LibTLS: Make enough stuff work to have a demo run

...maybe, sometimes :^)

4 files changed, 2270 insertions, 2 deletions

diff --git a/Libraries/LibHTTP/HttpsJob.cpp b/Libraries/LibHTTP/HttpsJob.cpp
index e783b815cd..ec23fbdaae 100644
--- a/Libraries/LibHTTP/HttpsJob.cpp
+++ b/Libraries/LibHTTP/HttpsJob.cpp
@@ -211,8 +211,20 @@ void HttpsJob::start()
 #endif
         on_socket_connected();
     };
-    m_socket->on_tls_error = [&](auto) {
-        finish_up();
+    m_socket->on_tls_error = [&](TLS::AlertDescription error) {
+        if (error == TLS::AlertDescription::HandshakeFailure) {
+            deferred_invoke([this](auto&) {
+                return did_fail(Core::NetworkJob::Error::ProtocolFailed);
+            });
+        } else if (error == TLS::AlertDescription::DecryptError) {
+            deferred_invoke([this](auto&) {
+                return did_fail(Core::NetworkJob::Error::ConnectionFailed);
+            });
+        } else {
+            deferred_invoke([this](auto&) {
+                return did_fail(Core::NetworkJob::Error::TransmissionFailed);
+            });
+        }
     };
     m_socket->on_tls_finished = [&] {
         finish_up();
diff --git a/Libraries/LibTLS/Makefile b/Libraries/LibTLS/Makefile
new file mode 100644
index 0000000000..e34ac6cd1b
--- /dev/null
+++ b/Libraries/LibTLS/Makefile
@@ -0,0 +1,16 @@
+LIBTLS_OBJS = TLSv12.o
+
+OBJS = $(LIBTLS_OBJS)
+
+LIBRARY = libtls.a
+
+install:
+	for dir in .; do \
+	    mkdir -p $(SERENITY_BASE_DIR)/Root/usr/include/LibTLS/$$dir; \
+	    cp $$dir/*.h $(SERENITY_BASE_DIR)/Root/usr/include/LibTLS/$$dir/; \
+	done
+	cp $(LIBRARY) $(SERENITY_BASE_DIR)/Root/usr/lib/
+
+include ../../Makefile.common
+
+include ../../Makefile.subdir
diff --git a/Libraries/LibTLS/TLSv12.cpp b/Libraries/LibTLS/TLSv12.cpp
new file mode 100644
index 0000000000..07eb74b362
--- /dev/null
+++ b/Libraries/LibTLS/TLSv12.cpp
@@ -0,0 +1,1836 @@
+/*
+ * 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 <LibCore/Timer.h>
+#include <LibCrypto/ASN1/DER.h>
+#include <LibCrypto/PK/Code/EMSA_PSS.h>
+#include <LibTLS/TLSv12.h>
+
+//#define TLS_DEBUG
+
+namespace {
+inline static void print_buffer(const ByteBuffer& buffer)
+{
+    for (size_t i { 0 }; i < buffer.size(); ++i)
+        dbgprintf("%02x ", buffer[i]);
+    dbgprintf("\n");
+}
+inline static void print_buffer(const u8* buffer, size_t size)
+{
+    for (size_t i { 0 }; i < size; ++i)
+        dbgprintf("%02x ", buffer[i]);
+    dbgprintf("\n");
+}
+}
+
+using namespace Crypto;
+
+namespace {
+struct OIDChain {
+    void* root;
+    u8* oid;
+};
+}
+
+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 void _set_algorithm(u32&, const u8* value, size_t length)
+    {
+        if (length != 9) {
+            dbg() << "unsupported algorithm " << value;
+        }
+
+        dbg() << "FIXME: Set algorithm";
+    }
+
+    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(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) {
+                dbg() << "could not read the certificate";
+                return position;
+            }
+
+            position += octets;
+            if (size - position < length) {
+                dbg() << "not enough data for sequence";
+                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(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) {
+            dbg() << "FIXME: Cert.fingerprint";
+        }
+        return position;
+    }
+}
+
+Optional<Certificate> TLSv12::parse_asn1(const ByteBuffer& buffer, bool)
+{
+    // 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;
+}
+
+ByteBuffer TLSv12::build_hello()
+{
+    // arc4random_buf(&m_context.local_random, 32);
+    auto packet_version = (u16)m_context.version;
+    auto version = (u16)m_context.version;
+    PacketBuilder builder { MessageType::Handshake, packet_version };
+    // client hello
+    builder.append((u8)0x1);
+
+    // hello length (for later)
+    u8 dummy[3];
+    builder.append(dummy, 3);
+
+    auto start_length = builder.length();
+
+    builder.append(version);
+    builder.append(m_context.local_random, sizeof(m_context.local_random));
+
+    builder.append(m_context.session_id_size);
+    if (m_context.session_id_size)
+        builder.append(m_context.session_id, m_context.session_id_size);
+
+    size_t extension_length = 0;
+    size_t alpn_length = 0;
+    size_t alpn_negotiated_length = 0;
+
+    // ALPN
+    if (!m_context.negotiated_alpn.is_null()) {
+        alpn_negotiated_length = m_context.negotiated_alpn.length();
+        alpn_length = alpn_negotiated_length + 1;
+        extension_length += alpn_length + 6;
+    } else if (m_context.alpn.size()) {
+        for (auto& alpn : m_context.alpn) {
+            size_t length = alpn.length();
+            alpn_length += length + 1;
+        }
+        if (alpn_length)
+            extension_length += alpn_length + 6;
+    }
+
+    // Ciphers
+    builder.append((u16)(2 * sizeof(u16)));
+    builder.append((u16)CipherSuite::RSA_WITH_AES_128_CBC_SHA256);
+    builder.append((u16)CipherSuite::RSA_WITH_AES_256_CBC_SHA256);
+
+    // we don't like compression
+    builder.append((u8)1);
+    builder.append((u8)0);
+
+    // set SNI if we have one
+    auto sni_length = 0;
+    if (!m_context.SNI.is_null())
+        sni_length = m_context.SNI.length();
+
+    if (sni_length)
+        extension_length += sni_length + 9;
+
+    builder.append((u16)extension_length);
+
+    if (sni_length) {
+        // SNI extension
+        builder.append((u16)0x00);
+        // extension length
+        builder.append((u16)(sni_length + 5));
+        // SNI length
+        builder.append((u16)(sni_length + 3));
+        // SNI type
+        builder.append((u8)0);
+        // SNI host length + value
+        builder.append((u16)sni_length);
+        builder.append((const u8*)m_context.SNI.characters(), sni_length);
+    }
+
+    if (alpn_length) {
+        // TODO
+        ASSERT_NOT_REACHED();
+    }
+
+    // set the "length" field of the packet
+    size_t remaining = builder.length() - start_length;
+    size_t payload_position = 6;
+    builder.set(payload_position, remaining / 0x10000);
+    remaining %= 0x10000;
+    builder.set(payload_position + 1, remaining / 0x100);
+    remaining %= 0x100;
+    builder.set(payload_position + 2, remaining);
+
+    auto packet = builder.build();
+    update_packet(packet);
+
+    return packet;
+}
+
+ByteBuffer TLSv12::build_alert(bool critical, u8 code)
+{
+    dbg() << "FIXME: build_alert";
+    (void)critical;
+    (void)code;
+    return {};
+}
+
+ByteBuffer TLSv12::build_finished()
+{
+    PacketBuilder builder { MessageType::Handshake, m_context.version, 12 + 64 };
+    builder.append((u8)0x14);
+    builder.append_u24(12);
+
+    size_t out_size = 12;
+    u8 out[out_size];
+    auto outbuffer = ByteBuffer::wrap(out, out_size);
+    auto dummy = ByteBuffer::create_zeroed(0);
+
+    auto digest = m_context.handshake_hash.hash.peek();
+    auto hashbuf = ByteBuffer::wrap(digest.data, m_context.handshake_hash.hash.DigestSize);
+    pseudorandom_function(outbuffer, m_context.master_key, (const u8*)"client finished", 15, hashbuf, dummy);
+
+    builder.append(outbuffer);
+    auto packet = builder.build();
+    update_packet(packet);
+
+    return packet;
+}
+
+ByteBuffer TLSv12::build_certificate()
+{
+    dbg() << "FIXME: build_certificate";
+    return {};
+}
+
+ByteBuffer TLSv12::build_change_cipher_spec()
+{
+    PacketBuilder builder { MessageType::ChangeCipher, m_context.version, 64 };
+    builder.append((u8)1);
+    auto packet = builder.build();
+    update_packet(packet);
+    m_context.local_sequence_number = 0;
+    return packet;
+}
+
+ByteBuffer TLSv12::build_server_key_exchange()
+{
+    dbg() << "FIXME: build_server_key_exchange";
+    return {};
+}
+
+ByteBuffer TLSv12::build_client_key_exchange()
+{
+    PacketBuilder builder { MessageType::Handshake, m_context.version };
+    builder.append((u8)0x10);
+    build_random(builder);
+
+    m_context.connection_status = 2;
+
+    auto packet = builder.build();
+
+    update_packet(packet);
+
+    return packet;
+}
+
+bool TLSv12::expand_key()
+{
+    u8 key[192]; // soooooooo many constants
+    auto key_buffer = ByteBuffer::wrap(key, 192);
+
+    if (m_context.master_key.size() == 0) {
+        dbg() << "expand_key() with empty master key";
+        return false;
+    }
+
+    auto key_size = key_length();
