Commit Graph

346 Commits

Author SHA1 Message Date
Ulrich Weigand a998cae021 [compiler-rt][SystemZ] Skip fuzzer/full-coverage.test
This test is currently marked as XFAIL on s390x, but it is randomly
passing, causing build bot issues.  Setting as UNSUPPORTED for now.
2020-10-28 16:39:46 +01:00
Max Moroz dc62d5ec97 [libFuzzer] Added -print_full_coverage flag.
-print_full_coverage=1 produces a detailed branch coverage dump when run on a single file.
Uses same infrastructure as -print_coverage flag, but prints all branches (regardless of coverage status) in an easy-to-parse format.
Usage: For internal use with machine learning fuzzing models which require detailed coverage information on seed files to generate mutations.

Differential Revision: https://reviews.llvm.org/D85928
2020-10-23 16:05:54 -07:00
Vitaly Buka f16c4a3704 [NFC][fuzzer] Simplify StrcmpTest.cpp
The test started to consistently fail after unrelated
2ffaa9a173.

Even before the patch it was possible to fail the test,
e.g. -seed=1660180256 on my workstation.

Also this checks do not look related to strcmp.
2020-09-18 00:36:48 -07:00
Matt Morehouse f3c2e0bcee [libFuzzer] Enable entropic by default.
Entropic has performed at least on par with vanilla scheduling on
Clusterfuzz, and has shown a slight coverage improvement on FuzzBench:
https://www.fuzzbench.com/reports/2020-08-31/index.html

Reviewed By: Dor1s

Differential Revision: https://reviews.llvm.org/D87476
2020-09-16 10:44:34 -07:00
mhl 66df98945e [libfuzzer] Reduce default verbosity when printing large mutation sequences
When using a custom mutator (e.g. thrift mutator, similar to LPM)
that calls back into libfuzzer's mutations via `LLVMFuzzerMutate`, the mutation
sequences needed to achieve new coverage can get prohibitively large.

Printing these large sequences has two downsides:

1) It makes the logs hard to understand for a human.
2) The performance cost slows down fuzzing.

In this patch I change the `PrintMutationSequence` function to take a max
number of entries, to achieve this goal. I also update `PrintStatusForNewUnit`
to default to printing only 10 entries, in the default verbosity level (1),
requiring the user to set verbosity to 2 if they want the full mutation
sequence.

For our use case, turning off verbosity is not an option, as that would also
disable `PrintStats()` which is very useful for infrastructure that analyzes
the logs in realtime. I imagine most users of libfuzzer always want those logs
in the default.

I built a fuzzer locally with this patch applied to libfuzzer.

When running with the default verbosity, I see logs like this:

    #65 NEW    cov: 4799 ft: 10443 corp: 41/1447Kb lim: 64000 exec/s: 1 rss: 575Mb L: 28658/62542 MS: 196 Custom-CrossOver-ChangeBit-EraseBytes-ChangeBit-ChangeBit-ChangeBit-CrossOver-ChangeBit-CrossOver- DE: "\xff\xff\xff\x0e"-"\xfe\xff\xff\x7f"-"\xfe\xff\xff\x7f"-"\x17\x00\x00\x00\x00\x00\x00\x00"-"\x00\x00\x00\xf9"-"\xff\xff\xff\xff"-"\xfa\xff\xff\xff"-"\xf7\xff\xff\xff"-"@\xff\xff\xff\xff\xff\xff\xff"-"E\x00"-
    #67 NEW    cov: 4810 ft: 10462 corp: 42/1486Kb lim: 64000 exec/s: 1 rss: 577Mb L: 39823/62542 MS: 135 Custom-CopyPart-ShuffleBytes-ShuffleBytes-ChangeBit-ChangeBinInt-EraseBytes-ChangeBit-ChangeBinInt-ChangeBit- DE: "\x01\x00\x00\x00\x00\x00\x01\xf1"-"\x00\x00\x00\x07"-"\x00\x0d"-"\xfd\xff\xff\xff"-"\xfe\xff\xff\xf4"-"\xe3\xff\xff\xff"-"\xff\xff\xff\xf1"-"\xea\xff\xff\xff"-"\x00\x00\x00\xfd"-"\x01\x00\x00\x05"-

Staring hard at the logs it's clear that the cap of 10 is applied.

When running with verbosity level 2, the logs look like the below:

