ladybird/Userland/Libraries/LibWebSocket/WebSocket.cpp
2024-06-22 18:53:24 +02:00

657 lines
25 KiB
C++

/*
* Copyright (c) 2021, Dex♪ <dexes.ttp@gmail.com>
* Copyright (c) 2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Base64.h>
#include <AK/Random.h>
#include <LibCrypto/Hash/HashManager.h>
#include <LibWebSocket/Impl/WebSocketImplSerenity.h>
#include <LibWebSocket/WebSocket.h>
#include <unistd.h>
namespace WebSocket {
// Note : The websocket protocol is defined by RFC 6455, found at https://tools.ietf.org/html/rfc6455
// In this file, section numbers will refer to the RFC 6455
NonnullRefPtr<WebSocket> WebSocket::create(ConnectionInfo connection, RefPtr<WebSocketImpl> impl)
{
return adopt_ref(*new WebSocket(move(connection), move(impl)));
}
WebSocket::WebSocket(ConnectionInfo connection, RefPtr<WebSocketImpl> impl)
: m_connection(move(connection))
, m_impl(move(impl))
{
}
void WebSocket::start()
{
VERIFY(m_state == WebSocket::InternalState::NotStarted);
if (!m_impl)
m_impl = adopt_ref(*new WebSocketImplSerenity);
m_impl->on_connection_error = [this] {
dbgln("WebSocket: Connection error (underlying socket)");
fatal_error(WebSocket::Error::CouldNotEstablishConnection);
};
m_impl->on_connected = [this] {
if (m_state != WebSocket::InternalState::EstablishingProtocolConnection)
return;
m_state = WebSocket::InternalState::SendingClientHandshake;
send_client_handshake();
drain_read();
};
m_impl->on_ready_to_read = [this] {
drain_read();
};
m_state = WebSocket::InternalState::EstablishingProtocolConnection;
m_impl->connect(m_connection);
}
ReadyState WebSocket::ready_state()
{
switch (m_state) {
case WebSocket::InternalState::NotStarted:
case WebSocket::InternalState::EstablishingProtocolConnection:
case WebSocket::InternalState::SendingClientHandshake:
case WebSocket::InternalState::WaitingForServerHandshake:
return ReadyState::Connecting;
case WebSocket::InternalState::Open:
return ReadyState::Open;
case WebSocket::InternalState::Closing:
return ReadyState::Closing;
case WebSocket::InternalState::Closed:
case WebSocket::InternalState::Errored:
return ReadyState::Closed;
default:
VERIFY_NOT_REACHED();
return ReadyState::Closed;
}
}
ByteString WebSocket::subprotocol_in_use()
{
return m_subprotocol_in_use;
}
void WebSocket::send(Message const& message)
{
// Calling send on a socket that is not opened is not allowed
VERIFY(m_state == WebSocket::InternalState::Open);
VERIFY(m_impl);
if (message.is_text())
send_frame(WebSocket::OpCode::Text, message.data(), true);
else
send_frame(WebSocket::OpCode::Binary, message.data(), true);
}
void WebSocket::close(u16 code, ByteString const& message)
{
VERIFY(m_impl);
switch (m_state) {
case InternalState::NotStarted:
case InternalState::EstablishingProtocolConnection:
case InternalState::SendingClientHandshake:
case InternalState::WaitingForServerHandshake:
// FIXME: Fail the connection.
m_state = InternalState::Closing;
break;
case InternalState::Open: {
auto message_bytes = message.bytes();
auto close_payload = ByteBuffer::create_uninitialized(message_bytes.size() + 2).release_value_but_fixme_should_propagate_errors(); // FIXME: Handle possible OOM situation.
