LibTLS: Split large application data packets into chunks

Each TLS record has a limited max size, we should respect that and split
the packets.
Fixes RecordOverflow errors when a packet larger than 18432 bytes is
sent over.
This commit is contained in:
Ali Mohammad Pur 2021-10-01 22:41:44 +03:30 committed by Ali Mohammad Pur
parent c3b14588ec
commit ab46864674
Notes: sideshowbarker 2024-07-18 03:10:19 +09:00
2 changed files with 32 additions and 18 deletions

View File

@ -37,24 +37,31 @@ void TLSv12::alert(AlertLevel level, AlertDescription code)
void TLSv12::write_packet(ByteBuffer& packet)
{
auto schedule_or_perform_flush = [&](bool immediate) {
if (m_context.connection_status > ConnectionStatus::Disconnected) {
if (!m_has_scheduled_write_flush && !immediate) {
dbgln_if(TLS_DEBUG, "Scheduling write of {}", m_context.tls_buffer.size());
deferred_invoke([this] { write_into_socket(); });
m_has_scheduled_write_flush = true;
} else {
// multiple packet are available, let's flush some out
dbgln_if(TLS_DEBUG, "Flushing scheduled write of {}", m_context.tls_buffer.size());
write_into_socket();
// the deferred invoke is still in place
m_has_scheduled_write_flush = true;
}
}
};
// Record size limit is 18432 bytes, leave some headroom and flush at 16K.
if (m_context.tls_buffer.size() + packet.size() > 16 * KiB)
schedule_or_perform_flush(true);
auto ok = m_context.tls_buffer.try_append(packet.data(), packet.size());
if (!ok) {
// Toooooo bad, drop the record on the ground.
return;
}
if (m_context.connection_status > ConnectionStatus::Disconnected) {
if (!m_has_scheduled_write_flush) {
dbgln_if(TLS_DEBUG, "Scheduling write of {}", m_context.tls_buffer.size());
deferred_invoke([this] { write_into_socket(); });
m_has_scheduled_write_flush = true;
} else {
// multiple packet are available, let's flush some out
dbgln_if(TLS_DEBUG, "Flushing scheduled write of {}", m_context.tls_buffer.size());
write_into_socket();
// the deferred invoke is still in place
m_has_scheduled_write_flush = true;
}
}
schedule_or_perform_flush(false);
}
void TLSv12::update_packet(ByteBuffer& packet)

View File

@ -10,6 +10,11 @@
#include <LibCrypto/PK/Code/EMSA_PSS.h>
#include <LibTLS/TLSv12.h>
// Each record can hold at most 18432 bytes, leaving some headroom and rounding down to
// a nice number gives us a maximum of 16 KiB for user-supplied application data,
// which will be sent as a single record containing a single ApplicationData message.
constexpr static size_t MaximumApplicationDataChunkSize = 16 * KiB;
namespace TLS {
Optional<ByteBuffer> TLSv12::read()
@ -67,12 +72,14 @@ bool TLSv12::write(ReadonlyBytes buffer)
return false;
}
PacketBuilder builder { MessageType::ApplicationData, m_context.options.version, buffer.size() };
builder.append(buffer);
auto packet = builder.build();
for (size_t offset = 0; offset < buffer.size(); offset += MaximumApplicationDataChunkSize) {
PacketBuilder builder { MessageType::ApplicationData, m_context.options.version, buffer.size() - offset };
builder.append(buffer.slice(offset, min(buffer.size() - offset, MaximumApplicationDataChunkSize)));
auto packet = builder.build();
update_packet(packet);
write_packet(packet);
update_packet(packet);
write_packet(packet);
}
return true;
}