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@0x/contracts-staking: Add more overflow safeguards to LibFixedMath.

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This commit is contained in:
Lawrence Forman 2019-10-10 09:15:00 +09:00
parent 09c0b83fe3
commit 063d6ff24e
3 changed files with 193 additions and 12 deletions
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13
contracts/staking/contracts/src/libs/LibFixedMath.sol
View File

@ -95,6 +95,12 @@ library LibFixedMath {
/// @dev Returns the absolute value of a fixed point number.
function abs(int256 f) internal pure returns (int256 c) {
if (f == MIN_FIXED_VAL) {
LibRichErrors.rrevert(LibFixedMathRichErrors.SignedValueError(
LibFixedMathRichErrors.ValueErrorCodes.TOO_SMALL,
f
));
}
if (f >= 0) {
c = f;
} else {
@ -361,6 +367,13 @@ library LibFixedMath {
b
));
}
if (a == MIN_FIXED_VAL && b == -1) {
LibRichErrors.rrevert(LibFixedMathRichErrors.BinOpError(
LibFixedMathRichErrors.BinOpErrorCodes.DIVISION_OVERFLOW,
a,
b
));
}
c = a / b;
}

3
contracts/staking/contracts/src/libs/LibFixedMathRichErrors.sol
View File

@ -31,7 +31,8 @@ library LibFixedMathRichErrors {
enum BinOpErrorCodes {
ADDITION_OVERFLOW,
MULTIPLICATION_OVERFLOW,
DIVISION_BY_ZERO
DIVISION_BY_ZERO,
DIVISION_OVERFLOW
}
// bytes4(keccak256("SignedValueError(uint8,int256)"))

