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Check for segwit block with no witness commit

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This commit is contained in:
junderw 2019-01-17 17:10:52 +09:00
parent e52abecee2
commit 4c6ea80459
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GPG key ID: B256185D3A971908
3 changed files with 100 additions and 39 deletions
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67
src/block.js
View file

@ -9,10 +9,8 @@ const typeforce = require('typeforce');
const varuint = require('varuint-bitcoin');
const errorMerkleNoTxes = new TypeError('Cannot compute merkle root for zero transactions');
const errorWitnessNotSegwit = new TypeError('Cannot compute witness commit for non-segwit block');
const errorBufferTooSmall = new Error('Buffer too small (< 80 bytes)');
function txesHaveWitness(transactions) {
return transactions !== undefined &&
transactions instanceof Array &&
function txesHaveWitnessCommit(transactions) {
return transactions instanceof Array &&
transactions[0] &&
transactions[0].ins &&
transactions[0].ins instanceof Array &&
@ -21,6 +19,14 @@ function txesHaveWitness(transactions) {
transactions[0].ins[0].witness instanceof Array &&
transactions[0].ins[0].witness.length > 0;
}
function anyTxHasWitness(transactions) {
return transactions instanceof Array &&
transactions.some(tx => typeof tx === 'object' &&
tx.ins instanceof Array &&
tx.ins.some(input => typeof input === 'object' &&
input.witness instanceof Array &&
input.witness.length > 0));
}
class Block {
constructor() {
this.version = 1;
@ -34,7 +40,7 @@ class Block {
}
static fromBuffer(buffer) {
if (buffer.length < 80)
throw errorBufferTooSmall;
throw new Error('Buffer too small (< 80 bytes)');
let offset = 0;
const readSlice = (n) => {
offset += n;
@ -75,18 +81,10 @@ class Block {
const tx = readTransaction();
block.transactions.push(tx);
}
let witnessCommit = block.getWitnessCommit();
// This Block contains a witness commit
if (block.hasWitnessCommit()) {
// The merkle root for the witness data is in an OP_RETURN output.
// There is no rule for the index of the output, so use filter to find it.
// The root is prepended with 0xaa21a9ed so check for 0x6a24aa21a9ed
// If multiple commits are found, the output with highest index is assumed.
let witnessCommits = block.transactions[0].outs
.filter(out => out.script.slice(0, 6).equals(Buffer.from('6a24aa21a9ed', 'hex')))
.map(out => out.script.slice(6, 38));
// Use the commit with the highest output (should only be one though)
block.witnessCommit = witnessCommits[witnessCommits.length - 1];
}
if (witnessCommit)
block.witnessCommit = witnessCommit;
return block;
}
static fromHex(hex) {
@ -103,7 +101,7 @@ class Block {
typeforce([{ getHash: types.Function }], transactions);
if (transactions.length === 0)
throw errorMerkleNoTxes;
if (forWitness && !txesHaveWitness(transactions))
if (forWitness && !txesHaveWitnessCommit(transactions))
throw errorWitnessNotSegwit;
const hashes = transactions.map(transaction => transaction.getHash(forWitness));
const rootHash = fastMerkleRoot(hashes, bcrypto.hash256);
@ -111,8 +109,34 @@ class Block {
? bcrypto.hash256(Buffer.concat([rootHash, transactions[0].ins[0].witness[0]]))
: rootHash;
}
getWitnessCommit() {
if (!txesHaveWitnessCommit(this.transactions))
return null;
// The merkle root for the witness data is in an OP_RETURN output.
// There is no rule for the index of the output, so use filter to find it.
// The root is prepended with 0xaa21a9ed so check for 0x6a24aa21a9ed
// If multiple commits are found, the output with highest index is assumed.
let witnessCommits = this.transactions[0].outs
.filter(out => out.script.slice(0, 6).equals(Buffer.from('6a24aa21a9ed', 'hex')))
.map(out => out.script.slice(6, 38));
if (witnessCommits.length === 0)
return null;
// Use the commit with the highest output (should only be one though)
let result = witnessCommits[witnessCommits.length - 1];
if (!(result instanceof Buffer && result.length === 32))
return null;
return result;
}
hasWitnessCommit() {
return txesHaveWitness(this.transactions);
if (this.witnessCommit instanceof Buffer &&
this.witnessCommit.length === 32)
return true;
if (this.getWitnessCommit() !== null)
return true;
return false;
}
hasWitness() {
return anyTxHasWitness(this.transactions);
}
byteLength(headersOnly) {
if (headersOnly || !this.transactions)
@ -168,8 +192,13 @@ class Block {
return this.toBuffer(headersOnly).toString('hex');
}
checkTxRoots() {
// If the Block has segwit transactions but no witness commit,
// there's no way it can be valid, so fail the check.
let hasWitnessCommit = this.hasWitnessCommit();
if (!hasWitnessCommit && this.hasWitness())
return false;
return this.__checkMerkleRoot() &&
(this.hasWitnessCommit() ? this.__checkWitnessCommit() : true);
(hasWitnessCommit ? this.__checkWitnessCommit() : true);
}
checkMerkleRoot() {
console.warn('Deprecation Warning: Block method checkMerkleRoot will be ' +