close_payload.overwrite(0, (u8*)&code, 2);
close_payload.overwrite(2, message_bytes.data(), message_bytes.size());
send_frame(WebSocket::OpCode::ConnectionClose, close_payload, true);
m_state = InternalState::Closing;
break;
}
default:
break;
}
}
void WebSocket::drain_read()
{
if (m_impl->eof()) {
// The connection got closed by the server
m_state = WebSocket::InternalState::Closed;
notify_close(m_last_close_code, m_last_close_message, true);
discard_connection();
return;
}
switch (m_state) {
case InternalState::NotStarted:
case InternalState::EstablishingProtocolConnection:
case InternalState::SendingClientHandshake: {
auto initializing_bytes = m_impl->read(1024);
if (!initializing_bytes.is_error())
dbgln("drain_read() was called on a websocket that isn't opened yet. Read {} bytes from the socket.", initializing_bytes.value().size());
} break;
case InternalState::WaitingForServerHandshake: {
read_server_handshake();
} break;
case InternalState::Open:
case InternalState::Closing: {
auto result = m_impl->read(65536);
if (result.is_error()) {
fatal_error(WebSocket::Error::ServerClosedSocket);
return;
}
auto bytes = result.release_value();
m_buffered_data.append(bytes.data(), bytes.size());
read_frame();
} break;
case InternalState::Closed:
case InternalState::Errored: {
auto closed_bytes = m_impl->read(1024);
if (!closed_bytes.is_error())
dbgln("drain_read() was called on a closed websocket. Read {} bytes from the socket.", closed_bytes.value().size());
} break;
default:
VERIFY_NOT_REACHED();
}
}
// The client handshake message is defined in the second list of section 4.1
void WebSocket::send_client_handshake()
{
VERIFY(m_impl);
VERIFY(m_state == WebSocket::InternalState::SendingClientHandshake);
StringBuilder builder;
// 2. and 3. GET /resource name/ HTTP 1.1
builder.appendff("GET {} HTTP/1.1\r\n", m_connection.resource_name());
// 4. Host
auto url = m_connection.url();
builder.appendff("Host: {}", url.serialized_host().release_value_but_fixme_should_propagate_errors());
if (!m_connection.is_secure() && url.port_or_default() != 80)
builder.appendff(":{}", url.port_or_default());
else if (m_connection.is_secure() && url.port_or_default() != 443)
builder.appendff(":{}", url.port_or_default());
builder.append("\r\n"sv);
// 5. and 6. Connection Upgrade
builder.append("Upgrade: websocket\r\n"sv);
builder.append("Connection: Upgrade\r\n"sv);
// 7. 16-byte nonce encoded as Base64
u8 nonce_data[16];
fill_with_random(nonce_data);
// FIXME: change to TRY() and make method fallible
m_websocket_key = MUST(encode_base64({ nonce_data, 16 })).to_byte_string();
builder.appendff("Sec-WebSocket-Key: {}\r\n", m_websocket_key);
// 8. Origin (optional field)
if (!m_connection.origin().is_empty()) {
builder.appendff("Origin: {}\r\n", m_connection.origin());
}
// 9. Websocket version
builder.append("Sec-WebSocket-Version: 13\r\n"sv);
// 10. Websocket protocol (optional field)
if (!m_connection.protocols().is_empty()) {
builder.append("Sec-WebSocket-Protocol: "sv);
builder.join(',', m_connection.protocols());
builder.append("\r\n"sv);
}
// 11. Websocket extensions (optional field)
if (!m_connection.extensions().is_empty()) {
builder.append("Sec-WebSocket-Extensions: "sv);
builder.join(',', m_connection.extensions());
builder.append("\r\n"sv);
}
// 12. Additional headers
for (auto& header : m_connection.headers().headers()) {
builder.appendff("{}: {}\r\n", header.name, header.value);
}
builder.append("\r\n"sv);
m_state = WebSocket::InternalState::WaitingForServerHandshake;
auto success = m_impl->send(builder.string_view().bytes());
VERIFY(success);
}
// The server handshake message is defined in the third list of section 4.1
void WebSocket::read_server_handshake()
{
VERIFY(m_impl);
VERIFY(m_state == WebSocket::InternalState::WaitingForServerHandshake);
// Read the server handshake
if (!m_impl->can_read_line())
return;
if (!m_has_read_server_handshake_first_line) {
auto header = m_impl->read_line(PAGE_SIZE).release_value_but_fixme_should_propagate_errors();
auto parts = header.split(' ');
if (parts.size() < 2) {
dbgln("WebSocket: Server HTTP Handshake contained HTTP header was malformed");
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
discard_connection();
return;
}
if (parts[0] != "HTTP/1.1") {
dbgln("WebSocket: Server HTTP Handshake contained HTTP header {} which isn't supported", parts[0]);
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
discard_connection();
return;
}
if (parts[1] != "101") {
// 1. If the status code is not 101, handle as per HTTP procedures.
