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[api] Add message size limits to prevent memory exhaustion (#10936)

This commit is contained in:
J. Nick Koston
2025-10-07 19:47:31 -05:00
committed by GitHub
parent 7682b4e9a3
commit 5aff20a624
4 changed files with 35 additions and 21 deletions

View File

@@ -18,6 +18,17 @@ namespace esphome::api {
// uncomment to log raw packets
//#define HELPER_LOG_PACKETS
// Maximum message size limits to prevent OOM on constrained devices
// Handshake messages are limited to a small size for security
static constexpr uint16_t MAX_HANDSHAKE_SIZE = 128;
// Data message limits vary by platform based on available memory
#ifdef USE_ESP8266
static constexpr uint16_t MAX_MESSAGE_SIZE = 8192; // 8 KiB for ESP8266
#else
static constexpr uint16_t MAX_MESSAGE_SIZE = 32768; // 32 KiB for ESP32 and other platforms
#endif
// Forward declaration
struct ClientInfo;

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@@ -168,11 +168,12 @@ APIError APINoiseFrameHelper::try_read_frame_() {
// read body
uint16_t msg_size = (((uint16_t) rx_header_buf_[1]) << 8) | rx_header_buf_[2];
if (state_ != State::DATA && msg_size > 128) {
// for handshake message only permit up to 128 bytes
// Check against size limits to prevent OOM: MAX_HANDSHAKE_SIZE for handshake, MAX_MESSAGE_SIZE for data
uint16_t limit = (state_ == State::DATA) ? MAX_MESSAGE_SIZE : MAX_HANDSHAKE_SIZE;
if (msg_size > limit) {
state_ = State::FAILED;
HELPER_LOG("Bad packet len for handshake: %d", msg_size);
return APIError::BAD_HANDSHAKE_PACKET_LEN;
HELPER_LOG("Bad packet: message size %u exceeds maximum %u", msg_size, limit);
return (state_ == State::DATA) ? APIError::BAD_DATA_PACKET : APIError::BAD_HANDSHAKE_PACKET_LEN;
}
// Reserve space for body

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@@ -115,10 +115,10 @@ APIError APIPlaintextFrameHelper::try_read_frame_() {
continue;
}
if (msg_size_varint->as_uint32() > std::numeric_limits<uint16_t>::max()) {
if (msg_size_varint->as_uint32() > MAX_MESSAGE_SIZE) {
state_ = State::FAILED;
HELPER_LOG("Bad packet: message size %" PRIu32 " exceeds maximum %u", msg_size_varint->as_uint32(),
std::numeric_limits<uint16_t>::max());
MAX_MESSAGE_SIZE);
return APIError::BAD_DATA_PACKET;
}
rx_header_parsed_len_ = msg_size_varint->as_uint16();