Rayhaan JaufeerallyandClaude Fable 5.1
9367c38907
Rhai made a decision about a route cost one to three microseconds, some two hundred times what the same costs in Rust. That was bearable where a function is asked once for an UPDATE, and is not where every route is weighed against every peer, as it is when routes are passed on. What is wanted of a policy (mark routes by where they came from, mark what is announced, let communities say who is told what) needs no language; it is to be configuration, done natively. Kept from that work: route selection goes by a LOCAL_PREF that policy set on a route from an external peer, and the lab's configuration can be added to by a phase. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
51 lines
2.0 KiB
Markdown
51 lines
2.0 KiB
Markdown
# Fuzz targets
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Coverage-guided fuzzing of everything that reads input we do not control.
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The property tests (`cargo test`, e.g. `crates/packet/tests/properties.rs`)
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check the same things on generated input and run on every build; these
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targets go further by letting libFuzzer follow code coverage for as long as
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you leave them running.
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| Target | Input |
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|----------------|------------------------------------------------------------------|
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| `message` | Raw bytes as they come off a TCP connection |
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| `message_body` | A message body behind a correct header (reaches the body parsers) |
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| `prefix_text` | A prefix as text |
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| `config` | The configuration file |
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| `rtr` | A stream of RTR PDUs, as an RPKI cache sends them |
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| `netlink` | Messages from the kernel's routing socket |
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| `attrs` | The routing table's reading of stored attribute bytes |
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For the two message targets a finding is either a panic, or a message the
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decoder accepted that cannot be written and read back as itself.
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## Running
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libFuzzer needs a nightly toolchain and `cargo-fuzz`:
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```bash
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rustup toolchain install nightly
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cargo install cargo-fuzz
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```
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Then, from this directory:
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```bash
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cargo +nightly fuzz run message_body corpus/message_body seeds/message_body -- -max_total_time=300
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```
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The first directory is the working corpus, which the fuzzer adds to and
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which is not checked in. `seeds/` holds a few valid inputs to start from.
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Leave out `-max_total_time` to run until interrupted.
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## When it finds something
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The input is saved under `artifacts/<target>/`. Reproduce it with
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```bash
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cargo +nightly fuzz run message_body artifacts/message_body/crash-...
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```
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Fix the bug, and add a unit test with the input next to the code it broke,
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so that `cargo test` keeps it fixed without anyone having to run the fuzzer.
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