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LibCrypto+LibWeb: Implement ECDSA.sign
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Gained ~20 tests, failing only on P-521.
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@devgianlu
devgianlu committed Dec 2, 2024
1 parent 00ff626 commit c62e00a
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Showing 3 changed files with 159 additions and 42 deletions.
63 changes: 63 additions & 0 deletions Libraries/LibCrypto/Curves/SECPxxxr1.h
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Original file line number Diff line number Diff line change
Expand Up @@ -315,6 +315,69 @@ class SECPxxxr1 : public EllipticCurve {
SECPxxxr1Signature { r_bigint, s_bigint });
}

ErrorOr<SECPxxxr1Signature> sign_scalar(ReadonlyBytes hash, UnsignedBigInteger private_key)
{
auto d = unsigned_big_integer_to_storage_type(private_key);

auto k_int = TRY(generate_private_key_scalar());
auto k = unsigned_big_integer_to_storage_type(k_int);
auto k_mo = to_montgomery_order(k);

auto kG = TRY(generate_public_key_internal(k));
auto r = kG.x;

if (r.is_zero_constant_time()) {
// Retry with a new k
return sign_scalar(hash, private_key);
}

// Compute z from the hash
StorageType z = 0u;
for (size_t i = 0; i < KEY_BYTE_SIZE && i < hash.size(); i++) {
z <<= 8;
z |= hash[i];
}

// Compute s = k^-1 * (z + r * d) mod n
auto r_mo = to_montgomery_order(r);
auto z_mo = to_montgomery_order(z);
auto d_mo = to_montgomery_order(d);

// r * d mod n
auto rd_mo = modular_multiply_order(r_mo, d_mo);

// z + (r * d) mod n
auto z_plus_rd_mo = modular_add_order(z_mo, rd_mo);

// k^-1 mod n
auto k_inv_mo = modular_inverse_order(k_mo);

// s = k^-1 * (z + r * d) mod n
auto s_mo = modular_multiply_order(z_plus_rd_mo, k_inv_mo);
auto s = from_montgomery_order(s_mo);

if (s.is_zero_constant_time()) {
// Retry with a new k
return sign_scalar(hash, private_key);
}

return SECPxxxr1Signature { storage_type_to_unsigned_big_integer(r), storage_type_to_unsigned_big_integer(s) };
}

ErrorOr<ByteBuffer> sign(ReadonlyBytes hash, ReadonlyBytes private_key_bytes)
{
auto signature = TRY(sign_scalar(hash, UnsignedBigInteger::import_data(private_key_bytes.data(), private_key_bytes.size())));

Crypto::ASN1::Encoder asn1_encoder;
TRY(asn1_encoder.write_constructed(ASN1::Class::Universal, ASN1::Kind::Sequence, [&]() -> ErrorOr<void> {
TRY(asn1_encoder.write(signature.r));
TRY(asn1_encoder.write(signature.s));
return {};
}));

return asn1_encoder.finish();
}

private:
StorageType unsigned_big_integer_to_storage_type(UnsignedBigInteger big)
{
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100 changes: 77 additions & 23 deletions Libraries/LibWeb/Crypto/CryptoAlgorithms.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2359,35 +2359,93 @@ WebIDL::ExceptionOr<GC::Ref<JS::ArrayBuffer>> ECDSA::sign(AlgorithmParams const&
auto& vm = realm.vm();
auto const& normalized_algorithm = static_cast<EcdsaParams const&>(params);

(void)vm;
(void)message;

// 1. If the [[type]] internal slot of key is not "private", then throw an InvalidAccessError.
if (key->type() != Bindings::KeyType::Private)
return WebIDL::InvalidAccessError::create(realm, "Key is not a private key"_string);

// 2. Let hashAlgorithm be the hash member of normalizedAlgorithm.
[[maybe_unused]] auto const& hash_algorithm = normalized_algorithm.hash;
auto const& hash_algorithm = TRY(normalized_algorithm.hash.name(vm));

// 3. Let M be the result of performing the digest operation specified by hashAlgorithm using message.
::Crypto::Hash::HashKind hash_kind;
if (hash_algorithm == "SHA-1") {
hash_kind = ::Crypto::Hash::HashKind::SHA1;
} else if (hash_algorithm == "SHA-256") {
hash_kind = ::Crypto::Hash::HashKind::SHA256;
} else if (hash_algorithm == "SHA-384") {
hash_kind = ::Crypto::Hash::HashKind::SHA384;
} else if (hash_algorithm == "SHA-512") {
hash_kind = ::Crypto::Hash::HashKind::SHA512;
} else {
return WebIDL::NotSupportedError::create(m_realm, MUST(String::formatted("Invalid hash function '{}'", hash_algorithm)));
}
::Crypto::Hash::Manager hash { hash_kind };
hash.update(message);
auto digest = hash.digest();

auto M = TRY_OR_THROW_OOM(vm, ByteBuffer::copy(digest.immutable_data(), hash.digest_size()));

