/*
* Copyright (c) 2020, Ali Mohammad Pur <ali.mpfard@gmail.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/Endian.h>
#include <LibCore/DateTime.h>
#include <LibCore/Timer.h>
#include <LibCrypto/ASN1/DER.h>
#include <LibCrypto/ASN1/PEM.h>
#include <LibCrypto/PK/Code/EMSA_PSS.h>
#include <LibTLS/TLSv12.h>
#ifndef SOCK_NONBLOCK
# include <sys/ioctl.h>
#endif
//#define TLS_DEBUG
namespace {
struct OIDChain {
void* root { nullptr };
u8* oid { nullptr };
};
}
namespace TLS {
// "for now" q&d implementation of ASN1
namespace {
static bool _asn1_is_field_present(const u32* fields, const u32* prefix)
{
size_t i = 0;
while (prefix[i]) {
if (fields[i] != prefix[i])
return false;
++i;
}
return true;
}
static bool _asn1_is_oid(const u8* oid, const u8* compare, size_t length = 3)
{
size_t i = 0;
while (oid[i] && i < length) {
if (oid[i] != compare[i])
return false;
++i;
}
return true;
}
static bool _set_algorithm(CertificateKeyAlgorithm& algorithm, const u8* value, size_t length)
{
if (length == 7) {
// Elliptic Curve pubkey
dbg() << "Cert.algorithm: EC, unsupported";
return false;
}
if (length == 8) {
// named EC key
dbg() << "Cert.algorithm: Named EC (" << *value << "), unsupported";
return false;
}
if (length == 5) {
// named EC SECP key
dbg() << "Cert.algorithm: Named EC secp (" << *value << "), unsupported";
return false;
}
if (length != 9) {
dbg() << "Invalid certificate algorithm";
return false;
}
if (_asn1_is_oid(value, Constants::RSA_SIGN_RSA_OID, 9)) {
algorithm = CertificateKeyAlgorithm::RSA_RSA;
return true;
}
if (_asn1_is_oid(value, Constants::RSA_SIGN_SHA256_OID, 9)) {
algorithm = CertificateKeyAlgorithm::RSA_SHA256;
return true;
}
if (_asn1_is_oid(value, Constants::RSA_SIGN_SHA512_OID, 9)) {
algorithm = CertificateKeyAlgorithm::RSA_SHA512;
return true;
}
if (_asn1_is_oid(value, Constants::RSA_SIGN_SHA1_OID, 9)) {
algorithm = CertificateKeyAlgorithm::RSA_SHA1;
return true;
}
if (_asn1_is_oid(value, Constants::RSA_SIGN_MD5_OID, 9)) {
algorithm = CertificateKeyAlgorithm::RSA_MD5;
return true;
}
dbg() << "Unsupported RSA Signature mode " << value[8];
return false;
}
static size_t _get_asn1_length(const u8* buffer, size_t length, size_t& octets)
{
octets = 0;
if (length < 1)
return 0;
u8 size = buffer[0];
if (size & 0x80) {
octets = size & 0x7f;
if (octets > length - 1) {
return 0;
}
auto reference_octets = octets;
if (octets > 4)
reference_octets = 4;
size_t long_size = 0, coeff = 1;
for (auto i = reference_octets; i > 0; --i) {
long_size += buffer[i] * coeff;
coeff *= 0x100;
}
++octets;
return long_size;
}
++octets;
return size;
}
static ssize_t _parse_asn1(const Context& context, Certificate& cert, const u8* buffer, size_t size, int level, u32* fields, u8* has_key, int client_cert, u8* root_oid, OIDChain* chain)
{
OIDChain local_chain;
local_chain.root = chain;
size_t position = 0;
// parse DER...again
size_t index = 0;
u8 oid[16] { 0 };
local_chain.oid = oid;
if (has_key)
*has_key = 0;
u8 local_has_key = 0;
const u8* cert_data = nullptr;
size_t cert_length = 0;
while (position < size) {
size_t start_position = position;
if (size - position < 2) {
dbg() << "not enough data for certificate size";
return (i8)Error::NeedMoreData;
}
u8 first = buffer[position++];
u8 type = first & 0x1f;
u8 constructed = first & 0x20;
size_t octets = 0;
u32 temp;
index++;
if (level <= 0xff)
fields[level - 1] = index;
size_t length = _get_asn1_length((const u8*)&buffer[position], size - position, octets);
if (octets > 4 || octets > size - position) {
#ifdef TLS_DEBUG
dbg() << "could not read the certificate";
#endif
return position;
}
position += octets;
if (size - position < length) {
#ifdef TLS_DEBUG
dbg() << "not enough data for sequence";
#endif
return (i8)Error::NeedMoreData;
}
if (length && constructed) {
switch (type) {
case 0x03:
break;