    #66    NEW    cov: 4700 ft: 10188 corp: 37/1186Kb lim: 64000 exec/s: 2 rss: 509Mb L: 47616/61231 MS: 520 Custom-CopyPart-ChangeBinInt-ChangeBit-ChangeByte-EraseBytes-PersAutoDict-CopyPart-ShuffleBytes-ChangeBit-ShuffleBytes-CopyPart-EraseBytes-CopyPart-ChangeBinInt-CopyPart-ChangeByte-ShuffleBytes-ChangeBinInt-ShuffleBytes-ChangeBit-CMP-ShuffleBytes-ChangeBit-CrossOver-ChangeBinInt-ChangeByte-ShuffleBytes-CrossOver-EraseBytes-ChangeBinInt-InsertRepeatedBytes-PersAutoDict-InsertRepeatedBytes-InsertRepeatedBytes-CrossOver-ChangeByte-ShuffleBytes-CopyPart-ShuffleBytes-CopyPart-CrossOver-ChangeBit-ShuffleBytes-CrossOver-PersAutoDict-ChangeByte-ChangeBit-ShuffleBytes-CrossOver-ChangeByte-EraseBytes-CopyPart-ChangeBinInt-PersAutoDict-CrossOver-ShuffleBytes-CrossOver-CrossOver-EraseBytes-CrossOver-EraseBytes-CrossOver-ChangeBit-ChangeBinInt-ChangeByte-EraseBytes-ShuffleBytes-ShuffleBytes-ChangeBit-EraseBytes-ChangeBinInt-ChangeBit-ChangeBinInt-CopyPart-EraseBytes-PersAutoDict-EraseBytes-CopyPart-ChangeBinInt-ChangeByte-CrossOver-ChangeBinInt-ShuffleBytes-PersAutoDict-PersAutoDict-ChangeBinInt-CopyPart-ChangeBinInt-CrossOver-ChangeBit-ChangeBinInt-CopyPart-ChangeByte-ChangeBit-CopyPart-CrossOver-ChangeByte-ChangeBit-ChangeByte-ShuffleBytes-CMP-ChangeBit-CopyPart-ChangeBit-ChangeByte-ChangeBinInt-PersAutoDict-ChangeBinInt-CrossOver-ChangeBinInt-ChangeBit-ChangeBinInt-ChangeBinInt-PersAutoDict-ChangeBinInt-ChangeBinInt-ChangeByte-CopyPart-ShuffleBytes-ChangeByte-ChangeBit-ChangeByte-ChangeByte-EraseBytes-CrossOver-ChangeByte-ChangeByte-EraseBytes-EraseBytes-InsertRepeatedBytes-ShuffleBytes-CopyPart-CopyPart-ChangeBit-ShuffleBytes-PersAutoDict-ShuffleBytes-ChangeBit-ChangeByte-ChangeBit-ShuffleBytes-ChangeByte-ChangeBinInt-CrossOver-ChangeBinInt-ChangeBit-EraseBytes-CopyPart-ChangeByte-CrossOver-EraseBytes-CrossOver-ChangeByte-ShuffleBytes-ChangeByte-ChangeBinInt-CrossOver-ChangeByte-InsertRepeatedBytes-InsertByte-ShuffleBytes-PersAutoDict-ChangeBit-ChangeByte-ChangeBit-ShuffleBytes-ShuffleBytes-CopyPart-ShuffleBytes-EraseBytes-ShuffleBytes-ShuffleBytes-CrossOver-ChangeBinInt-CopyPart-CopyPart-CopyPart-EraseBytes-EraseBytes-ChangeByte-ChangeBinInt-ShuffleBytes-CMP-InsertByte-EraseBytes-ShuffleBytes-CopyPart-ChangeBit-CrossOver-CopyPart-CopyPart-ShuffleBytes-ChangeByte-ChangeByte-ChangeBinInt-EraseBytes-ChangeByte-ChangeBinInt-ChangeBit-ChangeBit-ChangeByte-ShuffleBytes-PersAutoDict-PersAutoDict-CMP-ChangeBit-ShuffleBytes-PersAutoDict-ChangeBinInt-EraseBytes-EraseBytes-ShuffleBytes-ChangeByte-ShuffleBytes-ChangeBit-EraseBytes-CMP-ShuffleBytes-ChangeByte-ChangeBinInt-EraseBytes-ChangeBinInt-ChangeByte-EraseBytes-ChangeByte-CrossOver-ShuffleBytes-EraseBytes-EraseBytes-ShuffleBytes-ChangeBit-EraseBytes-CopyPart-ShuffleBytes-ShuffleBytes-CrossOver-CopyPart-ChangeBinInt-ShuffleBytes-CrossOver-InsertByte-InsertByte-ChangeBinInt-ChangeBinInt-CopyPart-EraseBytes-ShuffleBytes-ChangeBit-ChangeBit-EraseBytes-ChangeByte-ChangeByte-ChangeBinInt-CrossOver-ChangeBinInt-ChangeBinInt-ShuffleBytes-ShuffleBytes-ChangeByte-ChangeByte-ChangeBinInt-ShuffleBytes-CrossOver-EraseBytes-CopyPart-CopyPart-CopyPart-ChangeBit-ShuffleBytes-ChangeByte-EraseBytes-ChangeByte-InsertRepeatedBytes-InsertByte-InsertRepeatedBytes-PersAutoDict-EraseBytes-ShuffleBytes-ChangeByte-ShuffleBytes-ChangeBinInt-ShuffleBytes-ChangeBinInt-ChangeBit-CrossOver-CrossOver-ShuffleBytes-CrossOver-CopyPart-CrossOver-CrossOver-CopyPart-ChangeByte-ChangeByte-CrossOver-ChangeBit-ChangeBinInt-EraseBytes-ShuffleBytes-EraseBytes-CMP-PersAutoDict-PersAutoDict-InsertByte-ChangeBit-ChangeByte-CopyPart-CrossOver-ChangeByte-ChangeBit-ChangeByte-CopyPart-ChangeBinInt-EraseBytes-CrossOver-ChangeBit-CrossOver-PersAutoDict-CrossOver-ChangeByte-CrossOver-ChangeByte-ChangeByte-CrossOver-ShuffleBytes-CopyPart-CopyPart-ShuffleBytes-ChangeByte-ChangeByte-ChangeBinInt-ChangeBinInt-ChangeBinInt-ChangeBinInt-ShuffleBytes-CrossOver-ChangeBinInt-ShuffleBytes-ChangeBit-PersAutoDict-ChangeBinInt-ShuffleBytes-ChangeBinInt-ChangeByte-CrossOver-ChangeBit-CopyPart-ChangeBit-ChangeBit-CopyPart-ChangeByte-PersAutoDict-ChangeBit-ShuffleBytes-ChangeByte-ChangeBit-CrossOver-ChangeByte-CrossOver-ChangeByte-CrossOver-ChangeBit-ChangeByte-ChangeBinInt-PersAutoDict-CopyPart-ChangeBinInt-ChangeBit-CrossOver-ChangeBit-PersAutoDict-ShuffleBytes-EraseBytes-CrossOver-ChangeByte-ChangeBinInt-ShuffleBytes-ChangeBinInt-InsertRepeatedBytes-PersAutoDict-CrossOver-ChangeByte-Custom-PersAutoDict-CopyPart-CopyPart-ChangeBinInt-ShuffleBytes-ChangeBinInt-ChangeBit-ShuffleBytes-CrossOver-CMP-ChangeByte-CopyPart-ShuffleBytes-CopyPart-CopyPart-CrossOver-CrossOver-CrossOver-ShuffleBytes-ChangeByte-ChangeBinInt-ChangeBit-ChangeBit-ChangeBit-ChangeByte-EraseBytes-ChangeByte-ChangeBit-ChangeByte-ChangeByte-CopyPart-PersAutoDict-ChangeBinInt-PersAutoDict-PersAutoDict-PersAutoDict-CopyPart-CopyPart-CrossOver-ChangeByte-ChangeBinInt-ShuffleBytes-ChangeBit-CopyPart-EraseBytes-CopyPart-CopyPart-CrossOver-ChangeByte-EraseBytes-ShuffleBytes-ChangeByte-CopyPart-EraseBytes-CopyPart-CrossOver-ChangeBinInt-ChangeBinInt-InsertByte-ChangeBinInt-ChangeBit-ChangeByte-CopyPart-ChangeByte-EraseBytes-ChangeByte-ChangeBit-ChangeByte-ShuffleBytes-CopyPart-ChangeBinInt-EraseBytes-CrossOver-ChangeBit-ChangeBit-CrossOver-EraseBytes-ChangeBinInt-CopyPart-CopyPart-ChangeBinInt-ChangeBit-EraseBytes-InsertRepeatedBytes-EraseBytes-ChangeBit-CrossOver-CrossOver-EraseBytes-EraseBytes-ChangeByte-CopyPart-CopyPart-ShuffleBytes-ChangeByte-ChangeBit-ChangeByte-EraseBytes-ChangeBit-ChangeByte-ChangeByte-CrossOver-CopyPart-EraseBytes-ChangeByte-EraseBytes-ChangeByte-ShuffleBytes-ShuffleBytes-ChangeByte-CopyPart-ChangeByte-ChangeByte-ChangeBit-CopyPart-ChangeBit-ChangeBinInt-CopyPart-ShuffleBytes-ChangeBit-ChangeBinInt-ChangeBit-EraseBytes-CMP-CrossOver-CopyPart-ChangeBinInt-CrossOver-CrossOver-CopyPart-CrossOver-CrossOver-InsertByte-InsertByte-CopyPart-Custom- DE: "warn"-"\x00\x00\x00\x80"-"\xfe\xff\xff\xfb"-"\xff\xff"-"\x10\x00\x00\x00"-"\xfe\xff\xff\xff"-"\xff\xff\xff\xf6"-"U\x01\x00\x00\x00\x00\x00\x00"-"\xd9\xff\xff\xff"-"\xfe\xff\xff\xea"-"\xf0\xff\xff\xff"-"\xfc\xff\xff\xff"-"warn"-"\xff\xff\xff\xff"-"\xfe\xff\xff\xfb"-"\x00\x00\x00\x80"-"\xfe\xff\xff\xf1"-"\xfe\xff\xff\xea"-"\x00\x00\x00\x00\x00\x00\x012"-"\xe2\x00"-"\xfb\xff\xff\xff"-"\x00\x00\x00\x00"-"\xe9\xff\xff\xff"-"\xff\xff"-"\x00\x00\x00\x80"-"\x01\x00\x04\xc9"-"\xf0\xff\xff\xff"-"\xf9\xff\xff\xff"-"\xff\xff\xff\xff\xff\xff\xff\x12"-"\xe2\x00"-"\xfe\xff\xff\xff"-"\xfe\xff\xff\xea"-"\xff\xff\xff\xff"-"\xf4\xff\xff\xff"-"\xe9\xff\xff\xff"-"\xf1\xff\xff\xff"-
    #48    NEW    cov: 4502 ft: 9151 corp: 27/750Kb lim: 64000 exec/s: 2 rss: 458Mb L: 50772/50772 MS: 259 ChangeByte-ShuffleBytes-ChangeBinInt-ChangeByte-ChangeByte-ChangeByte-ChangeByte-ChangeBit-CopyPart-CrossOver-CopyPart-ChangeByte-CrossOver-CopyPart-ChangeBit-ChangeByte-EraseBytes-ChangeByte-CopyPart-CopyPart-CopyPart-ChangeBit-EraseBytes-ChangeBinInt-CrossOver-CopyPart-CrossOver-CopyPart-ChangeBit-ChangeByte-ChangeBit-InsertByte-CrossOver-InsertRepeatedBytes-InsertRepeatedBytes-InsertRepeatedBytes-ChangeBinInt-EraseBytes-InsertRepeatedBytes-InsertByte-ChangeBit-ShuffleBytes-ChangeBit-ChangeBit-CopyPart-ChangeBit-ChangeByte-CrossOver-ChangeBinInt-ChangeByte-CrossOver-CMP-ChangeByte-CrossOver-ChangeByte-ShuffleBytes-ShuffleBytes-ChangeByte-ChangeBinInt-CopyPart-EraseBytes-CrossOver-ChangeBit-ChangeBinInt-InsertByte-ChangeBit-CopyPart-ChangeBinInt-ChangeByte-CrossOver-ChangeBit-EraseBytes-CopyPart-ChangeBinInt-ChangeBit-ChangeBit-ChangeByte-CopyPart-ChangeBinInt-CrossOver-PersAutoDict-ChangeByte-ChangeBit-ChangeByte-ChangeBinInt-ChangeBinInt-EraseBytes-CopyPart-CopyPart-ChangeByte-ChangeByte-EraseBytes-PersAutoDict-CopyPart-ChangeByte-ChangeByte-EraseBytes-CrossOver-CopyPart-CopyPart-CopyPart-ChangeByte-ChangeBit-CMP-CopyPart-ChangeBinInt-ChangeBinInt-CrossOver-ChangeBit-ChangeBit-EraseBytes-ChangeByte-ShuffleBytes-ChangeBit-ChangeBinInt-CMP-InsertRepeatedBytes-CopyPart-Custom-ChangeByte-CrossOver-EraseBytes-ChangeBit-CopyPart-CrossOver-CMP-ShuffleBytes-EraseBytes-CrossOver-PersAutoDict-ChangeByte-CrossOver-CopyPart-CrossOver-CrossOver-ShuffleBytes-ChangeBinInt-CrossOver-ChangeBinInt-ShuffleBytes-PersAutoDict-ChangeByte-EraseBytes-ChangeBit-CrossOver-EraseBytes-CrossOver-ChangeBit-ChangeBinInt-EraseBytes-InsertByte-InsertRepeatedBytes-InsertByte-InsertByte-ChangeByte-ChangeBinInt-ChangeBit-CrossOver-ChangeByte-CrossOver-EraseBytes-ChangeByte-ShuffleBytes-ChangeBit-ChangeBit-ShuffleBytes-CopyPart-ChangeByte-PersAutoDict-ChangeBit-ChangeByte-InsertRepeatedBytes-CMP-CrossOver-ChangeByte-EraseBytes-ShuffleBytes-CrossOver-ShuffleBytes-ChangeBinInt-ChangeBinInt-CopyPart-PersAutoDict-ShuffleBytes-ChangeBit-CopyPart-ShuffleBytes-CopyPart-EraseBytes-ChangeByte-ChangeBit-ChangeBit-ChangeBinInt-ChangeByte-CopyPart-EraseBytes-ChangeBinInt-EraseBytes-EraseBytes-PersAutoDict-CMP-PersAutoDict-CrossOver-CrossOver-ChangeBit-CrossOver-PersAutoDict-CrossOver-CopyPart-ChangeByte-EraseBytes-ChangeByte-ShuffleBytes-ChangeByte-ChangeByte-CrossOver-ChangeBit-EraseBytes-ChangeByte-EraseBytes-ChangeBinInt-CrossOver-CrossOver-EraseBytes-ChangeBinInt-CrossOver-ChangeBit-ShuffleBytes-ChangeBit-ChangeByte-EraseBytes-ChangeBit-CrossOver-CrossOver-CrossOver-ChangeByte-ChangeBit-ShuffleBytes-ChangeBit-ChangeBit-EraseBytes-CrossOver-CrossOver-CopyPart-ShuffleBytes-ChangeByte-ChangeByte-CopyPart-CrossOver-CopyPart-CrossOver-CrossOver-EraseBytes-EraseBytes-ShuffleBytes-InsertRepeatedBytes-ChangeBit-CopyPart-Custom- DE: "\xfe\xff\xff\xfc"-"\x00\x00\x00\x00"-"F\x00"-"\xf3\xff\xff\xff"-"St9exception"-"_\x00\x00\x00"-"\xf6\xff\xff\xff"-"\xfe\xff\xff\xff"-"\x00\x00\x00\x00"-"p\x02\x00\x00\x00\x00\x00\x00"-"\xfe\xff\xff\xfb"-"\xff\xff"-"\xff\xff\xff\xff"-"\x01\x00\x00\x07"-"\xfe\xff\xff\xfe"-

