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Process and verify merkle proofs (and multiproof) with custom hash function (#4887)

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Co-authored-by: ernestognw <ernestognw@gmail.com>
This commit is contained in:
Hadrien Croubois
2024-07-15 18:08:58 +02:00
committed by GitHub
parent 4b33d326fa
commit b73bcb231f
10 changed files with 779 additions and 269 deletions
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352
contracts/utils/cryptography/MerkleProof.sol
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@ -1,5 +1,6 @@
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/MerkleProof.sol)
// This file was procedurally generated from scripts/generate/templates/MerkleProof.js.
pragma solidity ^0.8.20;
@ -18,6 +19,11 @@ import {Hashes} from "./Hashes.sol";
* the Merkle tree could be reinterpreted as a leaf value.
* OpenZeppelin's JavaScript library generates Merkle trees that are safe
* against this attack out of the box.
*
* NOTE: This library supports proof verification for merkle trees built using
* custom _commutative_ hashing functions (i.e. `H(a, b) == H(b, a)`). Proving
* leaf inclusion in trees built using non-commutative hashing functions requires
* additional logic that is not supported by this library.
*/
library MerkleProof {
/**
@ -30,23 +36,20 @@ library MerkleProof {
* defined by `root`. For this, a `proof` must be provided, containing
* sibling hashes on the branch from the leaf to the root of the tree. Each
* pair of leaves and each pair of pre-images are assumed to be sorted.
*
* This version handles proofs in memory with the default hashing function.
*/
function verify(bytes32[] memory proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
return processProof(proof, leaf) == root;
}
/**
* @dev Calldata version of {verify}
*/
function verifyCalldata(bytes32[] calldata proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
return processProofCalldata(proof, leaf) == root;
}
/**
* @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
* from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
* hash matches the root of the tree. When processing the proof, the pairs
* of leafs & pre-images are assumed to be sorted.
*
* This version handles proofs in memory with the default hashing function.
*/
function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
bytes32 computedHash = leaf;
@ -57,7 +60,61 @@ library MerkleProof {
}
/**
* @dev Calldata version of {processProof}
* @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
* defined by `root`. For this, a `proof` must be provided, containing
* sibling hashes on the branch from the leaf to the root of the tree. Each
* pair of leaves and each pair of pre-images are assumed to be sorted.
*
* This version handles proofs in memory with a custom hashing function.
*/
function verify(
bytes32[] memory proof,
bytes32 root,
bytes32 leaf,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bool) {
return processProof(proof, leaf, hasher) == root;
}
/**
* @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
* from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
* hash matches the root of the tree. When processing the proof, the pairs
* of leafs & pre-images are assumed to be sorted.
*
* This version handles proofs in memory with a custom hashing function.
*/
function processProof(
bytes32[] memory proof,
bytes32 leaf,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bytes32) {
bytes32 computedHash = leaf;
for (uint256 i = 0; i < proof.length; i++) {
computedHash = hasher(computedHash, proof[i]);
}
return computedHash;
}
/**
* @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
* defined by `root`. For this, a `proof` must be provided, containing
* sibling hashes on the branch from the leaf to the root of the tree. Each
* pair of leaves and each pair of pre-images are assumed to be sorted.
*
* This version handles proofs in calldata with the default hashing function.
*/
function verifyCalldata(bytes32[] calldata proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
return processProof(proof, leaf) == root;
}
/**
* @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
* from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
* hash matches the root of the tree. When processing the proof, the pairs
* of leafs & pre-images are assumed to be sorted.
*
* This version handles proofs in calldata with the default hashing function.
*/
function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {
bytes32 computedHash = leaf;
@ -67,10 +124,49 @@ library MerkleProof {
return computedHash;
}
/**
* @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
* defined by `root`. For this, a `proof` must be provided, containing
* sibling hashes on the branch from the leaf to the root of the tree. Each
* pair of leaves and each pair of pre-images are assumed to be sorted.
*
* This version handles proofs in calldata with a custom hashing function.
*/
function verifyCalldata(
bytes32[] calldata proof,
bytes32 root,
bytes32 leaf,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bool) {
return processProof(proof, leaf, hasher) == root;
}
/**
* @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
* from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
* hash matches the root of the tree. When processing the proof, the pairs
* of leafs & pre-images are assumed to be sorted.
