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Fix issue with detection of RIP7212 precompile (#5620)

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Co-authored-by: Arr00 <13561405+arr00@users.noreply.github.com>
Co-authored-by: Ernesto García <ernestognw@gmail.com>
This commit is contained in:
Hadrien Croubois
2025-04-03 17:02:04 +02:00
parent acaa5975dd
commit f3f0a6466f
7 changed files with 249 additions and 164 deletions
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42
contracts/utils/cryptography/P256.sol
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@ -90,10 +90,48 @@ library P256 {
) private view returns (bool valid, bool supported) {
if (!_isProperSignature(r, s) || !isValidPublicKey(qx, qy)) {
return (false, true); // signature is invalid, and its not because the precompile is missing
} else if (_rip7212(h, r, s, qx, qy)) {
return (true, true); // precompile is present, signature is valid
} else if (
// Given precompiles have no bytecode (i.e. `address(0x100).code.length == 0`), we use
// a valid signature with small `r` and `s` values to check if the precompile is present. Taken from
// https://github.com/C2SP/wycheproof/blob/4672ff74d68766e7785c2cac4c597effccef2c5c/testvectors/ecdsa_secp256r1_sha256_p1363_test.json#L1173-L1204
_rip7212(
0xbb5a52f42f9c9261ed4361f59422a1e30036e7c32b270c8807a419feca605023, // sha256("123400")
0x0000000000000000000000000000000000000000000000000000000000000005,
0x0000000000000000000000000000000000000000000000000000000000000001,
0xa71af64de5126a4a4e02b7922d66ce9415ce88a4c9d25514d91082c8725ac957,
0x5d47723c8fbe580bb369fec9c2665d8e30a435b9932645482e7c9f11e872296b
)
) {
return (false, true); // precompile is present, signature is invalid
} else {
return (false, false); // precompile is absent
}
}
(bool success, bytes memory returndata) = address(0x100).staticcall(abi.encode(h, r, s, qx, qy));
return (success && returndata.length == 0x20) ? (abi.decode(returndata, (bool)), true) : (false, false);
/**
* @dev Low level helper for {_tryVerifyNative}. Calls the precompile and checks if there is a return value.
*/
function _rip7212(bytes32 h, bytes32 r, bytes32 s, bytes32 qx, bytes32 qy) private view returns (bool isValid) {
assembly ("memory-safe") {
// Use the free memory pointer without updating it at the end of the function
let ptr := mload(0x40)
mstore(ptr, h)
mstore(add(ptr, 0x20), r)
mstore(add(ptr, 0x40), s)
mstore(add(ptr, 0x60), qx)
mstore(add(ptr, 0x80), qy)
// RIP-7212 precompiles return empty bytes when an invalid signature is passed, making it impossible
// to distinguish the presence of the precompile. Custom precompile implementations may decide to
// return `bytes32(0)` (i.e. false) without developers noticing, so we decide to evaluate the return value
// without expanding memory using scratch space.
mstore(0x00, 0) // zero out scratch space in case the precompile doesn't return anything
if iszero(staticcall(gas(), 0x100, ptr, 0xa0, 0x00, 0x20)) {
invalid()
}
isValid := mload(0x00)
}
}
/**