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EVM: fix zero curve encoding #1164

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Merged
merged 3 commits into from
Feb 5, 2023
Merged

EVM: fix zero curve encoding #1164

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242278c
EVM: reproduce ecMul precompile zero-scalar bug.
raulk Feb 4, 2023
dbc2a5d
EVM: fix encoding of zero
Stebalien Feb 4, 2023
342fce3
Merge branch 'next' into raulk/reproduce-ecmul-zero-bug
raulk Feb 4, 2023
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78 changes: 29 additions & 49 deletions actors/evm/src/interpreter/precompiles/evm.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -144,15 +144,13 @@ pub(super) fn modexp<RT: Runtime>(
Ok(output)
}

pub(super) fn curve_to_vec(curve: G1) -> Result<Vec<u8>, PrecompileError> {
AffineG1::from_jacobian(curve)
.map(|product| {
let mut output = vec![0; 64];
product.x().to_big_endian(&mut output[0..32]).unwrap();
product.y().to_big_endian(&mut output[32..64]).unwrap();
output
})
.ok_or(PrecompileError::EcErr(substrate_bn::CurveError::InvalidEncoding))
pub(super) fn curve_to_vec(curve: G1) -> Vec<u8> {
let mut output = vec![0; 64];
if let Some(product) = AffineG1::from_jacobian(curve) {
product.x().to_big_endian(&mut output[0..32]).unwrap();
product.y().to_big_endian(&mut output[32..64]).unwrap();
}
output
}

/// add 2 points together on an elliptic curve
Expand All @@ -165,7 +163,7 @@ pub(super) fn ec_add<RT: Runtime>(
let point1: G1 = input_params.read_value()?;
let point2: G1 = input_params.read_value()?;

curve_to_vec(point1 + point2)
Ok(curve_to_vec(point1 + point2))
}

/// multiply a point on an elliptic curve by a scalar value
Expand All @@ -178,7 +176,7 @@ pub(super) fn ec_mul<RT: Runtime>(
let point: G1 = input_params.read_value()?;
let scalar: Fr = input_params.read_value()?;

curve_to_vec(point * scalar)
Ok(curve_to_vec(point * scalar))
}

/// pairs multple groups of twisted bn curves
Expand Down Expand Up @@ -467,27 +465,14 @@ mod tests {
let res = ec_add(&mut system, &input, PrecompileContext::default()).unwrap();
assert_eq!(res, expected);
// zero sum test
let input = hex::decode(
"\
0000000000000000000000000000000000000000000000000000000000000000\
0000000000000000000000000000000000000000000000000000000000000000\
0000000000000000000000000000000000000000000000000000000000000000\
0000000000000000000000000000000000000000000000000000000000000000",
)
.unwrap();
let res = ec_add(&mut system, &input, PrecompileContext::default());
assert!(matches!(
res,
Err(PrecompileError::EcErr(substrate_bn::CurveError::InvalidEncoding))
));
let input = vec![0; 32 * 4];
let res = ec_add(&mut system, &input, PrecompileContext::default()).unwrap();
assert_eq!(res, vec![0; 64]);

// no input test
// no input test (auto zero extend)
let input = [];
let res = ec_add(&mut system, &input, PrecompileContext::default());
assert!(matches!(
res,
Err(PrecompileError::EcErr(substrate_bn::CurveError::InvalidEncoding))
));
let res = ec_add(&mut system, &input, PrecompileContext::default()).unwrap();
assert_eq!(res, vec![0; 64]);

// point not on curve fail
let input = hex::decode(
Expand Down Expand Up @@ -526,27 +511,10 @@ mod tests {
let res = ec_mul(&mut system, &input, PrecompileContext::default()).unwrap();
assert_eq!(res, expected);

// out of gas test
let input = hex::decode(
"\
0000000000000000000000000000000000000000000000000000000000000000\
0000000000000000000000000000000000000000000000000000000000000000\
0200000000000000000000000000000000000000000000000000000000000000",
)
.unwrap();
let res = ec_mul(&mut system, &input, PrecompileContext::default());
assert!(matches!(
res,
Err(PrecompileError::EcErr(substrate_bn::CurveError::InvalidEncoding))
));

// no input test
let input = [0u8; 0];
let res = ec_mul(&mut system, &input, PrecompileContext::default());
assert!(matches!(
res,
Err(PrecompileError::EcErr(substrate_bn::CurveError::InvalidEncoding))
));
let res = ec_mul(&mut system, &input, PrecompileContext::default()).unwrap();
assert_eq!(res, vec![0u8; 64]);

// point not on curve fail
let input = hex::decode(
Expand All @@ -561,6 +529,18 @@ mod tests {
res,
Err(PrecompileError::EcErr(substrate_bn::CurveError::NotMember))
));

let input = hex::decode(
"\
035cf447ec2f8f21e6ea3d49d80a4a823834b1a776ab1733731587613f5065f8\
21c972c4e0c8eb2430171599b1f4900601fdb8f4b2d248d22ebefe3d5368a800\
0000000000000000000000000000000000000000000000000000000000000000\
0000000000000000000000000000000000000000000000000000000000000000\
",
)
.unwrap();
let res = ec_mul(&mut system, &input, PrecompileContext::default());
assert_eq!(vec![0u8; 64], res.unwrap());
}

#[test]
Expand Down