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crypto: reject small-order EdDSA points during verify #64026

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144 changes: 143 additions & 1 deletion src/crypto/crypto_sig.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,147 @@ bool ApplyRSAOptions(const EVPKeyPointer& pkey,
return true;
}

constexpr size_t kEd25519PointSize = 32;
constexpr size_t kEd448PointSize = 57;

// Ed25519 has cofactor 8, so the first eight entries are the full
// canonical small-order subgroup: identity, one point of order 2,
// two points of order 4, and four points of order 8.
constexpr unsigned char kEd25519SmallOrderPoints[][kEd25519PointSize] = {
// Identity.
{0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
// Order 2.
{0xec, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f},
// Order 4.
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
// Order 8.
{0xc7, 0x17, 0x6a, 0x70, 0x3d, 0x4d, 0xd8, 0x4f, 0xba, 0x3c, 0x0b,
0x76, 0x0d, 0x10, 0x67, 0x0f, 0x2a, 0x20, 0x53, 0xfa, 0x2c, 0x39,
0xcc, 0xc6, 0x4e, 0xc7, 0xfd, 0x77, 0x92, 0xac, 0x03, 0x7a},
{0xc7, 0x17, 0x6a, 0x70, 0x3d, 0x4d, 0xd8, 0x4f, 0xba, 0x3c, 0x0b,
0x76, 0x0d, 0x10, 0x67, 0x0f, 0x2a, 0x20, 0x53, 0xfa, 0x2c, 0x39,
0xcc, 0xc6, 0x4e, 0xc7, 0xfd, 0x77, 0x92, 0xac, 0x03, 0xfa},
{0x26, 0xe8, 0x95, 0x8f, 0xc2, 0xb2, 0x27, 0xb0, 0x45, 0xc3, 0xf4,
0x89, 0xf2, 0xef, 0x98, 0xf0, 0xd5, 0xdf, 0xac, 0x05, 0xd3, 0xc6,
0x33, 0x39, 0xb1, 0x38, 0x02, 0x88, 0x6d, 0x53, 0xfc, 0x05},
{0x26, 0xe8, 0x95, 0x8f, 0xc2, 0xb2, 0x27, 0xb0, 0x45, 0xc3, 0xf4,
0x89, 0xf2, 0xef, 0x98, 0xf0, 0xd5, 0xdf, 0xac, 0x05, 0xd3, 0xc6,
0x33, 0x39, 0xb1, 0x38, 0x02, 0x88, 0x6d, 0x53, 0xfc, 0x85},
// Non-canonical encodings of the same small-order points.
{0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
{0xec, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
{0xee, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f},
{0xee, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
{0xed, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
{0xed, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f},
};

// Ed448 has cofactor 4, so these four entries are the full canonical
// small-order subgroup: identity, one point of order 2, and two points
// of order 4.
constexpr unsigned char kEd448SmallOrderPoints[][kEd448PointSize] = {
// Identity.
{0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
// Order 2.
{0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00},
// Order 4.
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80},
};

template <size_t PointSize, size_t Count>
bool ContainsPoint(const unsigned char* candidate,
const unsigned char (&points)[Count][PointSize]) {
for (const auto& point : points) {
if (memcmp(candidate, point, PointSize) == 0) return true;
}
return false;
}

bool IsSmallOrderEdDsaPoint(int id,
const unsigned char* candidate,
size_t size) {
switch (id) {
case EVP_PKEY_ED25519:
return size == kEd25519PointSize &&
ContainsPoint(candidate, kEd25519SmallOrderPoints);
case EVP_PKEY_ED448:
return size == kEd448PointSize &&
ContainsPoint(candidate, kEd448SmallOrderPoints);
default:
return false;
}
}

bool HasSmallOrderEdDsaPoint(const EVPKeyPointer& key,
const ByteSource& signature) {
const int id = key.id();
size_t point_size;

switch (id) {
case EVP_PKEY_ED25519:
point_size = kEd25519PointSize;
break;
case EVP_PKEY_ED448:
point_size = kEd448PointSize;
break;
default:
return false;
}

if (signature.size() != point_size * 2) return false;

if (IsSmallOrderEdDsaPoint(id, signature.data<unsigned char>(), point_size)) {
return true;
}

