[llvm] r244084 - [libFuzzer] use data-flow feedback from strcmp
Kostya Serebryany
kcc at google.com
Wed Aug 5 11:23:02 PDT 2015
Author: kcc
Date: Wed Aug 5 13:23:01 2015
New Revision: 244084
URL: http://llvm.org/viewvc/llvm-project?rev=244084&view=rev
Log:
[libFuzzer] use data-flow feedback from strcmp
Modified:
llvm/trunk/docs/LibFuzzer.rst
llvm/trunk/lib/Fuzzer/FuzzerTraceState.cpp
llvm/trunk/lib/Fuzzer/test/CMakeLists.txt
llvm/trunk/lib/Fuzzer/test/fuzzer-dfsan.test
llvm/trunk/lib/Fuzzer/test/fuzzer.test
Modified: llvm/trunk/docs/LibFuzzer.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LibFuzzer.rst?rev=244084&r1=244083&r2=244084&view=diff
==============================================================================
--- llvm/trunk/docs/LibFuzzer.rst (original)
+++ llvm/trunk/docs/LibFuzzer.rst Wed Aug 5 13:23:01 2015
@@ -282,7 +282,7 @@ Data-flow-guided fuzzing
With an additional compiler flag ``-fsanitize-coverage=trace-cmp`` (see SanitizerCoverageTraceDataFlow_)
and extra run-time flag ``-use_traces=1`` the fuzzer will try to apply *data-flow-guided fuzzing*.
That is, the fuzzer will record the inputs to comparison instructions, switch statements,
-and several libc functions (``memcmp``, ``strncmp``, etc).
+and several libc functions (``memcmp``, ``strcmp``, ``strncmp``, etc).
It will later use those recorded inputs during mutations.
This mode can be combined with DataFlowSanitizer_ to achieve better sensitivity.
Modified: llvm/trunk/lib/Fuzzer/FuzzerTraceState.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerTraceState.cpp?rev=244084&r1=244083&r2=244084&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/FuzzerTraceState.cpp (original)
+++ llvm/trunk/lib/Fuzzer/FuzzerTraceState.cpp Wed Aug 5 13:23:01 2015
@@ -356,8 +356,9 @@ void TraceState::TraceCmpCallback(uintpt
CSP->Counter[ComputeCmp(CmpSize, CmpType, Arg1, Arg2)]++;
size_t C0 = CSP->Counter[0];
size_t C1 = CSP->Counter[1];
- if (!CSP->IsInterestingCmpTarget())
- return;
+ // FIXME: is this a good idea or a bad?
+ // if (!CSP->IsInterestingCmpTarget())
+ // return;
if (Options.Verbosity >= 3)
Printf("TraceCmp: %p %zd/%zd; %zd %zd\n", CSP->PC, C0, C1, Arg1, Arg2);
Added += TryToAddDesiredData(Arg1, Arg2, CmpSize);
@@ -479,6 +480,23 @@ void dfsan_weak_hook_strncmp(void *calle
TS->DFSanCmpCallback(PC, n, fuzzer::ICMP_EQ, S1, S2, L1, L2);
}
+void dfsan_weak_hook_strcmp(void *caller_pc, const char *s1, const char *s2,
+ dfsan_label s1_label, dfsan_label s2_label) {
+ if (!TS) return;
+ uintptr_t PC = reinterpret_cast<uintptr_t>(caller_pc);
+ uint64_t S1 = 0, S2 = 0;
+ size_t Len1 = strlen(s1);
+ size_t Len2 = strlen(s2);
+ size_t N = std::min(Len1, Len2);
+ if (N <= 1) return; // Not interesting.
+ // Simplification: handle only first 8 bytes.
+ memcpy(&S1, s1, std::min(N, sizeof(S1)));
+ memcpy(&S2, s2, std::min(N, sizeof(S2)));
+ dfsan_label L1 = dfsan_read_label(s1, Len1);
+ dfsan_label L2 = dfsan_read_label(s2, Len2);
+ TS->DFSanCmpCallback(PC, N, fuzzer::ICMP_EQ, S1, S2, L1, L2);
+}
+
void __sanitizer_weak_hook_memcmp(void *caller_pc, const void *s1,
const void *s2, size_t n) {
if (!TS) return;
@@ -506,6 +524,22 @@ void __sanitizer_weak_hook_strncmp(void
TS->TraceCmpCallback(PC, n, fuzzer::ICMP_EQ, S1, S2);
}
+void __sanitizer_weak_hook_strcmp(void *caller_pc, const char *s1,
+ const char *s2) {
+ if (!TS) return;
+ uintptr_t PC = reinterpret_cast<uintptr_t>(caller_pc);
+ uint64_t S1 = 0, S2 = 0;
+ size_t Len1 = strlen(s1);
+ size_t Len2 = strlen(s2);
+ size_t N = std::min(Len1, Len2);
+ if (N <= 1) return; // Not interesting.