// FIXME : This could be a redirect or a 401 authentication request, which we do not handle.
dbgln("WebSocket: Server HTTP Handshake return status {} which isn't supported", parts[1]);
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
m_has_read_server_handshake_first_line = true;
}
// Read the rest of the reply until we find an empty line
while (m_impl->can_read_line()) {
auto line = m_impl->read_line(PAGE_SIZE).release_value_but_fixme_should_propagate_errors();
if (line.is_whitespace()) {
// We're done with the HTTP headers.
// Fail the connection if we're missing any of the following:
if (!m_has_read_server_handshake_upgrade) {
// 2. |Upgrade| should be present
dbgln("WebSocket: Server HTTP Handshake didn't contain an |Upgrade| header");
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
if (!m_has_read_server_handshake_connection) {
// 2. |Connection| should be present
dbgln("WebSocket: Server HTTP Handshake didn't contain a |Connection| header");
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
if (!m_has_read_server_handshake_accept) {
// 2. |Sec-WebSocket-Accept| should be present
dbgln("WebSocket: Server HTTP Handshake didn't contain a |Sec-WebSocket-Accept| header");
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
m_state = WebSocket::InternalState::Open;
notify_open();
return;
}
auto parts = line.split(':');
if (parts.size() < 2) {
// The header field is not valid
dbgln("WebSocket: Got invalid header line {} in the Server HTTP handshake", line);
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
auto header_name = parts[0];
if (header_name.equals_ignoring_ascii_case("Upgrade"sv)) {
// 2. |Upgrade| should be case-insensitive "websocket"
if (!parts[1].trim_whitespace().equals_ignoring_ascii_case("websocket"sv)) {
dbgln("WebSocket: Server HTTP Handshake Header |Upgrade| should be 'websocket', got '{}'. Failing connection.", parts[1]);
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
m_has_read_server_handshake_upgrade = true;
continue;
}
if (header_name.equals_ignoring_ascii_case("Connection"sv)) {
// 3. |Connection| should be case-insensitive "Upgrade"
if (!parts[1].trim_whitespace().equals_ignoring_ascii_case("Upgrade"sv)) {
dbgln("WebSocket: Server HTTP Handshake Header |Connection| should be 'Upgrade', got '{}'. Failing connection.", parts[1]);
return;
}
m_has_read_server_handshake_connection = true;
continue;
}
if (header_name.equals_ignoring_ascii_case("Sec-WebSocket-Accept"sv)) {
// 4. |Sec-WebSocket-Accept| should be base64(SHA1(|Sec-WebSocket-Key| + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"))
auto expected_content = ByteString::formatted("{}258EAFA5-E914-47DA-95CA-C5AB0DC85B11", m_websocket_key);
Crypto::Hash::Manager hash;
hash.initialize(Crypto::Hash::HashKind::SHA1);
hash.update(expected_content);
auto expected_sha1 = hash.digest();
// FIXME: change to TRY() and make method fallible
auto expected_sha1_string = MUST(encode_base64({ expected_sha1.immutable_data(), expected_sha1.data_length() }));
if (!parts[1].trim_whitespace().equals_ignoring_ascii_case(expected_sha1_string)) {
dbgln("WebSocket: Server HTTP Handshake Header |Sec-Websocket-Accept| should be '{}', got '{}'. Failing connection.", expected_sha1_string, parts[1]);
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
m_has_read_server_handshake_accept = true;
continue;
}
if (header_name.equals_ignoring_ascii_case("Sec-WebSocket-Extensions"sv)) {
// 5. |Sec-WebSocket-Extensions| should not contain an extension that doesn't appear in m_connection->extensions()
auto server_extensions = parts[1].split(',');
for (auto const& extension : server_extensions) {
