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LibTLS: Add support for curve x448

This commit is contained in:
stelar7 2022-02-18 17:43:50 +01:00 committed by Ali Mohammad Pur
parent 0df7ad7493
commit 125a43e203
3 changed files with 78 additions and 16 deletions

View file

@ -11,6 +11,7 @@
#include <LibCrypto/ASN1/DER.h>
#include <LibCrypto/BigInt/UnsignedBigInteger.h>
#include <LibCrypto/Curves/X25519.h>
#include <LibCrypto/Curves/X448.h>
#include <LibCrypto/NumberTheory/ModularFunctions.h>
#include <LibCrypto/PK/Code/EMSA_PSS.h>
#include <LibTLS/TLSv12.h>
@ -294,19 +295,68 @@ void TLSv12::build_dhe_rsa_pre_master_secret(PacketBuilder& builder)
builder.append(dh_Yc_bytes);
}
ErrorOr<ByteBuffer> TLSv12::named_curve_multiply(NamedCurve curve, ReadonlyBytes a, ReadonlyBytes b)
{
switch (curve) {
case NamedCurve::x25519:
return Crypto::Curves::X25519::compute_coordinate(a, b);
case NamedCurve::x448:
return Crypto::Curves::X448::compute_coordinate(a, b);
default:
dbgln("No known handler for multiplying curve {}", static_cast<u16>(curve));
TODO();
}
}
ErrorOr<ByteBuffer> TLSv12::named_curve_generator_point(NamedCurve curve)
{
auto key_size = named_curve_key_size(curve) / 8;
auto generator_point_data_result = ByteBuffer::create_zeroed(key_size);
if (generator_point_data_result.is_error()) {
dbgln("Failed to generate curve multiplication point: not enough memory");
return AK::Error::from_string_literal("Failed to generate curve multiplication point: not enough memory");
}
auto generator_point_data = generator_point_data_result.release_value();
switch (curve) {
case NamedCurve::x25519:
ByteReader::store(generator_point_data.offset_pointer(0), 9);
break;
case NamedCurve::x448:
ByteReader::store(generator_point_data.offset_pointer(0), 5);
break;
default:
dbgln("No known handler for generator point of curve {}", static_cast<u16>(curve));
TODO();
}
return generator_point_data;
}
void TLSv12::build_ecdhe_rsa_pre_master_secret(PacketBuilder& builder)
{
size_t const key_size = named_curve_key_size(NamedCurve::x25519) / 8;
u8 generator_point[key_size] { 9 };
ReadonlyBytes generator_point_bytes { generator_point, key_size };
size_t const key_size = named_curve_key_size(m_context.server_curve_choice) / 8;
auto generator_point_result = named_curve_generator_point(m_context.server_curve_choice);
if (generator_point_result.is_error()) {
dbgln("Failed to build ECDHE_RSA premaster secret: not enough memory");
return;
}
auto generator_point = generator_point_result.release_value();
ReadonlyBytes generator_point_bytes = generator_point;
// Create a random private key
u8 private_key[key_size];
fill_with_random(private_key, key_size);
ReadonlyBytes private_key_bytes { private_key, key_size };
auto private_key_result = ByteBuffer::create_uninitialized(key_size);
if (private_key_result.is_error()) {
dbgln("Failed to build ECDHE_RSA premaster secret: not enough memory");
return;
}
auto private_key = private_key_result.release_value();
fill_with_random(private_key.data(), key_size);
ReadonlyBytes private_key_bytes = private_key;
// Calculate the public key by multiplying the private key with 9
auto public_key_result = Crypto::Curves::X25519::compute_coordinate(private_key_bytes, generator_point_bytes);
// Calculate the public key by multiplying the private key with the generator point
auto public_key_result = named_curve_multiply(m_context.server_curve_choice, private_key_bytes, generator_point_bytes);
if (public_key_result.is_error()) {
dbgln("Failed to build ECDHE_RSA premaster secret: not enough memory");
return;
@ -315,7 +365,7 @@ void TLSv12::build_ecdhe_rsa_pre_master_secret(PacketBuilder& builder)
// Calculate the pre master secret by multiplying the client private key and the server public key
ReadonlyBytes server_public_key_bytes = m_context.server_diffie_hellman_params.p;
auto pre_master_secret_result = Crypto::Curves::X25519::compute_coordinate(private_key_bytes, server_public_key_bytes);
auto pre_master_secret_result = named_curve_multiply(m_context.server_curve_choice, private_key_bytes, server_public_key_bytes);
if (pre_master_secret_result.is_error()) {
dbgln("Failed to build ECDHE_RSA premaster secret: not enough memory");
return;

