Files
ServerCore/TCPServer.cpp
T
Brad Arant c3e8d70774 Fix numerous thread/socket lifecycle crashes and TLS/epoll write-stall busy-loop
Thread/EPoll lifecycle:
- Thread::~Thread() now actually joins/frees its worker thread (was
  empty - the OS thread kept running against already-freed EPoll/Socket
  objects on any early teardown, a confirmed "double free" crash)
- EPoll::~EPoll() calls stop() if never explicitly stopped, for the
  same reason
- epoll_wait() now uses a 1s timeout instead of blocking forever, so a
  worker thread can actually notice isStopping() and let itself be
  joined
- EPoll::processCommand() iterated threads by value, silently
  double-freeing the real vector's Thread the moment each copy went
  out of scope
- ThreadScope gained onThreadStart()/onThreadEnd() hooks (actually
  wired up now - the constructor that was supposed to store the scope
  discarded it) for per-thread C-library init (e.g. MySQL client)

Socket/TCPSocket/TLS:
- Socket::writeSocket(): give up and shut down a connection after 50
  consecutive zero-progress sends instead of retrying forever -
  SSL_ERROR_WANT_READ on a write needs a READ to make progress, but
  resetSocket() re-arms EPOLLWRNORM regardless, which an
  already-writable TCP socket satisfies immediately - a real stuck
  connection generated 55GB, then 12.9GB of debug log this way before
  being caught
- Socket::writeSocket() now honors sendData()'s actual return value
  (previously discarded, entry popped unconditionally after one call) -
  a large response could get silently truncated past what fit in one
  write()/SSL_write() call
- TLS::registerSocket()/sendData()/receiveData(): `initialized` now
  only goes true once SSL_set_fd() has actually succeeded, and
  sendData()/receiveData() check it first - fixes a real SIGSEGV where
  a new session's own queued greeting could reach SSL_write() on a
  different epoll thread before this session's handshake setup had run
- TCPServer::connectionRequest() now performs the TLS handshake ON THE
  ACCEPTED SESSION, not the listening server itself (was building SSL
  state on the wrong object, leaving every session's own `ssl`
  uninitialized)
- TCPServer::receiveData() always uses the plain (non-TLS) read path -
  the listening socket is never itself a TLS peer
- TCPSocket's block-mode literal reading used an unset `blockLength`
  field instead of `blockSize`, and could busy-spin forever on a
  multi-packet literal
- TCPSocket line scanning replaced an unbounded strcspn() (assumes a
  NUL-terminated buffer; read past a non-NUL-terminated receive buffer
  into adjacent heap memory) with a bounds-checked memchr() scan

Protocol/session handling:
- CommandList::processRequest() now case-folds the command keyword
  before lookup - SMTP/POP3/IMAP commands are spec-required to be
  case-insensitive; a client sending "Mail From:" instead of
  "MAIL FROM:" previously failed to dispatch at all
- TCPSession::protocol() no longer drops blank lines while a handler
  has grabbed input (e.g. __SMTP_DATA reading a message body, an IMAP
  APPEND literal) - those handlers depend on seeing blank lines as
  real content, not commands; this silently corrupted any message body
  containing a blank line
- TCPSession's uuid alias fixed: streaming a raw uuid_t via operator<<
  triggered libstdc++'s unsigned-char* overload (strlen() on 16 binary
  bytes, a real stack-buffer-overflow read), and `alias` pointed at a
  stack-local that was already destroyed by the time the constructor
  returned
- INotify::processEvent() only treats event->name as a NUL-terminated
  string when event->len > 0 (per inotify(7)) instead of unconditional
  strlen() on a field the kernel doesn't guarantee is even present -
  a confirmed heap-buffer-overflow read that had been misdiagnosed as
  a MySQL thread-safety issue
2026-09-03 05:17:41 +00:00