auto trimmed_extension = extension.trim_whitespace();
bool found_extension = false;
for (auto const& supported_extension : m_connection.extensions()) {
if (trimmed_extension.equals_ignoring_ascii_case(supported_extension)) {
found_extension = true;
}
}
if (!found_extension) {
dbgln("WebSocket: Server HTTP Handshake Header |Sec-WebSocket-Extensions| contains '{}', which is not supported by the client. Failing connection.", trimmed_extension);
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
}
continue;
}
if (header_name.equals_ignoring_ascii_case("Sec-WebSocket-Protocol"sv)) {
// 6. If the response includes a |Sec-WebSocket-Protocol| header field and this header field indicates the use of a subprotocol that was not present in the client's handshake (the server has indicated a subprotocol not requested by the client), the client MUST _Fail the WebSocket Connection_.
// Additionally, Section 4.2.2 says this is "Either a single value representing the subprotocol the server is ready to use or null."
auto server_protocol = parts[1].trim_whitespace();
bool found_protocol = false;
for (auto const& supported_protocol : m_connection.protocols()) {
if (server_protocol.equals_ignoring_ascii_case(supported_protocol)) {
found_protocol = true;
}
}
if (!found_protocol) {
dbgln("WebSocket: Server HTTP Handshake Header |Sec-WebSocket-Protocol| contains '{}', which is not supported by the client. Failing connection.", server_protocol);
fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
return;
}
m_subprotocol_in_use = server_protocol;
continue;
}
}
// If needed, we will keep reading the header on the next drain_read call
}
void WebSocket::read_frame()
{
VERIFY(m_impl);
VERIFY(m_state == WebSocket::InternalState::Open || m_state == WebSocket::InternalState::Closing);
size_t cursor = 0;
auto get_buffered_bytes = [&](size_t count) -> ReadonlyBytes {
if (cursor + count > m_buffered_data.size())
return {};
auto bytes = m_buffered_data.span().slice(cursor, count);
cursor += count;
return bytes;
};
auto head_bytes = get_buffered_bytes(2);
if (head_bytes.is_null() || head_bytes.is_empty()) {
// The connection got closed.
m_state = WebSocket::InternalState::Closed;
notify_close(m_last_close_code, m_last_close_message, true);
discard_connection();
return;
}
auto op_code = (WebSocket::OpCode)(head_bytes[0] & 0x0f);
bool is_final_frame = head_bytes[0] & 0x80;
bool is_masked = head_bytes[1] & 0x80;
// Parse the payload length.
size_t payload_length;
auto payload_length_bits = head_bytes[1] & 0x7f;
if (payload_length_bits == 127) {
// A code of 127 means that the next 8 bytes contains the payload length
auto actual_bytes = get_buffered_bytes(8);
if (actual_bytes.is_null())
return;
u64 full_payload_length = (u64)((u64)(actual_bytes[0] & 0xff) << 56)
| (u64)((u64)(actual_bytes[1] & 0xff) << 48)
| (u64)((u64)(actual_bytes[2] & 0xff) << 40)
| (u64)((u64)(actual_bytes[3] & 0xff) << 32)
| (u64)((u64)(actual_bytes[4] & 0xff) << 24)
| (u64)((u64)(actual_bytes[5] & 0xff) << 16)
| (u64)((u64)(actual_bytes[6] & 0xff) << 8)
| (u64)((u64)(actual_bytes[7] & 0xff) << 0);
VERIFY(full_payload_length <= NumericLimits<size_t>::max());
payload_length = (size_t)full_payload_length;
} else if (payload_length_bits == 126) {
// A code of 126 means that the next 2 bytes contains the payload length
auto actual_bytes = get_buffered_bytes(2);
if (actual_bytes.is_null())
return;
payload_length = (size_t)((size_t)(actual_bytes[0] & 0xff) << 8)
| (size_t)((size_t)(actual_bytes[1] & 0xff) << 0);
} else {
payload_length = (size_t)payload_length_bits;
}
// Parse the mask, if it exists.