+    auto mac_size = mac_length();
+    auto iv_size = 16;
+
+    pseudorandom_function(
+        key_buffer,
+        m_context.master_key,
+        (const u8*)"key expansion", 13,
+        ByteBuffer::wrap(m_context.remote_random, 32),
+        ByteBuffer::wrap(m_context.local_random, 32));
+
+    size_t offset = 0;
+    memcpy(m_context.crypto.local_mac, key + offset, mac_size);
+    offset += mac_size;
+    memcpy(m_context.crypto.remote_mac, key + offset, mac_size);
+    offset += mac_size;
+
+    auto client_key = key + offset;
+    offset += key_size;
+    auto server_key = key + offset;
+    offset += key_size;
+    auto client_iv = key + offset;
+    offset += iv_size;
+    auto server_iv = key + offset;
+    offset += iv_size;
+
+#ifdef TLS_DEBUG
+    dbg() << "client key";
+    print_buffer(client_key, key_size);
+    dbg() << "server key";
+    print_buffer(server_key, key_size);
+    dbg() << "client iv";
+    print_buffer(client_iv, iv_size);
+    dbg() << "server iv";
+    print_buffer(server_iv, iv_size);
+    dbg() << "client mac key";
+    print_buffer(m_context.crypto.local_mac, 32);
+    dbg() << "server mac key";
+    print_buffer(m_context.crypto.remote_mac, 32);
+#endif
+
+    memcpy(m_context.crypto.local_iv, client_iv, iv_size);
+    memcpy(m_context.crypto.remote_iv, server_iv, iv_size);
+
+    m_aes_local = make<Crypto::Cipher::AESCipher::CBCMode>(ByteBuffer::wrap(client_key, key_size), key_size * 8, Crypto::Cipher::Intent::Encryption, Crypto::Cipher::PaddingMode::RFC5246);
+    m_aes_remote = make<Crypto::Cipher::AESCipher::CBCMode>(ByteBuffer::wrap(server_key, key_size), key_size * 8, Crypto::Cipher::Intent::Decryption, Crypto::Cipher::PaddingMode::RFC5246);
+
+    m_context.crypto.created = 1;
+
+    return true;
+}
+
+void TLSv12::pseudorandom_function(ByteBuffer& output, const ByteBuffer& secret, const u8* label, size_t label_length, const ByteBuffer& seed, const ByteBuffer& seed_b)
+{
+    if (!secret.size()) {
+        dbg() << "null secret";
+        return;
+    }
+
+    Crypto::Authentication::HMAC<Crypto::Hash::SHA256> hmac(secret);
+
+    auto l_seed_size = label_length + seed.size() + seed_b.size();
+    u8 l_seed[l_seed_size];
+    auto label_seed_buffer = ByteBuffer::wrap(l_seed, l_seed_size);
+    label_seed_buffer.overwrite(0, label, label_length);
+    label_seed_buffer.overwrite(label_length, seed.data(), seed.size());
+    label_seed_buffer.overwrite(label_length + seed.size(), seed_b.data(), seed_b.size());
+
+    u8 digest[hmac.DigestSize];
+
+    auto digest_0 = ByteBuffer::wrap(digest, hmac.DigestSize);
+
+    digest_0.overwrite(0, hmac.process(label_seed_buffer).data, hmac.DigestSize);
+
+    size_t index = 0;
+    while (index < output.size()) {
+        hmac.update(digest_0);
+        hmac.update(label_seed_buffer);
+        auto digest_1 = hmac.digest();
+
+        auto copy_size = min(hmac.DigestSize, output.size() - index);
+
+        output.overwrite(index, digest_1.data, copy_size);
+        index += copy_size;
+
+        digest_0.overwrite(0, hmac.process(digest_0).data, hmac.DigestSize);
+    }
+}
+
+bool TLSv12::compute_master_secret(size_t length)
+{
+    if (m_context.premaster_key.size() == 0 || length < 48) {
+        dbg() << "there's no way I can make a master secret like this";
+        dbg() << "I'd like to talk to your manager about this length of " << length;
+        return false;
+    }
+
+    m_context.master_key.clear();
+    m_context.master_key.grow(length);
+
+    pseudorandom_function(
+        m_context.master_key,
+        m_context.premaster_key,
+        (const u8*)"master secret", 13,
+        ByteBuffer::wrap(m_context.local_random, 32),
+        ByteBuffer::wrap(m_context.remote_random, 32));
+
+    m_context.premaster_key.clear();
+#ifdef TLS_DEBUG
+    dbg() << "master key:";
+    print_buffer(m_context.master_key);
+#endif
+    expand_key();
+    return true;
+}
+
+void TLSv12::build_random(PacketBuilder& builder)
+{
+    u8 random_bytes[48] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 };
+    size_t bytes = 48;
+
+    //    arc4random_buf(random_bytes, bytes);
+
+    if (m_context.is_server) {
+        dbg() << "Server mode not supported";
+        return;
+    } else {
+        *(u16*)random_bytes = convert_between_host_and_network((u16)Version::V12);
+    }
+
+    m_context.premaster_key = ByteBuffer::copy(random_bytes, bytes);
+
+    const auto& certificate = m_context.certificates[0];
+#ifdef TLS_DEBUG
+    dbg() << "PreMaster secret";
+    print_buffer(m_context.premaster_key);
+#endif
+
+    Crypto::PK::RSA_PKCS1_EME rsa(certificate.public_key.modulus(), 0, certificate.public_key.public_exponent());
+
+    u8 out[rsa.output_size()];
+    auto outbuf = ByteBuffer::wrap(out, rsa.output_size());
+    rsa.encrypt(m_context.premaster_key, outbuf);
+
+#ifdef TLS_DEBUG
+    dbg() << "Encrypted: ";
+    print_buffer(outbuf);
+#endif
+
+    if (!compute_master_secret(bytes)) {
+        dbg() << "oh noes we could not derive a master key :(";
+        return;
+    }
+
+    builder.append_u24(outbuf.size() + 2);
+    builder.append((u16)outbuf.size());
+    builder.append(outbuf);
+}
+
+Optional<ByteBuffer> TLSv12::read()
+{
+    if (m_context.application_buffer.size()) {
+        auto buf = m_context.application_buffer.slice(0, m_context.application_buffer.size());
+        m_context.application_buffer.clear();
+        return buf;
+    } else
+        return {};
+}
+
+ByteBuffer TLSv12::read(size_t max_size)
+{
+    if (m_context.application_buffer.size()) {
+        auto length = min(m_context.application_buffer.size(), max_size);
+        auto buf = m_context.application_buffer.slice(0, length);
+        m_context.application_buffer = m_context.application_buffer.slice(length, m_context.application_buffer.size() - length);
+        return buf;
+    } else
+        return {};
+}
+
+ByteBuffer TLSv12::read_line(size_t max_size)
+{
+    if (!can_read_line())
+        return {};
+
+    auto* start = m_context.application_buffer.data();
+    auto* newline = (u8*)memchr(m_context.application_buffer.data(), '\n', m_context.application_buffer.size());
+    ASSERT(newline);
+
+    size_t offset = newline - start;
+
+    if (offset > max_size)
+        return {};
+
+    auto buffer = ByteBuffer::copy(start, offset);
+    m_context.application_buffer = m_context.application_buffer.slice(offset + 1, m_context.application_buffer.size() - offset - 1);
+
+    return buffer;
+}
+
+bool TLSv12::write(const ByteBuffer& buffer)
+{
+    if (m_context.connection_status != 0xff) {
+        dbg() << "write request while not connected";
+        return false;
+    }
+
+    PacketBuilder builder { MessageType::ApplicationData, m_context.version, buffer.size() };
+    builder.append(buffer);
+    auto packet = builder.build();
+
+    update_packet(packet);
+    write_packet(packet);
+
+    return true;
+}
+
+void TLSv12::write_packet(ByteBuffer& packet)
+{
+    m_context.tls_buffer.append(packet.data(), packet.size());
+}
+
+void TLSv12::update_packet(ByteBuffer& packet)
+{
+    u32 header_size = 5;
+    *(u16*)packet.offset_pointer(3) = convert_between_host_and_network((u16)(packet.size() - header_size));
+
+    if (packet[0] != (u8)MessageType::ChangeCipher) {
+        if (packet[0] == (u8)MessageType::Handshake && packet.size() > header_size) {
+            u8 handshake_type = packet[header_size];
+            if (handshake_type != 0x00 && handshake_type != 0x03) {
+                update_hash(packet.slice_view(header_size, packet.size() - header_size));
+            }
+        }
+        if (m_context.cipher_spec_set && m_context.crypto.created) {
+            size_t length = packet.size() - header_size + mac_length();
+            auto block_size = m_aes_local->cipher().block_size();
+            // if length is a multiple of block size, pad it up again
+            // since it seems no one handles aligned unpadded blocks
+            size_t padding = 0;
+            if (length % block_size == 0) {
+                padding = block_size;
+                length += padding;
+            }
+            size_t mac_size = mac_length();
+
+            if (m_context.crypto.created == 1) {
+                // `buffer' will continue to be encrypted
+                auto buffer = ByteBuffer::create_zeroed(length);
+                size_t buffer_position = 0;
+                u16 aligned_length = length + block_size - length % block_size;
