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Diffstat (limited to 'docs/env_variables.md')
| -rw-r--r-- | docs/env_variables.md | 37 |
1 files changed, 14 insertions, 23 deletions
diff --git a/docs/env_variables.md b/docs/env_variables.md index 409425f1..572fad01 100644 --- a/docs/env_variables.md +++ b/docs/env_variables.md @@ -130,16 +130,15 @@ Then there are a few specific features that are only available in instrumentatio PCGUARD - our own pcgard based instrumentation (default) NATIVE - clang's original pcguard based instrumentation CLASSIC - classic AFL (map[cur_loc ^ prev_loc >> 1]++) (default) - CFG - InsTrim instrumentation (see below) LTO - LTO instrumentation (see below) CTX - context sensitive instrumentation (see below) NGRAM-x - deeper previous location coverage (from NGRAM-2 up to NGRAM-16) GCC - outdated gcc instrumentation CLANG - outdated clang instrumentation - In CLASSIC (default) and CFG/INSTRIM you can also specify CTX and/or - NGRAM, seperate the options with a comma "," then, e.g.: - `AFL_LLVM_INSTRUMENT=CFG,CTX,NGRAM-4` - Not that this is a good idea to use both CTX and NGRAM :) + In CLASSIC you can also specify CTX and/or NGRAM, seperate the options + with a comma "," then, e.g.: + `AFL_LLVM_INSTRUMENT=CLASSIC,CTX,NGRAM-4` + Note that this is actually not a good idea to use both CTX and NGRAM :) ### LTO @@ -173,24 +172,6 @@ Then there are a few specific features that are only available in instrumentatio See [instrumentation/README.lto.md](../instrumentation/README.lto.md) for more information. -### INSTRIM - - This feature increases the speed by ~15% without any disadvantages to the - classic instrumentation. - - Note that there is also an LTO version (if you have llvm 11 or higher) - - that is the best instrumentation we have. Use `afl-clang-lto` to activate. - The InsTrim LTO version additionally has all the options and features of - LTO (see above). - - - Setting `AFL_LLVM_INSTRIM` or `AFL_LLVM_INSTRUMENT=CFG` activates this mode - - - Setting `AFL_LLVM_INSTRIM_LOOPHEAD=1` expands on INSTRIM to optimize loops. - afl-fuzz will only be able to see the path the loop took, but not how - many times it was called (unless it is a complex loop). - - See [instrumentation/README.instrim.md](../instrumentation/README.instrim.md) - ### NGRAM - Setting `AFL_LLVM_NGRAM_SIZE` or `AFL_LLVM_INSTRUMENT=NGRAM-{value}` @@ -424,6 +405,16 @@ checks or alter some of the more exotic semantics of the tool: - Setting `AFL_FORCE_UI` will force painting the UI on the screen even if no valid terminal was detected (for virtual consoles) + - If you are using persistent mode (you should, see [instrumentation/README.persistent_mode.md](instrumentation/README.persistent_mode.md)) + some targets keep inherent state due which a detected crash testcase does + not crash the target again when the testcase is given. To be able to still + re-trigger these crashes you can use the `AFL_PERSISTENT_RECORD` variable + with a value of how many previous fuzz cases to keep prio a crash. + if set to e.g. 10, then the 9 previous inputs are written to + out/default/crashes as RECORD:000000,cnt:000000 to RECORD:000000,cnt:000008 + and RECORD:000000,cnt:000009 being the crash case. + NOTE: This option needs to be enabled in config.h first! + - If you are Jakub, you may need `AFL_I_DONT_CARE_ABOUT_MISSING_CRASHES`. Others need not apply, unless they also want to disable the `/proc/sys/kernel/core_pattern` check. |