These are prohibitively large and of limited value in the default case (when
someone is running the fuzzer, not debugging it), in my opinion.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86658
2020-09-16 09:20:57 -07:00
Vitaly Buka 3023f057d8 [NFC][lsan][fuzzer] Relax fuzzer-leak.test
With lsan we can't guarantee to catch leak on the same iteration.
2020-09-14 23:50:52 -07:00
Dokyung Song 1bb1eac6b1 [libFuzzer] Add a command-line option for tracing mutation of corpus inputs in the dot graph format.
This patch adds a new command-line option -mutation_graph_file=FILE for
debugging purposes, which traces how corpus inputs evolve during a fuzzing
run. For each new input that is added to the corpus, a new vertex corresponding
to the added input, as well as a new edge that connects its base input to itself
are written to the given file. Each vertex is labeled with the filename of the
input, and each edge is labeled with the mutation sequence that led to the input
w.r.t. its base input.

The format of the mutation graph file is the dot file format. Once prepended and
appended with "graph {" and "}", respectively, the graph becomes a valid dot
file and can be visualized.

Differential Revision: https://reviews.llvm.org/D86560
2020-09-09 03:28:53 +00:00
Dokyung Song 5cda4dc7b4 [libFuzzer] Scale energy assigned to each input based on input execution time.
This patch scales the energy computed by the Entropic schedule based on the
execution time of each input. The input execution time is compared with the
average execution time of inputs in the corpus, and, based on the amount by
which they differ, the energy is scaled from 0.1x (for inputs executing slow) to
3x (for inputs executing fast). Note that the exact scaling criteria and formula
is borrowed from AFL.

On FuzzBench, this gives a sizeable throughput increase, which in turn leads to
more coverage on several benchmarks. For details, see the following report.

https://storage.googleapis.com/fuzzer-test-suite-public/exectime-report/index.html

Differential Revision: https://reviews.llvm.org/D86092
2020-09-03 20:38:20 +00:00
Dokyung Song b53243e194 [libFuzzer] Evenly select inputs to cross over with from the corpus regardless of the input's coverage.
This patch adds an option "cross_over_uniform_dist", which, if 1, considers all
inputs in the corpus for the crossover input selection. More specifically, this
patch uses a uniform distribution of all inputs in the corpus for the CrossOver
input selection. Note that input selection for mutation is still fully
determined by the scheduling policy (i.e., vanilla or Entropic); the uniform
distribution only applies to the secondary input selection, only for the
crossover mutation of the base input chosen by the scheduling policy. This way
the corpus inputs that have useful fragments in them, even though they are
deprioritized by the scheduling policy, have chances of getting mixed with other
inputs that are prioritized and selected as base input for mutation.

Differential Revision: https://reviews.llvm.org/D86954
2020-09-03 19:47:00 +00:00
Dokyung Song 62673c430d [libFuzzer] Add an option to keep initial seed inputs around.
This patch adds an option "keep_seed" to keep all initial seed inputs in the
corpus. Previously, only the initial seed inputs that find new coverage were
added to the corpus, and all the other initial inputs were discarded. We
observed in some circumstances that useful initial seed inputs are discarded as
they find no new coverage, even though they contain useful fragments in them
(e.g., SQLITE3 FuzzBench benchmark). This newly added option provides a way to
keeping seed inputs in the corpus for those circumstances. With this patch, and
with -keep_seed=1, all initial seed inputs are kept in the corpus regardless of
whether they find new coverage or not. Further, these seed inputs are not
replaced with smaller inputs even if -reduce_inputs=1.

Differential Revision: https://reviews.llvm.org/D86577
2020-09-03 15:54:39 +00:00
Matt Morehouse 711b980654 [fuzzer] Create user provided fuzzer writeable directories when requested if they dont exist
Currently, libFuzzer will exit with an error message if a non-existent
directory is provided for any of the appropriate arguments. For cases
where libFuzzer is used in a specialized embedded environment, it would
be much easier to have libFuzzer create the directories for the user.

This patch accommodates for this scenario by allowing the user to provide
the argument `-create_missing_dirs=1` which makes libFuzzer attempt to
create the `artifact_prefix`, `exact_artifact_path`,
`features_dir` and/or corpus directory if they don't already exist rather
than throw an error and exit.

Split off from D84808 as requested [here](https://reviews.llvm.org/D84808#2208546).

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86733
2020-09-03 08:31:59 -07:00
Matt Morehouse 7139736261 Revert "[libfuzzer] Reduce default verbosity when printing large mutation sequences"
This reverts commit 2665425908 due to
buildbot failure.
2020-09-01 12:49:41 -07:00
Matt Morehouse 10670bdf54 Revert "[fuzzer] Create user provided fuzzer writeable directories when requested if they dont exist"
This reverts commit cb8912799d, since the
test fails on Windows.
2020-09-01 12:05:46 -07:00
Matt Morehouse cb8912799d [fuzzer] Create user provided fuzzer writeable directories when requested if they dont exist
Currently, libFuzzer will exit with an error message if a non-existent
directory is provided for any of the appropriate arguments. For cases
where libFuzzer is used in a specialized embedded environment, it would
be much easier to have libFuzzer create the directories for the user.