+
+                // we need enough space for a header, 16 bytes of IV and whatever the packet contains
+                auto ct = ByteBuffer::create_zeroed(aligned_length + header_size + 16);
+
+                // copy the header over
+                ct.overwrite(0, packet.data(), header_size - 2);
+
+                // copy the packet, sans the header
+                buffer.overwrite(buffer_position, packet.offset_pointer(header_size), packet.size() - header_size);
+                buffer_position += packet.size() - header_size;
+
+                // get the appropricate HMAC value for the entire packet
+                auto mac = hmac_message(packet, {}, mac_size, true);
+
+                // write the MAC
+                buffer.overwrite(buffer_position, mac.data(), mac.size());
+                buffer_position += mac.size();
+
+                // if there's some padding to be done (since a packet MUST always be padded)
+                // apply it manually
+                if (padding) {
+                    memset(buffer.offset_pointer(buffer_position), padding - 1, padding);
+                    buffer_position += padding;
+                }
+
+                // should be the same value, but the manual padding
+                // throws a wrench into our plans
+                buffer.trim(buffer_position);
+
+                // make a random seed IV for this message
+                u8 record_iv[16] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+                // arc4random_buf(record_iv, 16);
+
+                auto iv = ByteBuffer::wrap(record_iv, 16);
+
+                // write it into the ciphertext portion of the message
+                ct.overwrite(header_size, record_iv, 16);
+                ct.trim(length + block_size - length % block_size + header_size + block_size - padding);
+
+                // get a block to encrypt into
+                auto view = ct.slice_view(header_size + 16, length + block_size - length % block_size + block_size - padding - 16);
+
+                // encrypt the message
+                m_aes_local->encrypt(buffer, view, iv);
+
+                // store the correct ciphertext length into the packet
+                u16 ct_length = (u16)ct.size() - header_size;
+                *(u16*)ct.offset_pointer(header_size - 2) = convert_between_host_and_network(ct_length);
+
+                // replace the packet with the ciphertext
+                packet = ct;
+            }
+        }
+    }
+    ++m_context.local_sequence_number;
+}
+
+ssize_t TLSv12::handle_hello(const ByteBuffer& buffer, size_t& write_packets)
+{
+    write_packets = 0;
+    if (m_context.connection_status != 0 && m_context.connection_status != 4) {
+        dbg() << "unexpected hello message";
+        return (i8)Error::UnexpectedMessage;
+    }
+    ssize_t res = 0;
+    size_t min_hello_size = 41;
+
+    if (min_hello_size > buffer.size()) {
+        dbg() << "need more data";
+        return (i8)Error::NeedMoreData;
+    }
+    size_t following_bytes = buffer[0] * 0x10000 + buffer[1] * 0x100 + buffer[2];
+    res += 3;
+    if (buffer.size() - res < following_bytes) {
+        dbg() << "not enough data after header: " << buffer.size() - res << " < " << following_bytes;
+        return (i8)Error::NeedMoreData;
+    }
+
+    if (buffer.size() - res < 2) {
+        dbg() << "not enough data for version";
+        return (i8)Error::NeedMoreData;
+    }
+    auto version = (Version)convert_between_host_and_network(*(const u16*)buffer.offset_pointer(res));
+
+    res += 2;
+    if (!version_supported(version))
+        return (i8)Error::NotSafe;
+
+    memcpy(m_context.remote_random, buffer.offset_pointer(res), sizeof(m_context.remote_random));
+    res += sizeof(m_context.remote_random);
+
+    u8 session_length = buffer[res++];
+    if (buffer.size() - res < session_length) {
+        dbg() << "not enough data for session id";
+        return (i8)Error::NeedMoreData;
+    }
+
+    if (session_length && session_length <= 32) {
+        memcpy(m_context.session_id, buffer.offset_pointer(res), session_length);
+        m_context.session_id_size = session_length;
+        dbg() << "Remote session ID:";
+        print_buffer(ByteBuffer::wrap(m_context.session_id, session_length));
+    } else {
+        m_context.session_id_size = 0;
+    }
+    res += session_length;
+
+    if (buffer.size() - res < 2) {
+        dbg() << "not enough data for cipher suite listing";
+        return (i8)Error::NeedMoreData;
+    }
+    auto cipher = (CipherSuite)convert_between_host_and_network(*(const u16*)buffer.offset_pointer(res));
+    res += 2;
+    if (!cipher_supported(cipher)) {
+        m_context.cipher = CipherSuite::Invalid;
+        dbg() << "No supported cipher could be agreed upon";
+        return (i8)Error::NoCommonCipher;
+    }
+    m_context.cipher = cipher;
+    dbg() << "Cipher: " << (u16)cipher;
+
+    if (buffer.size() - res < 1) {
+        dbg() << "not enough data for compression spec";
+        return (i8)Error::NeedMoreData;
+    }
+    u8 compression = buffer[res++];
+    if (compression != 0) {
+        dbg() << "Server told us to compress, we will not!";
+        return (i8)Error::CompressionNotSupported;
+    }
+
+    if (res > 0) {
+        if (m_context.connection_status != 4)
+            m_context.connection_status = 1;
+        if (m_context.is_server) {
+            dbg() << "unsupported: server mode";
+            write_packets = 2;
+        }
+    }
+
+    if (res > 2) {
+        res += 2;
+    }
+
+    while ((ssize_t)buffer.size() - res >= 4) {
+        u16 extension_type = convert_between_host_and_network(*(const u16*)buffer.offset_pointer(res));
+        res += 2;
+        u16 extension_length = convert_between_host_and_network(*(const u16*)buffer.offset_pointer(res));
+        res += 2;
+
+        dbg() << "extension " << extension_type << " with length " << extension_length;
+        if (extension_length) {
+            if (buffer.size() - res < extension_length) {
+                dbg() << "not enough data for extension";
+                return (i8)Error::NeedMoreData;
+            }
+
+            // SNI
+            if (extension_type == 0x00) {
+                u16 sni_host_length = convert_between_host_and_network(*(const u16*)buffer.offset_pointer(res + 3));
+                if (buffer.size() - res - 5 < sni_host_length) {
+                    dbg() << "Not enough data for sni " << (buffer.size() - res - 5) << " < " << sni_host_length;
+                    return (i8)Error::NeedMoreData;
+                }
+
+                if (sni_host_length) {
+                    m_context.SNI = String { (const char*)buffer.offset_pointer(res + 5), sni_host_length };
+                    dbg() << "server name indicator: " << m_context.SNI;
+                }
+            } else if (extension_type == 0x10 && m_context.alpn.size()) {
+                if (buffer.size() - res > 2) {
+                    auto alpn_length = convert_between_host_and_network(*(const u16*)buffer.offset_pointer(res));
+                    if (alpn_length && alpn_length <= extension_length - 2) {
+                        const u8* alpn = buffer.offset_pointer(res + 2);
+                        size_t alpn_position = 0;
+                        while (alpn_position < alpn_length) {
+                            u8 alpn_size = alpn[alpn_position++];
+                            if (alpn_size + alpn_position >= extension_length)
+                                break;
+                            String alpn_str { (const char*)alpn + alpn_position, alpn_length };
+                            if (alpn_size && m_context.alpn.contains_slow(alpn_str)) {
+                                m_context.negotiated_alpn = alpn_str;
+                                dbg() << "negotiated alpn: " << alpn_str;
+                                break;
+                            }
+                            alpn_position += alpn_length;
+                            if (!m_context.is_server) // server hello must contain one ALPN
+                                break;
+                        }
+                    }
+                }
+            } else if (extension_type == 0x0d) {
+                dbg() << "supported signatures: ";
+                print_buffer(buffer.slice_view(res, extension_length));
+                // FIXME: what are we supposed to do here?
