From 920e9402a4d6101bbbed2ef7584d85a3c3de0eaa Mon Sep 17 00:00:00 2001 From: Joshua Rogers Date: Fri, 2 Apr 2021 22:23:11 +0000 Subject: Add support for standalone leak-sanitizer, introducting the environment variable AFL_USE_LSAN. AFL_USE_LSAN introduces the macro __AFL_CHECK_LEAK() which will check for a memory leak when the macro is run. This is especially helpful when using __AFL_LOOP(). If __AFL_LEAK_CHECK() is not used when AFL_USE_LSAN=1 is set, the leak checker will run when the program exits. --- docs/notes_for_asan.md | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'docs/notes_for_asan.md') diff --git a/docs/notes_for_asan.md b/docs/notes_for_asan.md index 2b3bc028..26f34fad 100644 --- a/docs/notes_for_asan.md +++ b/docs/notes_for_asan.md @@ -28,6 +28,13 @@ Note that ASAN is incompatible with -static, so be mindful of that. (You can also use AFL_USE_MSAN=1 to enable MSAN instead.) +When compiling with AFL_USE_LSAN, the leak sanitizer will normally run +when the program exits. In order to utilize this check at different times, +such as at the end of a loop, you may use the macro __AFL_CHECK_LEAK();. +This macro will report a crash in afl-fuzz if any memory is left leaking +at this stage. You can also use LSAN_OPTIONS and a supressions file +for more fine-tuned checking, however make sure you keep exitcode=23. + NOTE: if you run several secondary instances, only one should run the target compiled with ASAN (and UBSAN, CFISAN), the others should run the target with no sanitizers compiled in. -- cgit 1.4.1 From 6514e33ab6733dd4e7ae0d3eeec83db06b3f451f Mon Sep 17 00:00:00 2001 From: Joshua Rogers Date: Fri, 2 Apr 2021 22:32:38 +0000 Subject: Replace __AFL_CHECK_LEAK with __AFL_LEAK_CHECK to be more proper. Fix spelling mistakes. Correctly call LSAN_ERROR not MSAN_ERROR. --- docs/env_variables.md | 8 ++++---- docs/notes_for_asan.md | 2 +- src/afl-analyze.c | 2 +- src/afl-cc.c | 2 +- 4 files changed, 7 insertions(+), 7 deletions(-) (limited to 'docs/notes_for_asan.md') diff --git a/docs/env_variables.md b/docs/env_variables.md index 682ab7f1..85c2efd7 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 itt. 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 @@ -66,8 +66,8 @@ make fairly broad use of environmental variables instead: - 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_CHECK_LEAK(); which will cause + 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). @@ -637,7 +637,7 @@ optimal values if not already present in the environment: ``` - Similarly, the default `LSAN_OPTIONS` are set to: ``` - exit_code=86 + exit_code=23 fast_unwind_on_malloc=0 ```` Be sure to include the first ones for LSAN and MSAN when customizing diff --git a/docs/notes_for_asan.md b/docs/notes_for_asan.md index 26f34fad..f55aeaf2 100644 --- a/docs/notes_for_asan.md +++ b/docs/notes_for_asan.md @@ -30,7 +30,7 @@ Note that ASAN is incompatible with -static, so be mindful of that. When compiling with AFL_USE_LSAN, the leak sanitizer will normally run when the program exits. In order to utilize this check at different times, -such as at the end of a loop, you may use the macro __AFL_CHECK_LEAK();. +such as at the end of a loop, you may use the macro __AFL_LEAK_CHECK();. This macro will report a crash in afl-fuzz if any memory is left leaking at this stage. You can also use LSAN_OPTIONS and a supressions file for more fine-tuned checking, however make sure you keep exitcode=23. diff --git a/src/afl-analyze.c b/src/afl-analyze.c index 90305714..f961f13a 100644 --- a/src/afl-analyze.c +++ b/src/afl-analyze.c @@ -832,7 +832,7 @@ static void set_up_environment(void) { "handle_sigill=0", 0); setenv("LSAN_OPTIONS", - "exitcode=" STRINGIFY(MSAN_ERROR) ":" + "exitcode=" STRINGIFY(LSAN_ERROR) ":" "fast_unwind_on_malloc=0", 0); diff --git a/src/afl-cc.c b/src/afl-cc.c index e0478503..975b28d1 100644 --- a/src/afl-cc.c +++ b/src/afl-cc.c @@ -923,7 +923,7 @@ static void edit_params(u32 argc, char **argv, char **envp) { } cc_params[cc_par_cnt++] = - "-D__AFL_CHECK_LEAK()=__lsan_do_leak_check()"; + "-D__AFL_LEAK_CHECK()=__lsan_do_leak_check()"; cc_params[cc_par_cnt++] = "-D__AFL_COVERAGE_START_OFF()=int __afl_selective_coverage_start_off = " -- cgit 1.4.1