
return claimedRound == commitRound
case notify:
return v.validateCertificate(ctx, m.Cert)
default:
logger.With().Warning("unknown message type encountered during syntactic validation",
log.String("msg_type", m.Type.String()),
)
return false
}
}
var (
errNilValidators = errors.New("validators param is nil")
errNilAggMsgs = errors.New("aggMsg is nil")
errNilMsgsSlice = errors.New("messages slice is nil")
errMsgsCountMismatch = errors.New("number of messages does not match the threshold")
errDupSender = errors.New("duplicate sender detected")
errInnerSyntax = errors.New("invalid syntax for inner message")
errInnerEligibility = errors.New("inner message is not eligible")
errInnerFunc = errors.New("inner message did not pass validation function")
)
// validate the provided aggregated messages by the provided validators.
func (v *syntaxContextValidator) validateAggregatedMessage(ctx context.Context, aggMsg *AggregatedMessages, validators []func(m *Message) bool) error {
if validators == nil {
return errNilValidators
}
if aggMsg == nil {
return errNilAggMsgs
}
if len(aggMsg.Messages) == 0 {
return errNilMsgsSlice
}
senders := make(map[types.NodeID]struct{})
for _, innerMsg := range aggMsg.Messages {
// check if exist in cache of valid messages
if nodeID := v.validMsgsTracker.NodeID(&innerMsg); nodeID != types.EmptyNodeID {
// validate unique sender
if _, exist := senders[nodeID]; exist {
return errDupSender
}
senders[nodeID] = struct{}{}
// passed validation, continue to next message
continue
}
// extract public key
if !v.edVerifier.Verify(signing.HARE, innerMsg.SmesherID, innerMsg.SignedBytes(), innerMsg.Signature) {
return fmt.Errorf("failed to verify signature")
}
// validate unique sender
if _, exist := senders[innerMsg.SmesherID]; exist { // pub already exist
return errDupSender
}
senders[innerMsg.SmesherID] = struct{}{} // mark sender as exist
if err := checkIdentity(ctx, v.Log, &innerMsg, v.stateQuerier); err != nil {
return fmt.Errorf("new message: %w", err)
}
// validate with attached validators
for _, vFunc := range validators {
if !vFunc(&innerMsg) {
return errInnerFunc
}
}
if !v.SyntacticallyValidateMessage(ctx, &innerMsg) {
return errInnerSyntax
}
// validate role
if !v.roleValidator.Validate(ctx, &innerMsg) {
return errInnerEligibility
}
v.eTracker.Track(innerMsg.SmesherID, innerMsg.Round, innerMsg.Eligibility.Count, true)
// the message is valid, track it
v.validMsgsTracker.Track(&innerMsg)
}
var ci CountInfo
v.eTracker.ForEach(aggMsg.Messages[0].Round, func(node types.NodeID, cr *Cred) {
// only counts the eligibility count from seen msgs
if _, ok := senders[node]; ok {
if cr.Honest {
ci.IncHonest(cr.Count)
} else {
ci.IncDishonest(cr.Count)
}
} else if !cr.Honest {
ci.IncKnownEquivocator(cr.Count)
}
})
if ci.Meet(v.threshold) {
if ci.numDishonest > 0 {
v.Log.With().Warning("counting votes from malicious identities in aggregated messages",
log.Object("eligibility_count", &ci))
}
return nil
}
return fmt.Errorf("%w: expected %v, actual dishonest %v honest %v",
errMsgsCountMismatch, v.threshold, ci.dhCount, ci.hCount)
}
func (v *syntaxContextValidator) validateSVP(ctx context.Context, msg *Message) bool {
logger := v.WithContext(ctx)
defer func(startTime time.Time) {
logger.With().Debug("svp validation duration",
log.String("duration", time.Since(startTime).String()))
}(time.Now())
proposalIter := inferIteration(msg.Round)
validateSameIteration := func(m *Message) bool {
statusIter := inferIteration(m.Round)
if proposalIter != statusIter { // not same iteration
