Merge pull request #1896 from Roasbeef/witness-wire-hot-fix

wire: remove erroneous witness size check in wire parsing

blockchain/weight.go

@@ -7,9 +7,9 @@ package blockchain
 import (
 	"fmt"
 
+	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/btcsuite/btcd/btcutil"
 )
 
 const (

wire/msgtx.go

@@ -103,27 +103,28 @@ const (
 	maxWitnessItemsPerInput = 500000
 
 	// maxWitnessItemSize is the maximum allowed size for an item within
-	// an input's witness data. This number is derived from the fact that
-	// for script validation, each pushed item onto the stack must be less
-	// than 10k bytes.
-	maxWitnessItemSize = 11000
+	// an input's witness data. This value is bounded by the largest
+	// possible block size, post segwit v1 (taproot).
+	maxWitnessItemSize = 4_000_000
 )
 
 // TxFlagMarker is the first byte of the FLAG field in a bitcoin tx
 // message. It allows decoders to distinguish a regular serialized
 // transaction from one that would require a different parsing logic.
 //
 // Position of FLAG in a bitcoin tx message:
-//   ┌─────────┬────────────────────┬─────────────┬─────┐
-//   │ VERSION │ FLAG               │ TX-IN-COUNT │ ... │
-//   │ 4 bytes │ 2 bytes (optional) │ varint      │     │
-//   └─────────┴────────────────────┴─────────────┴─────┘
+//
+//	┌─────────┬────────────────────┬─────────────┬─────┐
+//	│ VERSION │ FLAG               │ TX-IN-COUNT │ ... │
+//	│ 4 bytes │ 2 bytes (optional) │ varint      │     │
+//	└─────────┴────────────────────┴─────────────┴─────┘
 //
 // Zooming into the FLAG field:
-//   ┌── FLAG ─────────────┬────────┐
-//   │ TxFlagMarker (0x00) │ TxFlag │
-//   │ 1 byte              │ 1 byte │
-//   └─────────────────────┴────────┘
+//
+//	┌── FLAG ─────────────┬────────┐
+//	│ TxFlagMarker (0x00) │ TxFlag │
+//	│ 1 byte              │ 1 byte │
+//	└─────────────────────┴────────┘
 const TxFlagMarker = 0x00
 
 // TxFlag is the second byte of the FLAG field in a bitcoin tx message.
@@ -586,8 +587,9 @@ func (msg *MsgTx) BtcDecode(r io.Reader, pver uint32, enc MessageEncoding) error
 			// item itself.
 			txin.Witness = make([][]byte, witCount)
 			for j := uint64(0); j < witCount; j++ {
-				txin.Witness[j], err = readScript(r, pver,
-					maxWitnessItemSize, "script witness item")
+				txin.Witness[j], err = readScript(
+					r, pver, maxWitnessItemSize, "script witness item",
+				)
 				if err != nil {
 					returnScriptBuffers()
 					return err