11 Commits

Author SHA1 Message Date
Andrew Kelley
517cfb0dd1 fuzzing: progress towards web UI
* libfuzzer: close file after mmap
* fuzzer/main.js: connect with EventSource and debug dump the messages.
  currently this prints how many fuzzer runs have been attempted to
  console.log.
* extract some `std.debug.Info` logic into `std.debug.Coverage`.
  Prepares for consolidation across multiple different executables which
  share source files, and makes it possible to send all the
  PC/SourceLocation mapping data with 4 memcpy'd arrays.
* std.Build.Fuzz:
  - spawn a thread to watch the message queue and signal event
    subscribers.
  - track coverage map data
  - respond to /events URL with EventSource messages on a timer
2024-08-07 00:48:32 -07:00
Andrew Kelley
e0ffac4e3c introduce a web interface for fuzzing
* new .zig-cache subdirectory: 'v'
  - stores coverage information with filename of hash of PCs that want
    coverage. This hash is a hex encoding of the 64-bit coverage ID.
* build runner
  * fixed bug in file system inputs when a compile step has an
    overridden zig_lib_dir field set.
  * set some std lib options optimized for the build runner
    - no side channel mitigations
    - no Transport Layer Security
    - no crypto fork safety
  * add a --port CLI arg for choosing the port the fuzzing web interface
    listens on. it defaults to choosing a random open port.
  * introduce a web server, and serve a basic single page application
    - shares wasm code with autodocs
    - assets are created live on request, for convenient development
      experience. main.wasm is properly cached if nothing changes.
    - sources.tar comes from file system inputs (introduced with the
      `--watch` feature)
  * receives coverage ID from test runner and sends it on a thread-safe
    queue to the WebServer.
* test runner
  - takes a zig cache directory argument now, for where to put coverage
    information.
  - sends coverage ID to parent process
* fuzzer
  - puts its logs (in debug mode) in .zig-cache/tmp/libfuzzer.log
  - computes coverage_id and makes it available with
    `fuzzer_coverage_id` exported function.
  - the memory-mapped coverage file is now namespaced by the coverage id
    in hex encoding, in `.zig-cache/v`
* tokenizer
  - add a fuzz test to check that several properties are upheld
2024-08-07 00:48:32 -07:00
Andrew Kelley
ffc050e055 fuzzer: log errors and move deduplicated runs to shared mem 2024-08-07 00:48:32 -07:00
Andrew Kelley
97643c1ecc fuzzer: track code coverage from all runs
When a unique run is encountered, track it in a bit set memory-mapped
into the fuzz directory so it can be observed by other processes, even
while the fuzzer is running.
2024-08-07 00:48:32 -07:00
Andrew Kelley
688c2df646 fuzzer: use the cmp values
seems to provide better scoring
2024-07-25 18:52:21 -07:00
Andrew Kelley
6a63372053 fuzzer: basic implementation
just some experimentation. I didn't expect this to be effective so
quickly but it already can find a comparison made with mem.eql
2024-07-25 18:52:21 -07:00
Andrew Kelley
a3c74aca99 add --debug-rt CLI arg to the compiler + bonus edits
The flag makes compiler_rt and libfuzzer be in debug mode.

Also:
* fuzzer: override debug logs and disable debug logs for frequently
  called functions
* std.Build.Fuzz: fix bug of rerunning the old unit test binary
* report errors from rebuilding the unit tests better
* link.Elf: additionally add tsan lib and fuzzer lib to the hash
2024-07-25 18:52:21 -07:00
Andrew Kelley
6f3767862d implement std.testing.fuzzInput
For now this returns a dummy fuzz input.
2024-07-25 18:52:20 -07:00
Andrew Kelley
dbbe2f1094 libfuzzer: log all the libcalls to stderr 2024-07-22 14:26:17 -07:00
Andrew Kelley
7930efc60b libfuzzer: implement enough symbols for hello world 2024-07-22 13:07:02 -07:00
Andrew Kelley
54b7e144b1 initial support for integrated fuzzing
* Add the `-ffuzz` and `-fno-fuzz` CLI arguments.
* Detect fuzz testing flags from zig cc.
* Set the correct clang flags when fuzz testing is requested. It can be
  combined with TSAN and UBSAN.
* Compilation: build fuzzer library when needed which is currently an
  empty zig file.
* Add optforfuzzing to every function in the llvm backend for modules
  that have requested fuzzing.
* In ZigLLVMTargetMachineEmitToFile, add the optimization passes for
  sanitizer coverage.
* std.mem.eql uses a naive implementation optimized for fuzzing when
  builtin.fuzz is true.

Tracked by #20702
2024-07-22 13:07:02 -07:00