case 0x10:
if (level == 2 && index == 1) {
cert_length = length + position - start_position;
cert_data = buffer + start_position;
}
// public key data
if (!cert.version && _asn1_is_field_present(fields, Constants::priv_der_id)) {
temp = length + position - start_position;
if (cert.der.size() < temp) {
cert.der.grow(temp);
} else {
cert.der.trim(temp);
}
cert.der.overwrite(0, buffer + start_position, temp);
}
break;
default:
break;
}
local_has_key = false;
_parse_asn1(context, cert, buffer + position, length, level + 1, fields, &local_has_key, client_cert, root_oid, &local_chain);
if ((local_has_key && (!context.is_server || client_cert)) || (client_cert || _asn1_is_field_present(fields, Constants::pk_id))) {
temp = length + position - start_position;
if (cert.der.size() < temp) {
cert.der.grow(temp);
} else {
cert.der.trim(temp);
}
cert.der.overwrite(0, buffer + start_position, temp);
}
} else {
switch (type) {
case 0x00:
return position;
break;
case 0x01:
temp = buffer[position];
break;
case 0x02:
if (_asn1_is_field_present(fields, Constants::pk_id)) {
if (has_key)
*has_key = true;
if (index == 1)
cert.public_key.set(
Crypto::UnsignedBigInteger::import_data(buffer + position, length),
cert.public_key.public_exponent());
else if (index == 2)
cert.public_key.set(
cert.public_key.modulus(),
Crypto::UnsignedBigInteger::import_data(buffer + position, length));
} else if (_asn1_is_field_present(fields, Constants::serial_id)) {
cert.serial_number = Crypto::UnsignedBigInteger::import_data(buffer + position, length);
}
if (_asn1_is_field_present(fields, Constants::version_id)) {
if (length == 1)
cert.version = buffer[position];
}
// print_buffer(ByteBuffer::wrap(const_cast<u8*>(buffer) + position, length));
break;
case 0x03:
if (_asn1_is_field_present(fields, Constants::pk_id)) {
if (has_key)
*has_key = true;
}
if (_asn1_is_field_present(fields, Constants::sign_id)) {
auto* value = buffer + position;
auto len = length;
if (!value[0] && len % 2) {
++value;
--len;
}
cert.sign_key = ByteBuffer::copy(value, len);
} else {
if (buffer[position] == 0 && length > 256) {
_parse_asn1(context, cert, buffer + position + 1, length - 1, level + 1, fields, &local_has_key, client_cert, root_oid, &local_chain);
} else {
_parse_asn1(context, cert, buffer + position, length, level + 1, fields, &local_has_key, client_cert, root_oid, &local_chain);
}
}
break;
case 0x04:
_parse_asn1(context, cert, buffer + position, length, level + 1, fields, &local_has_key, client_cert, root_oid, &local_chain);
break;
case 0x05:
break;
case 0x06:
if (_asn1_is_field_present(fields, Constants::pk_id)) {
_set_algorithm(cert.key_algorithm, buffer + position, length);
}
if (_asn1_is_field_present(fields, Constants::algorithm_id)) {
_set_algorithm(cert.algorithm, buffer + position, length);
}
if (length < 16)
memcpy(oid, buffer + position, length);
else
memcpy(oid, buffer + position, 16);
if (root_oid)
memcpy(root_oid, oid, 16);
break;
case 0x09:
break;
case 0x17:
case 0x018:
// time
// ignore
break;
case 0x013:
case 0x0c:
case 0x14:
case 0x15:
case 0x16:
case 0x19:
case 0x1a:
case 0x1b:
case 0x1c:
case 0x1d:
case 0x1e:
// printable string and such
if (_asn1_is_field_present(fields, Constants::issurer_id)) {
if (_asn1_is_oid(oid, Constants::country_oid)) {
cert.issuer_country = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::state_oid)) {
cert.issuer_state = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::location_oid)) {
cert.issuer_location = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::entity_oid)) {
cert.issuer_entity = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::subject_oid)) {
cert.issuer_subject = String { (const char*)buffer + position, length };
}
} else if (_asn1_is_field_present(fields, Constants::owner_id)) {
if (_asn1_is_oid(oid, Constants::country_oid)) {