*
* This version handles proofs in calldata with a custom hashing function.
*/
function processProofCalldata(
bytes32[] calldata proof,
bytes32 leaf,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bytes32) {
bytes32 computedHash = leaf;
for (uint256 i = 0; i < proof.length; i++) {
computedHash = hasher(computedHash, proof[i]);
}
return computedHash;
}
/**
* @dev Returns true if the `leaves` can be simultaneously proven to be a part of a Merkle tree defined by
* `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
*
* This version handles multiproofs in memory with the default hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. See {processMultiProof} for details.
*/
function multiProofVerify(
@ -82,26 +178,14 @@ library MerkleProof {
return processMultiProof(proof, proofFlags, leaves) == root;
}
/**
* @dev Calldata version of {multiProofVerify}
*
* CAUTION: Not all Merkle trees admit multiproofs. See {processMultiProof} for details.
*/
function multiProofVerifyCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32 root,
bytes32[] memory leaves
) internal pure returns (bool) {
return processMultiProofCalldata(proof, proofFlags, leaves) == root;
}
/**
* @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
* proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
* leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
* respectively.
*
* This version handles multiproofs in memory with the default hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
* is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
* tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
@ -116,17 +200,15 @@ library MerkleProof {
// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
// the Merkle tree.
uint256 leavesLen = leaves.length;
uint256 proofLen = proof.length;
uint256 totalHashes = proofFlags.length;
// Check proof validity.
if (leavesLen + proofLen != totalHashes + 1) {
if (leavesLen + proof.length != proofFlags.length + 1) {
revert MerkleProofInvalidMultiproof();
}
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
bytes32[] memory hashes = new bytes32[](totalHashes);
bytes32[] memory hashes = new bytes32[](proofFlags.length);
uint256 leafPos = 0;
uint256 hashPos = 0;
uint256 proofPos = 0;
@ -135,7 +217,7 @@ library MerkleProof {
// get the next hash.
// - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
// `proof` array.
for (uint256 i = 0; i < totalHashes; i++) {
for (uint256 i = 0; i < proofFlags.length; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i]
? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
@ -143,12 +225,12 @@ library MerkleProof {
hashes[i] = Hashes.commutativeKeccak256(a, b);
}
if (totalHashes > 0) {
if (proofPos != proofLen) {
if (proofFlags.length > 0) {
if (proofPos != proof.length) {
revert MerkleProofInvalidMultiproof();
}
unchecked {
return hashes[totalHashes - 1];
return hashes[proofFlags.length - 1];
}
} else if (leavesLen > 0) {
return leaves[0];
@ -158,31 +240,55 @@ library MerkleProof {
}
/**
* @dev Calldata version of {processMultiProof}.
* @dev Returns true if the `leaves` can be simultaneously proven to be a part of a Merkle tree defined by
* `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
*
* This version handles multiproofs in memory with a custom hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. See {processMultiProof} for details.
*/
function processMultiProofCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32[] memory leaves
) internal pure returns (bytes32 merkleRoot) {
function multiProofVerify(
bytes32[] memory proof,
bool[] memory proofFlags,
bytes32 root,
bytes32[] memory leaves,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bool) {
return processMultiProof(proof, proofFlags, leaves, hasher) == root;
}
/**
* @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
* proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
* leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
* respectively.
*
* This version handles multiproofs in memory with a custom hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
* is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
* tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
*/
function processMultiProof(
bytes32[] memory proof,
bool[] memory proofFlags,
bytes32[] memory leaves,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bytes32 merkleRoot) {
// This function rebuilds the root hash by traversing the tree up from the leaves. The root is rebuilt by
// consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
// the Merkle tree.
uint256 leavesLen = leaves.length;
uint256 proofLen = proof.length;
uint256 totalHashes = proofFlags.length;
// Check proof validity.
if (leavesLen + proofLen != totalHashes + 1) {
if (leavesLen + proof.length != proofFlags.length + 1) {
revert MerkleProofInvalidMultiproof();
}
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
bytes32[] memory hashes = new bytes32[](totalHashes);
bytes32[] memory hashes = new bytes32[](proofFlags.length);
uint256 leafPos = 0;
uint256 hashPos = 0;
uint256 proofPos = 0;
@ -191,7 +297,85 @@ library MerkleProof {
// get the next hash.
// - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
// `proof` array.
for (uint256 i = 0; i < totalHashes; i++) {
for (uint256 i = 0; i < proofFlags.length; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i]
? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
: proof[proofPos++];
hashes[i] = hasher(a, b);
}
if (proofFlags.length > 0) {
if (proofPos != proof.length) {
revert MerkleProofInvalidMultiproof();
}
unchecked {
return hashes[proofFlags.length - 1];
}
} else if (leavesLen > 0) {
return leaves[0];
} else {
return proof[0];
}
}
/**
* @dev Returns true if the `leaves` can be simultaneously proven to be a part of a Merkle tree defined by
* `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
*
* This version handles multiproofs in calldata with the default hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. See {processMultiProof} for details.
*/
function multiProofVerifyCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32 root,
bytes32[] calldata leaves
) internal pure returns (bool) {
return processMultiProof(proof, proofFlags, leaves) == root;
}
/**
* @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
* proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
* leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
* respectively.
*
* This version handles multiproofs in calldata with the default hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
* is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
* tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
*/
function processMultiProofCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32[] calldata leaves
) internal pure returns (bytes32 merkleRoot) {
// This function rebuilds the root hash by traversing the tree up from the leaves. The root is rebuilt by
// consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
// the Merkle tree.
uint256 leavesLen = leaves.length;
// Check proof validity.
if (leavesLen + proof.length != proofFlags.length + 1) {
revert MerkleProofInvalidMultiproof();
}
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
bytes32[] memory hashes = new bytes32[](proofFlags.length);
uint256 leafPos = 0;
uint256 hashPos = 0;
uint256 proofPos = 0;
// At each step, we compute the next hash using two values:
// - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
// get the next hash.
// - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
// `proof` array.
for (uint256 i = 0; i < proofFlags.length; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i]
? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
@ -199,12 +383,92 @@ library MerkleProof {
hashes[i] = Hashes.commutativeKeccak256(a, b);
}
if (totalHashes > 0) {
if (proofPos != proofLen) {
if (proofFlags.length > 0) {
if (proofPos != proof.length) {
revert MerkleProofInvalidMultiproof();
}
unchecked {
return hashes[totalHashes - 1];
return hashes[proofFlags.length - 1];
}
} else if (leavesLen > 0) {
return leaves[0];
} else {
return proof[0];
}
}
/**
* @dev Returns true if the `leaves` can be simultaneously proven to be a part of a Merkle tree defined by
* `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
*
* This version handles multiproofs in calldata with a custom hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. See {processMultiProof} for details.
*/
function multiProofVerifyCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32 root,
bytes32[] calldata leaves,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bool) {
return processMultiProof(proof, proofFlags, leaves, hasher) == root;
}
/**
* @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
* proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
* leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
* respectively.
*
* This version handles multiproofs in calldata with a custom hashing function.
*
* CAUTION: Not all Merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
* is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
* tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
*/
function processMultiProofCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32[] calldata leaves,
function(bytes32, bytes32) view returns (bytes32) hasher
) internal view returns (bytes32 merkleRoot) {
// This function rebuilds the root hash by traversing the tree up from the leaves. The root is rebuilt by
// consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
// the Merkle tree.
uint256 leavesLen = leaves.length;
// Check proof validity.
if (leavesLen + proof.length != proofFlags.length + 1) {
revert MerkleProofInvalidMultiproof();
}
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
bytes32[] memory hashes = new bytes32[](proofFlags.length);
uint256 leafPos = 0;
uint256 hashPos = 0;
uint256 proofPos = 0;
// At each step, we compute the next hash using two values:
// - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
// get the next hash.
// - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
// `proof` array.
for (uint256 i = 0; i < proofFlags.length; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i]
? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
: proof[proofPos++];
hashes[i] = hasher(a, b);
}
if (proofFlags.length > 0) {
if (proofPos != proof.length) {
revert MerkleProofInvalidMultiproof();
}
unchecked {
return hashes[proofFlags.length - 1];
}
} else if (leavesLen > 0) {
return leaves[0];