+ // Simplification: handle only first 8 bytes.
+ memcpy(&S1, s1, std::min(N, sizeof(S1)));
+ memcpy(&S2, s2, std::min(N, sizeof(S2)));
+ TS->TraceCmpCallback(PC, N, fuzzer::ICMP_EQ, S1, S2);
+}
+
+
void __sanitizer_cov_trace_cmp(uint64_t SizeAndType, uint64_t Arg1,
uint64_t Arg2) {
if (!TS) return;
Modified: llvm/trunk/lib/Fuzzer/test/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/test/CMakeLists.txt?rev=244084&r1=244083&r2=244084&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/test/CMakeLists.txt (original)
+++ llvm/trunk/lib/Fuzzer/test/CMakeLists.txt Wed Aug 5 13:23:01 2015
@@ -7,6 +7,7 @@ set(CMAKE_CXX_FLAGS_RELEASE "${LIBFUZZER
set(DFSanTests
MemcmpTest
SimpleCmpTest
+ StrcmpTest
StrncmpTest
SwitchTest
)
@@ -21,6 +22,7 @@ set(Tests
NullDerefTest
SimpleCmpTest
SimpleTest
+ StrcmpTest
StrncmpTest
SwitchTest
TimeoutTest
Modified: llvm/trunk/lib/Fuzzer/test/fuzzer-dfsan.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/test/fuzzer-dfsan.test?rev=244084&r1=244083&r2=244084&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/test/fuzzer-dfsan.test (original)
+++ llvm/trunk/lib/Fuzzer/test/fuzzer-dfsan.test Wed Aug 5 13:23:01 2015
@@ -15,5 +15,8 @@ RUN: LLVMFuzzer-MemcmpTest-DFSan -use_tr
RUN: not LLVMFuzzer-StrncmpTest-DFSan -use_traces=1 -seed=1 -runs=10000 -timeout=5 2>&1 | FileCheck %s --check-prefix=CHECK3
RUN: LLVMFuzzer-StrncmpTest-DFSan -use_traces=1 -seed=1 -runs=2 -timeout=5 -verbosity=3 2>&1 | FileCheck %s -check-prefix=CHECK_DFSanCmpCallback
+RUN: not LLVMFuzzer-StrcmpTest-DFSan -use_traces=1 -seed=1 -runs=10000 -timeout=5 2>&1 | FileCheck %s --check-prefix=CHECK3
+RUN: LLVMFuzzer-StrcmpTest-DFSan -use_traces=1 -seed=1 -runs=2 -timeout=5 -verbosity=3 2>&1 | FileCheck %s -check-prefix=CHECK_DFSanCmpCallback
+
RUN: not LLVMFuzzer-SwitchTest-DFSan -use_traces=1 -seed=1 -runs=100000 -timeout=5 2>&1 | FileCheck %s --check-prefix=CHECK4
RUN: LLVMFuzzer-SwitchTest-DFSan -use_traces=1 -seed=1 -runs=2 -timeout=5 -verbosity=3 2>&1 | FileCheck %s -check-prefix=CHECK_DFSanSwitchCallback
Modified: llvm/trunk/lib/Fuzzer/test/fuzzer.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/test/fuzzer.test?rev=244084&r1=244083&r2=244084&view=diff
==============================================================================
--- llvm/trunk/lib/Fuzzer/test/fuzzer.test (original)
+++ llvm/trunk/lib/Fuzzer/test/fuzzer.test Wed Aug 5 13:23:01 2015
@@ -32,5 +32,8 @@ Done1000000: Done 1000000 runs in
RUN: not LLVMFuzzer-StrncmpTest -use_traces=1 -seed=1 -runs=10000 2>&1 | FileCheck %s
RUN: LLVMFuzzer-StrncmpTest -seed=1 -runs=1000000 2>&1 | FileCheck %s --check-prefix=Done1000000
+RUN: not LLVMFuzzer-StrcmpTest -use_traces=1 -seed=1 -runs=10000 2>&1 | FileCheck %s
+RUN: LLVMFuzzer-StrcmpTest -seed=1 -runs=1000000 2>&1 | FileCheck %s --check-prefix=Done1000000
+
RUN: not LLVMFuzzer-SwitchTest -use_traces=1 -seed=1 -runs=1000000 2>&1 | FileCheck %s
RUN: LLVMFuzzer-SwitchTest -seed=1 -runs=1000000 2>&1 | FileCheck %s --check-prefix=Done1000000
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