From 22d3a5e90abd58c6a4bb68bf1b3f7ece8283f5bb Mon Sep 17 00:00:00 2001 From: Dominik Maier Date: Fri, 7 Aug 2020 16:55:58 +0200 Subject: enabled Wextra, fixed bugs --- src/afl-forkserver.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'src/afl-forkserver.c') diff --git a/src/afl-forkserver.c b/src/afl-forkserver.c index 47493eba..15935ab0 100644 --- a/src/afl-forkserver.c +++ b/src/afl-forkserver.c @@ -145,6 +145,10 @@ restart_select: if (likely(sret > 0)) { restart_read: + if (*stop_soon_p) { + // Early return - the user wants to quit. + return 0; + } len_read = read(fd, (u8 *)buf, 4); if (likely(len_read == 4)) { // for speed we put this first @@ -691,7 +695,7 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, } offset = 0; - while (offset < status && (u8)dict[offset] + offset < status) { + while (offset < (u32)status && (u8)dict[offset] + offset < (u32)status) { fsrv->function_ptr(fsrv->function_opt, dict + offset + 1, (u8)dict[offset]); -- cgit 1.4.1 From 699ebaa8e210e0d72ad7e3ac6f4a580cfbe37eae Mon Sep 17 00:00:00 2001 From: Dominik Maier Date: Fri, 7 Aug 2020 17:32:41 +0200 Subject: code format --- include/debug.h | 4 ++-- src/afl-forkserver.c | 6 +++++- src/afl-fuzz-one.c | 6 ++++-- src/afl-fuzz-redqueen.c | 11 ++++++----- src/afl-showmap.c | 3 ++- 5 files changed, 19 insertions(+), 11 deletions(-) (limited to 'src/afl-forkserver.c') diff --git a/include/debug.h b/include/debug.h index 79b05c5f..ae2946f0 100644 --- a/include/debug.h +++ b/include/debug.h @@ -281,7 +281,7 @@ #define ck_write(fd, buf, len, fn) \ do { \ \ - s32 _len = (s32)(len); \ + s32 _len = (s32)(len); \ s32 _res = write(fd, buf, _len); \ if (_res != _len) RPFATAL(_res, "Short write to %s", fn); \ \ @@ -290,7 +290,7 @@ #define ck_read(fd, buf, len, fn) \ do { \ \ - s32 _len = (s32)(len); \ + s32 _len = (s32)(len); \ s32 _res = read(fd, buf, _len); \ if (_res != _len) RPFATAL(_res, "Short read from %s", fn); \ \ diff --git a/src/afl-forkserver.c b/src/afl-forkserver.c index 15935ab0..752641d7 100644 --- a/src/afl-forkserver.c +++ b/src/afl-forkserver.c @@ -146,9 +146,12 @@ restart_select: restart_read: if (*stop_soon_p) { + // Early return - the user wants to quit. return 0; + } + len_read = read(fd, (u8 *)buf, 4); if (likely(len_read == 4)) { // for speed we put this first @@ -695,7 +698,8 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, } offset = 0; - while (offset < (u32)status && (u8)dict[offset] + offset < (u32)status) { + while (offset < (u32)status && + (u8)dict[offset] + offset < (u32)status) { fsrv->function_ptr(fsrv->function_opt, dict + offset + 1, (u8)dict[offset]); diff --git a/src/afl-fuzz-one.c b/src/afl-fuzz-one.c index 9d09f6af..74e09ee3 100644 --- a/src/afl-fuzz-one.c +++ b/src/afl-fuzz-one.c @@ -4454,7 +4454,8 @@ pacemaker_fuzzing: retry_splicing_puppet: - if (afl->use_splicing && splice_cycle++ < (u32)afl->SPLICE_CYCLES_puppet && + if (afl->use_splicing && + splice_cycle++ < (u32)afl->SPLICE_CYCLES_puppet && afl->queued_paths > 1 && afl->queue_cur->len > 1) { struct queue_entry *target; @@ -4524,7 +4525,8 @@ pacemaker_fuzzing: the last differing byte. Bail out if the difference is just a single byte or so. */ - locate_diffs(in_buf, new_buf, MIN(len, (s32)target->len), &f_diff, &l_diff); + locate_diffs(in_buf, new_buf, MIN(len, (s32)target->len), &f_diff, + &l_diff); if (f_diff < 0 || l_diff < 2 || f_diff == l_diff) { diff --git a/src/afl-fuzz-redqueen.c b/src/afl-fuzz-redqueen.c index 1cfe8802..9716be95 100644 --- a/src/afl-fuzz-redqueen.c +++ b/src/afl-fuzz-redqueen.c @@ -352,7 +352,7 @@ static u8 cmp_extend_encoding(afl_state_t *afl, struct cmp_header *h, } - if (use_num && (u64) num == pattern) { + if (use_num && (u64)num == pattern) { size_t old_len = endptr - buf_8; size_t num_len = snprintf(NULL, 0, "%lld", num); @@ -659,9 +659,9 @@ static u8 cmp_fuzz(afl_state_t *afl, u32 key, u8 *orig_buf, u8 *buf, u32 len) { } -static u8 rtn_extend_encoding(afl_state_t *afl, - u8 *pattern, u8 *repl, u8 *o_pattern, u32 idx, - u8 *orig_buf, u8 *buf, u32 len, u8 *status) { +static u8 rtn_extend_encoding(afl_state_t *afl, u8 *pattern, u8 *repl, + u8 *o_pattern, u32 idx, u8 *orig_buf, u8 *buf, + u32 len, u8 *status) { u32 i; u32 its_len = MIN((u32)32, len - idx); @@ -853,7 +853,8 @@ u8 input_to_state_stage(afl_state_t *afl, u8 *orig_buf, u8 *buf, u32 len, if (afl->shm.cmp_map->headers[k].type == CMP_TYPE_INS) { - afl->stage_max += MIN((u32)(afl->shm.cmp_map->headers[k].hits), (u32)CMP_MAP_H); + afl->stage_max += + MIN((u32)(afl->shm.cmp_map->headers[k].hits), (u32)CMP_MAP_H); } else { diff --git a/src/afl-showmap.c b/src/afl-showmap.c index 4962006e..0aa116e5 100644 --- a/src/afl-showmap.c +++ b/src/afl-showmap.c @@ -256,7 +256,8 @@ static u32 write_results_to_file(afl_forkserver_t *fsrv, u8 *outfile) { /* Execute target application. */ -static void showmap_run_target_forkserver(afl_forkserver_t *fsrv, u8 *mem, u32 len) { +static void showmap_run_target_forkserver(afl_forkserver_t *fsrv, u8 *mem, + u32 len) { afl_fsrv_write_to_testcase(fsrv, mem, len); -- cgit 1.4.1 From 701fb95d24cd754e9c116d81502b6057a29eb2bd Mon Sep 17 00:00:00 2001 From: van Hauser Date: Mon, 10 Aug 2020 23:42:33 +0200 Subject: LTO: make dynamic map the default --- docs/Changelog.md | 2 ++ llvm_mode/README.lto.md | 20 ++++------------- llvm_mode/afl-llvm-lto-instrumentation.so.cc | 33 +++++++++++++++++++++++----- src/afl-forkserver.c | 13 +++++------ 4 files changed, 40 insertions(+), 28 deletions(-) (limited to 'src/afl-forkserver.c') diff --git a/docs/Changelog.md b/docs/Changelog.md index f8742b1c..182a15b8 100644 --- a/docs/Changelog.md +++ b/docs/Changelog.md @@ -28,6 +28,8 @@ sending a mail to . sancov, and also supports function matching! - fixes for laf-intel float splitting (thanks to mark-griffin for reporting) + - LTO: switch default to the dynamic memory map, set AFL_LLVM_MAP_ADDR + for a fixed map address (eg. 0x10000) - LTO: autodictionary mode is a default - LTO: instrim instrumentation disabled, only classic support used as it is always better diff --git a/llvm_mode/README.lto.md b/llvm_mode/README.lto.md index 4d643324..9046c5a8 100644 --- a/llvm_mode/README.lto.md +++ b/llvm_mode/README.lto.md @@ -17,9 +17,6 @@ This version requires a current llvm 11+ compiled from the github master. 