+            }
+            res += extension_length;
+        }
+    }
+
+    return res;
+}
+
+ssize_t TLSv12::handle_finished(const ByteBuffer& buffer, size_t& write_packets)
+{
+    if (m_context.connection_status < 2 || m_context.connection_status == 0xff) {
+        dbg() << "unexpected finished message";
+        return (i8)Error::UnexpectedMessage;
+    }
+
+    write_packets = 0;
+
+    if (buffer.size() < 3) {
+        return (i8)Error::NeedMoreData;
+    }
+
+    size_t index = 3;
+
+    u32 size = buffer[0] * 0x10000 + buffer[1] * 0x100 + buffer[2];
+    index += 3;
+
+    if (size < 12) {
+        dbg() << "finished packet smaller than minimum size: " << size;
+        return (i8)Error::BrokenPacket;
+    }
+
+    if (size < buffer.size() - index) {
+        dbg() << "not enough data after length: " << size << " > " << buffer.size() - index;
+        return (i8)Error::NeedMoreData;
+    }
+
+    // TODO: Compare Hashes
+    dbg() << "FIXME: handle_finished :: Check message validity";
+    m_context.connection_status = 0xff;
+
+    return handle_message(buffer);
+}
+
+ssize_t TLSv12::handle_certificate(const ByteBuffer& buffer)
+{
+    ssize_t res = 0;
+
+    if (buffer.size() < 3) {
+        dbg() << "not enough certificate header data";
+        return (i8)Error::NeedMoreData;
+    }
+
+    u32 certificate_total_length = buffer[0] * 0x10000 + buffer[1] * 0x100 + buffer[2];
+
+    dbg() << "total length: " << certificate_total_length;
+
+    if (certificate_total_length <= 4)
+        return 3 * certificate_total_length;
+
+    res += 3;
+
+    if (certificate_total_length > buffer.size() - res) {
+        dbg() << "not enough data for claimed total cert length";
+        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) {
+            dbg() << "not enough data for certificate length";
+            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) {
+            dbg() << "not enough data for certificate body";
+            return (i8)Error::NeedMoreData;
+        }
+
+        auto res_cert = res;
+        auto remaining = certificate_size;
+        size_t certificates_in_chain = 0;
+
+        do {
+            if (remaining <= 3)
+                break;
+            ++certificates_in_chain;
+            if (buffer.size() < (size_t)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;
+        } 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;
+}
+
+ssize_t TLSv12::handle_server_key_exchange(const ByteBuffer&)
+{
+    dbg() << "FIXME: parse_server_key_exchange";
+    return 0;
+}
+
+ssize_t TLSv12::handle_server_hello_done(const ByteBuffer& buffer)
+{
+    if (buffer.size() < 3)
+        return (i8)Error::NeedMoreData;
+
+    size_t size = buffer[0] * 0x10000 + buffer[1] * 0x100 + buffer[2];
+
+    if (buffer.size() - 3 < size)
+        return (i8)Error::NeedMoreData;
+
+    return size + 3;
+}
+
+ssize_t TLSv12::handle_verify(const ByteBuffer&)
+{
+    dbg() << "FIXME: parse_verify";
+    return 0;
+}
+
+void TLSv12::update_hash(const ByteBuffer& message)
+{
+    m_context.handshake_hash.hash.update(message);
+}
+
+bool TLSv12::connect(const String& hostname, int port)
+{
+    set_sni(hostname);
+    return Core::Socket::connect(hostname, port);
+}
+
+bool TLSv12::common_connect(const struct sockaddr* saddr, socklen_t length)
+{
+    if (m_context.critical_error)
+        return false;
+
+    if (Core::Socket::is_connected()) {
+        if (established()) {
+            ASSERT_NOT_REACHED();
+        } else {
+            Core::Socket::close(); // reuse?
+        }
+    }
+
+    auto packet = build_hello();
+    write_packet(packet);
+
+    Core::Socket::on_connected = [this] {
+        Core::Socket::on_ready_to_read = [this] {
+            if (!Core::Socket::is_open()) {
+                // an abrupt closure (the server is a jerk)
+                dbg() << "Socket not open, assuming abrupt closure";
+                m_context.connection_finished = true;
+            }
+            if (m_context.critical_error) {
+                dbg() << "READ CRITICAL ERROR " << m_context.critical_error << " :(";
+                if (on_tls_error)
+                    on_tls_error((AlertDescription)m_context.critical_error);
+                return;
+            }
+            if (m_context.connection_finished) {
+                if (on_tls_finished)
+                    on_tls_finished();
+                if (m_context.tls_buffer.size()) {
+                    dbg() << "connection closed without finishing data transfer, " << m_context.tls_buffer.size() << " bytes still in buffer";
+                } else {
+                    m_context.connection_finished = false;
+                }
+                if (!m_context.application_buffer.size())
+                    m_context.connection_status = 0;
+                return;
+            }
+            flush();
+            consume(Core::Socket::read(4096)); // FIXME: how much is proper?
+            if (established() && m_context.application_buffer.size())
+                if (on_tls_ready_to_read)
+                    on_tls_ready_to_read(*this);
+        };
+        Core::Socket::on_ready_to_write = [this] {
+            if (!Core::Socket::is_open()) {
+                // an abrupt closure (the server is a jerk)
+                dbg() << "Socket not open, assuming abrupt closure";
+                m_context.connection_finished = true;
+            }
+            if (m_context.critical_error) {
+                dbg() << "WRITE CRITICAL ERROR " << m_context.critical_error << " :(";
+                if (on_tls_error)
+                    on_tls_error((AlertDescription)m_context.critical_error);
+                return;
+            }
+            if (m_context.connection_finished) {
+                if (on_tls_finished)
+                    on_tls_finished();
+                if (m_context.tls_buffer.size()) {
+                    dbg() << "connection closed without finishing data transfer, " << m_context.tls_buffer.size() << " bytes still in buffer";
+                } else {
+                    m_context.connection_finished = false;
+                    dbg() << "FINISHED";
+                }
+                if (!m_context.application_buffer.size()) {
+                    m_context.connection_status = 0;
+                    return;
+                }
+            }
+            flush();
+            if (established() && !m_context.application_buffer.size()) // hey client, you still have stuff to read...