This patch accommodates for this scenario by allowing the user to provide
the argument `-create_missing_dirs=1` which makes libFuzzer attempt to
create the `artifact_prefix`, `exact_artifact_path`,
`features_dir` and/or corpus directory if they don't already exist rather
than throw an error and exit.

Split off from D84808 as requested [here](https://reviews.llvm.org/D84808#2208546).

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86733
2020-09-01 11:50:47 -07:00
mhl 2665425908 [libfuzzer] Reduce default verbosity when printing large mutation sequences
When using a custom mutator (e.g. thrift mutator, similar to LPM)
that calls back into libfuzzer's mutations via `LLVMFuzzerMutate`, the mutation
sequences needed to achieve new coverage can get prohibitively large.

Printing these large sequences has two downsides:

1) It makes the logs hard to understand for a human.
2) The performance cost slows down fuzzing.

In this patch I change the `PrintMutationSequence` function to take a max
number of entries, to achieve this goal. I also update `PrintStatusForNewUnit`
to default to printing only 10 entries, in the default verbosity level (1),
requiring the user to set verbosity to 2 if they want the full mutation
sequence.

For our use case, turning off verbosity is not an option, as that would also
disable `PrintStats()` which is very useful for infrastructure that analyzes
the logs in realtime. I imagine most users of libfuzzer always want those logs
in the default.

I built a fuzzer locally with this patch applied to libfuzzer.

When running with the default verbosity, I see logs like this:

    #65 NEW    cov: 4799 ft: 10443 corp: 41/1447Kb lim: 64000 exec/s: 1 rss: 575Mb L: 28658/62542 MS: 196 Custom-CrossOver-ChangeBit-EraseBytes-ChangeBit-ChangeBit-ChangeBit-CrossOver-ChangeBit-CrossOver- DE: "\xff\xff\xff\x0e"-"\xfe\xff\xff\x7f"-"\xfe\xff\xff\x7f"-"\x17\x00\x00\x00\x00\x00\x00\x00"-"\x00\x00\x00\xf9"-"\xff\xff\xff\xff"-"\xfa\xff\xff\xff"-"\xf7\xff\xff\xff"-"@\xff\xff\xff\xff\xff\xff\xff"-"E\x00"-
    #67 NEW    cov: 4810 ft: 10462 corp: 42/1486Kb lim: 64000 exec/s: 1 rss: 577Mb L: 39823/62542 MS: 135 Custom-CopyPart-ShuffleBytes-ShuffleBytes-ChangeBit-ChangeBinInt-EraseBytes-ChangeBit-ChangeBinInt-ChangeBit- DE: "\x01\x00\x00\x00\x00\x00\x01\xf1"-"\x00\x00\x00\x07"-"\x00\x0d"-"\xfd\xff\xff\xff"-"\xfe\xff\xff\xf4"-"\xe3\xff\xff\xff"-"\xff\xff\xff\xf1"-"\xea\xff\xff\xff"-"\x00\x00\x00\xfd"-"\x01\x00\x00\x05"-

Staring hard at the logs it's clear that the cap of 10 is applied.

When running with verbosity level 2, the logs look like the below:

