Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 165 insertions, 0 deletions

diff --git a/src/rocksdb/fuzz/README.md b/src/rocksdb/fuzz/README.md
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+# Fuzzing RocksDB
+
+## Overview
+
+This directory contains [fuzz tests](https://en.wikipedia.org/wiki/Fuzzing) for RocksDB.
+RocksDB testing infrastructure currently includes unit tests and [stress tests](https://github.com/facebook/rocksdb/wiki/Stress-test),
+we hope fuzz testing can catch more bugs.
+
+## Prerequisite
+
+We use [LLVM libFuzzer](http://llvm.org/docs/LibFuzzer.html) as the fuzzying engine,
+so make sure you have [clang](https://clang.llvm.org/get_started.html) as your compiler.
+
+Some tests rely on [structure aware fuzzing](https://github.com/google/fuzzing/blob/master/docs/structure-aware-fuzzing.md).
+We use [protobuf](https://developers.google.com/protocol-buffers) to define structured input to the fuzzer,
+and use [libprotobuf-mutator](https://github.com/google/libprotobuf-mutator) as the custom libFuzzer mutator.
+So make sure you have protobuf and libprotobuf-mutator installed, and make sure `pkg-config` can find them.
+On some systems, there are both protobuf2 and protobuf3 in the package management system,
+make sure protobuf3 is installed.
+
+If you do not want to install protobuf library yourself, you can rely on libprotobuf-mutator to download protobuf
+for you. For details about installation, please refer to [libprotobuf-mutator README](https://github.com/google/libprotobuf-mutator#readme)
+
+## Example
+
+This example shows you how to do structure aware fuzzing to `rocksdb::SstFileWriter`.
+
+After walking through the steps to create the fuzzer, we'll introduce a bug into `rocksdb::SstFileWriter::Put`,
+then show that the fuzzer can catch the bug.
+
+### Design the test
+
+We want the fuzzing engine to automatically generate a list of database operations,
+then we apply these operations to `SstFileWriter` in sequence,
+finally, after the SST file is generated, we use `SstFileReader` to check the file's checksum.
+
+### Define input
+
+We define the database operations in protobuf, each operation has a type of operation and a key value pair,
+see [proto/db_operation.proto](proto/db_operation.proto) for details.
+
+### Define tests with the input
+
+In [sst_file_writer_fuzzer.cc](sst_file_writer_fuzzer.cc),
+we define the tests to be run on the generated input:
+
+```
+DEFINE_PROTO_FUZZER(DBOperations& input) {
+  // apply the operations to SstFileWriter and use SstFileReader to verify checksum.
+  // ...
+}
+```
+
+`SstFileWriter` requires the keys of the operations to be unique and be in ascending order,
+but the fuzzing engine generates the input randomly, so we need to process the generated input before
+passing it to `DEFINE_PROTO_FUZZER`, this is accomplished by registering a post processor:
+
+```
+protobuf_mutator::libfuzzer::PostProcessorRegistration<DBOperations>
+```
+
+### Compile and link the fuzzer
+
+In the rocksdb root directory, compile rocksdb library by `make static_lib`.
+
+Go to the `fuzz` directory,
+run `make sst_file_writer_fuzzer` to generate the fuzzer,
+it will compile rocksdb static library, generate protobuf, then compile and link `sst_file_writer_fuzzer`.
+
+### Introduce a bug
+
+Manually introduce a bug to `SstFileWriter::Put`:
+
+```
+diff --git a/table/sst_file_writer.cc b/table/sst_file_writer.cc
+index ab1ee7c4e..c7da9ffa0 100644
+--- a/table/sst_file_writer.cc
++++ b/table/sst_file_writer.cc
+@@ -277,6 +277,11 @@ Status SstFileWriter::Add(const Slice& user_key, const Slice& value) {
+ }
+
+ Status SstFileWriter::Put(const Slice& user_key, const Slice& value) {
++  if (user_key.starts_with("!")) {
++    if (value.ends_with("!")) {
++      return Status::Corruption("bomb");
++    }
++  }
+   return rep_->Add(user_key, value, ValueType::kTypeValue);
+ }
+```
+
+The bug is that for `Put`, if `user_key` starts with `!` and `value` ends with `!`, then corrupt.
+
+### Run fuzz testing to catch the bug
+
+Run the fuzzer by `time ./sst_file_writer_fuzzer`.
