diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/FAQ.md | 10 | ||||
| -rw-r--r-- | docs/best_practices.md | 27 | ||||
| -rw-r--r-- | docs/custom_mutators.md | 10 | ||||
| -rw-r--r-- | docs/fuzzing_in_depth.md | 10 | ||||
| -rw-r--r-- | docs/important_changes.md | 4 |
5 files changed, 37 insertions, 24 deletions
diff --git a/docs/FAQ.md b/docs/FAQ.md index ae4a77dc..49444999 100644 --- a/docs/FAQ.md +++ b/docs/FAQ.md @@ -12,7 +12,9 @@ If you find an interesting or important question missing, submit it via American Fuzzy Lop (AFL) was developed by Michał "lcamtuf" Zalewski starting in 2013/2014, and when he left Google end of 2017 he stopped developing it. - At the end of 2019, the Google fuzzing team took over maintenance of AFL, however it is only accepting PRs from the community and is not developing enhancements anymore. + At the end of 2019, the Google fuzzing team took over maintenance of AFL, + however, it is only accepting PRs from the community and is not developing + enhancements anymore. In the second quarter of 2019, 1 1/2 years later, when no further development of AFL had happened and it became clear there would none be coming, AFL++ was born, where initially community patches were collected and applied for bug fixes and enhancements. Then from various AFL spin-offs - mostly academic research - features were integrated. @@ -121,8 +123,10 @@ If you find an interesting or important question missing, submit it via Sending the same input again and again should take the exact same path through the target every time. If that is the case, the stability is 100%. - If however randomness happens, e.g. a thread reading other external data, reaction to timing, etc., then in some of the re-executions with the same data the edge coverage result will be different accross runs. - Those edges that change are then flagged "unstable". + If, however, randomness happens, e.g. a thread reading other external data, + reaction to timing, etc., then in some of the re-executions with the same data + the edge coverage result will be different accross runs. Those edges that + change are then flagged "unstable". The more "unstable" edges, the more difficult for AFL++ to identify valid new paths. diff --git a/docs/best_practices.md b/docs/best_practices.md index 979849f4..15f8870c 100644 --- a/docs/best_practices.md +++ b/docs/best_practices.md @@ -54,9 +54,11 @@ to emulate the network. This is also much faster than the real network would be. See [utils/socket_fuzzing/](../utils/socket_fuzzing/). There is an outdated AFL++ branch that implements networking if you are -desperate though: [https://github.com/AFLplusplus/AFLplusplus/tree/networking](https://github.com/AFLplusplus/AFLplusplus/tree/networking) - -however a better option is AFLnet ([https://github.com/aflnet/aflnet](https://github.com/aflnet/aflnet)) -which allows you to define network state with different type of data packets. +desperate though: +[https://github.com/AFLplusplus/AFLplusplus/tree/networking](https://github.com/AFLplusplus/AFLplusplus/tree/networking) +- however, a better option is AFLnet +([https://github.com/aflnet/aflnet](https://github.com/aflnet/aflnet)) which +allows you to define network state with different type of data packets. ## Improvements @@ -72,13 +74,16 @@ which allows you to define network state with different type of data packets. ### Improving stability -For fuzzing a 100% stable target that covers all edges is the best case. -A 90% stable target that covers all edges is however better than a 100% stable target that ignores 10% of the edges. +For fuzzing a 100% stable target that covers all edges is the best case. A 90% +stable target that covers all edges is, however, better than a 100% stable +target that ignores 10% of the edges. With instability, you basically have a partial coverage loss on an edge, with ignored functions you have a full loss on that edges. -There are functions that are unstable, but also provide value to coverage, e.g., init functions that use fuzz data as input. -If however a function that has nothing to do with the input data is the source of instability, e.g., checking jitter, or is a hash map function etc., then it should not be instrumented. +There are functions that are unstable, but also provide value to coverage, e.g., +init functions that use fuzz data as input. If, however, a function that has +nothing to do with the input data is the source of instability, e.g., checking +jitter, or is a hash map function etc., then it should not be instrumented. To be able to exclude these functions (based on AFL++'s measured stability), the following process will allow to identify functions with