Instead of making the filter_block fn in the ChainWatchInterface trait return both a list of indexes of transaction positions within the block and references to the transactions themselves, return only the list of indexes and then build the reference list at the callsite. While this may be slightly less effecient from a memory locality perspective, it shouldn't be materially different. This should make it more practical to generate bindings for filter_block as it no longer needs to reference Rust Transaction objects that are contained in a Rust Block object (which we'd otherwise just pass over the FFI in fully-serialized form). |
||
---|---|---|
.. | ||
src | ||
.gitignore | ||
Cargo.toml | ||
ci-fuzz.sh | ||
README.md | ||
targets.h |
Fuzzing
Fuzz tests generate a ton of random parameter arguments to the program and then validate that none cause it to crash.
How does it work?
Typically, Travis CI will run travis-fuzz.sh
on one of the environments the automated tests are configured for.
This is the most time-consuming component of the continuous integration workflow, so it is recommended that you detect
issues locally, and Travis merely acts as a sanity check. Fuzzing is further only effective with
a lot of CPU time, indicating that if crash scenarios are discovered on Travis with its low
runtime constraints, the crash is caused relatively easily.
How do I run fuzz tests locally?
You typically won't need to run the entire combination of different fuzzing tools. For local execution, honggfuzz
should be more than sufficient.
Setup
To install honggfuzz
, simply run
cargo update
cargo install --force honggfuzz
Execution
To run the Hongg fuzzer, do
export CPU_COUNT=1 # replace as needed
export HFUZZ_BUILD_ARGS="--features honggfuzz_fuzz"
export HFUZZ_RUN_ARGS="-n $CPU_COUNT --exit_upon_crash"
export TARGET="msg_ping_target" # replace with the target to be fuzzed
cargo hfuzz run $TARGET
To see a list of available fuzzing targets, run:
ls ./src/bin/
A fuzz test failed on Travis, what do I do?
You're trying to create a PR, but need to find the underlying cause of that pesky fuzz failure blocking the merge?
Worry not, for this is easily traced.
If your Travis output log looks like this:
Size:639 (i,b,hw,ed,ip,cmp): 0/0/0/0/0/1, Tot:0/0/0/2036/5/28604
Seen a crash. Terminating all fuzzing threads
… # a lot of lines in between
<0x0000555555565559> [func:UNKNOWN file: line:0 module:/home/travis/build/rust-bitcoin/rust-lightning/fuzz/hfuzz_target/x86_64-unknown-linux-gnu/release/full_stack_target]
<0x0000000000000000> [func:UNKNOWN file: line:0 module:UNKNOWN]
=====================================================================
2d3136383734090101010101010101010101010101010101010101010101
010101010100040101010101010101010101010103010101010100010101
0069d07c319a4961
The command "if [ "$(rustup show | grep default | grep stable)" != "" ]; then cd fuzz && cargo test --verbose && ./travis-fuzz.sh; fi" exited with 1.
Note that the penultimate stack trace line ends in release/full_stack_target]
. That indicates that
the failing target was full_stack
. To reproduce the error locally, simply copy the hex,
and run the following from the fuzz
directory:
export TARGET="full_stack" # adjust for your output
export HEX="2d3136383734090101010101010101010101010101010101010101010101\
010101010100040101010101010101010101010103010101010100010101\
0069d07c319a4961" # adjust for your output
mkdir -p ./test_cases/$TARGET
echo $HEX | xxd -r -p > ./test_cases/$TARGET/any_filename_works
export RUST_BACKTRACE=1
cargo test
This will reproduce the failing fuzz input and yield a usable stack trace.