libFuzzer+ASan+UBSan harness for guac_parser_append() — the C state
machine that parses all Guacamole wire-format input in guacd. 3.2M
iterations found no memory corruption; one non-exploitable signed
integer overflow (UBSan) in the length prefix accumulator noted in
FINDINGS.md.
Also adds FINDINGS.md for the Rust protocol parser fuzzer documenting
the UTF-8 boundary panic fix from v0.1.3.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add cargo-fuzz targets for the Guacamole protocol parser:
- protocol_parse: single instruction parsing
- protocol_stream: streaming parser with chunked input
Fix panic in Instruction::parse when a length prefix splits a multi-byte
UTF-8 character (found by fuzzer within seconds). Now returns
ParseError::Truncated instead of panicking on invalid char boundary.
Run with: cargo +nightly fuzz run protocol_parse
cargo +nightly fuzz run protocol_stream
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Dave Kempe