    #66    NEW    cov: 4700 ft: 10188 corp: 37/1186Kb lim: 64000 exec/s: 2 rss: 509Mb L: 47616/61231 MS: 520 Custom-CopyPart-ChangeBinInt-ChangeBit-ChangeByte-EraseBytes-PersAutoDict-CopyPart-ShuffleBytes-ChangeBit-ShuffleBytes-CopyPart-EraseBytes-CopyPart-ChangeBinInt-CopyPart-ChangeByte-ShuffleBytes-ChangeBinInt-ShuffleBytes-ChangeBit-CMP-ShuffleBytes-ChangeBit-CrossOver-ChangeBinInt-ChangeByte-ShuffleBytes-CrossOver-EraseBytes-ChangeBinInt-InsertRepeatedBytes-PersAutoDict-InsertRepeatedBytes-InsertRepeatedBytes-CrossOver-ChangeByte-ShuffleBytes-CopyPart-ShuffleBytes-CopyPart-CrossOver-ChangeBit-ShuffleBytes-CrossOver-PersAutoDict-ChangeByte-ChangeBit-ShuffleBytes-CrossOver-ChangeByte-EraseBytes-CopyPart-ChangeBinInt-PersAutoDict-CrossOver-ShuffleBytes-CrossOver-CrossOver-EraseBytes-CrossOver-EraseBytes-CrossOver-ChangeBit-ChangeBinInt-ChangeByte-EraseBytes-ShuffleBytes-ShuffleBytes-ChangeBit-EraseBytes-ChangeBinInt-ChangeBit-ChangeBinInt-CopyPart-EraseBytes-PersAutoDict-EraseBytes-CopyPart-ChangeBinInt-ChangeByte-CrossOver-ChangeBinInt-ShuffleBytes-PersAutoDict-PersAutoDict-ChangeBinInt-CopyPart-ChangeBinInt-CrossOver-ChangeBit-ChangeBinInt-CopyPart-ChangeByte-ChangeBit-CopyPart-CrossOver-ChangeByte-ChangeBit-ChangeByte-ShuffleBytes-CMP-ChangeBit-CopyPart-ChangeBit-ChangeByte-ChangeBinInt-PersAutoDict-ChangeBinInt-CrossOver-ChangeBinInt-ChangeBit-ChangeBinInt-ChangeBinInt-PersAutoDict-ChangeBinInt-ChangeBinInt-ChangeByte-CopyPart-ShuffleBytes-ChangeByte-ChangeBit-ChangeByte-ChangeByte-EraseBytes-CrossOver-ChangeByte-ChangeByte-EraseBytes-EraseBytes-InsertRepeatedBytes-ShuffleBytes-CopyPart-CopyPart-ChangeBit-ShuffleBytes-PersAutoDict-ShuffleBytes-ChangeBit-ChangeByte-ChangeBit-ShuffleBytes-ChangeByte-ChangeBinInt-CrossOver-ChangeBinInt-ChangeBit-EraseBytes-CopyPart-ChangeByte-CrossOver-EraseBytes-CrossOver-ChangeByte-ShuffleBytes-ChangeByte-ChangeBinInt-CrossOver-ChangeByte-InsertRepeatedBytes-InsertByte-ShuffleBytes-PersAutoDict-ChangeBit-ChangeByte-ChangeBit-ShuffleBytes-ShuffleBytes-CopyPart-ShuffleBytes-EraseBytes-ShuffleBytes-ShuffleBytes-CrossOver-ChangeBinInt-CopyPart-CopyPart-CopyPart-EraseBytes-EraseBytes-ChangeByte-ChangeBinInt-ShuffleBytes-CMP-InsertByte-EraseBytes-ShuffleBytes-CopyPart-ChangeBit-CrossOver-CopyPart-CopyPart-ShuffleBytes-ChangeByte-ChangeByte-ChangeBinInt-EraseBytes-ChangeByte-ChangeBinInt-ChangeBit-ChangeBit-ChangeByte-ShuffleBytes-PersAutoDict-PersAutoDict-CMP-ChangeBit-ShuffleBytes-PersAutoDict-ChangeBinInt-EraseBytes-EraseBytes-ShuffleBytes-ChangeByte-ShuffleBytes-ChangeBit-EraseBytes-CMP-ShuffleBytes-ChangeByte-ChangeBinInt-EraseBytes-ChangeBinInt-ChangeByte-EraseBytes-ChangeByte-CrossOver-ShuffleBytes-EraseBytes-EraseBytes-ShuffleBytes-ChangeBit-EraseBytes-CopyPart-ShuffleBytes-ShuffleBytes-CrossOver-CopyPart-ChangeBinInt-ShuffleBytes-CrossOver-InsertByte-InsertByte-ChangeBinInt-ChangeBinInt-CopyPart-EraseBytes-ShuffleBytes-ChangeBit-ChangeBit-EraseBytes-ChangeByte-ChangeByte-ChangeBinInt-CrossOver-ChangeBinInt-ChangeBinInt-ShuffleBytes-ShuffleBytes-ChangeByte-ChangeByte-ChangeBinInt-ShuffleBytes-CrossOver-EraseBytes-CopyPart-CopyPart-CopyPart-ChangeBit-ShuffleBytes-ChangeByte-EraseBytes-ChangeByte-InsertRepeatedBytes-InsertByte-InsertRepeatedBytes-PersAutoDict-EraseBytes-ShuffleBytes-ChangeByte-ShuffleBytes-ChangeBinInt-ShuffleBytes-ChangeBinInt-ChangeBit-CrossOver-CrossOver-ShuffleBytes-CrossOver-CopyPart-CrossOver-CrossOver-CopyPart-ChangeByte-ChangeByte-CrossOver-ChangeBit-ChangeBinInt-EraseBytes-ShuffleBytes-EraseBytes-CMP-PersAutoDict-PersAutoDict-InsertByte-ChangeBit-ChangeByte-CopyPart-CrossOver-ChangeByte-ChangeBit-ChangeByte-CopyPart-ChangeBinInt-EraseBytes-CrossOver-ChangeBit-CrossOver-PersAutoDict-CrossOver-ChangeByte-CrossOver-ChangeByte-ChangeByte-CrossOver-ShuffleBytes-CopyPart-CopyPart-ShuffleBytes-ChangeByte-ChangeByte-ChangeBinInt-ChangeBinInt-ChangeBinInt-ChangeBinInt-ShuffleBytes-CrossOver-ChangeBinInt-ShuffleBytes-ChangeBit-PersAutoDict-ChangeBinInt-ShuffleBytes-ChangeBinInt-ChangeByte-CrossOver-ChangeBit-CopyPart-ChangeBit-ChangeBit-CopyPart-ChangeByte-PersAutoDict-ChangeBit-ShuffleBytes-ChangeByte-ChangeBit-CrossOver-ChangeByte-CrossOver-ChangeByte-CrossOver-ChangeBit-ChangeByte-ChangeBinInt-PersAutoDict-CopyPart-ChangeBinInt-ChangeBit-CrossOver-ChangeBit-PersAutoDict-ShuffleBytes-EraseBytes-CrossOver-ChangeByte-ChangeBinInt-ShuffleBytes-ChangeBinInt-InsertRepeatedBytes-PersAutoDict-CrossOver-ChangeByte-Custom-PersAutoDict-CopyPart-CopyPart-ChangeBinInt-ShuffleBytes-ChangeBinInt-ChangeBit-ShuffleBytes-CrossOver-CMP-ChangeByte-CopyPart-ShuffleBytes-CopyPart-CopyPart-CrossOver-CrossOver-CrossOver-ShuffleBytes-ChangeByte-ChangeBinInt-ChangeBit-ChangeBit-ChangeBit-ChangeByte-EraseBytes-ChangeByte-ChangeBit-ChangeByte-ChangeByte-CopyPart-PersAutoDict-ChangeBinInt-PersAutoDict-PersAutoDict-PersAutoDict-CopyPart-CopyPart-CrossOver-ChangeByte-ChangeBinInt-ShuffleBytes-ChangeBit-CopyPart-EraseBytes-CopyPart-CopyPart-CrossOver-ChangeByte-EraseBytes-ShuffleBytes-ChangeByte-CopyPart-EraseBytes-CopyPart-CrossOver-ChangeBinInt-ChangeBinInt-InsertByte-ChangeBinInt-ChangeBit-ChangeByte-CopyPart-ChangeByte-EraseBytes-ChangeByte-ChangeBit-ChangeByte-ShuffleBytes-CopyPart-ChangeBinInt-EraseBytes-CrossOver-ChangeBit-ChangeBit-CrossOver-EraseBytes-ChangeBinInt-CopyPart-CopyPart-ChangeBinInt-ChangeBit-EraseBytes-InsertRepeatedBytes-EraseBytes-ChangeBit-CrossOver-CrossOver-EraseBytes-EraseBytes-ChangeByte-CopyPart-CopyPart-ShuffleBytes-ChangeByte-ChangeBit-ChangeByte-EraseBytes-ChangeBit-ChangeByte-ChangeByte-CrossOver-CopyPart-EraseBytes-ChangeByte-EraseBytes-ChangeByte-ShuffleBytes-ShuffleBytes-ChangeByte-CopyPart-ChangeByte-ChangeByte-ChangeBit-CopyPart-ChangeBit-ChangeBinInt-CopyPart-ShuffleBytes-ChangeBit-ChangeBinInt-ChangeBit-EraseBytes-CMP-CrossOver-CopyPart-ChangeBinInt-CrossOver-CrossOver-CopyPart-CrossOver-CrossOver-InsertByte-InsertByte-CopyPart-Custom- DE: "warn"-"\x00\x00\x00\x80"-"\xfe\xff\xff\xfb"-"\xff\xff"-"\x10\x00\x00\x00"-"\xfe\xff\xff\xff"-"\xff\xff\xff\xf6"-"U\x01\x00\x00\x00\x00\x00\x00"-"\xd9\xff\xff\xff"-"\xfe\xff\xff\xea"-"\xf0\xff\xff\xff"-"\xfc\xff\xff\xff"-"warn"-"\xff\xff\xff\xff"-"\xfe\xff\xff\xfb"-"\x00\x00\x00\x80"-"\xfe\xff\xff\xf1"-"\xfe\xff\xff\xea"-"\x00\x00\x00\x00\x00\x00\x012"-"\xe2\x00"-"\xfb\xff\xff\xff"-"\x00\x00\x00\x00"-"\xe9\xff\xff\xff"-"\xff\xff"-"\x00\x00\x00\x80"-"\x01\x00\x04\xc9"-"\xf0\xff\xff\xff"-"\xf9\xff\xff\xff"-"\xff\xff\xff\xff\xff\xff\xff\x12"-"\xe2\x00"-"\xfe\xff\xff\xff"-"\xfe\xff\xff\xea"-"\xff\xff\xff\xff"-"\xf4\xff\xff\xff"-"\xe9\xff\xff\xff"-"\xf1\xff\xff\xff"-
    #48    NEW    cov: 4502 ft: 9151 corp: 27/750Kb lim: 64000 exec/s: 2 rss: 458Mb L: 50772/50772 MS: 259 ChangeByte-ShuffleBytes-ChangeBinInt-ChangeByte-ChangeByte-ChangeByte-ChangeByte-ChangeBit-CopyPart-CrossOver-CopyPart-ChangeByte-CrossOver-CopyPart-ChangeBit-ChangeByte-EraseBytes-ChangeByte-CopyPart-CopyPart-CopyPart-ChangeBit-EraseBytes-ChangeBinInt-CrossOver-CopyPart-CrossOver-CopyPart-ChangeBit-ChangeByte-ChangeBit-InsertByte-CrossOver-InsertRepeatedBytes-InsertRepeatedBytes-InsertRepeatedBytes-ChangeBinInt-EraseBytes-InsertRepeatedBytes-InsertByte-ChangeBit-ShuffleBytes-ChangeBit-ChangeBit-CopyPart-ChangeBit-ChangeByte-CrossOver-ChangeBinInt-ChangeByte-CrossOver-CMP-ChangeByte-CrossOver-ChangeByte-ShuffleBytes-ShuffleBytes-ChangeByte-ChangeBinInt-CopyPart-EraseBytes-CrossOver-ChangeBit-ChangeBinInt-InsertByte-ChangeBit-CopyPart-ChangeBinInt-ChangeByte-CrossOver-ChangeBit-EraseBytes-CopyPart-ChangeBinInt-ChangeBit-ChangeBit-ChangeByte-CopyPart-ChangeBinInt-CrossOver-PersAutoDict-ChangeByte-ChangeBit-ChangeByte-ChangeBinInt-ChangeBinInt-EraseBytes-CopyPart-CopyPart-ChangeByte-ChangeByte-EraseBytes-PersAutoDict-CopyPart-ChangeByte-ChangeByte-EraseBytes-CrossOver-CopyPart-CopyPart-CopyPart-ChangeByte-ChangeBit-CMP-CopyPart-ChangeBinInt-ChangeBinInt-CrossOver-ChangeBit-ChangeBit-EraseBytes-ChangeByte-ShuffleBytes-ChangeBit-ChangeBinInt-CMP-InsertRepeatedBytes-CopyPart-Custom-ChangeByte-CrossOver-EraseBytes-ChangeBit-CopyPart-CrossOver-CMP-ShuffleBytes-EraseBytes-CrossOver-PersAutoDict-ChangeByte-CrossOver-CopyPart-CrossOver-CrossOver-ShuffleBytes-ChangeBinInt-CrossOver-ChangeBinInt-ShuffleBytes-PersAutoDict-ChangeByte-EraseBytes-ChangeBit-CrossOver-EraseBytes-CrossOver-ChangeBit-ChangeBinInt-EraseBytes-InsertByte-InsertRepeatedBytes-InsertByte-InsertByte-ChangeByte-ChangeBinInt-ChangeBit-CrossOver-ChangeByte-CrossOver-EraseBytes-ChangeByte-ShuffleBytes-ChangeBit-ChangeBit-ShuffleBytes-CopyPart-ChangeByte-PersAutoDict-ChangeBit-ChangeByte-InsertRepeatedBytes-CMP-CrossOver-ChangeByte-EraseBytes-ShuffleBytes-CrossOver-ShuffleBytes-ChangeBinInt-ChangeBinInt-CopyPart-PersAutoDict-ShuffleBytes-ChangeBit-CopyPart-ShuffleBytes-CopyPart-EraseBytes-ChangeByte-ChangeBit-ChangeBit-ChangeBinInt-ChangeByte-CopyPart-EraseBytes-ChangeBinInt-EraseBytes-EraseBytes-PersAutoDict-CMP-PersAutoDict-CrossOver-CrossOver-ChangeBit-CrossOver-PersAutoDict-CrossOver-CopyPart-ChangeByte-EraseBytes-ChangeByte-ShuffleBytes-ChangeByte-ChangeByte-CrossOver-ChangeBit-EraseBytes-ChangeByte-EraseBytes-ChangeBinInt-CrossOver-CrossOver-EraseBytes-ChangeBinInt-CrossOver-ChangeBit-ShuffleBytes-ChangeBit-ChangeByte-EraseBytes-ChangeBit-CrossOver-CrossOver-CrossOver-ChangeByte-ChangeBit-ShuffleBytes-ChangeBit-ChangeBit-EraseBytes-CrossOver-CrossOver-CopyPart-ShuffleBytes-ChangeByte-ChangeByte-CopyPart-CrossOver-CopyPart-CrossOver-CrossOver-EraseBytes-EraseBytes-ShuffleBytes-InsertRepeatedBytes-ChangeBit-CopyPart-Custom- DE: "\xfe\xff\xff\xfc"-"\x00\x00\x00\x00"-"F\x00"-"\xf3\xff\xff\xff"-"St9exception"-"_\x00\x00\x00"-"\xf6\xff\xff\xff"-"\xfe\xff\xff\xff"-"\x00\x00\x00\x00"-"p\x02\x00\x00\x00\x00\x00\x00"-"\xfe\xff\xff\xfb"-"\xff\xff"-"\xff\xff\xff\xff"-"\x01\x00\x00\x07"-"\xfe\xff\xff\xfe"-

