From 9a1d526ed408cbd7d681be15c5512032f7632887 Mon Sep 17 00:00:00 2001 From: murx- Date: Sat, 8 Aug 2020 18:34:54 +0200 Subject: Add support for specific custom mutator name --- src/afl-fuzz-mutators.c | 1 + src/afl-fuzz-one.c | 2 ++ 2 files changed, 3 insertions(+) (limited to 'src') diff --git a/src/afl-fuzz-mutators.c b/src/afl-fuzz-mutators.c index b30106a0..0fa646f9 100644 --- a/src/afl-fuzz-mutators.c +++ b/src/afl-fuzz-mutators.c @@ -142,6 +142,7 @@ struct custom_mutator *load_custom_mutator(afl_state_t *afl, const char *fn) { struct custom_mutator *mutator = ck_alloc(sizeof(struct custom_mutator)); mutator->name = fn; + mutator->name_short = strrchr(fn, '/') + 1; ACTF("Loading custom mutator library from '%s'...", fn); dh = dlopen(fn, RTLD_NOW); diff --git a/src/afl-fuzz-one.c b/src/afl-fuzz-one.c index 74e09ee3..452c5298 100644 --- a/src/afl-fuzz-one.c +++ b/src/afl-fuzz-one.c @@ -1683,6 +1683,8 @@ custom_mutator_stage: has_custom_fuzz = true; + afl->stage_short = el->name_short; + for (afl->stage_cur = 0; afl->stage_cur < afl->stage_max; ++afl->stage_cur) { -- cgit 1.4.1 From a422fcaa40a3c7cd577b693060d9bc2e6c36cf73 Mon Sep 17 00:00:00 2001 From: Dominik Maier Date: Mon, 10 Aug 2020 19:04:51 +0200 Subject: fixed minor inconsistencies, reenabled warnings --- GNUmakefile | 3 ++- include/debug.h | 9 +++++++-- src/afl-fuzz-cmplog.c | 4 ---- src/afl-fuzz-run.c | 2 +- src/afl-fuzz.c | 3 ++- 5 files changed, 12 insertions(+), 9 deletions(-) (limited to 'src') diff --git a/GNUmakefile b/GNUmakefile index 86ae24b6..fe5f8c03 100644 --- a/GNUmakefile +++ b/GNUmakefile @@ -98,7 +98,7 @@ ifneq "$(shell uname -m)" "x86_64" endif CFLAGS ?= -O3 -funroll-loops $(CFLAGS_OPT) -override CFLAGS += -g -Wno-pointer-sign \ +override CFLAGS += -g -Wno-pointer-sign -Wno-variadic-macros -Wall -Wextra -Wpointer-arith \ -I include/ -DAFL_PATH=\"$(HELPER_PATH)\" \ -DBIN_PATH=\"$(BIN_PATH)\" -DDOC_PATH=\"$(DOC_PATH)\" @@ -198,6 +198,7 @@ else endif ifneq "$(filter Linux GNU%,$(shell uname))" "" + override CFLAGS += -D_FORTIFY_SOURCE=2 LDFLAGS += -ldl -lrt endif diff --git a/include/debug.h b/include/debug.h index ae2946f0..cb0a63e9 100644 --- a/include/debug.h +++ b/include/debug.h @@ -29,10 +29,15 @@ #include "config.h" /* __FUNCTION__ is non-iso */ -#ifdef __func__ - #define __FUNCTION__ __func__ +#ifndef __FUNCTION__ + #ifdef __func__ + #define __FUNCTION__ __func__ + #else + #define __FUNCTION__ "unknown_func" + #endif #endif + /******************* * Terminal colors * *******************/ diff --git a/src/afl-fuzz-cmplog.c b/src/afl-fuzz-cmplog.c index faf4dcb7..8ffc6e1b 100644 --- a/src/afl-fuzz-cmplog.c +++ b/src/afl-fuzz-cmplog.c @@ -29,10 +29,6 @@ #include "afl-fuzz.h" #include "cmplog.h" -typedef struct cmplog_data { - -} cmplog_data_t; - void cmplog_exec_child(afl_forkserver_t *fsrv, char **argv) { setenv("___AFL_EINS_ZWEI_POLIZEI___", "1", 1); diff --git a/src/afl-fuzz-run.c b/src/afl-fuzz-run.c index 8d652155..e69e9791 100644 --- a/src/afl-fuzz-run.c +++ b/src/afl-fuzz-run.c @@ -138,7 +138,7 @@ void write_to_testcase(afl_state_t *afl, void *mem, u32 len) { /* The same, but with an adjustable gap. Used for trimming. */ -static void write_with_gap(afl_state_t *afl, void *mem, u32 len, u32 skip_at, +static void write_with_gap(afl_state_t *afl, u8 *mem, u32 len, u32 skip_at, u32 skip_len) { s32 fd = afl->fsrv.out_fd; diff --git a/src/afl-fuzz.c b/src/afl-fuzz.c index 031c4049..009eaa12 100644 --- a/src/afl-fuzz.c +++ b/src/afl-fuzz.c @@ -289,8 +289,9 @@ int main(int argc, char **argv_orig, char **envp) { if (afl->cpu_to_bind != -1) FATAL("Multiple -b options not supported"); - if (sscanf(optarg, "%u", &afl->cpu_to_bind) < 0 || optarg[0] == '-') + if (sscanf(optarg, "%d", &afl->cpu_to_bind) < 0) { FATAL("Bad syntax used for -b"); + } break; -- cgit 1.4.1 From 7d7a8c7c39173c340a53868891d65b4477c296c0 Mon Sep 17 00:00:00 2001 From: Dominik Maier Date: Mon, 10 Aug 2020 19:05:22 +0200 Subject: code-format --- include/debug.h | 1 - src/afl-fuzz.c | 2 ++ 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'src') diff --git a/include/debug.h b/include/debug.h index cb0a63e9..5b1ae54d 100644 --- a/include/debug.h +++ b/include/debug.h @@ -37,7 +37,6 @@ #endif #endif - /******************* * Terminal colors * *******************/ diff --git a/src/afl-fuzz.c b/src/afl-fuzz.c index 009eaa12..5dd092f2 100644 --- a/src/afl-fuzz.c +++ b/src/afl-fuzz.c @@ -290,7 +290,9 @@ int main(int argc, char **argv_orig, char **envp) { if (afl->cpu_to_bind != -1) FATAL("Multiple -b options not supported"); if (sscanf(optarg, "%d", &afl->cpu_to_bind) < 0) { + FATAL("Bad syntax used for -b"); + } break; -- 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') 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