New mutation: InsertRepeatedBytes.
Updated mutation: EraseByte => EraseBytes.
This helps https://github.com/google/sanitizers/issues/710
where libFuzzer was not able to find a known bug.
Now it finds it in minutes.
Hopefully, the change is general enough to help other targets.
llvm-svn: 278687
The original `ExecuteCommand()` called `system()` from the C library.
The C library implementation of this on macOS contains a mutex which
serializes calls to `system()`. This prevented the `-jobs=` flag
from running copies of the fuzzing binary in parallel which is
the opposite of what is intended.
To fix this on macOS an alternative implementation of `ExecuteCommand()`
is provided that can be used concurrently. This is provided in
`FuzzerUtilDarwin.cpp` which is guarded to only compile code on Apple
platforms. The existing implementation has been moved to a new file
`FuzzerUtilLinux.cpp` which is guarded to only compile code on Linux.
This commit includes a simple test to check that LibFuzzer is being
executed in parallel when requested.
Differential Revision: https://reviews.llvm.org/D22742
llvm-svn: 278544
``afl_driver.cpp`` currently relies on weak symbols which doesn't
work properly under macOS. For now fix the build by providing a
dummy implementation of ``LLVMFuzzerInitialize(...)``. This is just
a temporary measure until we fix ``afl_driver.cpp`` for macOS.
llvm-svn: 274778
Summary: If AFL_DRIVER_EXTRA_STATS_FILENAME is set and valid, write to it peak_rss_mb and slowest_unit_time_sec. These are both stats that libFuzzer can print but afl cannot.
Reviewers: kcc, aizatsky, metzman
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D21742
llvm-svn: 274273
Summary:
[libFuzzer] Enable afl_driver to append stderr to a user specified file.
Append stderr of afl_driver to the file specified by the environmental variable
AFL_DRIVER_STDERR_DUPLICATE_FILENAME if it is set. This lets users see outputs
on crashes without rerunning crashing test cases (which won't work for crashes
that are difficult to reproduce). Before this patch, stderr would only be sent to afl-fuzz
and users would have no way of seeing it.
Reviewers: llvm-commits, aizatsky, kcc, vitalybuka
Subscribers: vitalybuka
Differential Revision: http://reviews.llvm.org/D21194
llvm-svn: 272858
The ``FuzzerMutate.ShuffleBytes2`` unit test was failing on
OSX due to the implementation of ``std::random_shuffle()``
being different between libcxx and libstdc++.
@kcc has decided (see http://reviews.llvm.org/D21218) it is acceptable
for there to be different mutation behavior on different platforms so
this commit just adjusts the test to perform the minimum number of
iterations (that is a power of 2) to see all the mutations the unit test
is looking for.
Differential Revision: http://reviews.llvm.org/D21359
llvm-svn: 272743
Summary:
[libFuzzer] Enable afl_driver to append stderr to a user specified file.
Append stderr of afl_driver to the file specified by the environmental variable
AFL_DRIVER_STDERR_DUPLICATE_FILENAME if it is set. This lets users see outputs
on crashes without rerunning crashing test cases (which won't work for crashes
that are difficult to reproduce). Before this patch, stderr would only be sent to afl-fuzz
and users would have no way of seeing it.
Reviewers: llvm-commits, aizatsky, kcc, vitalybuka
Subscribers: vitalybuka
Differential Revision: http://reviews.llvm.org/D21194
llvm-svn: 272706
On OSX this test sometimes fails due to the
``LLVMFuzzer-FullCoverageSetTest-TracePC`` program going over the
default 2GiB memory limit. This shouldn't be happening and needs
investigating. For now just disable the test so we can set up an
OSX buildbot.
Differential Revision: http://reviews.llvm.org/D21319
llvm-svn: 272696
The tests in ``fuzzer-traces-hooks.test`` only work on Linux because calls to hooks
(e.g. ``__sanitizer_weak_hook_memcmp()``) from inside the sanitizer
runtime are only implemented on Linux. Therefore these tests are set to
only run on Linux.
Differential Revision: http://reviews.llvm.org/D21253
llvm-svn: 272600
This fixes the following unit tests:
FuzzerDictionary.ParseOneDictionaryEntry
FuzzerDictionary.ParseDictionaryFile
The issue appears to be mixing non-ASan-ified code (LibFuzzer) and
ASan-ified code (the unittest) as the tests would pass fine if
everything was built with ASan enabled.
I believe the issue is that different implementations of std::vector<>
are being used in LibFuzzer and outside LibFuzzer (in the unittests).
For Libcxx (I've not seen the issue manifest for libstdc++) we can disable
the ASanified std::vector<> by definining the ``_LIBCPP_HAS_NO_ASAN`` macro.
Doing this fixes the tests on OSX.
Differential Revision: http://reviews.llvm.org/D21049
llvm-svn: 272374
This fixes linking problems on OSX.
Unfortunately it turns out we need to use an instance of the
``fuzzer::ExternalFunctions`` object in several places so this
commit also replaces all instances with a single global instance.
It also turns out initializing a global ``fuzzer::ExternalFunctions``
before main is entered (i.e. letting the object be initialised by the
global initializers) is not safe (on OSX the call to ``Printf()`` in the
CTOR crashes if it is called from a global initializer) so we instead
have a global ``fuzzer::ExternalFunctions*`` and initialize it inside
``FuzzerDriver()``.