These are prohibitively large and of limited value in the default case (when
someone is running the fuzzer, not debugging it), in my opinion.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86658
2020-09-01 11:14:36 -07:00
Dokyung Song c10e63677f Recommit "[libFuzzer] Fix arguments of InsertPartOf/CopyPartOf calls in CrossOver mutator."
The CrossOver mutator is meant to cross over two given buffers (referred to as
the first/second buffer henceforth). Previously InsertPartOf/CopyPartOf calls
used in the CrossOver mutator incorrectly inserted/copied part of the second
buffer into a "scratch buffer" (MutateInPlaceHere of the size
CurrentMaxMutationLen), rather than the first buffer. This is not intended
behavior, because the scratch buffer does not always (i) contain the content of
the first buffer, and (ii) have the same size as the first buffer;
CurrentMaxMutationLen is typically a lot larger than the size of the first
buffer. This patch fixes the issue by using the first buffer instead of the
scratch buffer in InsertPartOf/CopyPartOf calls.

A FuzzBench experiment was run to make sure that this change does not
inadvertently degrade the performance. The performance is largely the same; more
details can be found at:
https://storage.googleapis.com/fuzzer-test-suite-public/fixcrossover-report/index.html

This patch also adds two new tests, namely "cross_over_insert" and
"cross_over_copy", which specifically target InsertPartOf and CopyPartOf,
respectively.

- cross_over_insert.test checks if the fuzzer can use InsertPartOf to trigger
  the crash.

- cross_over_copy.test checks if the fuzzer can use CopyPartOf to trigger the
  crash.

These newly added tests were designed to pass with the current patch, but not
without the it (with 790878f291 these tests do not
pass). To achieve this, -max_len was intentionally given a high value. Without
this patch, InsertPartOf/CopyPartOf will generate larger inputs, possibly with
unpredictable data in it, thereby failing to trigger the crash.

The test pass condition for these new tests is narrowed down by (i) limiting
mutation depth to 1 (i.e., a single CrossOver mutation should be able to trigger
the crash) and (ii) checking whether the mutation sequence of "CrossOver-" leads
to the crash.

Also note that these newly added tests and an existing test (cross_over.test)
all use "-reduce_inputs=0" flags to prevent reducing inputs; it's easier to
force the fuzzer to keep original input string this way than tweaking
cov-instrumented basic blocks in the source code of the fuzzer executable.

Differential Revision: https://reviews.llvm.org/D85554
2020-08-27 21:48:45 +00:00
Dokyung Song 52f1df0923 Recommit "[libFuzzer] Fix value-profile-load test."
value-profile-load.test needs adjustment with a mutator change in
bb54bcf849, which reverted as of now, but will be
recommitted after landing this patch.

This patch makes value-profile-load.test more friendly to (and aware of) the
current value profiling strategy, which is based on the hamming as well as the
absolute distance. To this end, this patch adjusts the set of input values that
trigger an expected crash. More specifically, this patch now uses a single value
0x01effffe as a crashing input, because this value is close to values like
{0x1ffffff, 0xffffff, ...}, which are very likely to be added to the corpus per
the current hamming- and absolute-distance-based value profiling strategy. Note
that previously the crashing input values were {1234567 * {1, 2, ...}, s.t. <
INT_MAX}.

Every byte in the chosen value 0x01effeef is intentionally different; this was
to make it harder to find the value without the intermediate inputs added to the
corpus by the value profiling strategy.

Also note that LoadTest.cpp now uses a narrower condition (Size != 8) for
initial pruning of inputs, effectively preventing libFuzzer from generating
inputs longer than necessary and spending time on mutating such long inputs in
the corpus - a functionality not meant to be tested by this specific test.

Differential Revision: https://reviews.llvm.org/D86247
2020-08-27 19:12:30 +00:00
Matt Morehouse 2392ff093a [libFuzzer] Error and exit if user supplied fuzzer writeable directories don't exist
Currently, libFuzzer will exit with an error message if a non-existent
corpus directory is provided. However, if a user provides a non-existent
directory for the `artifact_prefix`, `exact_artifact_path`, or
`features_dir`, libFuzzer will continue execution but silently fail to
write artifacts/features.

To improve the user experience, this PR adds validation for the existence of
all user supplied directories before executing the main fuzzing loop. If they
don't exist, libFuzzer will exit with an error message.

Patch By: dgg5503

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D84808
2020-08-26 09:27:07 -07:00
Hans Wennborg 8421503300 Bump -len_control value in fuzzer-custommutator.test (PR47286)
to make the test more stable, as suggested by mmoroz.
2020-08-26 16:45:51 +02:00
Ilya Leoshkevich 151f603199 [libFuzzer] Un-XFAIL msan.test on SystemZ
After https://reviews.llvm.org/D86382 it works.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86184
2020-08-25 15:01:55 +02:00
Dokyung Song 9659b81b2a [libFuzzer] Make msan.test:SimpleCmpTest succeed with less trials.
Currently SimpleCmpTest passes after 9,831,994 trials on x86_64/Linux
when the number of given trials is 10,000,000, just a little bigger than
that. This patch modifies SimpleCmpTest.cpp so that the test passes with less
trials, reducing its chances of future failures as libFuzzer evolves. More
specifically, this patch changes a 32-bit equality check to a 8-bit equality
check, making this test pass at 4,635,303 trials.

Differential Revision: https://reviews.llvm.org/D86382
2020-08-24 14:45:39 +00:00
Azharuddin Mohammed 8831e34771 Revert "[libFuzzer] Fix arguments of InsertPartOf/CopyPartOf calls in CrossOver mutator."
This reverts commit bb54bcf849.

It is causing the value-profile-load.test test to fail on macOS.
2020-08-21 09:58:50 -07:00
Vitaly Buka 66c882e529 Revert "[libFuzzer] Fix value-profile-load test."
D86247 fails on Windows.