// 4. Let d be the ECDSA private key associated with key.
auto d = key->handle().get<::Crypto::PK::ECPrivateKey<>>();

// NOTE: We dont have sign() on the SECPxxxr1 curves, so we can't implement this yet
// FIXME: 3. Let M be the result of performing the digest operation specified by hashAlgorithm using message.
// FIXME: 4. Let d be the ECDSA private key associated with key.
// FIXME: 5. Let params be the EC domain parameters associated with key.
// FIXME: 6. If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":

// FIXME: 1. Perform the ECDSA signing process, as specified in [RFC6090], Section 5.4, with M as the message, using params as the EC domain parameters, and with d as the private key.
// FIXME: 2. Let r and s be the pair of integers resulting from performing the ECDSA signing process.
// FIXME: 3. Let result be an empty byte sequence.
// FIXME: 4. Let n be the smallest integer such that n * 8 is greater than the logarithm to base 2 of the order of the base point of the elliptic curve identified by params.
// FIXME: 5. Convert r to an octet string of length n and append this sequence of bytes to result.
// FIXME: 6. Convert s to an octet string of length n and append this sequence of bytes to result.
auto const& internal_algorithm = static_cast<EcKeyAlgorithm const&>(*key->algorithm());
auto const& named_curve = internal_algorithm.named_curve();

ByteBuffer result;

// FIXME: Otherwise, the namedCurve attribute of the [[algorithm]] internal slot of key is a value specified in an applicable specification:
// FIXME: Perform the ECDSA signature steps specified in that specification, passing in M, params and d and resulting in result.
// 6. If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256", "P-384" or "P-521":
if (named_curve.is_one_of("P-256"sv, "P-384"sv, "P-521"sv)) {
size_t coord_size;
Variant<Empty, ::Crypto::Curves::SECP256r1, ::Crypto::Curves::SECP384r1> curve;
if (named_curve == "P-256") {
coord_size = 32;
curve = ::Crypto::Curves::SECP256r1 {};
} else if (named_curve == "P-384") {
coord_size = 48;
curve = ::Crypto::Curves::SECP384r1 {};
} else if (named_curve == "P-521") {
// FIXME: Support P-521
coord_size = 66;
return WebIDL::NotSupportedError::create(m_realm, "'P-521' is not supported yet"_string);
} else {
VERIFY_NOT_REACHED();
}

// 1. Perform the ECDSA signing process, as specified in [RFC6090], Section 5.4, with M as the message,
// using params as the EC domain parameters, and with d as the private key.
// 2. Let r and s be the pair of integers resulting from performing the ECDSA signing process.
auto maybe_signature = curve.visit(
[](Empty const&) -> ErrorOr<::Crypto::Curves::SECPxxxr1Signature> { return Error::from_string_literal("Failed to create valid crypto instance"); },
[&](auto instance) { return instance.sign_scalar(M, d.d()); });

if (maybe_signature.is_error()) {
auto error_message = MUST(String::from_utf8(maybe_signature.error().string_literal()));
return WebIDL::OperationError::create(m_realm, error_message);
}

auto signature = maybe_signature.release_value();

// 3. Let result be an empty byte sequence.
result = TRY_OR_THROW_OOM(vm, ByteBuffer::create_zeroed(coord_size * 2));

// 4. Let n be the smallest integer such that n * 8 is greater than the logarithm to base 2 of the order of the base point of the elliptic curve identified by params.
// 5. Convert r to an octet string of length n and append this sequence of bytes to result.
VERIFY(signature.r.byte_length() <= coord_size);
(void)signature.r.export_data(result.span());

// 6. Convert s to an octet string of length n and append this sequence of bytes to result.
VERIFY(signature.s.byte_length() <= coord_size);
(void)signature.s.export_data(result.span().slice(coord_size));
} else {
// FIXME: Otherwise, the namedCurve attribute of the [[algorithm]] internal slot of key is a value specified in an applicable specification:
// FIXME: Perform the ECDSA signature steps specified in that specification, passing in M, params and d and resulting in result.
}

// NOTE: The spec jumps to 9 here for some reason
// FIXME: 9. Return the result of creating an ArrayBuffer containing result.
return WebIDL::NotSupportedError::create(realm, "ECDSA signing is not supported yet"_string);
// 9. Return the result of creating an ArrayBuffer containing result.
return JS::ArrayBuffer::create(m_realm, result);
}

// https://w3c.github.io/webcrypto/#ecdsa-operations
Expand Down Expand Up @@ -2420,11 +2478,7 @@ WebIDL::ExceptionOr<JS::Value> ECDSA::verify(AlgorithmParams const& params, GC::
hash.update(message);
auto digest = hash.digest();

auto result_buffer = ByteBuffer::copy(digest.immutable_data(), hash.digest_size());
if (result_buffer.is_error())
return WebIDL::OperationError::create(m_realm, "Failed to create result buffer"_string);

auto M = result_buffer.release_value();
auto M = TRY_OR_THROW_OOM(realm.vm(), ByteBuffer::copy(digest.immutable_data(), hash.digest_size()));