189
contracts/staking/test/unit_tests/lib_fixed_math_test.ts
View File

@ -7,7 +7,7 @@ import { artifacts, TestLibFixedMathContract } from '../../src';
import { assertRoughlyEquals, fromFixed, toDecimal, toFixed } from '../utils/number_utils';
blockchainTests.only('LibFixedMath unit tests', env => {
blockchainTests('LibFixedMath unit tests', env => {
let testContract: TestLibFixedMathContract;
before(async () => {
@ -21,6 +21,7 @@ blockchainTests.only('LibFixedMath unit tests', env => {
const BITS_OF_PRECISION = 127;
const FIXED_POINT_DIVISOR = new BigNumber(2).pow(BITS_OF_PRECISION);
const FIXED_1 = FIXED_POINT_DIVISOR;
const MAX_FIXED_VALUE = new BigNumber(2).pow(255).minus(1);
const MIN_FIXED_VALUE = new BigNumber(2).pow(255).times(-1);
const MIN_EXP_NUMBER = new BigNumber('-63.875');
@ -60,7 +61,35 @@ blockchainTests.only('LibFixedMath unit tests', env => {
it('abs(0) == 0', async () => {
const n = 0;
const r = await testContract.abs.callAsync(toFixed(n));
assertFixedEquals(r, n);
expect(r).to.bignumber.eq(0);
});
it('abs(MAX_FIXED) == MAX_FIXED', async () => {
const n = MAX_FIXED_VALUE;
const r = await testContract.abs.callAsync(n);
expect(r).to.bignumber.eq(n);
});
it('abs(MIN_FIXED) throws', async () => {
const n = MIN_FIXED_VALUE;
const expectedError = new FixedMathRevertErrors.SignedValueError(
FixedMathRevertErrors.ValueErrorCodes.TooSmall,
n,
);
const tx = testContract.abs.callAsync(n);
return expect(tx).to.revertWith(expectedError);
});
it('abs(int(-1)) == int(1)', async () => {
const n = -1;
const r = await testContract.abs.callAsync(new BigNumber(n));
expect(r).to.bignumber.eq(1);
});
it('abs(int(1)) == int(1)', async () => {
const n = 1;
const r = await testContract.abs.callAsync(new BigNumber(n));
expect(r).to.bignumber.eq(1);
});
});
@ -132,18 +161,62 @@ blockchainTests.only('LibFixedMath unit tests', env => {
return expect(tx).to.revertWith(expectedError);
});
it('int(-1) * int(1) / int(-1) == int(1)', async () => {
it('mulDiv(int(-1), int(1), int(-1)) == int(1)', async () => {
const [a, n, d] = [-1, 1, -1];
const r = await testContract.mulDiv.callAsync(new BigNumber(a), new BigNumber(n), new BigNumber(d));
assertFixedEquals(r, fromFixed(1));
});
it('-1 * int(1) / int(-1) == 1', async () => {
const [a, n, d] = [-1, 1, -1];
const r = await testContract.mulDiv.callAsync(toFixed(a), new BigNumber(n), new BigNumber(d));
assertFixedEquals(r, 1);
it('mulDiv(int(1), int(-1), int(-1)) == int(1)', async () => {
const [a, n, d] = [1, -1, -1];
const r = await testContract.mulDiv.callAsync(new BigNumber(a), new BigNumber(n), new BigNumber(d));
assertFixedEquals(r, fromFixed(1));
});
it('mulDiv(MIN_FIXED, int(-1), int(1)) throws', async () => {
const [a, n, d] = [MIN_FIXED_VALUE, -1, 1];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
n,
);
const tx = testContract.mulDiv.callAsync(a, new BigNumber(n), new BigNumber(d));
return expect(tx).to.revertWith(expectedError);
});
it('mulDiv(MIN_FIXED, int(-1), int(1)) throws', async () => {
const [a, n, d] = [MIN_FIXED_VALUE, -1, 1];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
n,
);
const tx = testContract.mulDiv.callAsync(a, new BigNumber(n), new BigNumber(d));
return expect(tx).to.revertWith(expectedError);
});
it('mulDiv(MIN_FIXED, int(1), int(-1)) throws', async () => {
const [a, n, d] = [MIN_FIXED_VALUE, 1, -1];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.DivisionOverflow,
a,
d,
);
const tx = testContract.mulDiv.callAsync(a, new BigNumber(n), new BigNumber(d));
return expect(tx).to.revertWith(expectedError);
});
it('mulDiv(MAX_FIXED, int(-1), int(1)) == -MAX_FIXED', async () => {
const [a, n, d] = [MAX_FIXED_VALUE, -1, 1];
const r = await testContract.mulDiv.callAsync(a, new BigNumber(n), new BigNumber(d));
expect(r).to.bignumber.eq(MAX_FIXED_VALUE.negated());
});
it('mulDiv(MAX_FIXED, int(1), int(-1)) == -MAX_FIXED', async () => {
const [a, n, d] = [MAX_FIXED_VALUE, 1, -1];
const r = await testContract.mulDiv.callAsync(a, new BigNumber(n), new BigNumber(d));
expect(r).to.bignumber.eq(MAX_FIXED_VALUE.negated());
});
});
describe('add()', () => {
@ -269,9 +342,8 @@ blockchainTests.only('LibFixedMath unit tests', env => {
const [a, b] = [MIN_FIXED_VALUE, MIN_FIXED_VALUE];
// This fails because `-MIN_FIXED_VALUE == MIN_FIXED_VALUE` because of
// twos-complement.
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.AdditionOverflow,
a,
const expectedError = new FixedMathRevertErrors.SignedValueError(
FixedMathRevertErrors.ValueErrorCodes.TooSmall,
b,
);
const tx = testContract.sub.callAsync(a, b);
@ -281,7 +353,7 @@ blockchainTests.only('LibFixedMath unit tests', env => {
it('MAX_FIXED - MAX_FIXED == 0', async () => {
const [a, b] = [MAX_FIXED_VALUE, MAX_FIXED_VALUE];
const r = await testContract.sub.callAsync(a, b);
return expect(r).to.bignumber.eq(0);
expect(r).to.bignumber.eq(0);
});
it('MIN_FIXED - MAX_FIXED throws', async () => {
@ -366,6 +438,73 @@ blockchainTests.only('LibFixedMath unit tests', env => {
const tx = testContract.mul.callAsync(a, b);
return expect(tx).to.revertWith(expectedError);
});
it('MAX_FIXED * int(1) == MAX_FIXED / FIXED_1', async () => {
const [a, b] = [MAX_FIXED_VALUE, 1];
const r = await testContract.mul.callAsync(a, new BigNumber(b));
expect(r).to.bignumber.eq(MAX_FIXED_VALUE.dividedToIntegerBy(FIXED_1));
});
it('MAX_FIXED * int(2) throws', async () => {
const [a, b] = [MAX_FIXED_VALUE, 2];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
b,
);
const tx = testContract.mul.callAsync(a, new BigNumber(b));
return expect(tx).to.revertWith(expectedError);
});
it('MAX_FIXED * MAX_FIXED throws', async () => {
const [a, b] = [MAX_FIXED_VALUE, MAX_FIXED_VALUE];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
b,
);
const tx = testContract.mul.callAsync(a, b);
return expect(tx).to.revertWith(expectedError);
});
it('MIN_FIXED * MIN_FIXED throws', async () => {
const [a, b] = [MIN_FIXED_VALUE, MIN_FIXED_VALUE];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
b,
);
const tx = testContract.mul.callAsync(a, b);
return expect(tx).to.revertWith(expectedError);
});
it('MAX_FIXED * MIN_FIXED throws', async () => {
const [a, b] = [MAX_FIXED_VALUE, MIN_FIXED_VALUE];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
b,
);
const tx = testContract.mul.callAsync(a, b);
return expect(tx).to.revertWith(expectedError);
});
it('MIN_FIXED * int(-1) throws', async () => {
const [a, b] = [MIN_FIXED_VALUE, -1];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
b,
);
const tx = testContract.mul.callAsync(a, new BigNumber(b));
return expect(tx).to.revertWith(expectedError);
});
it('MAX_FIXED * int(-1) == -MAX_FIXED / FIXED_1', async () => {
const [a, b] = [MAX_FIXED_VALUE, -1];
const r = await testContract.mul.callAsync(a, new BigNumber(b));
expect(r).to.bignumber.eq(MAX_FIXED_VALUE.negated().dividedToIntegerBy(FIXED_1));
});
});
describe('div()', () => {
@ -411,6 +550,34 @@ blockchainTests.only('LibFixedMath unit tests', env => {
const r = await testContract.div.callAsync(toFixed(a), toFixed(b));
assertFixedEquals(r, div(a, b));
});
it('MIN_FIXED / int(-1) throws', async () => {
const [a, b] = [MIN_FIXED_VALUE, -1];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
FIXED_1,
);
const tx = testContract.div.callAsync(a, new BigNumber(b));
return expect(tx).to.revertWith(expectedError);
});
it('MAX_FIXED / int(-1) throws', async () => {
const [a, b] = [MIN_FIXED_VALUE, -1];
const expectedError = new FixedMathRevertErrors.BinOpError(
FixedMathRevertErrors.BinOpErrorCodes.MultiplicationOverflow,
a,
FIXED_1,
);
const tx = testContract.div.callAsync(a, new BigNumber(b));
return expect(tx).to.revertWith(expectedError);
});
it('int(-1) / MIN_FIXED == 0', async () => {
const [a, b] = [-1, MIN_FIXED_VALUE];
const r = await testContract.div.callAsync(new BigNumber(a), b);
expect(r).to.bignumber.eq(0);
});
});
describe('uintMul()', () => {