logger.With().Warning("proposal validation failed: not same iteration",
log.Stringer("smesher", m.SmesherID),
m.Layer,
log.Uint32("expected", proposalIter),
log.Uint32("actual", statusIter))
return false
}
return true
}
logger = logger.WithFields(log.Stringer("smesher", msg.SmesherID), msg.Layer)
validators := []func(m *Message) bool{validateStatusType, validateSameIteration, v.statusValidator}
if err := v.validateAggregatedMessage(ctx, msg.Svp, validators); err != nil {
logger.With().Warning("invalid proposal", log.Err(err))
return false
}
maxCommittedRound := preRound
var maxSet []types.ProposalID
for _, status := range msg.Svp.Messages {
// track max
if status.CommittedRound > maxCommittedRound || maxCommittedRound == preRound {
maxCommittedRound = status.CommittedRound
maxSet = status.Values
}
}
if maxCommittedRound == preRound { // type A
if !v.validateSVPTypeA(ctx, msg) {
logger.Warning("proposal validation failed: type a validation failed")
return false
}
} else {
if !v.validateSVPTypeB(ctx, msg, NewSet(maxSet)) { // type B
logger.Warning("proposal validation failed: type b validation failed")
return false
}
}
return true
}
func (v *syntaxContextValidator) validateCertificate(ctx context.Context, cert *Certificate) bool {
logger := v.WithContext(ctx)
defer func(startTime time.Time) {
logger.With().Debug("certificate validation duration",
log.String("duration", time.Since(startTime).String()))
}(time.Now())
if cert == nil {
logger.Warning("certificate validation failed: certificate is nil")
return false
}
if cert.AggMsgs == nil {
logger.Warning("certificate validation failed: AggMsgs is nil")
return false
}
// refill Values
for _, commit := range cert.AggMsgs.Messages {
if commit.InnerMessage == nil {
logger.Warning("certificate validation failed: inner commit message is nil")
return false
}
// the values were removed to reduce data volume
commit.Values = cert.Values
}
// Note: no need to validate notify.Values=commits.Values because we refill the InnerMsg with notify.Values
validateSameK := func(m *Message) bool { return m.Round == cert.AggMsgs.Messages[0].Round }
validators := []func(m *Message) bool{validateCommitType, validateSameK}
if err := v.validateAggregatedMessage(ctx, cert.AggMsgs, validators); err != nil {
logger.With().Warning("invalid certificate", log.Err(err))
return false
}
return true
}
func validateCommitType(m *Message) bool {
return m.Type == commit
}
func validateStatusType(m *Message) bool {
return m.Type == status
}
// validate SVP for type A (where all Ki=-1).
func (v *syntaxContextValidator) validateSVPTypeA(ctx context.Context, m *Message) bool {
s := NewSet(m.Values)
unionSet := NewEmptySet(len(m.Values))
for _, status := range m.Svp.Messages {
statusSet := NewSet(status.Values)
// build union
for _, val := range statusSet.ToSlice() {
unionSet.Add(val) // assuming add is unique
}
}
if !unionSet.Equals(s) { // s should be the union of all statuses
v.WithContext(ctx).With().Warning("proposal type a validation failed: not a union",
log.String("expected", s.String()),
log.String("actual", unionSet.String()),
)
return false
}
return true
}
// validate SVP for type B (where exist Ki>=0).
func (v *syntaxContextValidator) validateSVPTypeB(ctx context.Context, msg *Message, maxSet *Set) bool {
// max set should be equal to the claimed set
s := NewSet(msg.Values)
if !s.Equals(maxSet) {
v.WithContext(ctx).With().Warning("proposal type b validation failed: max set not equal to proposed set",
log.String("expected", s.String()),
log.String("actual", maxSet.String()),
)
return false
}
return true
}