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Codechange: encapsulate writing data from Packets into sockets/files/buffers to prevent packet state modifications outside of the Packet

This commit is contained in:
Rubidium 2021-04-18 10:23:41 +02:00 committed by rubidium42
parent 98aa561cf7
commit d4f027c03b
6 changed files with 90 additions and 26 deletions
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52
src/network/core/packet.h
View File

@ -88,6 +88,58 @@ public:
size_t RemainingBytesToTransfer() const;
/**
* Transfer data from the packet to the given function. It starts reading at the
* position the last transfer stopped.
* See Packet::TransferIn for more information about transferring data to functions.
* @param transfer_function The function to pass the buffer as second parameter and the
* amount to write as third parameter. It returns the amount that
* was written or -1 upon errors.
* @param limit The maximum amount of bytes to transfer.
* @param destination The first parameter of the transfer function.
* @param args The fourth and further parameters to the transfer function, if any.
* @return The return value of the transfer_function.
*/
template <
typename A = size_t, ///< The type for the amount to be passed, so it can be cast to the right type.
typename F, ///< The type of the function.
typename D, ///< The type of the destination.
typename ... Args> ///< The types of the remaining arguments to the function.
ssize_t TransferOutWithLimit(F transfer_function, size_t limit, D destination, Args&& ... args)
{
size_t amount = std::min(this->RemainingBytesToTransfer(), limit);
if (amount == 0) return 0;
assert(this->pos < this->buffer.size());
assert(this->pos + amount <= this->buffer.size());
/* Making buffer a char means casting a lot in the Recv/Send functions. */
const char *output_buffer = reinterpret_cast<const char*>(this->buffer + this->pos);
ssize_t bytes = transfer_function(destination, output_buffer, static_cast<A>(amount), std::forward<Args>(args)...);
if (bytes > 0) this->pos += bytes;
return bytes;
}
/**
* Transfer data from the packet to the given function. It starts reading at the
* position the last transfer stopped.
* See Packet::TransferIn for more information about transferring data to functions.
* @param transfer_function The function to pass the buffer as second parameter and the
* amount to write as third parameter. It returns the amount that
* was written or -1 upon errors.
* @param destination The first parameter of the transfer function.
* @param args The fourth and further parameters to the transfer function, if any.
* @tparam A The type for the amount to be passed, so it can be cast to the right type.
* @tparam F The type of the transfer_function.
* @tparam D The type of the destination.
* @tparam Args The types of the remaining arguments to the function.
* @return The return value of the transfer_function.
*/
template <typename A = size_t, typename F, typename D, typename ... Args>
ssize_t TransferOut(F transfer_function, D destination, Args&& ... args)
{
return TransferOutWithLimit<A>(transfer_function, std::numeric_limits<size_t>::max(), destination, std::forward<Args>(args)...);
}
/**
* Transfer data from the given function into the packet. It starts writing at the
* position the last transfer stopped.

6
src/network/core/tcp.cpp
View File

@ -103,7 +103,7 @@ SendPacketsState NetworkTCPSocketHandler::SendPackets(bool closing_down)
p = this->packet_queue;
while (p != nullptr) {
res = send(this->sock, (const char*)p->buffer + p->pos, p->size - p->pos, 0);
res = p->TransferOut<int>(send, this->sock, 0);
if (res == -1) {
int err = GET_LAST_ERROR();
if (err != EWOULDBLOCK) {
@ -122,10 +122,8 @@ SendPacketsState NetworkTCPSocketHandler::SendPackets(bool closing_down)
return SPS_CLOSED;
}
p->pos += res;
/* Is this packet sent? */
if (p->pos == p->size) {
if (p->RemainingBytesToTransfer() == 0) {
/* Go to the next packet */
this->packet_queue = p->next;
delete p;

4
src/network/core/tcp_listen.h
View File

@ -63,7 +63,7 @@ public:
DEBUG(net, 1, "[%s] Banned ip tried to join (%s), refused", Tsocket::GetName(), entry.c_str());
if (send(s, (const char*)p.buffer, p.size, 0) < 0) {
if (p.TransferOut<int>(send, s, 0) < 0) {
DEBUG(net, 0, "send failed with error %d", GET_LAST_ERROR());
}
closesocket(s);
@ -80,7 +80,7 @@ public:
Packet p(Tfull_packet);
p.PrepareToSend();
if (send(s, (const char*)p.buffer, p.size, 0) < 0) {
if (p.TransferOut<int>(send, s, 0) < 0) {
DEBUG(net, 0, "send failed with error %d", GET_LAST_ERROR());
}
closesocket(s);