70
ts_src/block.ts
View file

@ -9,11 +9,9 @@ const varuint = require('varuint-bitcoin')
const errorMerkleNoTxes = new TypeError('Cannot compute merkle root for zero transactions')
const errorWitnessNotSegwit = new TypeError('Cannot compute witness commit for non-segwit block')
const errorBufferTooSmall = new Error('Buffer too small (< 80 bytes)')
function txesHaveWitness (transactions: Array<Transaction>): boolean {
return transactions !== undefined &&
transactions instanceof Array &&
function txesHaveWitnessCommit (transactions: Array<Transaction>): boolean {
return transactions instanceof Array &&
transactions[0] &&
transactions[0].ins &&
transactions[0].ins instanceof Array &&
@ -23,6 +21,19 @@ function txesHaveWitness (transactions: Array<Transaction>): boolean {
transactions[0].ins[0].witness.length > 0
}
function anyTxHasWitness (transactions: Array<Transaction>): boolean {
return transactions instanceof Array &&
transactions.some(tx =>
typeof tx === 'object' &&
tx.ins instanceof Array &&
tx.ins.some(input =>
typeof input === 'object' &&
input.witness instanceof Array &&
input.witness.length > 0
)
)
}
export class Block {
version: number
prevHash?: Buffer
@ -45,7 +56,7 @@ export class Block {
}
static fromBuffer (buffer: Buffer): Block {
if (buffer.length < 80) throw errorBufferTooSmall
if (buffer.length < 80) throw new Error('Buffer too small (< 80 bytes)')
let offset: number = 0
const readSlice = (n: number): Buffer => {
@ -95,19 +106,9 @@ export class Block {
block.transactions.push(tx)
}
let witnessCommit = block.getWitnessCommit()
// This Block contains a witness commit
if (block.hasWitnessCommit()) {
// The merkle root for the witness data is in an OP_RETURN output.
// There is no rule for the index of the output, so use filter to find it.
// The root is prepended with 0xaa21a9ed so check for 0x6a24aa21a9ed
// If multiple commits are found, the output with highest index is assumed.
let witnessCommits = block.transactions[0].outs
.filter(out => out.script.slice(0, 6).equals(Buffer.from('6a24aa21a9ed', 'hex')))
.map(out => out.script.slice(6, 38))
// Use the commit with the highest output (should only be one though)
block.witnessCommit = witnessCommits[witnessCommits.length - 1]
}
if (witnessCommit) block.witnessCommit = witnessCommit
return block
}
@ -127,7 +128,7 @@ export class Block {
static calculateMerkleRoot (transactions: Array<Transaction>, forWitness?: boolean): Buffer {
typeforce([{ getHash: types.Function }], transactions)
if (transactions.length === 0) throw errorMerkleNoTxes
if (forWitness && !txesHaveWitness(transactions)) throw errorWitnessNotSegwit
if (forWitness && !txesHaveWitnessCommit(transactions)) throw errorWitnessNotSegwit
const hashes = transactions.map(transaction => transaction.getHash(forWitness!))
@ -138,8 +139,33 @@ export class Block {
: rootHash
}
getWitnessCommit (): Buffer | null {
if (!txesHaveWitnessCommit(this.transactions!)) return null
// The merkle root for the witness data is in an OP_RETURN output.
// There is no rule for the index of the output, so use filter to find it.
// The root is prepended with 0xaa21a9ed so check for 0x6a24aa21a9ed
// If multiple commits are found, the output with highest index is assumed.
let witnessCommits = this.transactions![0].outs
.filter(out => out.script.slice(0, 6).equals(Buffer.from('6a24aa21a9ed', 'hex')))
.map(out => out.script.slice(6, 38))
if (witnessCommits.length === 0) return null
// Use the commit with the highest output (should only be one though)
let result = witnessCommits[witnessCommits.length - 1]
if (!(result instanceof Buffer && result.length === 32)) return null
return result
}
hasWitnessCommit (): boolean {
return txesHaveWitness(this.transactions!)
if (this.witnessCommit instanceof Buffer &&
this.witnessCommit.length === 32) return true
if (this.getWitnessCommit() !== null) return true
return false
}
hasWitness (): boolean {
return anyTxHasWitness(this.transactions!)
}
byteLength (headersOnly: boolean): number {
@ -209,8 +235,12 @@ export class Block {
}
checkTxRoots (): boolean {
// If the Block has segwit transactions but no witness commit,
// there's no way it can be valid, so fail the check.
let hasWitnessCommit = this.hasWitnessCommit()
if (!hasWitnessCommit && this.hasWitness()) return false
return this.__checkMerkleRoot() &&
(this.hasWitnessCommit() ? this.__checkWitnessCommit() : true)
(hasWitnessCommit ? this.__checkWitnessCommit() : true)
}
checkMerkleRoot (): boolean {

2
types/block.d.ts vendored
View file

@ -14,7 +14,9 @@ export declare class Block {
static fromHex(hex: string): Block;
static calculateTarget(bits: number): Buffer;
static calculateMerkleRoot(transactions: Array<Transaction>, forWitness?: boolean): Buffer;
getWitnessCommit(): Buffer | null;
hasWitnessCommit(): boolean;
hasWitness(): boolean;
byteLength(headersOnly: boolean): number;
getHash(): Buffer;
getId(): string;