5. If any problems arise be sure to set `AR=llvm-ar RANLIB=llvm-ranlib`. Some targets might need `LD=afl-clang-lto` and others `LD=afl-ld-lto`. -6. If a target uses _init functions or early constructors then additionally - set `AFL_LLVM_MAP_DYNAMIC=1` as your target will crash otherwise! - ## Introduction and problem description A big issue with how afl/afl++ works is that the basic block IDs that are @@ -128,14 +125,14 @@ on start. This improves coverage statistically by 5-10% :) ## Fixed memory map -To speed up fuzzing, the shared memory map is hard set to a specific address, -by default 0x10000. In most cases this will work without any problems. +To speed up fuzzing, it is possible to set a fixed shared memory map. +Recommened is the value 0x10000. +In most cases this will work without any problems. However if a target uses +early constructors, ifuncs or a deferred forkserver this can crash the target. On unusual operating systems/processors/kernels or weird libraries this might fail so to change the fixed address at compile time set AFL_LLVM_MAP_ADDR with a better value (a value of 0 or empty sets the map address to be dynamic - the original afl way, which is slower). -AFL_LLVM_MAP_DYNAMIC can be set so the shared memory address is dynamic (which -is safer but also slower). ## Document edge IDs @@ -262,15 +259,6 @@ If this succeeeds then there is an issue with afl-clang-lto. Please report at Even some targets where clang-12 fails can be build if the fail is just in `./configure`, see `Solving difficult targets` above. -### Target crashes immediately - -If the target is using early constructors (priority values smaller than 6) -or have their own _init/.init functions and these are instrumented then the -target will likely crash when started. This can be avoided by compiling with -`AFL_LLVM_MAP_DYNAMIC=1` . - -This can e.g. happen with OpenSSL. - ## History This was originally envisioned by hexcoder- in Summer 2019, however we saw no diff --git a/llvm_mode/afl-llvm-lto-instrumentation.so.cc b/llvm_mode/afl-llvm-lto-instrumentation.so.cc index 38c3f202..ddfcb400 100644 --- a/llvm_mode/afl-llvm-lto-instrumentation.so.cc +++ b/llvm_mode/afl-llvm-lto-instrumentation.so.cc @@ -49,6 +49,7 @@ #include "llvm/Analysis/MemorySSAUpdater.h" #include "llvm/Analysis/ValueTracking.h" #include "llvm/Pass.h" +#include "llvm/IR/Constants.h" #include "afl-llvm-common.h" @@ -135,7 +136,10 @@ bool AFLLTOPass::runOnModule(Module &M) { if (getenv("AFL_LLVM_LTO_AUTODICTIONARY")) autodictionary = 1; - if (getenv("AFL_LLVM_MAP_DYNAMIC")) map_addr = 0; + // we make this the default as the fixed map has problems with + // defered forkserver, early constructors, ifuncs and maybe more + /*if (getenv("AFL_LLVM_MAP_DYNAMIC"))*/ + map_addr = 0; if (getenv("AFL_LLVM_SKIPSINGLEBLOCK")) function_minimum_size = 2; @@ -196,7 +200,8 @@ bool AFLLTOPass::runOnModule(Module &M) { ConstantInt *Zero = ConstantInt::get(Int8Ty, 0); ConstantInt *One = ConstantInt::get(Int8Ty, 1); - /* This dumps all inialized global strings - might be useful in the future + // This dumps all inialized global strings - might be useful in the future + /* for (auto G=M.getGlobalList().begin(); G!=M.getGlobalList().end(); G++) { GlobalVariable &GV=*G; @@ -212,7 +217,21 @@ bool AFLLTOPass::runOnModule(Module &M) { } - */ + */ + + if (map_addr) + for (GlobalIFunc &IF : M.ifuncs()) { + + // No clue how to follow these up and find the resolver function. + // If we would know that resolver function name we could just skip + // instrumenting it and everything would be fine :-( + // StringRef ifunc_name = IF.getName(); + // Constant *r = IF.getResolver(); + FATAL( + "Target uses ifunc attribute, dynamic map cannot be used, remove " + "AFL_LLVM_MAP_DYNAMIC"); + + } /* Instrument all the things! */ @@ -220,8 +239,12 @@ bool AFLLTOPass::runOnModule(Module &M) { for (auto &F : M) { - // fprintf(stderr, "DEBUG: Module %s Function %s\n", - // M.getName().str().c_str(), F.getName().str().c_str()); + /*For debugging + AttributeSet X = F.getAttributes().getFnAttributes(); + fprintf(stderr, "DEBUG: Module %s Function %s attributes %u\n", + M.getName().str().c_str(), F.getName().str().c_str(), + X.getNumAttributes()); + */ if (F.size() < function_minimum_size) continue; if (isIgnoreFunction(&F)) continue; diff --git a/src/afl-forkserver.c b/src/afl-forkserver.c index 752641d7..1ececf27 100644 --- a/src/afl-forkserver.c +++ b/src/afl-forkserver.c @@ -293,8 +293,8 @@ static void report_error_and_exit(int error) { FATAL( "the fuzzing target reports that hardcoded map address might be the " "reason the mmap of the shared memory failed. Solution: recompile " - "the target with either afl-clang-lto and the environment variable " - "AFL_LLVM_MAP_DYNAMIC set or recompile with afl-clang-fast."); + "the target with either afl-clang-lto and do not set " + "AFL_LLVM_MAP_ADDR or recompile with afl-clang-fast."); break; case FS_ERROR_SHM_OPEN: FATAL("the fuzzing target reports that the shm_open() call failed."); @@ -828,8 +828,8 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, SAYF("\n" cLRD "[-] " cRST "Hmm, looks like the target binary terminated before we could" " complete a handshake with the injected code.\n" - "If the target was compiled with afl-clang-lto then recompiling with" - " AFL_LLVM_MAP_DYNAMIC might solve your problem.\n" + "If the target was compiled with afl-clang-lto and AFL_LLVM_MAP_ADDR" + " then recompiling without this parameter.\n" "Otherwise there is a horrible bug in the fuzzer.\n" "Poke for troubleshooting tips.\n"); @@ -860,9 +860,8 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, " - the target was compiled with afl-clang-lto and a constructor " "was\n" - " instrumented, recompiling with AFL_LLVM_MAP_DYNAMIC might solve " - "your\n" - " problem\n\n" + " instrumented, recompiling without AFL_LLVM_MAP_ADDR might solve " + "your problem\n\n" " - Less likely, there is a horrible bug in the fuzzer. If other " "options\n" -- cgit 1.4.1 From b38837f4ff8f2e52597b7908b9226500e5c61933 Mon Sep 17 00:00:00 2001 From: van Hauser Date: Wed, 12 Aug 2020 14:14:44 +0200 Subject: setting attribute hot intelligently gives 0.5% speed --- docs/Changelog.md | 2 +- src/afl-forkserver.c | 4 ++-- src/afl-fuzz-bitmap.c | 8 ++++---- src/afl-fuzz-run.c | 6 +++--- 4 files changed, 10 insertions(+), 10 deletions(-) (limited to 'src/afl-forkserver.c') diff --git a/docs/Changelog.md b/docs/Changelog.md index eda57a1a..edcdac58 100644 --- a/docs/Changelog.md +++ b/docs/Changelog.md @@ -26,7 +26,7 @@ sending a mail to . AFL_LLVM_WHITELIST and AFL_LLVM_INSTRUMENT_FILE are deprecated and are matched to AFL_LLVM_ALLOWLIST). The format is compatible to llvm sancov, and also supports function matching! - - added nozero counting to trace-pc/pcgard + - added neverzero counting to trace-pc/pcgard - fixes for laf-intel float splitting (thanks to mark-griffin for reporting) - LTO: switch default to the dynamic memory map, set AFL_LLVM_MAP_ADDR diff --git a/src/afl-forkserver.c b/src/afl-forkserver.c index 1ececf27..6819fc8a 100644 --- a/src/afl-forkserver.c +++ b/src/afl-forkserver.c @@ -122,7 +122,7 @@ void afl_fsrv_init_dup(afl_forkserver_t *fsrv_to, afl_forkserver_t *from) { Returns the time passed to read. If the wait times out, returns timeout_ms + 1; Returns 0 if an error occurred (fd closed, signal, ...); */ -static u32 read_s32_timed(s32 fd, s32 *buf, u32 timeout_ms, +static u32 __attribute__ ((hot)) read_s32_timed(s32 fd, s32 *buf, u32 timeout_ms, volatile u8 *stop_soon_p) { fd_set readfds; @@ -322,7 +322,7 @@ static void report_error_and_exit(int error) { cloning a stopped child. So, we just execute once, and then send commands through a pipe. The other part of this logic is in afl-as.h / llvm_mode */ -void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, +void __attribute__ ((hot)) afl_fsrv_start(afl_forkserver_t *fsrv, char **argv, volatile u8 *stop_soon_p, u8 debug_child_output) { int st_pipe[2], ctl_pipe[2]; diff --git a/src/afl-fuzz-bitmap.c b/src/afl-fuzz-bitmap.c index aa8d5a18..f6389c06 100644 --- a/src/afl-fuzz-bitmap.c +++ b/src/afl-fuzz-bitmap.c @@ -57,7 +57,7 @@ void write_bitmap(afl_state_t *afl) { This function is called after every exec() on a fairly large buffer, so it needs to be fast. We do this in 32-bit and 64-bit flavors. */ -u8 has_new_bits(afl_state_t *afl, u8 *virgin_map) { +u8 __attribute__ ((hot)) has_new_bits(afl_state_t *afl, u8 *virgin_map) { #ifdef WORD_SIZE_64 @@ -347,7 +347,7 @@ void init_count_class16(void) { #ifdef WORD_SIZE_64 -void classify_counts(afl_forkserver_t *fsrv) { +void __attribute__ ((hot)) classify_counts(afl_forkserver_t *fsrv) { u64 *mem = (u64 *)fsrv->trace_bits; @@ -376,7 +376,7 @@ void classify_counts(afl_forkserver_t *fsrv) { #else -void classify_counts(afl_forkserver_t *fsrv) { +void __attribute__ ((hot)) classify_counts(afl_forkserver_t *fsrv) { u32 *mem = (u32 *)fsrv->trace_bits; @@ -534,7 +534,7 @@ static void write_crash_readme(afl_state_t *afl) { save or queue the input test case for further analysis if so. Returns 1 if entry is saved, 0 otherwise. */ -u8 save_if_interesting(afl_state_t *afl, void *mem, u32 len, u8 fault) { +u8 __attribute__ ((hot)) save_if_interesting(afl_state_t *afl, void *mem, u32 len, u8 fault) { if (unlikely(len == 0)) { return 0; } diff --git a/src/afl-fuzz-run.c b/src/afl-fuzz-run.c index e69e9791..97fcb3c8 100644 --- a/src/afl-fuzz-run.c +++ b/src/afl-fuzz-run.c @@ -38,7 +38,7 @@ u64 time_spent_working = 0; /* Execute target application, monitoring for timeouts. Return status information. The called program will update afl->fsrv->trace_bits. */ -fsrv_run_result_t fuzz_run_target(afl_state_t *afl, afl_forkserver_t *fsrv, +fsrv_run_result_t __attribute__ ((hot)) fuzz_run_target(afl_state_t *afl, afl_forkserver_t *fsrv, u32 timeout) { #ifdef PROFILING @@ -72,7 +72,7 @@ fsrv_run_result_t fuzz_run_target(afl_state_t *afl, afl_forkserver_t *fsrv, old file is unlinked and a new one is created. Otherwise, afl->fsrv.out_fd is rewound and truncated. */ -void write_to_testcase(afl_state_t *afl, void *mem, u32 len) { +void __attribute__ ((hot)) write_to_testcase(afl_state_t *afl, void *mem, u32 len) { #ifdef _AFL_DOCUMENT_MUTATIONS s32 doc_fd; @@ -858,7 +858,7 @@ abort_trimming: error conditions, returning 1 if it's time to bail out. This is a helper function for fuzz_one(). */ -u8 common_fuzz_stuff(afl_state_t *afl, u8 *out_buf, u32 len) { +u8 __attribute__ ((hot)) common_fuzz_stuff(afl_state_t *afl, u8 *out_buf, u32 len) { u8 fault; -- cgit 1.4.1