This reverts commit 428bebaf10.
2020-08-20 17:49:12 -07:00
Vitaly Buka ea9bf460a8 [NFC][libFuzzer] Try to fix test on Windows
Broken after D86247
2020-08-20 17:33:51 -07:00
Dokyung Song 428bebaf10 [libFuzzer] Fix value-profile-load test.
The behavior of the CrossOver mutator has changed with
bb54bcf849. This seems to affect the
value-profile-load test on Darwin. This patch provides a wider margin for
determining success of the value-profile-load test, by testing the targeted
functionality (i.e., GEP index value profile) more directly and faster. To this
end, LoadTest.cpp now uses a narrower condition (Size != 8) for initial pruning
of inputs, effectively preventing libFuzzer from generating inputs longer than
necessary and spending time on mutating such long inputs in the corpus - a
functionality not meant to be tested by this specific test.

Previously, on x86/Linux, it required 6,597,751 execs with -use_value_profile=1
and 19,605,575 execs with -use_value_profile=0 to hit the crash. With this
patch, the test passes with 174,493 execs, providing a wider margin from the
given trials of 10,000,000. Note that, without the value profile (i.e.,
-use_value_profile=0), the test wouldn't pass as it still requires 19,605,575
execs to hit the crash.

Differential Revision: https://reviews.llvm.org/D86247
2020-08-19 22:14:43 +00:00
Dokyung Song bb54bcf849 [libFuzzer] Fix arguments of InsertPartOf/CopyPartOf calls in CrossOver mutator.
The CrossOver mutator is meant to cross over two given buffers (referred to as
the first/second buffer henceforth). Previously InsertPartOf/CopyPartOf calls
used in the CrossOver mutator incorrectly inserted/copied part of the second
buffer into a "scratch buffer" (MutateInPlaceHere of the size
CurrentMaxMutationLen), rather than the first buffer. This is not intended
behavior, because the scratch buffer does not always (i) contain the content of
the first buffer, and (ii) have the same size as the first buffer;
CurrentMaxMutationLen is typically a lot larger than the size of the first
buffer. This patch fixes the issue by using the first buffer instead of the
scratch buffer in InsertPartOf/CopyPartOf calls.

A FuzzBench experiment was run to make sure that this change does not
inadvertently degrade the performance. The performance is largely the same; more
details can be found at:
https://storage.googleapis.com/fuzzer-test-suite-public/fixcrossover-report/index.html

This patch also adds two new tests, namely "cross_over_insert" and
"cross_over_copy", which specifically target InsertPartOf and CopyPartOf,
respectively.

- cross_over_insert.test checks if the fuzzer can use InsertPartOf to trigger
  the crash.

- cross_over_copy.test checks if the fuzzer can use CopyPartOf to trigger the
  crash.

These newly added tests were designed to pass with the current patch, but not
without the it (with 790878f291 these tests do not
pass). To achieve this, -max_len was intentionally given a high value. Without
this patch, InsertPartOf/CopyPartOf will generate larger inputs, possibly with
unpredictable data in it, thereby failing to trigger the crash.

The test pass condition for these new tests is narrowed down by (i) limiting
mutation depth to 1 (i.e., a single CrossOver mutation should be able to trigger
the crash) and (ii) checking whether the mutation sequence of "CrossOver-" leads
to the crash.

Also note that these newly added tests and an existing test (cross_over.test)
all use "-reduce_inputs=0" flags to prevent reducing inputs; it's easier to
force the fuzzer to keep original input string this way than tweaking
cov-instrumented basic blocks in the source code of the fuzzer executable.

Differential Revision: https://reviews.llvm.org/D85554
2020-08-18 16:09:18 +00:00
Ilya Leoshkevich f5a252ed68 [SanitizerCoverage] Use zeroext for cmp parameters on all targets
Commit 9385aaa848 ("[sancov] Fix PR33732") added zeroext to
__sanitizer_cov_trace(_const)?_cmp[1248] parameters for x86_64 only,
however, it is useful on other targets, in particular, on SystemZ: it
fixes swap-cmp.test.

Therefore, use it on all targets. This is safe: if target ABI does not
require zero extension for a particular parameter, zeroext is simply
ignored. A similar change has been implemeted as part of commit
3bc439bdff ("[MSan] Add instrumentation for SystemZ"), and there were
no problems with it.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D85689
2020-08-12 18:38:12 +02:00
Ilya Leoshkevich 9df7ee34e1 [libFuzzer] Fix minimizing timeouts
When one tries to minimize timeouts using -minimize_crash=1,
minimization immediately fails. The following sequence of events is
responsible for this:

[parent] SIGALRM occurs
[parent] read() returns -EINTR (or -ERESTARTSYS according to strace)
[parent] fgets() returns NULL
[parent] ExecuteCommand() closes child's stdout and returns
[child ] SIGALRM occurs
[child ] AlarmCallback() attempts to write "ALARM: ..." to stdout
[child ] Dies with SIGPIPE without calling DumpCurrentUnit()
[parent] Does not see -exact_artifact_path and exits

When minimizing, the timer in parent is not necessary, so fix by not
setting it in this case.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D85359
2020-08-11 22:16:12 +02:00
Ilya Leoshkevich ea9b82da41 [libFuzzer] Enable for SystemZ
* Add SystemZ to the list of supported architectures.

* XFAIL a few tests.

Coverage reporting is broken, and is not easy to fix (see comment in
coverage.test). Interaction with sanitizers needs to be investigated
more thoroughly, since they appear to reduce coverage in certain cases.
2020-08-04 21:53:27 +02:00
Matt Morehouse e2d0b44a7c [DFSan] Add efficient fast16labels instrumentation mode.
Adds the -fast-16-labels flag, which enables efficient instrumentation
for DFSan when the user needs <=16 labels.  The instrumentation
eliminates most branches and most calls to __dfsan_union or
__dfsan_union_load.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D84371
2020-07-29 18:58:47 +00:00
Dokyung Song b52b2e1c18 Recommit "[libFuzzer] Disable implicit builtin knowledge about memcmp-like functions when -fsanitize=fuzzer-no-link is given."
Summary: This patch disables implicit builtin knowledge about memcmp-like functions when compiling the program for fuzzing, i.e., when -fsanitize=fuzzer(-no-link) is given. This allows libFuzzer to always intercept memcmp-like functions as it effectively disables optimizing calls to such functions into different forms. This is done by adding a set of flags (-fno-builtin-memcmp and others) in the clang driver. Individual -fno-builtin-* flags previously used in several libFuzzer tests are now removed, as it is now done automatically in the clang driver.

The patch was once reverted in 8ef9e2bf35, as this patch was dependent on a reverted commit f78d9fceea. This reverted commit was recommitted in 831ae45e3d, so relanding this dependent patch too.

Reviewers: morehouse, hctim

Subscribers: cfe-commits, #sanitizers

Tags: #clang, #sanitizers

Differential Revision: https://reviews.llvm.org/D83987
2020-07-27 18:27:49 +00:00
Jon Roelofs 4dc3014c51 [compiler-rt][fuzzer] Disable bcmp.test on darwin
It broke one of the buildbots:

http://lab.llvm.org:8080/green/job/clang-stage1-RA/13026/console
2020-07-24 14:54:17 -06:00
Dokyung Song 8a4878cc11 [libFuzzer] Disable noasan-memcmp64.test and bcmp.test on Windows.
Summary: This patch disables (i) noasan-memcmp64.test on Windows as libFuzzer's interceptors are only supported on Linux for now, and (ii) bcmp.test as on Windows bcmp is not available in strings.h.

Reviewers: morehouse, hctim, kcc

Subscribers: #sanitizers

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D84536
2020-07-24 16:40:11 +00:00
Fangrui Song f7ffb122d0 [libFuzzer] Instrument bcmp
If we define memcmp in an archive, bcmp should be defined as well (many libc
define bcmp/memcmp in one object file).  Otherwise if the application calls bcmp
or strcmp which gets optimized to bcmp (SimplifyLibCalls), the undefined
reference may pull in an optimized bcmp/strcmp implementation (libc replacement)
later on the linker command line.  If both libFuzzer's memcmp and the optimized
memcmp are strong => there will be a multiple definition error.
2020-07-24 00:24:46 -07:00
Dokyung Song 769dab207e [libFuzzer] Disable interceptor tests on non-Linux platforms.
Summary: libFuzzer's interceptor support added in 831ae45e3d currently only works on Linux. This patch disables the test cases added as part of that commit on non-Linux platforms.