2
src/network/core/udp.cpp
View File

@ -99,7 +99,7 @@ void NetworkUDPSocketHandler::SendPacket(Packet *p, NetworkAddress *recv, bool a
}
/* Send the buffer */
int res = sendto(s.second, (const char*)p->buffer, p->size, 0, (const struct sockaddr *)send.GetAddress(), send.GetAddressLength());
ssize_t res = p->TransferOut<int>(sendto, s.second, 0, (const struct sockaddr *)send.GetAddress(), send.GetAddressLength());
DEBUG(net, 7, "[udp] sendto(%s)", send.GetAddressAsString().c_str());
/* Check for any errors, but ignore it otherwise */

36
src/network/network_client.cpp
View File

@ -35,7 +35,6 @@
/* This file handles all the client-commands */
/** Read some packets, and when do use that data as initial load filter. */
struct PacketReader : LoadFilter {
static const size_t CHUNK = 32 * 1024; ///< 32 KiB chunks of memory.
@ -59,35 +58,38 @@ struct PacketReader : LoadFilter {
}
}
/**
* Simple wrapper around fwrite to be able to pass it to Packet's TransferOut.
* @param destination The reader to add the data to.
* @param source The buffer to read data from.
* @param amount The number of bytes to copy.
* @return The number of bytes that were copied.
*/
static inline ssize_t TransferOutMemCopy(PacketReader *destination, const char *source, size_t amount)
{
memcpy(destination->buf, source, amount);
destination->buf += amount;
destination->written_bytes += amount;
return amount;
}
/**
* Add a packet to this buffer.
* @param p The packet to add.
*/
void AddPacket(const Packet *p)
void AddPacket(Packet *p)
{
assert(this->read_bytes == 0);
size_t in_packet = p->size - p->pos;
size_t to_write = std::min<size_t>(this->bufe - this->buf, in_packet);
const byte *pbuf = p->buffer + p->pos;
this->written_bytes += in_packet;
if (to_write != 0) {
memcpy(this->buf, pbuf, to_write);
this->buf += to_write;
}
p->TransferOutWithLimit(TransferOutMemCopy, this->bufe - this->buf, this);
/* Did everything fit in the current chunk, then we're done. */
if (to_write == in_packet) return;
if (p->RemainingBytesToTransfer() == 0) return;
/* Allocate a new chunk and add the remaining data. */
pbuf += to_write;
to_write = in_packet - to_write;
this->blocks.push_back(this->buf = CallocT<byte>(CHUNK));
this->bufe = this->buf + CHUNK;
memcpy(this->buf, pbuf, to_write);
this->buf += to_write;
p->TransferOutWithLimit(TransferOutMemCopy, this->bufe - this->buf, this);
}
size_t Read(byte *rbuf, size_t size) override

16
src/network/network_content.cpp
View File

@ -459,6 +459,18 @@ static bool GunzipFile(const ContentInfo *ci)
#endif /* defined(WITH_ZLIB) */
}
/**
* Simple wrapper around fwrite to be able to pass it to Packet's TransferOut.
* @param file The file to write data to.
* @param buffer The buffer to write to the file.
* @param amount The number of bytes to write.
* @return The number of bytes that were written.
*/
static inline ssize_t TransferOutFWrite(FILE *file, const char *buffer, size_t amount)
{
return fwrite(buffer, 1, amount, file);
}
bool ClientNetworkContentSocketHandler::Receive_SERVER_CONTENT(Packet *p)
{
if (this->curFile == nullptr) {
@ -476,8 +488,8 @@ bool ClientNetworkContentSocketHandler::Receive_SERVER_CONTENT(Packet *p)
}
} else {
/* We have a file opened, thus are downloading internal content */
size_t toRead = (size_t)(p->size - p->pos);
if (fwrite(p->buffer + p->pos, 1, toRead, this->curFile) != toRead) {
size_t toRead = p->RemainingBytesToTransfer();
if (toRead != 0 && (size_t)p->TransferOut(TransferOutFWrite, this->curFile) != toRead) {
DeleteWindowById(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_CONTENT_DOWNLOAD);
ShowErrorMessage(STR_CONTENT_ERROR_COULD_NOT_DOWNLOAD, STR_CONTENT_ERROR_COULD_NOT_DOWNLOAD_FILE_NOT_WRITABLE, WL_ERROR);
this->Close();