+                if (on_tls_ready_to_write)
+                    on_tls_ready_to_write(*this);
+        };
+        if (on_tls_connected)
+            on_tls_connected();
+    };
+    bool success = Core::Socket::common_connect(saddr, length);
+    if (!success)
+        return false;
+
+    return true;
+}
+
+bool TLSv12::flush()
+{
+    auto out_buffer = write_buffer().data();
+    size_t out_buffer_index { 0 };
+    size_t out_buffer_length = write_buffer().size();
+
+    if (out_buffer_length == 0)
+        return true;
+
+#ifdef TLS_DEBUG
+    dbg() << "SENDING...";
+    print_buffer(out_buffer, out_buffer_length);
+#endif
+    if (Core::Socket::write(&out_buffer[out_buffer_index], out_buffer_length)) {
+        write_buffer().clear();
+        return true;
+    } else
+        return false;
+}
+
+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 = convert_between_host_and_network(*(u16*)m_context.message_buffer.offset_pointer(index + size_offset)) + header_size;
+        if (length > buffer_length) {
+            dbg() << "Need more data: " << length << " | " << buffer_length;
+            break;
+        }
+        auto consumed = handle_message(m_context.message_buffer.slice_view(index, length));
+        if (consumed > 0)
+            dbg() << "consumed " << (size_t)consumed << " bytes";
+        else
+            dbg() << "error: " << (int)consumed;
+
+        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);
+    }
+}
+
+ssize_t TLSv12::handle_message(const ByteBuffer& buffer)
+{
+    auto res { 5ll };
+    size_t header_size = res;
+    ssize_t payload_res = 0;
+
+#ifdef TLS_DEBUG
+    dbg() << "buffer size: " << buffer.size();
+#endif
+    if (buffer.size() < 5) {
+        return (i8)Error::NeedMoreData;
+    }
+
+    auto type = (MessageType)buffer[0];
+    size_t buffer_position { 1 };
+
+    // FIXME: Read the version and verify it
+#ifdef TLS_DEBUG
+    auto version = (Version) * (const u16*)buffer.offset_pointer(buffer_position);
+    dbg() << "type: " << (u8)type << " version: " << (u16)version;
+#endif
+    buffer_position += 2;
+
+    auto length = convert_between_host_and_network(*(const u16*)buffer.offset_pointer(buffer_position));
+    dbg() << "record length: " << length << " at offset: " << buffer_position;
+    buffer_position += 2;
+
+    if (buffer_position + length > buffer.size()) {
+        dbg() << "record length more than what we have: " << buffer.size();
+        return (i8)Error::NeedMoreData;
+    }
+
+#ifdef TLS_DEBUG
+    dbg() << "message type: " << (u8)type << ", length: " << length;
+#endif
+    ByteBuffer plain = buffer.slice_view(buffer_position, buffer.size() - buffer_position);
+
+    if (m_context.cipher_spec_set && type != MessageType::ChangeCipher) {
+#ifdef TLS_DEBUG
+        dbg() << "Encrypted: ";
+        print_buffer(buffer.slice_view(header_size, length));
+#endif
+
+        ASSERT(m_aes_remote);
+
+        auto decrypted = m_aes_remote->create_aligned_buffer(length - 16);
+        auto iv = buffer.slice_view(header_size, 16);
+
+        m_aes_remote->decrypt(buffer.slice_view(header_size + 16, length - 16), decrypted, iv);
+
+        length = decrypted.size();
+
+#ifdef TLS_DEBUG
+        dbg() << "Decrypted: ";
+        print_buffer(decrypted);
+#endif
+
+        auto mac_size = mac_length();
+        if (length < mac_size) {
+            dbg() << "broken packet";
+            auto packet = build_alert(true, (u8)AlertDescription::DecryptError);
+            write_packet(packet);
+            return (i8)Error::BrokenPacket;
+        }
+
+        const u8* message_hmac = decrypted.offset_pointer(length - mac_size);
+        u8 temp_buf[5];
+        memcpy(temp_buf, buffer.offset_pointer(0), 3);
+        *(u16*)(temp_buf + 3) = convert_between_host_and_network(length);
+        auto hmac = hmac_message(ByteBuffer::wrap(temp_buf, 5), decrypted, mac_size);
+        auto message_mac = ByteBuffer::wrap(message_hmac, mac_size);
+        if (hmac != message_mac) {
+            dbg() << "integrity check failed (mac length " << length << ")";
+            dbg() << "mac received:";
+            print_buffer(message_mac);
+            dbg() << "mac computed:";
+            print_buffer(hmac);
+            auto packet = build_alert(true, (u8)AlertDescription::BadRecordMAC);
+            write_packet(packet);
+
+            return (i8)Error::IntegrityCheckFailed;
+        }
+        plain = decrypted.slice(0, length - mac_size);
+    }
+    m_context.remote_sequence_number++;
+
+    switch (type) {
+    case MessageType::ApplicationData:
+        if (m_context.connection_status != 0xff) {
+            dbg() << "unexpected application data";
+            payload_res = (i8)Error::UnexpectedMessage;
+            auto packet = build_alert(true, (u8)AlertDescription::UnexpectedMessage);
+            write_packet(packet);
+        } else {
+#ifdef TLS_DEBUG
+            dbg() << "application data message of size " << plain.size();
+#endif
+
+            m_context.application_buffer.append(plain.data(), plain.size());
+        }
+        break;
+    case MessageType::Handshake:
+#ifdef TLS_DEBUG
+        dbg() << "tls handshake message";
+#endif
+        payload_res = handle_payload(plain);
+        break;
+    case MessageType::ChangeCipher:
+        if (m_context.connection_status != 2) {
+            dbg() << "unexpected change cipher message";
+            auto packet = build_alert(true, (u8)AlertDescription::UnexpectedMessage);
+            payload_res = (i8)Error::UnexpectedMessage;
+        } else {
+#ifdef TLS_DEBUG
+            dbg() << "change cipher spec message";
+#endif
+            m_context.cipher_spec_set = true;
+            m_context.remote_sequence_number = 0;
+        }
+        break;
+    case MessageType::Alert:
+        dbg() << "alert message of length " << length;
+        if (length >= 2) {
+            print_buffer(plain);
+            auto level = plain[0];
+            auto code = plain[1];
+            if (level == (u8)AlertLevel::Critical) {
+                dbg() << "We were alerted of a critical error: " << code;
+                m_context.critical_error = code;
+                res = (i8)Error::UnknownError;
+            } else {
+                dbg() << "Alert: " << code;
+            }
+            if (code == 0) {
+                // close notify
+                res += 2;
+                auto closure_alert = build_alert(true, (u8)AlertDescription::CloseNotify);
+                write_packet(closure_alert);
+                flush();
+                m_context.connection_finished = true;
+            }
+            m_context.error_code = (Error)code;
+        }
+        break;
+    default:
+        dbg() << "message not understood";
+        return (i8)Error::NotUnderstood;
+    }
+
+    if (payload_res < 0)
+        return payload_res;
+
+    if (res > 0)
+        return header_size + length;
+
+    return res;
+}
+
+ByteBuffer TLSv12::hmac_message(const ByteBuffer& buf, const Optional<ByteBuffer> buf2, size_t mac_length, bool local)
+{
+    u64 sequence_number = convert_between_host_and_network(local ? m_context.local_sequence_number : m_context.remote_sequence_number);
+    auto digest = [&](auto& hmac) {
+#ifdef TLS_DEBUG
+        dbg() << "========================= PACKET DATA ==========================";
+        print_buffer((const u8*)&sequence_number, sizeof(u64));
+        print_buffer(buf);
+        if (buf2.has_value())
+            print_buffer(buf2.value());
+        dbg() << "========================= PACKET DATA ==========================";
+#endif
+        hmac.update((const u8*)&sequence_number, sizeof(u64));
+        hmac.update(buf);
+        if (buf2.has_value() && buf2.value().size()) {
+            hmac.update(buf2.value());
+        }
+        auto mac = ByteBuffer::copy(hmac.digest().data, hmac.DigestSize);