cert.country = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::state_oid)) {
cert.state = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::location_oid)) {
cert.location = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::entity_oid)) {
cert.entity = String { (const char*)buffer + position, length };
} else if (_asn1_is_oid(oid, Constants::subject_oid)) {
cert.subject = String { (const char*)buffer + position, length };
}
}
break;
default:
// dbg() << "unused field " << type;
break;
}
}
position += length;
}
if (level == 2 && cert.sign_key.size() && cert_length && cert_data) {
cert.fingerprint.clear();
Crypto::Hash::Manager hash;
switch (cert.key_algorithm) {
case CertificateKeyAlgorithm::RSA_MD5:
hash.initialize(Crypto::Hash::HashKind::MD5);
break;
case CertificateKeyAlgorithm::RSA_SHA1:
hash.initialize(Crypto::Hash::HashKind::SHA1);
break;
case CertificateKeyAlgorithm::RSA_SHA256:
hash.initialize(Crypto::Hash::HashKind::SHA256);
break;
case CertificateKeyAlgorithm::RSA_SHA512:
hash.initialize(Crypto::Hash::HashKind::SHA512);
break;
default:
#ifdef TLS_DEBUG
dbg() << "Unsupported hash mode " << (u32)cert.key_algorithm;
#endif
// fallback to md5, it will fail later
hash.initialize(Crypto::Hash::HashKind::MD5);
break;
}
hash.update(cert_data, cert_length);
auto fingerprint = hash.digest();
cert.fingerprint.grow(fingerprint.data_length());
cert.fingerprint.overwrite(0, fingerprint.immutable_data(), fingerprint.data_length());
#ifdef TLS_DEBUG
dbg() << "Certificate fingerprint:";
print_buffer(cert.fingerprint);
#endif
}
return position;
}
}
Optional<Certificate> TLSv12::parse_asn1(const ByteBuffer& buffer, bool) const
{
// FIXME: Our ASN.1 parser is not quite up to the task of
// parsing this X.509 certificate, so for the
// time being, we will "parse" the certificate
// manually right here.
Certificate cert;
u32 fields[0xff];
_parse_asn1(m_context, cert, buffer.data(), buffer.size(), 1, fields, nullptr, 0, nullptr, nullptr);
#ifdef TLS_DEBUG
dbg() << "Certificate issued for " << cert.subject << " by " << cert.issuer_subject;
#endif
return cert;
}
ssize_t TLSv12::handle_certificate(const ByteBuffer& buffer)
{
ssize_t res = 0;
if (buffer.size() < 3) {
#ifdef TLS_DEBUG
dbg() << "not enough certificate header data";
#endif
return (i8)Error::NeedMoreData;
}
u32 certificate_total_length = buffer[0] * 0x10000 + buffer[1] * 0x100 + buffer[2];
#ifdef TLS_DEBUG
dbg() << "total length: " << certificate_total_length;
#endif
if (certificate_total_length <= 4)
return 3 * certificate_total_length;
res += 3;
if (certificate_total_length > buffer.size() - res) {
#ifdef TLS_DEBUG
dbg() << "not enough data for claimed total cert length";
#endif
return (i8)Error::NeedMoreData;
}
size_t size = certificate_total_length;
size_t index = 0;
bool valid_certificate = false;
while (size > 0) {
++index;
if (buffer.size() - res < 3) {
#ifdef TLS_DEBUG
dbg() << "not enough data for certificate length";
#endif
return (i8)Error::NeedMoreData;
}
size_t certificate_size = buffer[res] * 0x10000 + buffer[res + 1] * 0x100 + buffer[res + 2];
res += 3;
if (buffer.size() - res < certificate_size) {
#ifdef TLS_DEBUG
dbg() << "not enough data for certificate body";
#endif
return (i8)Error::NeedMoreData;
}
auto res_cert = res;
auto remaining = certificate_size;
size_t certificates_in_chain = 0;
do {
if (remaining <= 3) {
dbg() << "Ran out of data";
break;
}
++certificates_in_chain;
if (buffer.size() < (size_t)res_cert + 3) {
dbg() << "not enough data to read cert size (" << buffer.size() << " < " << res_cert + 3 << ")";
break;
}
size_t certificate_size_specific = buffer[res_cert] * 0x10000 + buffer[res_cert + 1] * 0x100 + buffer[res_cert + 2];
res_cert += 3;
remaining -= 3;
if (certificate_size_specific > remaining) {