variable edges. @@ -116,8 +121,12 @@ Four steps are required to do this and it also requires quite some knowledge of If `PCGUARD` is used, then you need to follow this guide (needs llvm 12+!): [https://clang.llvm.org/docs/SanitizerCoverage.html#partially-disabling-instrumentation](https://clang.llvm.org/docs/SanitizerCoverage.html#partially-disabling-instrumentation) - Only exclude those functions from instrumentation that provide no value for coverage - that is if it does not process any fuzz data directly or indirectly (e.g. hash maps, thread management etc.). - If however a function directly or indirectly handles fuzz data, then you should not put the function in a deny instrumentation list and rather live with the instability it comes with. + Only exclude those functions from instrumentation that provide no value for + coverage - that is if it does not process any fuzz data directly or + indirectly (e.g. hash maps, thread management etc.). If, however, a + function directly or indirectly handles fuzz data, then you should not put + the function in a deny instrumentation list and rather live with the + instability it comes with. 4. Recompile the target diff --git a/docs/custom_mutators.md b/docs/custom_mutators.md index 4018d633..fc5ecbf9 100644 --- a/docs/custom_mutators.md +++ b/docs/custom_mutators.md @@ -112,11 +112,11 @@ def deinit(): # optional for Python - `fuzz_count` (optional): - When a queue entry is selected to be fuzzed, afl-fuzz selects the number - of fuzzing attempts with this input based on a few factors. - If however the custom mutator wants to set this number instead on how often - it is called for a specific queue entry, use this function. - This function is most useful if `AFL_CUSTOM_MUTATOR_ONLY` is **not** used. + When a queue entry is selected to be fuzzed, afl-fuzz selects the number of + fuzzing attempts with this input based on a few factors. If, however, the + custom mutator wants to set this number instead on how often it is called + for a specific queue entry, use this function. This function is most useful + if `AFL_CUSTOM_MUTATOR_ONLY` is **not** used. - `fuzz` (optional): diff --git a/docs/fuzzing_in_depth.md b/docs/fuzzing_in_depth.md index 92b3cf86..96e709ab 100644 --- a/docs/fuzzing_in_depth.md +++ b/docs/fuzzing_in_depth.md @@ -131,8 +131,8 @@ The following options are available when you instrument with LTO mode have to compile the target twice, once specifically with/for this mode by setting `AFL_LLVM_CMPLOG=1`, and pass this binary to afl-fuzz via the `-c` parameter. Note that you can compile also just a cmplog binary and use that - for both however there will be a performance penality. You can read more about - this in + for both, however, there will be a performance penality. You can read more + about this in [instrumentation/README.cmplog.md](../instrumentation/README.cmplog.md). If you use LTO, LLVM or GCC_PLUGIN mode @@ -151,7 +151,7 @@ only instrument parts of the target that you are interested in: inlined and then would not match! See [instrumentation/README.instrument_list.md](../instrumentation/README.instrument_list.md) -There are many more options and modes available however these are most of the +There are many more options and modes available, however, these are most of the time less effective. See: * [instrumentation/README.ctx.md](../instrumentation/README.ctx.md) * [instrumentation/README.ngram.md](../instrumentation/README.ngram.md) @@ -369,8 +369,8 @@ This step is highly recommended! ### c) Minimizing all corpus files The shorter the input files that still traverse the same path within the target, -the better the fuzzing will be. This minimization is done with `afl-tmin` -however it is a long process as this has to be done for every file: +the better the fuzzing will be. This minimization is done with `afl-tmin`, +however, it is a long process as this has to be done for every file: ``` mkdir input diff --git a/docs/important_changes.md b/docs/important_changes.md index 726de64d..6cd00791 100644 --- a/docs/important_changes.md +++ b/docs/important_changes.md @@ -15,8 +15,8 @@ With AFL++ 3.15 we introduced the following changes from previous behaviors: With AFL++ 3.14 we introduced the following changes from previous behaviors: * afl-fuzz: deterministic fuzzing it not a default for -M main anymore - * afl-cmin/afl-showmap -i now descends into subdirectories (afl-cmin.bash - however does not) + * afl-cmin/afl-showmap -i now descends into subdirectories (afl-cmin.bash, + however, does not) With AFL++ 3.10 we introduced the following changes from previous behaviors: * The '+' feature of the '-t' option now means to auto-calculate the timeout |