+#ifdef TLS_DEBUG
+        dbg() << "HMAC of the block for sequence number " << m_context.local_sequence_number;
+        print_buffer(mac);
+#endif
+        return mac;
+    };
+    switch (mac_length) {
+    case Crypto::Hash::SHA256::DigestSize: {
+        Crypto::Authentication::HMAC<Crypto::Hash::SHA256> hmac(ByteBuffer::wrap(local ? m_context.crypto.local_mac : m_context.crypto.remote_mac, 32));
+        return digest(hmac);
+    }
+    case Crypto::Hash::SHA512::DigestSize: {
+        Crypto::Authentication::HMAC<Crypto::Hash::SHA512> hmac(ByteBuffer::wrap(local ? m_context.crypto.local_mac : m_context.crypto.remote_mac, 32));
+        return digest(hmac);
+    }
+    default:
+        return {};
+    }
+}
+
+ssize_t TLSv12::handle_payload(const ByteBuffer& vbuffer)
+{
+    if (m_context.connection_status == 0xff) {
+        auto packet = build_alert(false, (u8)AlertDescription::NoRenegotiation);
+        write_packet(packet);
+        return 1;
+    }
+    auto buffer = vbuffer;
+    auto buffer_length = buffer.size();
+    auto original_length = buffer_length;
+    while (buffer_length >= 4 && !m_context.critical_error) {
+        ssize_t payload_res = 0;
+        if (buffer_length < 1)
+            return (i8)Error::NeedMoreData;
+        auto type = buffer[0];
+        size_t write_packets = 0;
+        size_t payload_size = buffer[1] * 0x10000 + buffer[2] * 0x100 + buffer[3] + 3;
+#ifdef TLS_DEBUG
+        dbg() << "payload size: " << payload_size << " buffer length: " << buffer_length;
+#endif
+        if (payload_size + 1 > buffer_length)
+            return (i8)Error::NeedMoreData;
+
+        switch (type) {
+        // hello request
+        case 0x00:
+            if (m_context.handshake_messages[0] >= 1) {
+                dbg() << "unexpected hello request message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[0];
+            dbg() << "hello request (renegotiation?)";
+            if (m_context.connection_status == 0xff) {
+                // renegotiation
+                payload_res = (i8)Error::NoRenegotiation;
+            } else {
+                // :shrug:
+                payload_res = (i8)Error::UnexpectedMessage;
+            }
+            break;
+        // client hello
+        case 0x01:
+            // FIXME: We only support client mode right now
+            if (m_context.is_server) {
+                ASSERT_NOT_REACHED();
+            }
+            payload_res = (i8)Error::UnexpectedMessage;
+            break;
+        // server hello
+        case 0x02:
+            if (m_context.handshake_messages[2] >= 1) {
+                dbg() << "unexpected server hello message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[2];
+#ifdef TLS_DEBUG
+            dbg() << "server hello";
+#endif
+            if (m_context.is_server) {
+                dbg() << "unsupported: server mode";
+                ASSERT_NOT_REACHED();
+            } else {
+                payload_res = handle_hello(buffer.slice_view(1, payload_size), write_packets);
+            }
+            break;
+        // hello verify request
+        case 0x03:
+            dbg() << "unsupported: DTLS";
+            payload_res = (i8)Error::UnexpectedMessage;
+            break;
+        // certificate
+        case 0x0b:
+            if (m_context.handshake_messages[4] >= 1) {
+                dbg() << "unexpected certificate message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[4];
+#ifdef TLS_DEBUG
+            dbg() << "certificate";
+#endif
+            if (m_context.connection_status == 1) {
+                if (m_context.is_server) {
+                    dbg() << "unsupported: server mode";
+                    ASSERT_NOT_REACHED();
+                }
+                payload_res = handle_certificate(buffer.slice_view(1, payload_size));
+            } else {
+                payload_res = (i8)Error::UnexpectedMessage;
+            }
+            break;
+        // server key exchange
+        case 0x0c:
+            if (m_context.handshake_messages[5] >= 1) {
+                dbg() << "unexpected server key exchange message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[5];
+#ifdef TLS_DEBUG
+            dbg() << "server key exchange";
+#endif
+            if (m_context.is_server) {
+                dbg() << "unsupported: server mode";
+                ASSERT_NOT_REACHED();
+            } else {
+                payload_res = handle_server_key_exchange(buffer.slice_view(1, payload_size));
+            }
+            break;
+        // certificate request
+        case 0x0d:
+            if (m_context.handshake_messages[6] >= 1) {
+                dbg() << "unexpected certificate request message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[6];
+            if (m_context.is_server) {
+                dbg() << "invalid request";
+                dbg() << "unsupported: server mode";
+                ASSERT_NOT_REACHED();
+            } else {
+                // we do not support "certificate request"
+                dbg() << "certificate request";
+                ASSERT_NOT_REACHED();
+            }
+            break;
+        // server hello done
+        case 0x0e:
+            if (m_context.handshake_messages[7] >= 1) {
+                dbg() << "unexpected server hello done message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[7];
+#ifdef TLS_DEBUG
+            dbg() << "server hello done";
+#endif
+            if (m_context.is_server) {
+                dbg() << "unsupported: server mode";
+                ASSERT_NOT_REACHED();
+            } else {
+                payload_res = handle_server_hello_done(buffer.slice_view(1, payload_size));
+                if (payload_res > 0)
+                    write_packets = 1;
+            }
+            break;
+        // certificate verify
+        case 0x0f:
+            if (m_context.handshake_messages[8] >= 1) {
+                dbg() << "unexpected certificate verify message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[8];
+#ifdef TLS_DEBUG
+            dbg() << "certificate verify";
+#endif
+            if (m_context.connection_status == 2) {
+                payload_res = handle_verify(buffer.slice_view(1, payload_size));
+            } else {
+                payload_res = (i8)Error::UnexpectedMessage;
+            }
+            break;
+        // client key exchange
+        case 0x10:
+            if (m_context.handshake_messages[9] >= 1) {
+                dbg() << "unexpected client key exchange message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[9];
+#ifdef TLS_DEBUG
+            dbg() << "client key exchange";
+#endif
+            if (m_context.is_server) {
+                dbg() << "unsupported: server mode";
+                ASSERT_NOT_REACHED();
+            } else {
+                payload_res = (i8)Error::UnexpectedMessage;
+            }
+            break;
+        // finished
+        case 0x14:
+            if (m_context.cached_handshake) {
+                m_context.cached_handshake.clear();
+            }
+            if (m_context.handshake_messages[10] >= 1) {
+                dbg() << "unexpected finished message";
+                payload_res = (i8)Error::UnexpectedMessage;
+                break;
+            }
+            ++m_context.handshake_messages[10];
+#ifdef TLS_DEBUG
+            dbg() << "finished";
+#endif
+            payload_res = handle_finished(buffer.slice_view(1, payload_size), write_packets);
+            if (payload_res > 0) {
+                memset(m_context.handshake_messages, 0, sizeof(m_context.handshake_messages));
+            }
+            break;
+        default:
+            dbg() << "message type not understood: " << type;
+            return (i8)Error::NotUnderstood;
+        }
+
+        if (type != 0x00) {
+            update_hash(buffer.slice_view(0, payload_size + 1));
