Fix : MultiSig with invalid pubkey should be a valid multisig

MetacoSA · Oct 24, 2014 · 30c4a36 · 30c4a36
1 parent dccb690
commit 30c4a36
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Showing 2 changed files with 48 additions and 21 deletions.
diff --git a/NBitcoin.Tests/script_tests.cs b/NBitcoin.Tests/script_tests.cs
@@ -138,6 +138,18 @@ public void CanCompressScript2()
 			Assert.Equal(script.ToString(), new Script(compressed, true).ToString());
 		}
 
+		[Fact]
+		[Trait("UnitTest", "UnitTest")]
+		public void PayToMultiSigTemplateShouldAcceptNonKeyParameters()
+		{
+			var tx = new Transaction("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");
+			var redeemScript = new PayToScriptHashTemplate().ExtractScriptSigParameters(tx.Inputs[1].ScriptSig).RedeemScript;
+			var result = new PayToMultiSigTemplate().ExtractScriptPubKeyParameters(redeemScript);
+			Assert.Equal(2, result.PubKeys.Length);
+			Assert.Equal(2, result.SignatureCount);
+			Assert.Equal(1, result.InvalidPubKeys.Length);
+		}
+
 		[Fact]
 		[Trait("UnitTest", "UnitTest")]
 		public void PayToPubkeyHashTemplateDoNotCrashOnInvalidSig()

diff --git a/NBitcoin/StandardScriptTemplate.cs b/NBitcoin/StandardScriptTemplate.cs
@@ -90,6 +90,12 @@ public PubKey[] PubKeys
 			get;
 			set;
 		}
+
+		public byte[][] InvalidPubKeys
+		{
+			get;
+			set;
+		}
 	}
 	public class PayToMultiSigTemplate : ScriptTemplate
 	{
@@ -120,46 +126,55 @@ protected override bool CheckScriptPubKeyCore(Script scriptPubKey, Op[] scriptPu
 			var sigCount = ops[0];
 			if(!sigCount.IsSmallUInt)
 				return false;
-
-			var expectedKeyCount = 0;
-			var keyCountIndex = 0;
-			for(int i = 1 ; i < ops.Length ; i++)
+			var pubKeyCount = ops[ops.Length - 2];
+			if(!pubKeyCount.IsSmallUInt)
+				return false;
+			var keyCount = (uint)pubKeyCount.GetValue();
+			if(1 + keyCount + 1 + 1 != ops.Length)
+				return false;
+			for(int i = 1 ; i < keyCount + 1; i++)
 			{
 				if(ops[i].PushData == null)
 					return false;
-				if(!PubKey.IsValidSize(ops[i].PushData.Length))
-				{
-					keyCountIndex = i;
-					break;
-				}
-				expectedKeyCount++;
 			}
-			if(!ops[keyCountIndex].IsSmallUInt)
-				return false;
-			if(ops[keyCountIndex].GetValue() != expectedKeyCount)
-				return false;
-			return ops[keyCountIndex + 1].Code == OpcodeType.OP_CHECKMULTISIG &&
-				  keyCountIndex + 1 == ops.Length - 1;
+			return ops[ops.Length - 1].Code == OpcodeType.OP_CHECKMULTISIG;
 		}
 
 		public PayToMultiSigTemplateParameters ExtractScriptPubKeyParameters(Script scriptPubKey)
 		{
+			if(!FastCheckScriptPubKey(scriptPubKey))
+				return null;
 			var ops = scriptPubKey.ToOps().ToArray();
 			if(!CheckScriptPubKeyCore(scriptPubKey, ops))
 				return null;
-			var sigCount = (byte)ops[0].PushData[0];
+
+			var sigCount = (int)ops[0].GetValue();
+			var keyCount = (int)ops[ops.Length - 2].GetValue();
+
 			List<PubKey> keys = new List<PubKey>();
-			for(int i = 1 ; i < ops.Length ; i++)
+			List<byte[]> invalidKeys = new List<byte[]>();
+			for(int i = 1 ; i < keyCount + 1; i++)
 			{
 				if(!PubKey.IsValidSize(ops[i].PushData.Length))
-					break;
-				keys.Add(new PubKey(ops[i].PushData));
+					invalidKeys.Add(ops[i].PushData);
+				else
+				{
+					try
+					{
+						keys.Add(new PubKey(ops[i].PushData));
+					}
+					catch(FormatException)
+					{
+						invalidKeys.Add(ops[i].PushData);
+					}
+				}
 			}
 
 			return new PayToMultiSigTemplateParameters()
 			{
 				SignatureCount = sigCount,
-				PubKeys = keys.ToArray()
+				PubKeys = keys.ToArray(),
+				InvalidPubKeys = invalidKeys.ToArray()
 			};
 		}