diff options
Diffstat (limited to 'docs/env_variables.md')
| -rw-r--r-- | docs/env_variables.md | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/docs/env_variables.md b/docs/env_variables.md index 899b36cc..0100ffac 100644 --- a/docs/env_variables.md +++ b/docs/env_variables.md @@ -55,7 +55,7 @@ make fairly broad use of environmental variables instead: overridden. - Setting `AFL_USE_ASAN` automatically enables ASAN, provided that your - compiler supports that. Note that fuzzing with ASAN is mildly challenging + compiler supports it. Note that fuzzing with ASAN is mildly challenging - see [notes_for_asan.md](notes_for_asan.md). (You can also enable MSAN via `AFL_USE_MSAN`; ASAN and MSAN come with the @@ -64,6 +64,13 @@ make fairly broad use of environmental variables instead: there is the Control Flow Integrity sanitizer that can be activated by `AFL_USE_CFISAN=1`) + - Setting `AFL_USE_LSAN` automatically enables Leak-Sanitizer, provided + that your compiler supports it. To perform a leak check within your + program at a certain point (such as at the end of an __AFL_LOOP), + you can run the macro __AFL_LEAK_CHECK(); which will cause + an abort if any memory is leaked (you can combine this with the + LSAN_OPTIONS=suppressions option to supress some known leaks). + - Setting `AFL_CC`, `AFL_CXX`, and `AFL_AS` lets you use alternate downstream compilation tools, rather than the default 'clang', 'gcc', or 'as' binaries in your `$PATH`. @@ -277,6 +284,9 @@ checks or alter some of the more exotic semantics of the tool: normally indicated by the cycle counter in the UI turning green. May be convenient for some types of automated jobs. + - `AFL_EXIT_ON_SEED_ISSUES` will restore the vanilla afl-fuzz behaviour + which does not allow crashes or timeout seeds in the initial -i corpus. + - `AFL_MAP_SIZE` sets the size of the shared map that afl-fuzz, afl-showmap, afl-tmin and afl-analyze create to gather instrumentation data from the target. This must be equal or larger than the size the target was @@ -372,8 +382,8 @@ 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), Unicorn mode (-U) and Frida mode (-O), `AFL_PATH` will - be searched for afl-qemu-trace. + - In QEMU mode (-Q) and Frida mode (-O), `AFL_PATH` will + be searched for afl-qemu-trace and afl-frida-trace.so. - 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 @@ -627,7 +637,14 @@ optimal values if not already present in the environment: msan_track_origins=0 allocator_may_return_null=1 ``` - Be sure to include the first one when customizing anything, since some - MSAN versions don't call `abort()` on error, and we need a way to detect - faults. + - Similarly, the default `LSAN_OPTIONS` are set to: +``` + exit_code=23 + fast_unwind_on_malloc=0 + symbolize=0 + print_suppressions=0 +``` + Be sure to include the first ones for LSAN and MSAN when customizing + anything, since some MSAN and LSAN versions don't call `abort()` on + error, and we need a way to detect faults. |