diff options
Diffstat (limited to 'instrumentation')
| -rw-r--r-- | instrumentation/README.llvm.md | 7 | ||||
| -rw-r--r-- | instrumentation/SanitizerCoverageLTO.so.cc | 7 | ||||
| -rw-r--r-- | instrumentation/SanitizerCoveragePCGUARD.so.cc | 6 | ||||
| -rw-r--r-- | instrumentation/afl-llvm-lto-instrumentation.so.cc | 11 | ||||
| -rw-r--r-- | instrumentation/afl-llvm-pass.so.cc | 116 |
5 files changed, 87 insertions, 60 deletions
diff --git a/instrumentation/README.llvm.md b/instrumentation/README.llvm.md index 02722588..8ce5afb9 100644 --- a/instrumentation/README.llvm.md +++ b/instrumentation/README.llvm.md @@ -144,9 +144,10 @@ is not optimal and was only fixed in llvm 9. You can set this with AFL_LLVM_NOT_ZERO=1 See [README.neverzero.md](README.neverzero.md) -Support for thread safe counters has been added for mode LLVM CLASSIC. -Activate it with `AFL_LLVM_THREADSAFE_INST=1`. The tradeoff is better precision in -multi threaded apps for a slightly higher instrumentation overhead. +Support for thread safe counters has been added for all modes. +Activate it with `AFL_LLVM_THREADSAFE_INST=1`. The tradeoff is better precision +in multi threaded apps for a slightly higher instrumentation overhead. +This also disables the nozero counter default for performance reasons. ## 4) Snapshot feature diff --git a/instrumentation/SanitizerCoverageLTO.so.cc b/instrumentation/SanitizerCoverageLTO.so.cc index 58969e18..20f1856e 100644 --- a/instrumentation/SanitizerCoverageLTO.so.cc +++ b/instrumentation/SanitizerCoverageLTO.so.cc @@ -1497,14 +1497,12 @@ void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, } /* Update bitmap */ - if (use_threadsafe_counters) { /* Atomic */ + if (use_threadsafe_counters) { /* Atomic */ IRB.CreateAtomicRMW(llvm::AtomicRMWInst::BinOp::Add, MapPtrIdx, One, llvm::AtomicOrdering::Monotonic); - } - else - { + } else { LoadInst *Counter = IRB.CreateLoad(MapPtrIdx); Counter->setMetadata(Mo->getMDKindID("nosanitize"), @@ -1524,6 +1522,7 @@ void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, ->setMetadata(Mo->getMDKindID("nosanitize"), MDNode::get(*Ct, None)); } + // done :) inst++; diff --git a/instrumentation/SanitizerCoveragePCGUARD.so.cc b/instrumentation/SanitizerCoveragePCGUARD.so.cc index dbddad0a..4a8c9e28 100644 --- a/instrumentation/SanitizerCoveragePCGUARD.so.cc +++ b/instrumentation/SanitizerCoveragePCGUARD.so.cc @@ -1069,16 +1069,14 @@ void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, /* Load counter for CurLoc */ - Value * MapPtrIdx = IRB.CreateGEP(MapPtr, CurLoc); + Value *MapPtrIdx = IRB.CreateGEP(MapPtr, CurLoc); if (use_threadsafe_counters) { IRB.CreateAtomicRMW(llvm::AtomicRMWInst::BinOp::Add, MapPtrIdx, One, llvm::AtomicOrdering::Monotonic); - } - else - { + } else { LoadInst *Counter = IRB.CreateLoad(MapPtrIdx); /* Update bitmap */ diff --git a/instrumentation/afl-llvm-lto-instrumentation.so.cc b/instrumentation/afl-llvm-lto-instrumentation.so.cc index b5fdb3d6..fe43fbe5 100644 --- a/instrumentation/afl-llvm-lto-instrumentation.so.cc +++ b/instrumentation/afl-llvm-lto-instrumentation.so.cc @@ -93,8 +93,8 @@ class AFLLTOPass : public ModulePass { uint32_t function_minimum_size = 1; uint32_t inst_blocks = 0, inst_funcs = 0, total_instr = 0; unsigned long long int map_addr = 0x10000; - const char *skip_nozero = NULL; - const char *use_threadsafe_counters = nullptr; + const char * skip_nozero = NULL; + const char * use_threadsafe_counters = nullptr; }; @@ -843,9 +843,12 @@ bool AFLLTOPass::runOnModule(Module &M) { /* Update bitmap */ if (use_threadsafe_counters) { + IRB.CreateAtomicRMW(llvm::AtomicRMWInst::BinOp::Add, MapPtrIdx, One, llvm::AtomicOrdering::Monotonic); + } else { + LoadInst *Counter = IRB.CreateLoad(MapPtrIdx); Counter->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None)); @@ -861,7 +864,9 @@ bool AFLLTOPass::runOnModule(Module &M) { } IRB.CreateStore(Incr, MapPtrIdx) - ->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None)); + ->setMetadata(M.getMDKindID("nosanitize"), + MDNode::get(C, None)); + } // done :) diff --git a/instrumentation/afl-llvm-pass.so.cc b/instrumentation/afl-llvm-pass.so.cc index fe9e2e40..62f8b2ed 100644 --- a/instrumentation/afl-llvm-pass.so.cc +++ b/instrumentation/afl-llvm-pass.so.cc @@ -81,12 +81,12 @@ class AFLCoverage : public ModulePass { bool runOnModule(Module &M) override; protected: - uint32_t ngram_size = 0; - uint32_t ctx_k = 0; - uint32_t map_size = MAP_SIZE; - uint32_t function_minimum_size = 1; - const char * ctx_str = NULL, *caller_str = NULL, *skip_nozero = NULL; - const char * use_threadsafe_counters = nullptr; + uint32_t ngram_size = 0; + uint32_t ctx_k = 0; + uint32_t map_size = MAP_SIZE; + uint32_t