unsigned char raw_public_key[kEd448PointSize];
size_t raw_public_key_size = point_size;
if (EVP_PKEY_get_raw_public_key(
key.get(), raw_public_key, &raw_public_key_size) != 1) {
return false;
}

return IsSmallOrderEdDsaPoint(id, raw_public_key, raw_public_key_size);
}

std::unique_ptr<BackingStore> Node_SignFinal(Environment* env,
EVPMDCtxPointer&& mdctx,
const EVPKeyPointer& pkey,
Expand Down Expand Up @@ -754,7 +895,8 @@ bool SignTraits::DeriveBits(Environment* env,
case SignConfiguration::Mode::Verify: {
auto buf = DataPointer::Alloc(1);
static_cast<char*>(buf.get())[0] = 0;
if (context.verify(params.data, params.signature)) {
if (context.verify(params.data, params.signature) &&
!HasSmallOrderEdDsaPoint(key, params.signature)) {
static_cast<char*>(buf.get())[0] = 1;
}
*out = ByteSource::Allocated(buf.release());
Expand Down
41 changes: 41 additions & 0 deletions test/parallel/test-webcrypto-sign-verify-eddsa.js
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,44 @@ const vectors = require('../fixtures/crypto/eddsa')();

const supportsContext = hasOpenSSL(3, 2);

const smallOrderVerifyVectors = [
{
name: 'Ed25519',
publicKey: Buffer.from(
'c7176a703d4dd84fba3c0b760d10670f2a2053fa2c39ccc64ec7fd7792ac03fa',
'hex'),
signature: Buffer.from(
'c7176a703d4dd84fba3c0b760d10670f2a2053fa2c39ccc64ec7fd7792ac037a' +
'0000000000000000000000000000000000000000000000000000000000000000',
'hex'),
data: Buffer.from(
'8c93255d71dcab10e8f379c26200f3c7bd5f09d9bc3068d3ef4edeb4853022b6',
'hex'),
},
];

if (!process.features.openssl_is_boringssl) {
smallOrderVerifyVectors.push({
name: 'Ed448',
publicKey: Buffer.concat([Buffer.from([1]), Buffer.alloc(56)]),
signature: Buffer.concat([Buffer.from([1]), Buffer.alloc(113)]),
data: Buffer.from([1, 2, 3]),
});
}

async function testSmallOrderVerify({ name, publicKey, signature, data }) {
const key = await subtle.importKey(
'raw',
publicKey,
{ name },
false,
['verify']);

assert.strictEqual(
await subtle.verify({ name }, key, signature, data),
false);
}

async function testVerify({ name,
context,
publicKeyBuffer,
Expand Down Expand Up @@ -260,6 +298,9 @@ async function testSign({ name,
variations.push(testVerify(vector));
variations.push(testSign(vector));
});
smallOrderVerifyVectors.forEach((vector) => {
variations.push(testSmallOrderVerify(vector));
});

await Promise.all(variations);
})().then(common.mustCall());
Expand Down
19 changes: 0 additions & 19 deletions test/wpt/status/WebCryptoAPI.cjs
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Original file line number Diff line number Diff line change
@@ -1,11 +1,7 @@
'use strict';

const os = require('node:os');

const { hasOpenSSL } = require('../../common/crypto.js');

const s390x = os.arch() === 's390x';

const conditionalFileSkips = {};
const conditionalSubtestSkips = {};

Expand Down Expand Up @@ -115,19 +111,4 @@ module.exports = {
'historical.any.js': {
'skip': 'Not relevant in Node.js context',
},
'sign_verify/eddsa_small_order_points.https.any.js': {
'fail': {
'note': 'see https://github.com/nodejs/node/issues/54572',
'expected': [
'Ed25519 Verification checks with small-order key of order - Test 1',
'Ed25519 Verification checks with small-order key of order - Test 2',
'Ed25519 Verification checks with small-order key of order - Test 12',
'Ed25519 Verification checks with small-order key of order - Test 13',
...(s390x ? [] : [
'Ed25519 Verification checks with small-order key of order - Test 0',
'Ed25519 Verification checks with small-order key of order - Test 11',
]),
],
},
},
};
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