Multiple unit tests depend also depend on the
``fuzzer::ExternalFunctions*`` global so a ``main()`` function has been
added that initializes it before running any tests.
Differential Revision: http://reviews.llvm.org/D20943
llvm-svn: 272072
This is necessary because the existing fuzzer-oom.test was Linux
specific due to its use of __sanitizer_print_memory_profile() which
is only available on Linux right now and so the test would fail on OSX.
Differential Revision: http://reviews.llvm.org/D20977
llvm-svn: 272061
Summary:
The option is very useful for testing, plus I intend to measure
its effect on fuzzer effectiveness.
Differential Revision: http://reviews.llvm.org/D21084
llvm-svn: 272035
This fixes a broken part of the build on OSX as the dataflow sanitizer is not supported
on OSX yet.
Differential Revision: http://reviews.llvm.org/D20894
llvm-svn: 271492
Add a new CMake function (``add_libfuzzer_test()``) to simplify
declaration of executables for testing LibFuzzer and use it to
reorganise how tests are declared.
Note that configuration of the lit configuration files has been moved
as late as possible because we are going to need to disable some tests
for some platforms and we will need to propagate this information into
the lit configuration.
Note the code for custom mains was removed because no tests are
currently written for this and Kostya seems happy to remove this.
Differential Revision: http://reviews.llvm.org/D20706
llvm-svn: 270958
Previously the flags were only being set correctly when the
build type was "Release". Now the build should work properly
for all the supported build types. When building libFuzzer
the optimization level respects whatever is used for the
rest of LLVM but for the LibFuzzer tests we force -O0.
Differential Revision: http://reviews.llvm.org/D20558
llvm-svn: 270912
Summary:
Fix the issue with the most recently discovered unit receiving much less attention.
Note: this is the second attempt (prev: r258473). Now, libc++ build is fixed.
Reviewers: aizatsky, kcc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D16487
llvm-svn: 258571
Summary:
Fix the issue with the most recently discovered unit receiving much less attention.
Note: I had to change the seed for one test to make it pass. Alternatively,
the number of runs could be increased. I believe that the average time of
'foo' discovery is not increased, just seed=1 was particularly convenient
for the previous PRNG scheme used.
Reviewers: aizatsky, kcc
Subscribers: llvm-commits, kcc
Differential Revision: http://reviews.llvm.org/D16419
llvm-svn: 258473
Summary:
Add a test for a data followed by 4-byte hash value.
I use a slightly modified Jenkins hash function,
as described in https://en.wikipedia.org/wiki/Jenkins_hash_function
The modification is to ensure that hash(zeros) != 0.
Reviewers: kcc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12648
llvm-svn: 247076
Summary:
This adds a SHA1 implementation taken from public domain code.
The change is trivial, but as it involves third-party code I'd like
a second pair of eyes before commit.
LibFuzzer can not use SHA1 from openssl because openssl may not be available
and because we may be fuzzing openssl itself.
Using sha1sum via a pipe is too slow.
Test Plan: n/a
Reviewers: chandlerc
Reviewed By: chandlerc
Subscribers: majnemer, llvm-commits
Differential Revision: http://reviews.llvm.org/D9733
llvm-svn: 237400
Summary:
This adds a simple DFSan-based (i.e. taint-guided) fuzzer mutator,
see the comments for details.
Test Plan: a test added
Reviewers: samsonov, pcc
Reviewed By: samsonov, pcc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8669
llvm-svn: 233613
Introduce -mllvm -sanitizer-coverage-8bit-counters=1
which adds imprecise thread-unfriendly 8-bit coverage counters.
The run-time library maps these 8-bit counters to 8-bit bitsets in the same way
AFL (http://lcamtuf.coredump.cx/afl/technical_details.txt) does:
counter values are divided into 8 ranges and based on the counter
value one of the bits in the bitset is set.
The AFL ranges are used here: 1, 2, 3, 4-7, 8-15, 16-31, 32-127, 128+.
These counters provide a search heuristic for single-threaded
coverage-guided fuzzers, we do not expect them to be useful for other purposes.
Depending on the value of -fsanitize-coverage=[123] flag,
these counters will be added to the function entry blocks (=1),
every basic block (=2), or every edge (=3).
Use these counters as an optional search heuristic in the Fuzzer library.
Add a test where this heuristic is critical.
llvm-svn: 231166
Summary: Make sure that FileCheck is built when running check-fuzzer
Test Plan:
run on bot:
lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fuzzer
Reviewers: samsonov
Reviewed By: samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7387
llvm-svn: 228045
Summary: Add test targets and the lit-style runner.
Test Plan: Run the tests on bot.
Reviewers: samsonov
Reviewed By: samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7217
llvm-svn: 227389
Summary:
A simple genetic in-process coverage-guided fuzz testing library.
I've used this fuzzer to test clang-format
(it found 12+ bugs, thanks djasper@ for the fixes!)
and it may also help us test other parts of LLVM.
So why not keep it in the LLVM repository?
I plan to add the cmake build rules later (in a separate patch, if that's ok)
and also add a clang-format-fuzzer target.
See README.txt for details.
Test Plan: Tests will follow separately.
Reviewers: djasper, chandlerc, rnk
Reviewed By: rnk
Subscribers: majnemer, ygribov, dblaikie, llvm-commits
Differential Revision: http://reviews.llvm.org/D7184
llvm-svn: 227252
Kostya Serebryany