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Updated readBytes4 to match spec + added unit tests. These are 3.5/3.6 from audit

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This commit is contained in:
Greg Hysen 2018-08-29 11:39:52 -07:00
parent f44644ad90
commit 1c3b2b7141
3 changed files with 42 additions and 4 deletions
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13
packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol vendored
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@ -105,11 +105,20 @@ contract AssetProxyOwner is
uint256 index
)
internal
pure
returns (bytes4 result)
{
require(b.length >= index + 4);
require(
b.length >= index + 4,
"GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED"
);
// Arrays are prefixed by a 32 byte length field
index += 32;
// Read the bytes4 from array memory
assembly {
result := mload(add(b, 32))
result := mload(add(b, index))
// Solidity does not require us to clean the trailing bytes.
// We do it anyway
result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)

7
packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol vendored
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@ -467,8 +467,13 @@ library LibBytes {
b.length >= index + 4,
"GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED"
);
// Arrays are prefixed by a 32 byte length field
index += 32;
// Read the bytes4 from array memory
assembly {
result := mload(add(b, 32))
result := mload(add(b, index))
// Solidity does not require us to clean the trailing bytes.
// We do it anyway
result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)

26
packages/contracts/test/libraries/lib_bytes.ts
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@ -41,6 +41,8 @@ describe('LibBytes', () => {
const testBytes32B = '0x534877abd8443578526845cdfef020047528759477fedef87346527659aced32';
const testUint256 = new BigNumber(testBytes32, 16);
const testUint256B = new BigNumber(testBytes32B, 16);
const testBytes4 = '0xabcdef12';
const testBytes4B = new BigNumber(testBytes4, 16);
let shortData: string;
let shortTestBytes: string;
let shortTestBytesAsBuffer: Buffer;
@ -462,8 +464,9 @@ describe('LibBytes', () => {
// AssertionError: expected promise to be rejected with an error including 'revert' but it was fulfilled with '0x08c379a0'
it('should revert if byte array has a length < 4', async () => {
const byteArrayLessThan4Bytes = '0x010101';
const offset = new BigNumber(0);
return expectContractCallFailed(
libBytes.publicReadBytes4.callAsync(byteArrayLessThan4Bytes, new BigNumber(0)),
libBytes.publicReadBytes4.callAsync(byteArrayLessThan4Bytes, offset),
RevertReason.LibBytesGreaterOrEqualTo4LengthRequired,
);
});
@ -472,6 +475,27 @@ describe('LibBytes', () => {
const expectedFirst4Bytes = byteArrayLongerThan32Bytes.slice(0, 10);
expect(first4Bytes).to.equal(expectedFirst4Bytes);
});
it('should successfully read bytes4 when the bytes4 takes up the whole array', async () => {
const testBytes4Offset = new BigNumber(0);
const bytes4 = await libBytes.publicReadBytes4.callAsync(testBytes4, testBytes4Offset);
return expect(bytes4).to.be.equal(testBytes4);
});
it('should successfully read bytes4 when it is offset in the array)', async () => {
const bytes4ByteArrayBuffer = ethUtil.toBuffer(testBytes4);
const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, bytes4ByteArrayBuffer]);
const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
const testBytes4Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
const bytes4 = await libBytes.publicReadBytes4.callAsync(combinedByteArray, testBytes4Offset);
return expect(bytes4).to.be.equal(testBytes4);
});
it('should fail if the length between the offset and end of the byte array is too short to hold a bytes4', async () => {
const badOffset = new BigNumber(ethUtil.toBuffer(testBytes4).byteLength);
return expectContractCallFailed(
libBytes.publicReadBytes4.callAsync(testBytes4, badOffset),
RevertReason.LibBytesGreaterOrEqualTo4LengthRequired,
);
});
});
describe('readBytesWithLength', () => {