// 4. Let Q be the ECDSA public key associated with key.
auto Q = key->handle().get<::Crypto::PK::ECPublicKey<>>();
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38 changes: 19 additions & 19 deletions Tests/LibWeb/Text/expected/wpt-import/WebCryptoAPI/sign_verify/ecdsa.https.any.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -6,42 +6,42 @@ Rerun

Found 253 tests

176 Pass
77 Fail
193 Pass
60 Fail
Details
Result Test Name MessagePass setup
Pass ECDSA P-256 with SHA-1 verification
Pass ECDSA P-256 with SHA-256 verification
Fail ECDSA P-256 with SHA-384 verification
Fail ECDSA P-256 with SHA-512 verification
Pass ECDSA P-256 with SHA-384 verification
Pass ECDSA P-256 with SHA-512 verification
Pass ECDSA P-384 with SHA-1 verification
Pass ECDSA P-384 with SHA-256 verification
Pass ECDSA P-384 with SHA-384 verification
Fail ECDSA P-384 with SHA-512 verification
Pass ECDSA P-384 with SHA-512 verification
Fail ECDSA P-521 with SHA-1 verification
Fail ECDSA P-521 with SHA-256 verification
Fail ECDSA P-521 with SHA-384 verification
Fail ECDSA P-521 with SHA-512 verification
Pass ECDSA P-256 with SHA-1 verification with altered signature after call
Pass ECDSA P-256 with SHA-256 verification with altered signature after call
Fail ECDSA P-256 with SHA-384 verification with altered signature after call
Fail ECDSA P-256 with SHA-512 verification with altered signature after call
Pass ECDSA P-256 with SHA-384 verification with altered signature after call
Pass ECDSA P-256 with SHA-512 verification with altered signature after call
Pass ECDSA P-384 with SHA-1 verification with altered signature after call
Pass ECDSA P-384 with SHA-256 verification with altered signature after call
Pass ECDSA P-384 with SHA-384 verification with altered signature after call
Fail ECDSA P-384 with SHA-512 verification with altered signature after call
Pass ECDSA P-384 with SHA-512 verification with altered signature after call
Fail ECDSA P-521 with SHA-1 verification with altered signature after call
Fail ECDSA P-521 with SHA-256 verification with altered signature after call
Fail ECDSA P-521 with SHA-384 verification with altered signature after call
Fail ECDSA P-521 with SHA-512 verification with altered signature after call
Pass ECDSA P-256 with SHA-1 with altered plaintext after call
Pass ECDSA P-256 with SHA-256 with altered plaintext after call
Fail ECDSA P-256 with SHA-384 with altered plaintext after call
Fail ECDSA P-256 with SHA-512 with altered plaintext after call
Pass ECDSA P-256 with SHA-384 with altered plaintext after call
Pass ECDSA P-256 with SHA-512 with altered plaintext after call
Pass ECDSA P-384 with SHA-1 with altered plaintext after call
Pass ECDSA P-384 with SHA-256 with altered plaintext after call
Pass ECDSA P-384 with SHA-384 with altered plaintext after call
Fail ECDSA P-384 with SHA-512 with altered plaintext after call
Pass ECDSA P-384 with SHA-512 with altered plaintext after call
Fail ECDSA P-521 with SHA-1 with altered plaintext after call
Fail ECDSA P-521 with SHA-256 with altered plaintext after call
Fail ECDSA P-521 with SHA-384 with altered plaintext after call
Expand Down Expand Up @@ -82,14 +82,14 @@ Pass ECDSA P-521 with SHA-1 no verify usage
Pass ECDSA P-521 with SHA-256 no verify usage
Pass ECDSA P-521 with SHA-384 no verify usage
Pass ECDSA P-521 with SHA-512 no verify usage
Fail ECDSA P-256 with SHA-1 round trip
Fail ECDSA P-256 with SHA-256 round trip
Fail ECDSA P-256 with SHA-384 round trip
Fail ECDSA P-256 with SHA-512 round trip
Fail ECDSA P-384 with SHA-1 round trip
Fail ECDSA P-384 with SHA-256 round trip
Fail ECDSA P-384 with SHA-384 round trip
Fail ECDSA P-384 with SHA-512 round trip
Pass ECDSA P-256 with SHA-1 round trip
Pass ECDSA P-256 with SHA-256 round trip
Pass ECDSA P-256 with SHA-384 round trip
Pass ECDSA P-256 with SHA-512 round trip
Pass ECDSA P-384 with SHA-1 round trip
Pass ECDSA P-384 with SHA-256 round trip
Pass ECDSA P-384 with SHA-384 round trip
Pass ECDSA P-384 with SHA-512 round trip
Fail ECDSA P-521 with SHA-1 round trip
Fail ECDSA P-521 with SHA-256 round trip
Fail ECDSA P-521 with SHA-384 round trip
Expand Down

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