+        }
+
+        // if something went wrong, send an alert about it
+        if (payload_res < 0) {
+            switch ((Error)payload_res) {
+            case Error::UnexpectedMessage: {
+                auto packet = build_alert(true, (u8)AlertDescription::UnexpectedMessage);
+                write_packet(packet);
+                break;
+            }
+            case Error::CompressionNotSupported: {
+                auto packet = build_alert(true, (u8)AlertDescription::DecompressionFailure);
+                write_packet(packet);
+                break;
+            }
+            case Error::BrokenPacket: {
+                auto packet = build_alert(true, (u8)AlertDescription::DecodeError);
+                write_packet(packet);
+                break;
+            }
+            case Error::NotVerified: {
+                auto packet = build_alert(true, (u8)AlertDescription::BadRecordMAC);
+                write_packet(packet);
+                break;
+            }
+            case Error::BadCertificate: {
+                auto packet = build_alert(true, (u8)AlertDescription::BadCertificate);
+                write_packet(packet);
+                break;
+            }
+            case Error::UnsupportedCertificate: {
+                auto packet = build_alert(true, (u8)AlertDescription::UnsupportedCertificate);
+                write_packet(packet);
+                break;
+            }
+            case Error::NoCommonCipher: {
+                auto packet = build_alert(true, (u8)AlertDescription::InsufficientSecurity);
+                write_packet(packet);
+                break;
+            }
+            case Error::NotUnderstood: {
+                auto packet = build_alert(true, (u8)AlertDescription::InternalError);
+                write_packet(packet);
+                break;
+            }
+            case Error::NoRenegotiation: {
+                auto packet = build_alert(true, (u8)AlertDescription::NoRenegotiation);
+                write_packet(packet);
+                break;
+            }
+            case Error::DecryptionFailed: {
+                auto packet = build_alert(true, (u8)AlertDescription::DecryptionFailed);
+                write_packet(packet);
+                break;
+            }
+            default:
+                break;
+            }
+            if (payload_res < 0)
+                return payload_res;
+        }
+        switch (write_packets) {
+        case 1:
+            if (m_context.client_verified == 2) {
+                auto packet = build_certificate();
+                write_packet(packet);
+                m_context.client_verified = 0;
+            }
+            // client handshake
+            {
+#ifdef TLS_DEBUG
+                dbg() << "> Key exchange";
+#endif
+                auto packet = build_client_key_exchange();
+                write_packet(packet);
+            }
+            {
+#ifdef TLS_DEBUG
+                dbg() << "> change cipher spec";
+#endif
+                auto packet = build_change_cipher_spec();
+                write_packet(packet);
+            }
+            m_context.cipher_spec_set = 1;
+            m_context.local_sequence_number = 0;
+            {
+#ifdef TLS_DEBUG
+                dbg() << "> client finished";
+#endif
+                auto packet = build_finished();
+                write_packet(packet);
+            }
+            m_context.cipher_spec_set = 0;
+            break;
+        case 2:
+            // server handshake
+            dbg() << "UNSUPPORTED: Server mode";
+            ASSERT_NOT_REACHED();
+            break;
+        case 3:
+            // finished
+            {
+#ifdef TLS_DEBUG
+                dbg() << "> change cipher spec";
+#endif
+                auto packet = build_change_cipher_spec();
+                write_packet(packet);
+            }
+            {
+#ifdef TLS_DEBUG
+                dbg() << "> client finished";
+#endif
+                auto packet = build_finished();
+                write_packet(packet);
+            }
+            m_context.connection_status = 0xff;
+            break;
+        }
+        payload_size++;
+        buffer_length -= payload_size;
+        buffer = buffer.slice(payload_size, buffer_length);
+    }
+    return original_length;
+}
+
+}
diff --git a/Libraries/LibTLS/TLSv12.h b/Libraries/LibTLS/TLSv12.h
new file mode 100644
index 0000000000..b70ca56fea
--- /dev/null
+++ b/Libraries/LibTLS/TLSv12.h
@@ -0,0 +1,404 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <AK/IPv4Address.h>
+#include <AK/WeakPtr.h>
+#include <LibCore/Notifier.h>
+#include <LibCore/Socket.h>
+#include <LibCore/TCPSocket.h>
+#include <LibCrypto/Authentication/HMAC.h>
+#include <LibCrypto/BigInt/UnsignedBigInteger.h>
+#include <LibCrypto/Cipher/AES.h>
+#include <LibCrypto/Hash/SHA2.h>
+#include <LibCrypto/PK/RSA.h>
+#include <LibTLS/TLSPacketBuilder.h>
+
+namespace TLS {
+
+class Socket;
+
+using HashFunction = Crypto::Hash::SHA256;
+
+enum class KeyExchangeAlgorithms {
+    DHE_DSS,
+    DHE_RSA,
+    DH_Anon,
+    RSA,
+    DH_DSS,
+    DH_RSA,
+    EC_DiffieHellman
+};
+
+enum class ClientCertificateType {
+    RSA_Sign = 1,
+    DSS_Sign = 2,
+    RSA_FixedDH = 3,
+    DSS_FixedDH = 4,
+    RSA_EphemeralDH = 5,
+    DSS_EphemeralDH = 6,
+    ECDSA_Sign = 64,
+    RSA_FixedECDH = 65,
+    ECDSA_FixedECDH = 66
+};
+
+enum class HashAlgorithm {
+    None = 0,
+    MD5 = 1,
+    SHA1 = 2,
+    SHA224 = 3,
+    SHA256 = 4,
+    SHA384 = 5,
+    SHA512 = 6
+};
+
+enum class SignatureAlgorithm {
+    Anonymous = 0,
+    RSA = 1,
+    DSA = 2,
+    ECDSA = 3
+};
+
+enum class CipherSuite {
+    Invalid = 0,
+    AES_128_GCM_SHA256 = 0x1301,
+    AES_256_GCM_SHA384 = 0x1302,
+    AES_128_CCM_SHA256 = 0x1304,
+    AES_128_CCM_8_SHA256 = 0x1305,
+
+    RSA_WITH_AES_128_CBC_SHA = 0x002F,
+    RSA_WITH_AES_256_CBC_SHA = 0x0035,
+    RSA_WITH_AES_128_CBC_SHA256 = 0x003C, // we support this
+    RSA_WITH_AES_256_CBC_SHA256 = 0x003D, //<- this is our guy
+    RSA_WITH_AES_128_GCM_SHA256 = 0x009C,
+    RSA_WITH_AES_256_GCM_SHA384 = 0x009D,
+};
+
+enum class AlertDescription : u8 {
+    CloseNotify = 0,
+    UnexpectedMessage = 10,
+    BadRecordMAC = 20,
+    DecryptionFailed = 21,
+    RecordOverflow = 22,
+    DecompressionFailure = 30,
+    HandshakeFailure = 40,
+    NoCertificate = 41,
+    BadCertificate = 42,
+    UnsupportedCertificate = 43,
+    CertificateRevoked = 44,
+    CertificateExpired = 45,
+    CertificateUnknown = 46,
+    IllegalParameter = 47,
+    UnknownCA = 48,
+    AccessDenied = 49,
+    DecodeError = 50,
+    DecryptError = 51,
+    ExportRestriction = 60,
+    ProtocolVersion = 70,
+    InsufficientSecurity = 71,
+    InternalError = 80,
+    InappropriateFallback = 86,
+    UserCanceled = 90,
+    NoRenegotiation = 100,
+    UnsupportedExtension = 110,
+    NoError = 255
+};
+
+enum class Error : i8 {
+    NoError = 0,
+    UnknownError = -1,
+    BrokenPacket = -2,
+    NotUnderstood = -3,
+    NoCommonCipher = -5,
+    UnexpectedMessage = -6,
+    CloseConnection = -7,
+    CompressionNotSupported = -8,
+    NotVerified = -9,
+    NotSafe = -10,
+    IntegrityCheckFailed = -11,
+    ErrorAlert = -12,
+    BrokenConnection = -13,
+    BadCertificate = -14,
+    UnsupportedCertificate = -15,
+    NoRenegotiation = -16,
+    FeatureNotSupported = -17,
+    DecryptionFailed = -20,
+    NeedMoreData = -21,
+};
+
+enum class AlertLevel : u8 {
+    Warning = 0x01,
+    Critical = 0x02
+};
+
+struct Certificate {
+    u16 version;
+    u32 algorithm;
+    u32 key_algorithm;
+    u32 ec_algorithm;
+    ByteBuffer exponent;
+    Crypto::PK::RSAPublicKey<Crypto::UnsignedBigInteger> public_key;
+    String issuer_country;
+    String issuer_state;
+    String issuer_location;
+    String issuer_entity;
+    String issuer_subject;
+    String not_before;