View file

@ -290,21 +290,26 @@ ssize_t TLSv12::handle_dhe_rsa_server_key_exchange(ReadonlyBytes buffer)
ssize_t TLSv12::handle_ecdhe_rsa_server_key_exchange(ReadonlyBytes buffer)
{
auto x25519_key_size_bytes = named_curve_key_size(NamedCurve::x25519) / 8;
if (buffer.size() < x25519_key_size_bytes + 7)
size_t size_required_for_curve_name = 6;
if (buffer.size() < size_required_for_curve_name)
return (i8)Error::NeedMoreData;
auto curve_type = buffer[3];
if (curve_type != (u8)ECCurveType::NamedCurve)
return (i8)Error::NotUnderstood;
auto curve = AK::convert_between_host_and_network_endian(ByteReader::load16(buffer.offset_pointer(4)));
if (curve != (u16)NamedCurve::x25519)
auto curve = static_cast<NamedCurve>(AK::convert_between_host_and_network_endian(ByteReader::load16(buffer.offset_pointer(4))));
if (!m_context.options.elliptic_curves.contains_slow(curve))
return (i8)Error::NotUnderstood;
m_context.server_curve_choice = curve;
auto curve_key_size_bytes = named_curve_key_size(curve) / 8;
if (buffer.size() < curve_key_size_bytes + 1)
return (i8)Error::NeedMoreData;
auto server_public_key_length = buffer[6];
if (server_public_key_length != x25519_key_size_bytes)
return (i8)Error::NotUnderstood;
if (server_public_key_length != curve_key_size_bytes)
return (i8)Error::FeatureNotSupported;
auto server_public_key = buffer.slice(7, server_public_key_length);
auto server_public_key_copy_result = ByteBuffer::copy(server_public_key);

View file

@ -242,7 +242,9 @@ struct Options {
{ HashAlgorithm::SHA384, SignatureAlgorithm::RSA },
{ HashAlgorithm::SHA256, SignatureAlgorithm::RSA },
{ HashAlgorithm::SHA1, SignatureAlgorithm::RSA });
OPTION_WITH_DEFAULTS(Vector<NamedCurve>, elliptic_curves, NamedCurve::x25519)
OPTION_WITH_DEFAULTS(Vector<NamedCurve>, elliptic_curves,
NamedCurve::x25519,
NamedCurve::x448)
OPTION_WITH_DEFAULTS(Vector<ECPointFormat>, supported_ec_point_formats, ECPointFormat::Uncompressed)
OPTION_WITH_DEFAULTS(bool, use_sni, true)
@ -331,6 +333,8 @@ struct Context {
ByteBuffer g;
ByteBuffer Ys;
} server_diffie_hellman_params;
NamedCurve server_curve_choice;
};
class TLSv12 final : public Core::Stream::Socket {
@ -461,6 +465,9 @@ private:
void build_dhe_rsa_pre_master_secret(PacketBuilder&);
void build_ecdhe_rsa_pre_master_secret(PacketBuilder&);
static ErrorOr<ByteBuffer> named_curve_multiply(NamedCurve curve, ReadonlyBytes a, ReadonlyBytes b);
static ErrorOr<ByteBuffer> named_curve_generator_point(NamedCurve curve);
ErrorOr<bool> flush();
void write_into_socket();
ErrorOr<void> read_from_socket();