@ -23,12 +23,12 @@ var (
// VerifyNonAdjacent verifies non-adjacent untrustedHeader against
// VerifyNonAdjacent verifies non-adjacent untrustedHeader against
// trustedHeader. It ensures that:
// trustedHeader. It ensures that:
//
//
// a) trustedHeader can still be trusted (if not, ErrOldHeaderExpired is returned);
// b) untrustedHeader is valid;
// a) trustedHeader can still be trusted (if not, ErrOldHeaderExpired is returned)
// b) untrustedHeader is valid (if not, ErrInvalidHeader is returned)
// c) trustLevel ([1/3, 1]) of trustedHeaderVals (or trustedHeaderNextVals)
// c) trustLevel ([1/3, 1]) of trustedHeaderVals (or trustedHeaderNextVals)
// signed correctly (if not, ErrNewValSetCantBeTrusted is returned);
// d) more than 2/3 of untrustedVals have signed h2 (if not,
// ErrNotEnoughVotingPowerSigned is returned);
// signed correctly (if not, ErrNewValSetCantBeTrusted is returned)
// d) more than 2/3 of untrustedVals have signed h2
// (otherwise, ErrInvalidHeader is returned)
// e) headers are non-adjacent.
// e) headers are non-adjacent.
func VerifyNonAdjacent ( func VerifyNonAdjacent (
chainID string , chainID string ,
@ -49,7 +49,7 @@ func VerifyNonAdjacent(
} }
if err := verifyNewHeaderAndVals ( chainID , untrustedHeader , untrustedVals , trustedHeader , now ) ; err != nil { if err := verifyNewHeaderAndVals ( chainID , untrustedHeader , untrustedVals , trustedHeader , now ) ; err != nil {
return err
return ErrInvalidHeader { err }
} }
// Ensure that +`trustLevel` (default 1/3) or more of last trusted validators signed correctly.
// Ensure that +`trustLevel` (default 1/3) or more of last trusted validators signed correctly.
@ -67,11 +67,11 @@ func VerifyNonAdjacent(
// Ensure that +2/3 of new validators signed correctly.
// Ensure that +2/3 of new validators signed correctly.
//
//
// NOTE: this should always be the last check because untrustedVals can be
// NOTE: this should always be the last check because untrustedVals can be
// intentionaly made very large to DOS the light client. not the case for
// intentionall y made very large to DOS the light client. not the case for
// VerifyAdjacent, where validator set is known in advance.
// VerifyAdjacent, where validator set is known in advance.
if err := untrustedVals . VerifyCommit ( chainID , untrustedHeader . Commit . BlockID , untrustedHeader . Height , if err := untrustedVals . VerifyCommit ( chainID , untrustedHeader . Commit . BlockID , untrustedHeader . Height ,
untrustedHeader . Commit ) ; err != nil { untrustedHeader . Commit ) ; err != nil {
return err
return ErrInvalidHeader { err }
} }
return nil return nil
@ -80,11 +80,11 @@ func VerifyNonAdjacent(
// VerifyAdjacent verifies directly adjacent untrustedHeader against
// VerifyAdjacent verifies directly adjacent untrustedHeader against
// trustedHeader. It ensures that:
// trustedHeader. It ensures that:
//
//
// a) trustedHeader can still be trusted (if not, ErrOldHeaderExpired is returned);
// b) untrustedHeader is valid;
// c) untrustedHeader.ValidatorsHash equals trustedHeader.NextValidatorsHash;
// d) more than 2/3 of new validators (untrustedVals) have signed h2 (if not,
// ErrNotEnoughVotingPowerSigned is returned);
// a) trustedHeader can still be trusted (if not, ErrOldHeaderExpired is returned)
// b) untrustedHeader is valid (if not, ErrInvalidHeader is returned)
// c) untrustedHeader.ValidatorsHash equals trustedHeader.NextValidatorsHash
// d) more than 2/3 of new validators (untrustedVals) have signed h2
// (otherwise, ErrInvalidHeader is returned)
// e) headers are adjacent.
// e) headers are adjacent.
func VerifyAdjacent ( func VerifyAdjacent (
chainID string , chainID string ,
@ -103,7 +103,7 @@ func VerifyAdjacent(
} }
if err := verifyNewHeaderAndVals ( chainID , untrustedHeader , untrustedVals , trustedHeader , now ) ; err != nil { if err := verifyNewHeaderAndVals ( chainID , untrustedHeader , untrustedVals , trustedHeader , now ) ; err != nil {
return err
return ErrInvalidHeader { err }
} }
// Check the validator hashes are the same
// Check the validator hashes are the same
@ -118,7 +118,7 @@ func VerifyAdjacent(
// Ensure that +2/3 of new validators signed correctly.
// Ensure that +2/3 of new validators signed correctly.
if err := untrustedVals . VerifyCommit ( chainID , untrustedHeader . Commit . BlockID , untrustedHeader . Height , if err := untrustedVals . VerifyCommit ( chainID , untrustedHeader . Commit . BlockID , untrustedHeader . Height ,
untrustedHeader . Commit ) ; err != nil { untrustedHeader . Commit ) ; err != nil {
return err
return ErrInvalidHeader { err }
} }
return nil return nil
@ -200,3 +200,34 @@ func HeaderExpired(h *types.SignedHeader, trustingPeriod time.Duration, now time
expirationTime := h . Time . Add ( trustingPeriod ) expirationTime := h . Time . Add ( trustingPeriod )
return ! expirationTime . After ( now ) return ! expirationTime . After ( now )
} }
// VerifyBackwards verifies an untrusted header with a height one less than
// that of an adjacent trusted header. It ensures that:
//
// a) untrusted header is valid
// b) untrusted header has a time before the trusted header
// c) that the LastBlockID hash of the trusted header is the same as the hash
// of the trusted header
//
// For any of these cases ErrInvalidHeader is returned.
func VerifyBackwards ( chainID string , untrustedHeader , trustedHeader * types . SignedHeader ) error {
if err := untrustedHeader . ValidateBasic ( chainID ) ; err != nil {
return ErrInvalidHeader { err }
}
if ! untrustedHeader . Time . Before ( trustedHeader . Time ) {
return ErrInvalidHeader {
errors . Errorf ( "expected older header time %v to be before new header time %v" ,
untrustedHeader . Time ,
trustedHeader . Time ) }
}
if ! bytes . Equal ( untrustedHeader . Hash ( ) , trustedHeader . LastBlockID . Hash ) {
return ErrInvalidHeader {
errors . Errorf ( "older header hash %X does not match trusted header's last block %X" ,
untrustedHeader . Hash ( ) ,
trustedHeader . LastBlockID . Hash ) }
}
return nil
}
Callum Waters
5 years ago
GitHub