// Note : this is technically non-conformant with Section 5.1 :
// > A server MUST NOT mask any frames that it sends to the client.
// > A client MUST close a connection if it detects a masked frame.
// > (These rules might be relaxed in a future specification.)
// But because it doesn't cost much, we can support receiving masked frames anyways.
u8 masking_key[4];
if (is_masked) {
auto masking_key_data = get_buffered_bytes(4);
if (masking_key_data.is_null())
return;
masking_key[0] = masking_key_data[0];
masking_key[1] = masking_key_data[1];
masking_key[2] = masking_key_data[2];
masking_key[3] = masking_key_data[3];
}
auto payload = ByteBuffer::create_uninitialized(payload_length).release_value_but_fixme_should_propagate_errors(); // FIXME: Handle possible OOM situation.
u64 read_length = 0;
while (read_length < payload_length) {
auto payload_part = get_buffered_bytes(payload_length - read_length);
if (payload_part.is_null())
return;
// We read at most "actual_length - read" bytes, so this is safe to do.
payload.overwrite(read_length, payload_part.data(), payload_part.size());
read_length += payload_part.size();
}
if (cursor == m_buffered_data.size()) {
m_buffered_data.clear();
} else {
Vector<u8> new_buffered_data;
new_buffered_data.append(m_buffered_data.data() + cursor, m_buffered_data.size() - cursor);
m_buffered_data = move(new_buffered_data);
}
if (is_masked) {
// Unmask the payload
for (size_t i = 0; i < payload.size(); ++i) {
payload[i] = payload[i] ^ (masking_key[i % 4]);
}
}
if (op_code == WebSocket::OpCode::ConnectionClose) {
if (payload.size() > 1) {
m_last_close_code = (((u16)(payload[0] & 0xff) << 8) | ((u16)(payload[1] & 0xff)));
m_last_close_message = ByteString(ReadonlyBytes(payload.offset_pointer(2), payload.size() - 2));
}
m_state = WebSocket::InternalState::Closing;
return;
}
if (op_code == WebSocket::OpCode::Ping) {
// Immediately send a pong frame as a reply, with the given payload.
send_frame(WebSocket::OpCode::Pong, payload, true);
return;
}
if (op_code == WebSocket::OpCode::Pong) {
// We can safely ignore the pong
return;
}
if (!is_final_frame) {
if (op_code != WebSocket::OpCode::Continuation) {
// First fragmented message
m_initial_fragment_opcode = op_code;
}
// First and next fragmented message
m_fragmented_data_buffer.append(payload.data(), payload_length);
return;
}
if (is_final_frame && op_code == WebSocket::OpCode::Continuation) {
// Last fragmented message
m_fragmented_data_buffer.append(payload.data(), payload_length);
op_code = m_initial_fragment_opcode;
payload.clear();
payload.append(m_fragmented_data_buffer.data(), m_fragmented_data_buffer.size());
m_fragmented_data_buffer.clear();
}
if (op_code == WebSocket::OpCode::Text) {
notify_message(Message(payload, true));
return;
}
if (op_code == WebSocket::OpCode::Binary) {
notify_message(Message(payload, false));
return;
}
dbgln("Websocket: Found unknown opcode {}", (u8)op_code);
}
void WebSocket::send_frame(WebSocket::OpCode op_code, ReadonlyBytes payload, bool is_final)
{
VERIFY(m_impl);
VERIFY(m_state == WebSocket::InternalState::Open);
u8 frame_head[1] = { (u8)((is_final ? 0x80 : 0x00) | ((u8)(op_code) & 0xf)) };
