BeamMP/BeamMP-Server
1
0
Fork 0
mirror of https://github.com/BeamMP/BeamMP-Server.git synced 2025-08-16 16:26:26 +00:00
Code Issues Packages Projects Releases Wiki Activity

refactor decompression limits and resizing

Browse Source
This commit is contained in:
Lion 2024-07-15 12:31:09 +02:00 committed by GitHub
parent 8b21b6cef3
commit 0950d367d4
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
1 changed files with 13 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/Common.cpp
View File

@ -387,13 +387,16 @@ void SplitString(const std::string& str, const char delim, std::vector<std::stri
} }
} }
static constexpr size_t STARTING_MAX_DECOMPRESSION_BUFFER_SIZE = 15 * 1024 * 1024;
static constexpr size_t MAX_DECOMPRESSION_BUFFER_SIZE = 30 * 1024 * 1024;
std::vector<uint8_t> DeComp(std::span<const uint8_t> input) { std::vector<uint8_t> DeComp(std::span<const uint8_t> input) {
beammp_debugf("got {} bytes of input data", input.size()); beammp_debugf("got {} bytes of input data", input.size());
// start with a decompression buffer of 5x the input size, clamped to a maximum of 15 MB. // start with a decompression buffer of 5x the input size, clamped to a maximum of 15 MB.
// this buffer can and will grow, but we don't want to start it too large. A 5x compression ratio // this buffer can and will grow, but we don't want to start it too large. A 5x compression ratio
// is pretty optimistic. // is pretty optimistic.
std::vector<uint8_t> output_buffer(std::min<size_t>(input.size() * 5, 15 * 1024 * 1024)); std::vector<uint8_t> output_buffer(std::min<size_t>(input.size() * 5, STARTING_MAX_DECOMPRESSION_BUFFER_SIZE));
uLongf output_size = output_buffer.size(); uLongf output_size = output_buffer.size();
@ -404,14 +407,17 @@ std::vector<uint8_t> DeComp(std::span<const uint8_t> input) {
reinterpret_cast<const Bytef*>(input.data()), reinterpret_cast<const Bytef*>(input.data()),
static_cast<uLongf>(input.size())); static_cast<uLongf>(input.size()));
if (res == Z_BUF_ERROR) { if (res == Z_BUF_ERROR) {
// We assume that a reasonable maximum size for decompressed packets is 30 MB. // We assume that a reasonable maximum size for decompressed packets exists. We want to avoid
// If this were to be an issue, this could be made configurable, however clients have a similar // a client effectively "zip bombing" us by sending a lot of small packets which decompress
// into huge data.
// If this limit were to be an issue, this could be made configurable, however clients have a similar
// limit. For that reason, we just reject packets which decompress into too much data. // limit. For that reason, we just reject packets which decompress into too much data.
if (output_buffer.size() > 30 * 1024 * 1024) { if (output_buffer.size() > MAX_DECOMPRESSION_BUFFER_SIZE) {
throw std::runtime_error("decompressed packet size of 30 MB exceeded"); throw std::runtime_error(fmt::format("decompressed packet size of {} bytes exceeded", MAX_DECOMPRESSION_BUFFER_SIZE));
} }
beammp_warn("zlib uncompress() failed, trying with 2x buffer size of " + std::to_string(output_buffer.size() * 2)); // if decompression fails, we double the buffer size (up to the allowed limit) and try again
output_buffer.resize(output_buffer.size() * 2); output_buffer.resize(std::max<size_t>(output_buffer.size() * 2, MAX_DECOMPRESSION_BUFFER_SIZE));
beammp_warnf("zlib uncompress() failed, trying with a larger buffer size of {}", output_buffer.size());
output_size = output_buffer.size(); output_size = output_buffer.size();
} else if (res != Z_OK) { } else if (res != Z_OK) {
beammp_error("zlib uncompress() failed: " + std::to_string(res)); beammp_error("zlib uncompress() failed: " + std::to_string(res));