private IFederationMember GetFederationMemberForBlockInternal(ChainedHeader chainedHeader, List <IFederationMember> federation)
{
if (chainedHeader.Height == 0)
{
return(federation.Last());
}
// Try to provide the public key that signed the block.
try
{
var header = chainedHeader.Header as PoABlockHeader;
var signature = ECDSASignature.FromDER(header.BlockSignature.Signature);
for (int recId = 0; recId < 4; recId++)
{
PubKey pubKeyForSig = PubKey.RecoverFromSignature(recId, signature, header.GetHash(), true);
if (pubKeyForSig == null)
{
break;
}
IFederationMember federationMember = federation.FirstOrDefault(m => m.PubKey == pubKeyForSig);
if (federationMember != null)
{
this.minersByBlockHash[chainedHeader.HashBlock] = federationMember;
return(federationMember);
}
}
}
catch (Exception)
{
}
return(null);
}
public void can_always_recover_pubkey_from_signature_when_stopping_at_null()
{
var rand = new Random();
for (int i = 0; i < 1000; i++)
{
var key = new Key();
PosBlock block = new PosBlock(new BlockHeader()
{
Time = (uint)rand.Next()
});
ECDSASignature signature = key.Sign(block.GetHash());
block.BlockSignature = new BlockSignature {
Signature = signature.ToDER()
};
Assert.True(key.PubKey.Verify(block.GetHash(), new ECDSASignature(block.BlockSignature.Signature)));
signature = ECDSASignature.FromDER(block.BlockSignature.Signature);
bool match = false;
for (int recId = 0; !match; recId++)
{
PubKey pubKeyForSig = PubKey.RecoverFromSignature(recId, signature, block.GetHash(), true);
if (pubKeyForSig == null)
{
break;
}
match = pubKeyForSig == key.PubKey;
}
Assert.True(match);
}
}
public override void Run(RuleContext context)
{
var header = context.ValidationContext.ChainedHeaderToValidate.Header as PoABlockHeader;
PubKey pubKey = this.slotsManager.GetFederationMemberForBlock(context.ValidationContext.ChainedHeaderToValidate, this.votingManager).PubKey;
if (!this.validator.VerifySignature(pubKey, header))
{
if (this.votingEnabled)
{
ChainedHeader currentHeader = context.ValidationContext.ChainedHeaderToValidate;
// If we're evaluating a batch of received headers it's possible that we're so far beyond the current tip
// that we have not yet processed all the votes that may determine the federation make-up.
bool mightBeInsufficient = currentHeader.Height - this.chainState.ConsensusTip.Height > this.maxReorg;
if (mightBeInsufficient)
{
// Mark header as insufficient to avoid banning the peer that presented it.
// When we advance consensus we will be able to validate it.
context.ValidationContext.InsufficientHeaderInformation = true;
}
}
try
{
// Gather all past and present mining public keys.
IEnumerable <PubKey> genesisFederation = ((PoAConsensusOptions)this.network.Consensus.Options).GenesisFederationMembers.Select(m => m.PubKey);
var knownKeys = new HashSet <PubKey>(genesisFederation);
foreach (Poll poll in this.votingManager.GetFinishedPolls().Where(x => ((x.VotingData.Key == VoteKey.AddFederationMember) || (x.VotingData.Key == VoteKey.KickFederationMember))))
{
IFederationMember federationMember = ((PoAConsensusFactory)(this.network.Consensus.ConsensusFactory)).DeserializeFederationMember(poll.VotingData.Data);
knownKeys.Add(federationMember.PubKey);
}
// Try to provide the public key that signed the block.
var signature = ECDSASignature.FromDER(header.BlockSignature.Signature);
for (int recId = 0; recId < 4; recId++)
{
PubKey pubKeyForSig = PubKey.RecoverFromSignature(recId, signature, header.GetHash(), true);
if (pubKeyForSig == null)
{
this.Logger.LogDebug($"Could not match candidate keys to any known key.");
break;
}
this.Logger.LogDebug($"Attempting to match candidate key '{ pubKeyForSig.ToHex() }' to known keys.");
if (!knownKeys.Any(pk => pk == pubKeyForSig))
{
continue;
}
IEnumerable <PubKey> modifiedFederation = this.votingManager?.GetModifiedFederation(context.ValidationContext.ChainedHeaderToValidate).Select(m => m.PubKey) ?? genesisFederation;
this.Logger.LogDebug($"Block is signed by '{0}' but expected '{1}' from: {2}.", pubKeyForSig.ToHex(), pubKey, string.Join(" ", modifiedFederation.Select(pk => pk.ToHex())));
break;
}
;
}
catch (Exception) { }
this.Logger.LogTrace("(-)[INVALID_SIGNATURE]");
PoAConsensusErrors.InvalidHeaderSignature.Throw();
}
}