+
+Here is the output on my machine:
+
+```
+Corruption: bomb
+==59680== ERROR: libFuzzer: deadly signal
+    #0 0x109487315 in __sanitizer_print_stack_trace+0x35 (libclang_rt.asan_osx_dynamic.dylib:x86_64+0x4d315)
+    #1 0x108d63f18 in fuzzer::PrintStackTrace() FuzzerUtil.cpp:205
+    #2 0x108d47613 in fuzzer::Fuzzer::CrashCallback() FuzzerLoop.cpp:232
+    #3 0x7fff6af535fc in _sigtramp+0x1c (libsystem_platform.dylib:x86_64+0x35fc)
+    #4 0x7ffee720f3ef  (<unknown module>)
+    #5 0x7fff6ae29807 in abort+0x77 (libsystem_c.dylib:x86_64+0x7f807)
+    #6 0x108cf1c4c in TestOneProtoInput(DBOperations&)+0x113c (sst_file_writer_fuzzer:x86_64+0x100302c4c)
+    #7 0x108cf09be in LLVMFuzzerTestOneInput+0x16e (sst_file_writer_fuzzer:x86_64+0x1003019be)
+    #8 0x108d48ce0 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) FuzzerLoop.cpp:556
+    #9 0x108d48425 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*) FuzzerLoop.cpp:470
+    #10 0x108d4a626 in fuzzer::Fuzzer::MutateAndTestOne() FuzzerLoop.cpp:698
+    #11 0x108d4b325 in fuzzer::Fuzzer::Loop(std::__1::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) FuzzerLoop.cpp:830
+    #12 0x108d37fcd in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) FuzzerDriver.cpp:829
+    #13 0x108d652b2 in main FuzzerMain.cpp:19
+    #14 0x7fff6ad5acc8 in start+0x0 (libdyld.dylib:x86_64+0x1acc8)
+
+NOTE: libFuzzer has rudimentary signal handlers.
+      Combine libFuzzer with AddressSanitizer or similar for better crash reports.
+SUMMARY: libFuzzer: deadly signal
+MS: 7 Custom-CustomCrossOver-InsertByte-Custom-ChangeBit-Custom-CustomCrossOver-; base unit: 90863b4d83c3f994bba0a417d0c2ee3b68f9e795
+0x6f,0x70,0x65,0x72,0x61,0x74,0x69,0x6f,0x6e,0x73,0x20,0x7b,0xa,0x20,0x20,0x6b,0x65,0x79,0x3a,0x20,0x22,0x21,0x22,0xa,0x20,0x20,0x76,0x61,0x6c,0x75,0x65,0x3a,0x20,0x22,0x21,0x22,0xa,0x20,0x20,0x74,0x79,0x70,0x65,0x3a,0x20,0x50,0x55,0x54,0xa,0x7d,0xa,0x6f,0x70,0x65,0x72,0x61,0x74,0x69,0x6f,0x6e,0x73,0x20,0x7b,0xa,0x20,0x20,0x6b,0x65,0x79,0x3a,0x20,0x22,0x2b,0x22,0xa,0x20,0x20,0x74,0x79,0x70,0x65,0x3a,0x20,0x50,0x55,0x54,0xa,0x7d,0xa,0x6f,0x70,0x65,0x72,0x61,0x74,0x69,0x6f,0x6e,0x73,0x20,0x7b,0xa,0x20,0x20,0x6b,0x65,0x79,0x3a,0x20,0x22,0x2e,0x22,0xa,0x20,0x20,0x74,0x79,0x70,0x65,0x3a,0x20,0x50,0x55,0x54,0xa,0x7d,0xa,0x6f,0x70,0x65,0x72,0x61,0x74,0x69,0x6f,0x6e,0x73,0x20,0x7b,0xa,0x20,0x20,0x6b,0x65,0x79,0x3a,0x20,0x22,0x5c,0x32,0x35,0x33,0x22,0xa,0x20,0x20,0x74,0x79,0x70,0x65,0x3a,0x20,0x50,0x55,0x54,0xa,0x7d,0xa,
+operations {\x0a  key: \"!\"\x0a  value: \"!\"\x0a  type: PUT\x0a}\x0aoperations {\x0a  key: \"+\"\x0a  type: PUT\x0a}\x0aoperations {\x0a  key: \".\"\x0a  type: PUT\x0a}\x0aoperations {\x0a  key: \"\\253\"\x0a  type: PUT\x0a}\x0a
+artifact_prefix='./'; Test unit written to ./crash-a1460be302d09b548e61787178d9edaa40aea467
+Base64: b3BlcmF0aW9ucyB7CiAga2V5OiAiISIKICB2YWx1ZTogIiEiCiAgdHlwZTogUFVUCn0Kb3BlcmF0aW9ucyB7CiAga2V5OiAiKyIKICB0eXBlOiBQVVQKfQpvcGVyYXRpb25zIHsKICBrZXk6ICIuIgogIHR5cGU6IFBVVAp9Cm9wZXJhdGlvbnMgewogIGtleTogIlwyNTMiCiAgdHlwZTogUFVUCn0K
+./sst_file_writer_fuzzer  5.97s user 4.40s system 64% cpu 16.195 total
+```
+
+Within 6 seconds, it catches the bug.
+
+The input that triggers the bug is persisted in `./crash-a1460be302d09b548e61787178d9edaa40aea467`:
+
+```
+$ cat ./crash-a1460be302d09b548e61787178d9edaa40aea467
+operations {
+  key: "!"
+  value: "!"
+  type: PUT
+}
+operations {
+  key: "+"
+  type: PUT
+}
+operations {
+  key: "."
+  type: PUT
+}
+operations {
+  key: "\253"
+  type: PUT
+}
+```
+
+### Reproduce the crash to debug
+
+The above crash can be reproduced by `./sst_file_writer_fuzzer ./crash-a1460be302d09b548e61787178d9edaa40aea467`,
+so you can debug the crash.
+
+## Future Work
+
+According to [OSS-Fuzz](https://github.com/google/oss-fuzz),
+`as of June 2020, OSS-Fuzz has found over 20,000 bugs in 300 open source projects.`
+
+RocksDB can join OSS-Fuzz together with other open source projects such as sqlite.