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Diffstat (limited to 'docs/env_variables.md')
| -rw-r--r-- | docs/env_variables.md | 51 |
1 files changed, 25 insertions, 26 deletions
diff --git a/docs/env_variables.md b/docs/env_variables.md index 83bc487f..8d482e20 100644 --- a/docs/env_variables.md +++ b/docs/env_variables.md @@ -137,16 +137,15 @@ 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sensitive instrumentation (see below) NGRAM-x - deeper previous location coverage (from NGRAM-2 up to NGRAM-16) GCC - outdated gcc instrumentation CLANG - outdated clang instrumentation - In CLASSIC (default) and CFG/INSTRIM you can also specify CTX and/or - NGRAM, seperate the options with a comma "," then, e.g.: -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 @@ -180,24 +179,6 @@ 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}` @@ -398,7 +379,8 @@ checks or alter some of the more exotic semantics of the tool: may complain of high load prematurely, especially on systems with low core counts. To avoid the alarming red color, you can set `AFL_NO_CPU_RED`. - - In QEMU mode (-Q), `AFL_PATH` will be searched for afl-qemu-trace. + - In QEMU mode (-Q), Unicorn mode (-U) and Frida mode (-O), `AFL_PATH` will + be searched for afl-qemu-trace. - In QEMU mode (-Q), setting `AFL_QEMU_CUSTOM_BIN` cause afl-fuzz to skip prepending `afl-qemu-trace` to your command line. Use this if you wish to use a @@ -415,6 +397,12 @@ checks or alter some of the more exotic semantics of the tool: without disrupting the afl-fuzz process itself. This is useful, among other things, for bootstrapping libdislocator.so. + - Setting `AFL_TARGET_ENV` causes AFL++ to set extra environment variables + for the target binary. Example: `AFL_TARGET_ENV="VAR1=1 VAR2='a b c'" afl-fuzz ... ` + This exists mostly for things like `LD_LIBRARY_PATH` but it would theoretically + allow fuzzing of AFL++ itself (with 'target' AFL++ using some AFL_ vars that + would disrupt work of 'fuzzer' AFL++). + - Setting `AFL_NO_UI` inhibits the UI altogether, and just periodically prints some basic stats. This behavior is also automatically triggered when the output from afl-fuzz is redirected to a file or to a pipe. @@ -425,8 +413,19 @@ 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. + Others need not apply, unless they also want to disable the + `/proc/sys/kernel/core_pattern` check. - Benchmarking only: `AFL_BENCH_JUST_ONE` causes the fuzzer to exit after processing the first queue entry; and `AFL_BENCH_UNTIL_CRASH` causes it to @@ -614,7 +613,7 @@ optimal values if not already present in the environment: override this by setting `LD_BIND_LAZY` beforehand, but it is almost certainly pointless. - - By default, `ASAN_OPTIONS` are set to: + - By default, `ASAN_OPTIONS` are set to (among others): ``` abort_on_error=1 detect_leaks=0 |