148 lines
5.4 KiB
C++

#include "TCPServer.h"
#include "EPoll.h"
#include "Exception.h"
#include "Log.h"
#include "TCPSession.h"
namespace core {
TCPServer::TCPServer(EPoll &ePoll, IPAddress address, TLSInfo *tlsInfo, std::string delimiter, int depth, std::string text)
: TCPSocket(ePoll, tlsInfo, text), commands(delimiter, depth) {
setDescriptor(socket(AF_INET, SOCK_STREAM, 0));
int yes = 1;
setsockopt(getDescriptor(), SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
if (bind(getDescriptor(), address.getPointer(), address.addressLength) < 0)
throw coreutils::Exception("Error on bind to socket: " + std::to_string(errno));
if (listen(getDescriptor(), 20) < 0)
throw coreutils::Exception("Error on listen to socket");
}
TCPServer::~TCPServer() {
coreutils::Log(coreutils::LOG_DEBUG_2) << "Closing server socket " << getDescriptor() << ".";
close(getDescriptor());
}
void TCPServer::connectionRequest() {
coreutils::Log(coreutils::LOG_DEBUG_2) << "Connection request is being received on socket " << getDescriptor() << ".";
lock.lock();
TCPSession *session = accept();
if (session)
sessions.push_back(session);
// Must run ON THE SESSION, not `this` (the listening server) - the
// unqualified registerSocket()/acceptSocket() calls this replaced
// built the SSL* handshake state on the SERVER's own TLS-base
// member instead of the newly accepted session's, leaving every
// session's own `ssl` uninitialized and segfaulting the first time
// real data arrived on it (SSL_read() against a never-SSL_new()'d
// pointer - confirmed via gdb). Sessions already correctly inherit
// this server's SSL_CTX at construction (TCPSession's own
// TLS(SSL_CTX*)-taking constructor) - performTLSHandshake() just
// needed to actually be invoked on that object.
if (session && tlsInfo)
session->performTLSHandshake();
lock.unlock();
}
void TCPServer::receiveData(coreutils::ZString &buffer) {
// See this override's own doc comment in TCPServer.h - the
// listening socket always uses the plain read()/ENOTCONN detection
// path, never TLS::receiveData(), regardless of whether this server
// is TLS-configured.
Socket::receiveData(buffer);
}
TCPSession * TCPServer::accept() {
try {
TCPSession *session = getSocketAccept(ePoll);
session->setDescriptor(::accept(getDescriptor(), (struct sockaddr *)&session->ipAddress.addr, &session->ipAddress.addressLength));
// if(blackList && blackList->contains(session->ipAddress.getClientAddress())) {
// session->shutdown();
// Log(LOG_WARN) << "Client at IP address " << session->ipAddress.getClientAddress() << " is blacklisted and was denied a connection.";
// return NULL;
// }
// if(whiteList && !whiteList->contains(session->ipAddress.getClientAddress())) {
// session->shutdown();
// Log(LOG_WARN) << "Client at IP address " << session->ipAddress.getClientAddress() << " is not authorized and was denied a connection.";
// return NULL;
// }
return session;
}
catch (coreutils::Exception e) {
coreutils::Log(coreutils::LOG_EXCEPT) << "Major error on session initialization. Error is '" << e.text << "'.";
}
catch (...) {
coreutils::Log(coreutils::LOG_EXCEPT) << "Unnspecified error on session initialization.";
}
return NULL;
}
void TCPServer::removeFromSessionList(TCPSession *session) {
std::vector<TCPSession *>::iterator cursor;
lock.lock();
for(cursor = sessions.begin(); cursor < sessions.end(); ++cursor)
if(*cursor == session) {
sessions.erase(cursor);
break;
}
lock.unlock();
}
void TCPServer::sessionErrorHandler(std::string errorString, std::stringstream &out) {
throw coreutils::Exception(errorString);
}
TCPSession * TCPServer::getSocketAccept(EPoll &ePoll) {
return new TCPSession(ePoll, this);
}
void TCPServer::output(std::stringstream &out) {
out << "Use the 'help' command to list the commands for this server." << std::endl;
}
int TCPServer::processCommand(coreutils::ZString &request, TCPSession &session) {
int sequence = 0;
for (auto *sessionx : sessions)
{
session.out << "|" << ++sequence;
sessionx->output(session.out);
session.out << "|" << std::endl;
}
return 1;
}
void TCPServer::sendToAll(std::stringstream &data) {
for (auto session : sessions)
session->write(data.str());
data.str("");
}
void TCPServer::sendToAll(std::stringstream &data, TCPSession &sender) {
for (auto session : sessions)
if (session != &sender)
session->write(data.str());
data.str("");
}
void TCPServer::sendToAll(std::stringstream &data, TCPSession &sender, SessionFilter filter) {
for (auto session : sessions)
if (filter.test(*session))
if (session != &sender)
session->write(data.str());
data.str("");
}
TCPSession *TCPServer::getSessionByAlias(void *alias) {
coreutils::Log(coreutils::LOG_DEBUG_1) << alias;
for (auto session : sessions)
if (session->compareAlias(alias))
return session;
return NULL;
}
}