m_impl->send(ReadonlyBytes(frame_head, 1));
// Section 5.1 : a client MUST mask all frames that it sends to the server
bool has_mask = true;
// FIXME: If the payload has a size > size_t max on a 32-bit platform, we could
// technically stream it via non-final packets. However, the size was already
// truncated earlier in the call stack when stuffing into a ReadonlyBytes
if (payload.size() > NumericLimits<u16>::max()) {
// Send (the 'mask' flag + 127) + the 8-byte payload length
if constexpr (sizeof(size_t) >= 8) {
u8 payload_length[9] = {
(u8)((has_mask ? 0x80 : 0x00) | 127),
(u8)((payload.size() >> 56) & 0xff),
(u8)((payload.size() >> 48) & 0xff),
(u8)((payload.size() >> 40) & 0xff),
(u8)((payload.size() >> 32) & 0xff),
(u8)((payload.size() >> 24) & 0xff),
(u8)((payload.size() >> 16) & 0xff),
(u8)((payload.size() >> 8) & 0xff),
(u8)((payload.size() >> 0) & 0xff),
};
m_impl->send(ReadonlyBytes(payload_length, 9));
} else {
u8 payload_length[9] = {
(u8)((has_mask ? 0x80 : 0x00) | 127),
0,
0,
0,
0,
(u8)((payload.size() >> 24) & 0xff),
(u8)((payload.size() >> 16) & 0xff),
(u8)((payload.size() >> 8) & 0xff),
(u8)((payload.size() >> 0) & 0xff),
};
m_impl->send(ReadonlyBytes(payload_length, 9));
}
} else if (payload.size() >= 126) {
// Send (the 'mask' flag + 126) + the 2-byte payload length
u8 payload_length[3] = {
(u8)((has_mask ? 0x80 : 0x00) | 126),
(u8)((payload.size() >> 8) & 0xff),
(u8)((payload.size() >> 0) & 0xff),
};
m_impl->send(ReadonlyBytes(payload_length, 3));
} else {
// Send the mask flag + the payload in a single byte
u8 payload_length[1] = {
(u8)((has_mask ? 0x80 : 0x00) | (u8)(payload.size() & 0x7f)),
};
m_impl->send(ReadonlyBytes(payload_length, 1));
}
if (has_mask) {
// Section 10.3 :
// > Clients MUST choose a new masking key for each frame, using an algorithm
// > that cannot be predicted by end applications that provide data
u8 masking_key[4];
fill_with_random(masking_key);
m_impl->send(ReadonlyBytes(masking_key, 4));
// don't try to send empty payload
if (payload.size() == 0)
return;
// Mask the payload
auto buffer_result = ByteBuffer::create_uninitialized(payload.size());
if (!buffer_result.is_error()) {
auto& masked_payload = buffer_result.value();
for (size_t i = 0; i < payload.size(); ++i) {
masked_payload[i] = payload[i] ^ (masking_key[i % 4]);
}
m_impl->send(masked_payload);
}
} else if (payload.size() > 0) {
m_impl->send(payload);
}
}
void WebSocket::fatal_error(WebSocket::Error error)
{
m_state = WebSocket::InternalState::Errored;
notify_error(error);
discard_connection();
}
void WebSocket::discard_connection()
{
deferred_invoke([this] {
VERIFY(m_impl);
m_impl->discard_connection();
m_impl->on_connection_error = nullptr;
m_impl->on_connected = nullptr;
m_impl->on_ready_to_read = nullptr;
m_impl = nullptr;
});
}
void WebSocket::notify_open()
{
if (!on_open)
return;
on_open();
}
void WebSocket::notify_close(u16 code, ByteString reason, bool was_clean)
{
if (!on_close)
return;
on_close(code, move(reason), was_clean);
}
void WebSocket::notify_error(WebSocket::Error error)
{
if (!on_error)
return;
on_error(error);
}
void WebSocket::notify_message(Message message)
{
if (!on_message)
return;
on_message(move(message));
}
}