+    String not_after;
+    String country;
+    String state;
+    String location;
+    String entity;
+    String subject;
+    u8** SAN;
+    u16 SAN_length;
+    u8* ocsp;
+    Crypto::UnsignedBigInteger serial_number;
+    ByteBuffer sign_key;
+    ByteBuffer fingerprint;
+    ByteBuffer der;
+    ByteBuffer data;
+};
+
+struct Hash {
+    Crypto::Hash::SHA256 hash;
+};
+
+struct Context {
+    String to_string() const;
+    bool verify() const;
+    bool verify_chain() const;
+
+    static void print_file(const StringView& fname);
+
+    u8 remote_random[32];
+    // To be predictable
+    u8 local_random[32] { 0 };
+    u8 session_id[32];
+    u8 session_id_size { 0 };
+    CipherSuite cipher;
+    Version version;
+    bool is_server { false };
+    Vector<Certificate> certificates;
+    Certificate private_key;
+    Vector<Certificate> client_certificates;
+    ByteBuffer master_key;
+    ByteBuffer premaster_key;
+    u8 cipher_spec_set { 0 };
+    struct {
+        int created { 0 };
+        u8 remote_mac[32];
+        u8 local_mac[32];
+        u8 local_iv[16];
+        u8 remote_iv[16];
+    } crypto;
+
+    Hash handshake_hash;
+
+    ByteBuffer message_buffer;
+    u64 remote_sequence_number { 0 };
+    u64 local_sequence_number { 0 };
+
+    u8 connection_status { 0 };
+    u8 critical_error { 0 };
+    Error error_code { Error::NoError };
+
+    ByteBuffer tls_buffer;
+
+    ByteBuffer application_buffer;
+
+    bool is_child { false };
+
+    String SNI; // I hate your existence
+
+    u8 request_client_certificate { 0 };
+
+    ByteBuffer cached_handshake;
+
+    u8 client_verified { 0 };
+
+    bool connection_finished { false };
+
+    // message flags
+    u8 handshake_messages[11] { 0 };
+    ByteBuffer user_data;
+    Vector<Certificate> root_ceritificates;
+
+    Vector<String> alpn;
+    StringView negotiated_alpn;
+};
+
+class TLSv12 : public Core::Socket {
+    C_OBJECT(TLSv12)
+public:
+    explicit TLSv12(Core::Object* parent, Version version = Version::V12)
+        : Core::Socket(Core::Socket::Type::TCP, parent)
+    {
+        m_context.version = version;
+        m_context.is_server = false;
+        m_context.tls_buffer = ByteBuffer::create_uninitialized(0);
+        int fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
+        if (fd < 0) {
+            set_error(errno);
+        } else {
+            set_fd(fd);
+            set_mode(IODevice::ReadWrite);
+            set_error(0);
+        }
+    }
+
+    ByteBuffer& write_buffer() { return m_context.tls_buffer; }
+    bool established() const { return m_context.connection_status == 0xff; }
+    virtual bool connect(const String&, int) override;
+
+    void set_sni(const StringView& sni)
+    {
+        if (m_context.is_server || m_context.critical_error || m_context.connection_status != 0) {
+            dbg() << "invalid state for set_sni";
+            return;
+        }
+        m_context.SNI = sni;
+    }
+
+    Optional<Certificate> parse_asn1(const ByteBuffer& buffer, bool client_cert = false);
+    bool load_certificates(const ByteBuffer& pem_buffer);
+    bool load_private_key(const ByteBuffer& pem_buffer);
+
+    ByteBuffer finish_build();
+
+    const StringView& alpn() const { return m_context.negotiated_alpn; }
+    void add_alpn(const StringView& alpn);
+    bool has_alpn(const StringView& alpn) const;
+
+    bool cipher_supported(CipherSuite suite) const
+    {
+        return suite == CipherSuite::RSA_WITH_AES_128_CBC_SHA256 || suite == CipherSuite::RSA_WITH_AES_256_CBC_SHA256;
+    }
+
+    bool version_supported(Version v) const
+    {
+        return v == Version::V12;
+    }
+
+    Optional<ByteBuffer> read();
+    ByteBuffer read(size_t max_size);
+
+    bool write(const ByteBuffer& buffer);
+    void alert(bool critical, u8 code);
+
+    bool can_read_line() const { return m_context.application_buffer.size() && memchr(m_context.application_buffer.data(), '\n', m_context.application_buffer.size()); }
+    bool can_read() const { return m_context.application_buffer.size() > 0; }
+    ByteBuffer read_line(size_t max_size);
+
+    Function<void(TLSv12&)> on_tls_ready_to_read;
+    Function<void(TLSv12&)> on_tls_ready_to_write;
+    Function<void(AlertDescription)> on_tls_error;
+    Function<void()> on_tls_connected;
+    Function<void()> on_tls_finished;
+
+private:
+    virtual bool common_connect(const struct sockaddr*, socklen_t) override;
+
+    void consume(const ByteBuffer& record);
+
+    ByteBuffer hmac_message(const ByteBuffer& buf, const Optional<ByteBuffer> buf2, size_t mac_length, bool local = false);
+
+    void update_packet(ByteBuffer& packet);
+    void update_hash(const ByteBuffer& in);
+
+    void write_packet(ByteBuffer& packet);
+
+    ByteBuffer build_client_key_exchange();
+    ByteBuffer build_server_key_exchange();
+
+    ByteBuffer build_hello();
+    ByteBuffer build_finished();
+    ByteBuffer build_certificate();
+    ByteBuffer build_done();
+    ByteBuffer build_alert(bool critical, u8 code);
+    ByteBuffer build_change_cipher_spec();
+    ByteBuffer build_verify_request();
+    void build_random(PacketBuilder&);
+
+    bool flush();
+
+    ssize_t handle_hello(const ByteBuffer& buffer, size_t&);
+    ssize_t handle_finished(const ByteBuffer& buffer, size_t&);
+    ssize_t handle_certificate(const ByteBuffer& buffer);
+    ssize_t handle_server_key_exchange(const ByteBuffer& buffer);
+    ssize_t handle_server_hello_done(const ByteBuffer& buffer);
+    ssize_t handle_verify(const ByteBuffer& buffer);
+    ssize_t handle_payload(const ByteBuffer& buffer);
+    ssize_t handle_message(const ByteBuffer& buffer);
+    ssize_t handle_random(const ByteBuffer& buffer);
+
+    size_t asn1_length(const ByteBuffer& buffer, size_t* octets);
+
+    void pseudorandom_function(ByteBuffer& output, const ByteBuffer& secret, const u8* label, size_t label_length, const ByteBuffer& seed, const ByteBuffer& seed_b);
+
+    size_t key_length() const { return m_aes_local ? m_aes_local->cipher().key().length() : 16; } // FIXME: generalize
+    size_t mac_length() const { return Crypto::Authentication::HMAC<Crypto::Hash::SHA256>::DigestSize; } // FIXME: generalize
+
+    bool expand_key();
+
+    bool compute_master_secret(size_t length);
+
+    Context m_context;
+    RefPtr<Core::Notifier> m_notifier;
+
+    OwnPtr<Crypto::Cipher::AESCipher::CBCMode> m_aes_local { nullptr };
+    OwnPtr<Crypto::Cipher::AESCipher::CBCMode> m_aes_remote { nullptr };
+};
+
+namespace Constants {
+    constexpr static const u32 version_id[] { 1, 1, 1, 0 };
+    constexpr static const u32 pk_id[] { 1, 1, 7, 0 };
+    constexpr static const u32 serial_id[] { 1, 1, 2, 1, 0 };
+    constexpr static const u32 issurer_id[] { 1, 1, 4, 0 };
+    constexpr static const u32 owner_id[] { 1, 1, 6, 0 };
+    constexpr static const u32 validity_id[] { 1, 1, 5, 0 };
+    constexpr static const u32 algorithm_id[] { 1, 1, 3, 0 };
+    constexpr static const u32 sign_id[] { 1, 3, 2, 1, 0 };
+    constexpr static const u32 priv_id[] { 1, 4, 0 };
+    constexpr static const u32 priv_der_id[] { 1, 3, 1, 0 };
+    constexpr static const u32 ecc_priv_id[] { 1, 2, 0 };
+
+    constexpr static const u8 country_oid[] { 0x55, 0x04, 0x06, 0x00 };
+    constexpr static const u8 state_oid[] { 0x55, 0x04, 0x08, 0x00 };
+    constexpr static const u8 location_oid[] { 0x55, 0x04, 0x07, 0x00 };
+    constexpr static const u8 entity_oid[] { 0x55, 0x04, 0x0A, 0x00 };
+    constexpr static const u8 subject_oid[] { 0x55, 0x04, 0x03, 0x00 };
+    constexpr static const u8 san_oid[] { 0x55, 0x1D, 0x11, 0x00 };
+    constexpr static const u8 ocsp_oid[] { 0x2B, 0x06, 0x01, 0x05, 0x05, 0x07, 0x30, 0x01, 0x00 };
+
+    constexpr static const u8 TLS_RSA_SIGN_SHA256_OID[] { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x0b, 0x00 };
+
+}
+
+namespace Utilities {
+}
+}