Reviewers: morehouse, hctim

Subscribers: #sanitizers

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D84434
2020-07-23 17:13:44 +00:00
Dokyung Song 831ae45e3d Recommit "[libFuzzer] Link libFuzzer's own interceptors when other compiler runtimes are not linked."
Summary: libFuzzer intercepts certain library functions such as memcmp/strcmp by defining weak hooks. Weak hooks, however, are called only when other runtimes such as ASan is linked. This patch defines libFuzzer's own interceptors, which is linked into the libFuzzer executable when other runtimes are not linked, i.e., when -fsanitize=fuzzer is given, but not others.

The patch once landed but was reverted in 8ef9e2bf35 due to an assertion failure caused by calling an intercepted function, strncmp, while initializing the interceptors in fuzzerInit(). This issue is now fixed by calling libFuzzer's own implementation of library functions (i.e., internal_*) when the fuzzer has not been initialized yet, instead of recursively calling fuzzerInit() again.

Reviewers: kcc, morehouse, hctim

Subscribers: #sanitizers, krytarowski, mgorny, cfe-commits

Tags: #clang, #sanitizers

Differential Revision: https://reviews.llvm.org/D83494
2020-07-23 15:59:07 +00:00
Richard Smith 8ef9e2bf35 Revert "[libFuzzer] Link libFuzzer's own interceptors when other compiler runtimes are not linked."
This causes binaries linked with this runtime to crash on startup if
dlsym uses any of the intercepted functions. (For example, that happens
when using tcmalloc as the allocator: dlsym attempts to allocate memory
with malloc, and tcmalloc uses strncmp within its implementation.)

Also revert dependent commit "[libFuzzer] Disable implicit builtin knowledge about memcmp-like functions when -fsanitize=fuzzer-no-link is given."

This reverts commit f78d9fceea and 12d1124c49.
2020-07-16 18:06:37 -07:00
Dokyung Song 12d1124c49 [libFuzzer] Disable implicit builtin knowledge about memcmp-like functions when -fsanitize=fuzzer-no-link is given.
Summary: This patch disables implicit builtin knowledge about memcmp-like functions when compiling the program for fuzzing, i.e., when -fsanitize=fuzzer(-no-link) is given. This allows libFuzzer to always intercept memcmp-like functions as it effectively disables optimizing calls to such functions into different forms. This is done by adding a set of flags (-fno-builtin-memcmp and others) in the clang driver. Individual -fno-builtin-* flags previously used in several libFuzzer tests are now removed, as it is now done automatically in the clang driver.

Reviewers: morehouse, hctim

Subscribers: cfe-commits, #sanitizers

Tags: #clang, #sanitizers

Differential Revision: https://reviews.llvm.org/D83987
2020-07-16 22:53:54 +00:00
Dokyung Song f78d9fceea [libFuzzer] Link libFuzzer's own interceptors when other compiler runtimes are not linked.
Summary: libFuzzer intercepts certain library functions such as memcmp/strcmp by defining weak hooks. Weak hooks, however, are called only when other runtimes such as ASan is linked. This patch defines libFuzzer's own interceptors, which is linked into the libFuzzer executable when other runtimes are not linked, i.e., when -fsanitize=fuzzer is given, but not others.

Reviewers: kcc, morehouse, hctim

Reviewed By: morehouse, hctim

Subscribers: krytarowski, mgorny, cfe-commits, #sanitizers

Tags: #clang, #sanitizers

Differential Revision: https://reviews.llvm.org/D83494
2020-07-16 20:26:35 +00:00
Mehdi Amini d31c9e5a46 Change filecheck default to dump input on failure
Having the input dumped on failure seems like a better
default: I debugged FileCheck tests for a while without knowing
about this option, which really helps to understand failures.

Remove `-dump-input-on-failure` and the environment variable
FILECHECK_DUMP_INPUT_ON_FAILURE which are now obsolete.

Differential Revision: https://reviews.llvm.org/D81422
2020-06-09 18:57:46 +00:00
Max Moroz 076475713c [libFuzzer] Fix denominator in the "inputs have DFT" log line.
Summary:
The number of "inputs have the Data Flow Trace" cannot be greater than
the number of inputs touching the focus function. The existing message is rather
confusing as the same log would mention a greater total number of traces a few
lines above.

Reviewers: kcc, metzman

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D74779
2020-02-19 11:05:14 -08:00
Dan Liew f5951bdc3a [compiler-rt] Provide a lit config variable that defines the minimum deployment OS version flag appropriate for the configured OS.
This patch defines `config.apple_platform_min_deployment_target_flag`
in the ASan, LibFuzzer, TSan, and UBSan lit test configs.

rdar://problem/59463146
2020-02-14 13:53:54 -08:00
Jonas Devlieghere 4fe839ef3a [CMake] Rename EXCLUDE_FROM_ALL and make it an argument to add_lit_testsuite
EXCLUDE_FROM_ALL means something else for add_lit_testsuite as it does
for something like add_executable. Distinguish between the two by
renaming the variable and making it an argument to add_lit_testsuite.

Differential revision: https://reviews.llvm.org/D74168
2020-02-06 15:33:18 -08:00
Max Moroz ad7b908b4e [libFuzzer] Make dataflow and focus functions more user friendly.
Summary:
- Fail loudly if SetFocusFunction failed when it should not. For more info see
  - https://github.com/google/oss-fuzz/issues/3311
  - https://github.com/google/sanitizers/issues/1190
- Fail loudly if CollectDataFlow is called without seed corpus.

Reviewers: kcc, metzman

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D73813
2020-02-03 08:36:03 -08:00
Dan Liew 9d9b470e69 [CMake] Refactor iOS simulator/device test configuration generation code for LibFuzzer.
Summary:
In order to do this `FUZZER_SUPPORTED_OS` had to be pulled out of
`lib/fuzzer/CMakeLists.txt` and into the main config so we can use it
from the `test/fuzzer/CMakeList.txt`. `FUZZER_SUPPORTED_OS` currently
has the same value of `SANITIZER_COMMON_SUPPORTED_OS` which preserves
the existing behaviour but this allows us in the future to adjust the
supported platforms independent of `SANITIZER_COMMON_SUPPORTED_OS`. This
mirrors the other sanitizers.

For non-Apple platforms `FUZZER_SUPPORTED_OS` is not defined and
surprisingly this was the behaviour before this patch because
`SANITIZER_COMMON_SUPPORTED_OS` was actually empty. This appears to
not matter right now because the functions that take an `OS` as an
argument seem to ignore it on non-Apple platforms.

While this change tries to be NFC it is technically not because we
now generate an iossim config whereas previously we didn't. This seems
like the right thing to do because the build system was configured to
compile LibFuzzer for iossim but previously we weren't generating a lit
test config for it. The device/simulator testing configs don't run by
default anyway so this shouldn't break testing.

This change relies on the get_capitalized_apple_platform() function
added in a previous commit.

rdar://problem/58798733

Reviewers: kubamracek, yln

Subscribers: mgorny, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D73243
2020-01-23 12:44:00 -08:00
Max Moroz 15f1d5d144 [libFuzzer] Add INFO output when LLVMFuzzerCustomMutator is found.
Summary:
there is an ongoing work on interchangeable custom mutators
(https://github.com/google/clusterfuzz/pull/1333/files#r367706283)
and having some sort of signalling from libFuzzer that it has loaded
a custom mutator would be helpful.

The initial idea was to make the mutator to print something, but given
the anticipated variety of different mutators, it does not seem possible
to make all of them print the same message to signal their execution.

Reviewers: kcc, metzman

Reviewed By: metzman

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D73136
2020-01-22 12:56:16 -08:00
Kamil Rytarowski d15241ed2c [compiler-rt] [fuzzer] Enable LSan in libFuzzer tests on NetBSD 2019-12-19 01:16:14 +01:00
Michał Górny d372576d8a [compiler-rt] [test] Disable ASLR for fuzzer tests on NetBSD 2019-12-18 16:51:31 +01:00
Alex Lorenz ad871e4295 [compiler-rt] Disable fuzzer large.test when LLVM_ENABLE_EXPENSIVE_CHECKS=ON
This test is timing out on Green Dragon http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-expensive/
and looks like it's not executed on other bots with expensive checks
enabled
http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-ubuntu
http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win

The test times out at the C++ source file takes too long to build (2+ hours on my machine), as
clang spends a lot of time in IR/MIR verifiers.

Differential Revision: https://reviews.llvm.org/D70024
2019-12-03 14:37:37 -08:00
Evgenii Stepanov 3f345732b4 Add missing lld checks in sanitizer tests.
Do not add an lld dependency when this target does not exist. In this
case the system installation of lld is used (or whatever is detected
with -fuse-ld=lld by default).
2019-10-28 10:32:46 -07:00