dbg() << "invalid certificate size (expected " << remaining << " but got " << certificate_size_specific << ")";
break;
}
remaining -= certificate_size_specific;
auto certificate = parse_asn1(buffer.slice_view(res_cert, certificate_size_specific), false);
if (certificate.has_value()) {
m_context.certificates.append(certificate.value());
valid_certificate = true;
}
res_cert += certificate_size_specific;
} while (remaining > 0);
if (remaining) {
dbg() << "extraneous " << remaining << " bytes left over after parsing certificates";
}
size -= certificate_size + 3;
res += certificate_size;
}
if (!valid_certificate)
return (i8)Error::UnsupportedCertificate;
if ((size_t)res != buffer.size())
dbg() << "some data left unread: " << (size_t)res << " bytes out of " << buffer.size();
return res;
}
void TLSv12::consume(const ByteBuffer& record)
{
if (m_context.critical_error) {
dbg() << "There has been a critical error (" << (i8)m_context.critical_error << "), refusing to continue";
return;
}
if (record.size() == 0) {
return;
}
#ifdef TLS_DEBUG
dbg() << "Consuming " << record.size() << " bytes";
#endif
m_context.message_buffer.append(record.data(), record.size());
size_t index { 0 };
size_t buffer_length = m_context.message_buffer.size();
size_t size_offset { 3 }; // read the common record header
size_t header_size { 5 };
#ifdef TLS_DEBUG
dbg() << "message buffer length " << buffer_length;
#endif
while (buffer_length >= 5) {
auto length = AK::convert_between_host_and_network_endian(*(u16*)m_context.message_buffer.offset_pointer(index + size_offset)) + header_size;
if (length > buffer_length) {
#ifdef TLS_DEBUG
dbg() << "Need more data: " << length << " | " << buffer_length;
#endif
break;
}
auto consumed = handle_message(m_context.message_buffer.slice_view(index, length));
#ifdef TLS_DEBUG
if (consumed > 0)
dbg() << "consumed " << (size_t)consumed << " bytes";
else
dbg() << "error: " << (int)consumed;
#endif
if (consumed != (i8)Error::NeedMoreData) {
if (consumed < 0) {
dbg() << "Consumed an error: " << (int)consumed;
if (!m_context.critical_error)
m_context.critical_error = (i8)consumed;
m_context.error_code = (Error)consumed;
break;
}
} else {
continue;
}
index += length;
buffer_length -= length;
if (m_context.critical_error) {
dbg() << "Broken connection";
m_context.error_code = Error::BrokenConnection;
break;
}
}
if (m_context.error_code != Error::NoError && m_context.error_code != Error::NeedMoreData) {
dbg() << "consume error: " << (i8)m_context.error_code;
m_context.message_buffer.clear();
return;
}
if (index) {
m_context.message_buffer = m_context.message_buffer.slice(index, m_context.message_buffer.size() - index);
}
}
void TLSv12::ensure_hmac(size_t digest_size, bool local)
{
if (local && m_hmac_local)
return;
if (!local && m_hmac_remote)
return;
auto hash_kind = Crypto::Hash::HashKind::None;
switch (digest_size) {
case Crypto::Hash::SHA1::DigestSize:
hash_kind = Crypto::Hash::HashKind::SHA1;
break;
case Crypto::Hash::SHA256::DigestSize:
hash_kind = Crypto::Hash::HashKind::SHA256;
break;
case Crypto::Hash::SHA512::DigestSize:
hash_kind = Crypto::Hash::HashKind::SHA512;
break;
default:
dbg() << "Failed to find a suitable hash for size " << digest_size;
break;
}
auto hmac = make<Crypto::Authentication::HMAC<Crypto::Hash::Manager>>(ByteBuffer::wrap(local ? m_context.crypto.local_mac : m_context.crypto.remote_mac, digest_size), hash_kind);
if (local)
m_hmac_local = move(hmac);
else
m_hmac_remote = move(hmac);
}
bool Certificate::is_valid() const
{
auto now = Core::DateTime::now();
if (!not_before.is_empty()) {
if (now.is_before(not_before)) {
dbg() << "certificate expired (not yet valid, signed for " << not_before << ")";
return false;
}
}
if (!not_after.is_empty()) {
if (!now.is_before(not_after)) {
dbg() << "certificate expired (expiry date " << not_after << ")";