function_minimum_size = 1; + const char *ctx_str = NULL, *caller_str = NULL, *skip_nozero = NULL; + const char *use_threadsafe_counters = nullptr; }; @@ -188,18 +188,30 @@ bool AFLCoverage::runOnModule(Module &M) { if ((isatty(2) && !getenv("AFL_QUIET")) || !!getenv("AFL_DEBUG")) { if (use_threadsafe_counters) { - if (!getenv("AFL_LLVM_NOT_ZERO")) { - skip_nozero = "1"; - SAYF(cCYA "afl-llvm-pass" VERSION cRST " using thread safe counters\n"); - } - else { - SAYF(cCYA "afl-llvm-pass" VERSION cRST - " using thread safe not-zero-counters\n"); - } - } - else - { - SAYF(cCYA "afl-llvm-pass" VERSION cRST " using non-thread safe instrumentation\n"); + + // disabled unless there is support for other modules as well + // (increases documentation complexity) + /* if (!getenv("AFL_LLVM_NOT_ZERO")) { */ + + skip_nozero = "1"; + SAYF(cCYA "afl-llvm-pass" VERSION cRST " using thread safe counters\n"); + + /* + + } else { + + SAYF(cCYA "afl-llvm-pass" VERSION cRST + " using thread safe not-zero-counters\n"); + + } + + */ + + } else { + + SAYF(cCYA "afl-llvm-pass" VERSION cRST + " using non-thread safe instrumentation\n"); + } } @@ -649,44 +661,44 @@ bool AFLCoverage::runOnModule(Module &M) { /* Update bitmap */ + if (use_threadsafe_counters) { /* Atomic */ - if (use_threadsafe_counters) {/* Atomic */ - - #if LLVM_VERSION_MAJOR < 9 +#if LLVM_VERSION_MAJOR < 9 if (neverZero_counters_str != - NULL) { // with llvm 9 we make this the default as the bug in llvm is then fixed - #else + NULL) { // with llvm 9 we make this the default as the bug in llvm + // is then fixed +#else if (!skip_nozero) { - #endif +#endif // register MapPtrIdx in a todo list todo.push_back(MapPtrIdx); - } - else - { + } else { + IRB.CreateAtomicRMW(llvm::AtomicRMWInst::BinOp::Add, MapPtrIdx, One, llvm::AtomicOrdering::Monotonic); + } - } - else - { + + } else { LoadInst *Counter = IRB.CreateLoad(MapPtrIdx); Counter->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None)); Value *Incr = IRB.CreateAdd(Counter, One); - #if LLVM_VERSION_MAJOR < 9 +#if LLVM_VERSION_MAJOR < 9 if (neverZero_counters_str != - NULL) { // with llvm 9 we make this the default as the bug in llvm is - // then fixed - #else + NULL) { // with llvm 9 we make this the default as the bug in llvm + // is then fixed +#else if (!skip_nozero) { - #endif +#endif /* hexcoder: Realize a counter that skips zero during overflow. - * Once this counter reaches its maximum value, it next increments to 1 + * Once this counter reaches its maximum value, it next increments to + * 1 * * Instead of * Counter + 1 -> Counter @@ -705,7 +717,7 @@ bool AFLCoverage::runOnModule(Module &M) { IRB.CreateStore(Incr, MapPtrIdx) ->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None)); - } /* non atomic case */ + } /* non atomic case */ /* Update prev_loc history vector (by placing cur_loc at the head of the vector and shuffle the other elements back by one) */ @@ -762,16 +774,19 @@ bool AFLCoverage::runOnModule(Module &M) { } - if (use_threadsafe_counters) { /*Atomic NeverZero */ + if (use_threadsafe_counters) { /*Atomic NeverZero */ // handle the list of registered blocks to instrument for (auto val : todo) { - /* hexcoder: Realize a thread-safe counter that skips zero during overflow. Once this counter reaches its maximum value, it next increments to 1 - * - * Instead of - * Counter + 1 -> Counter - * we inject now this - * Counter + 1 -> {Counter, OverflowFlag} - * Counter + OverflowFlag -> Counter + + /* hexcoder: Realize a thread-safe counter that skips zero during + * overflow. Once this counter reaches its maximum value, it next + * increments to 1 + * + * Instead of + * Counter + 1 -> Counter + * we inject now this + * Counter + 1 -> {Counter, OverflowFlag} + * Counter + OverflowFlag -> Counter */ /* equivalent c code looks like this @@ -781,12 +796,19 @@ bool AFLCoverage::runOnModule(Module &M) { int old = atomic_load_explicit(&Counter, memory_order_relaxed); int new; do { + if (old == 255) { + new = 1; + } else { + new = old + 1; + } + } while (!atomic_compare_exchange_weak_explicit(&Counter, &old, new, + memory_order_relaxed, memory_order_relaxed)); */ @@ -805,7 +827,8 @@ bool AFLCoverage::runOnModule(Module &M) { BasicBlock *BB = IRB.GetInsertBlock(); // insert a basic block with the corpus of a do while loop - // the calculation may need to repeat, if atomic compare_exchange is not successful + // the calculation may need to repeat, if atomic compare_exchange is not + // successful BasicBlock::iterator it(*Counter); it++; // split after load counter @@ -857,6 +880,7 @@ bool AFLCoverage::runOnModule(Module &M) { // if the cmpXchg was not successful, retry IRB.CreateCondBr(Success, end_bb, do_while_bb); + } } |