diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/Changelog.md | 3 | ||||
| -rw-r--r-- | docs/custom_mutators.md | 12 | ||||
| -rw-r--r-- | docs/env_variables.md | 11 | ||||
| -rw-r--r-- | docs/fuzzing_in_depth.md | 10 |
4 files changed, 32 insertions, 4 deletions
diff --git a/docs/Changelog.md b/docs/Changelog.md index eee88a51..8f71fd83 100644 --- a/docs/Changelog.md +++ b/docs/Changelog.md @@ -6,10 +6,13 @@ ### Version ++4.06a (dev) - afl-fuzz: - ensure temporary file descriptor is closed when not used + - added `AFL_NO_WARN_INSTABILITY` - afl-cc: - add CFI sanitizer variant to gcc targets - llvm 16 support (thanks to @devnexen!) - support llvm 15 native pcguard changes + - new custom module: autotoken, grammar free fuzzer for text inputs + - LTO autoken and llvm_mode: added AFL_LLVM_DICT2FILE_NO_MAIN support - better sanitizer default options support for all tools - unicorn_mode: updated and minor issues fixed - frida_mode: fix issue on MacOS diff --git a/docs/custom_mutators.md b/docs/custom_mutators.md index 4ffeda7a..82131c92 100644 --- a/docs/custom_mutators.md +++ b/docs/custom_mutators.md @@ -48,6 +48,7 @@ C/C++: ```c void *afl_custom_init(afl_state_t *afl, unsigned int seed); unsigned int afl_custom_fuzz_count(void *data, const unsigned char *buf, size_t buf_size); +void afl_custom_splice_optout(void *data); size_t afl_custom_fuzz(void *data, unsigned char *buf, size_t buf_size, unsigned char **out_buf, unsigned char *add_buf, size_t add_buf_size, size_t max_size); const char *afl_custom_describe(void *data, size_t max_description_len); size_t afl_custom_post_process(void *data, unsigned char *buf, size_t buf_size, unsigned char **out_buf); @@ -72,6 +73,9 @@ def init(seed): def fuzz_count(buf): return cnt +def splice_optout() + pass + def fuzz(buf, add_buf, max_size): return mutated_out @@ -132,6 +136,13 @@ def deinit(): # optional for Python for a specific queue entry, use this function. This function is most useful if `AFL_CUSTOM_MUTATOR_ONLY` is **not** used. +- `splice_optout` (optional): + + If this function is present, no splicing target is passed to the `fuzz` + function. This saves time if splicing data is not needed by the custom + fuzzing function. + This function is never called, just needs to be present to activate. + - `fuzz` (optional): This method performs custom mutations on a given input. It also accepts an @@ -139,6 +150,7 @@ def deinit(): # optional for Python sense to use it. You would only skip this if `post_process` is used to fix checksums etc. so if you are using it, e.g., as a post processing library. Note that a length > 0 *must* be returned! + The returned output buffer is under **your** memory management! - `describe` (optional): diff --git a/docs/env_variables.md b/docs/env_variables.md index 22a5c386..6cd4104b 100644 --- a/docs/env_variables.md +++ b/docs/env_variables.md @@ -129,6 +129,9 @@ subset of the settings discussed in section 1, with the exception of: write all constant string comparisons to this file to be used later with afl-fuzz' `-x` option. + - An option to `AFL_LLVM_DICT2FILE` is `AFL_LLVM_DICT2FILE_NO_MAIN=1` which + skill not parse `main()`. + - `TMPDIR` and `AFL_KEEP_ASSEMBLY`, since no temporary assembly files are created. @@ -354,6 +357,9 @@ checks or alter some of the more exotic semantics of the tool: - Setting `AFL_KEEP_TIMEOUTS` will keep longer running inputs if they reach new coverage + - On the contrary, if you are not interested in any timeouts, you can set + `AFL_IGNORE_TIMEOUTS` to get a bit of speed instead. + - `AFL_EXIT_ON_SEED_ISSUES` will restore the vanilla afl-fuzz behavior which does not allow crashes or timeout seeds in the initial -i corpus. @@ -474,7 +480,10 @@ checks or alter some of the more exotic semantics of the tool: output from afl-fuzz is redirected to a file or to a pipe. - Setting `AFL_NO_STARTUP_CALIBRATION` will skip the initial calibration - of all starting seeds, and start fuzzing at once. + of all starting seeds, and start fuzzing at once. Use with care, this + degrades the fuzzing performance! + + - Setting `AFL_NO_WARN_INSTABILITY` will suppress instability warnings. - In QEMU mode (-Q) and FRIDA mode (-O), `AFL_PATH` will be searched for afl-qemu-trace and afl-frida-trace.so. diff --git a/docs/fuzzing_in_depth.md b/docs/fuzzing_in_depth.md index 87f31a58..f75ca5dc 100644 --- a/docs/fuzzing_in_depth.md +++ b/docs/fuzzing_in_depth.md @@ -534,6 +534,8 @@ dictionaries/FORMAT.dict`. * With `afl-clang-fast`, you can set `AFL_LLVM_DICT2FILE=/full/path/to/new/file.dic` to automatically generate a dictionary during target compilation. + Adding `AFL_LLVM_DICT2FILE_NO_MAIN=1` to not parse main (usually command line + parameter parsing) is often a good idea too. * You also have the option to generate a dictionary yourself during an independent run of the target, see [utils/libtokencap/README.md](../utils/libtokencap/README.md). @@ -628,7 +630,8 @@ If you have a large corpus, a corpus from a previous run or are fuzzing in a CI, then also set `export AFL_CMPLOG_ONLY_NEW=1` and `export AFL_FAST_CAL=1`. If the queue in the CI is huge and/or the execution time is slow then you can also add `AFL_NO_STARTUP_CALIBRATION=1` to skip the initial queue calibration -phase and start fuzzing at once. +phase and start fuzzing at once - but only do this if the calibration phase +would be too long for your fuzz run time. You can also use different fuzzers. If you are using AFL spinoffs or AFL conforming fuzzers, then just use the same -o directory and give it a unique @@ -914,7 +917,8 @@ normal fuzzing campaigns as these are much shorter runnings. If the queue in the CI is huge and/or the execution time is slow then you can also add `AFL_NO_STARTUP_CALIBRATION=1` to skip the initial queue calibration -phase and start fuzzing at once. +phase and start fuzzing at once. But only do that if the calibration time is +too long for your overall available fuzz run time. 1. Always: * LTO has a much longer compile time which is diametrical to short fuzzing - @@ -935,7 +939,7 @@ phase and start fuzzing at once. 3. Also randomize the afl-fuzz runtime options, e.g.: * 65% for `AFL_DISABLE_TRIM` * 50% for `AFL_KEEP_TIMEOUTS` - * 50% use a dictionary generated by `AFL_LLVM_DICT2FILE` + * 50% use a dictionary generated by `AFL_LLVM_DICT2FILE` + `AFL_LLVM_DICT2FILE_NO_MAIN=1` * 40% use MOpt (`-L 0`) * 40% for `AFL_EXPAND_HAVOC_NOW` * 20% for old queue processing (`-Z`) |