return false;
}
}
return true;
}
void TLSv12::try_disambiguate_error() const
{
dbg() << "Possible failure cause(s): ";
switch ((AlertDescription)m_context.critical_error) {
case AlertDescription::HandshakeFailure:
if (!m_context.cipher_spec_set) {
dbg() << "- No cipher suite in common with " << m_context.SNI;
} else {
dbg() << "- Unknown internal issue";
}
break;
case AlertDescription::InsufficientSecurity:
dbg() << "- No cipher suite in common with " << m_context.SNI << " (the server is oh so secure)";
break;
case AlertDescription::ProtocolVersion:
dbg() << "- The server refused to negotiate with TLS 1.2 :(";
break;
case AlertDescription::UnexpectedMessage:
dbg() << "- We sent an invalid message for the state we're in.";
break;
case AlertDescription::BadRecordMAC:
dbg() << "- Bad MAC record from our side.";
dbg() << "- Ciphertext wasn't an even multiple of the block length.";
dbg() << "- Bad block cipher padding.";
dbg() << "- If both sides are compliant, the only cause is messages being corrupted in the network.";
break;
case AlertDescription::RecordOverflow:
dbg() << "- Sent a ciphertext record which has a length bigger than 18432 bytes.";
dbg() << "- Sent record decrypted to a compressed record that has a length bigger than 18432 bytes.";
dbg() << "- If both sides are compliant, the only cause is messages being corrupted in the network.";
break;
case AlertDescription::DecompressionFailure:
dbg() << "- We sent invalid input for decompression (e.g. data that would expand to excessive length)";
break;
case AlertDescription::IllegalParameter:
dbg() << "- We sent a parameter in the handshake that is out of range or inconsistent with the other parameters.";
break;
case AlertDescription::DecodeError:
dbg() << "- The message we sent cannot be decoded because a field was out of range or the length was incorrect.";
dbg() << "- If both sides are compliant, the only cause is messages being corrupted in the network.";
break;
case AlertDescription::DecryptError:
dbg() << "- A handshake crypto operation failed. This includes signature verification and validating Finished.";
break;
case AlertDescription::AccessDenied:
dbg() << "- The certificate is valid, but once access control was applied, the sender decided to stop negotiation.";
break;
case AlertDescription::InternalError:
dbg() << "- No one knows, but it isn't a protocol failure.";
break;
case AlertDescription::DecryptionFailed:
case AlertDescription::NoCertificate:
case AlertDescription::ExportRestriction:
dbg() << "- No one knows, the server sent a non-compliant alert.";
break;
default:
dbg() << "- No one knows.";
break;
}
}
TLSv12::TLSv12(Core::Object* parent, Version version)
: Core::Socket(Core::Socket::Type::TCP, parent)
{
m_context.version = version;
m_context.is_server = false;
m_context.tls_buffer = ByteBuffer::create_uninitialized(0);
#ifdef SOCK_NONBLOCK
int fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
#else
int fd = socket(AF_INET, SOCK_STREAM, 0);
int option = 1;
ioctl(fd, FIONBIO, &option);
#endif
if (fd < 0) {
set_error(errno);
} else {
set_fd(fd);
set_mode(IODevice::ReadWrite);
set_error(0);
}
}
bool TLSv12::add_client_key(const ByteBuffer& certificate_pem_buffer, const ByteBuffer& rsa_key) // FIXME: This should not be bound to RSA
{
if (certificate_pem_buffer.is_empty() || rsa_key.is_empty()) {
return true;
}
auto decoded_certificate = Crypto::decode_pem(certificate_pem_buffer, 0);
if (decoded_certificate.is_empty()) {
dbg() << "Certificate not PEM";
return false;
}
auto maybe_certificate = parse_asn1(decoded_certificate);
if (!maybe_certificate.has_value()) {
dbg() << "Invalid certificate";
return false;
}
Crypto::PK::RSA rsa(rsa_key);
auto certificate = maybe_certificate.value();
certificate.private_key = rsa.private_key();
return add_client_key(certificate);
}
}