Rayhaan JaufeerallyandClaude Fable 5.1
3d946c32ce
What the code-health review found, and what a fuzz target written for it
found in its first seconds.
- A set of attributes with the same attribute twice is refused by the
routing table. Its readers (the selection key, the path, the next hop)
could each take a different one of the two. The decoder never lets one
through; the new fuzz target `attrs` found that the table would.
- bgp_peer_up{peer}, to alert on a peer going away, and bgp_build_info.
Every metric is there from the first scrape. Alerts for a peer down,
hijack attempts and kernel errors are in the README.
- `bgp --check config` validates a configuration without starting, and
`--version` says which build it is. CI runs the first on the example
configuration, which a test now also parses with its commented fields
put in; the example had to learn about the next hop check.
- Path attributes have a module of their own, packet::attributes,
re-exported from packet::message as before.
- policy::From, which shadowed the trait, is RouteSource. The server's
connection, dialer and fsm modules are private. Logging arguments live
in the binary; the server library no longer depends on clap.
- One is_unicast_link_local (the standard library's) instead of two of
our own; SelectionKey::origin(); one place where an Import is made.
- READMEs say what the daemon does today rather than what it did not do
a year ago. Documentation links are checked in CI. Unused dependencies
and bgp_web::serve are gone; the Docker build is --locked and does not
ship the fuzz corpus.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2.0 KiB
Fuzz targets
Coverage-guided fuzzing of everything that reads input we do not control.
The property tests (cargo test, e.g. crates/packet/tests/properties.rs)
check the same things on generated input and run on every build; these
targets go further by letting libFuzzer follow code coverage for as long as
you leave them running.
| Target | Input |
|---|---|
message |
Raw bytes as they come off a TCP connection |
message_body |
A message body behind a correct header (reaches the body parsers) |
prefix_text |
A prefix as text |
config |
The configuration file |
rtr |
A stream of RTR PDUs, as an RPKI cache sends them |
netlink |
Messages from the kernel's routing socket |
attrs |
The routing table's reading of stored attribute bytes |
For the two message targets a finding is either a panic, or a message the decoder accepted that cannot be written and read back as itself.
Running
libFuzzer needs a nightly toolchain and cargo-fuzz:
rustup toolchain install nightly
cargo install cargo-fuzz
Then, from this directory:
cargo +nightly fuzz run message_body corpus/message_body seeds/message_body -- -max_total_time=300
The first directory is the working corpus, which the fuzzer adds to and
which is not checked in. seeds/ holds a few valid inputs to start from.
Leave out -max_total_time to run until interrupted.
When it finds something
The input is saved under artifacts/<target>/. Reproduce it with
cargo +nightly fuzz run message_body artifacts/message_body/crash-...
Fix the bug, and add a unit test with the input next to the code it broke,
so that cargo test keeps it fixed without anyone having to run the fuzzer.