projects / thirdparty / openssl.git / blame
| Commit | Line | Data |
|---|---|---|
| c38bb727 BL |
1 | # I Can Haz Fuzz? |
| 2 | ||
| f59d0131 KR |
3 | LibFuzzer |
| 4 | ========= | |
| 5 | ||
| fe2582a2 | 6 | Or, how to fuzz OpenSSL with [libfuzzer](http://llvm.org/docs/LibFuzzer.html). |
| c38bb727 BL |
7 | |
| 8 | Starting from a vanilla+OpenSSH server Ubuntu install. | |
| 9 | ||
| 10 | Use Chrome's handy recent build of clang. Older versions may also work. | |
| 11 | ||
| 12 | $ sudo apt-get install git | |
| 13 | $ mkdir git-work | |
| 14 | $ git clone https://chromium.googlesource.com/chromium/src/tools/clang | |
| 15 | $ clang/scripts/update.py | |
| 16 | ||
| 17 | You may want to git pull and re-run the update from time to time. | |
| 18 | ||
| 19 | Update your path: | |
| 20 | ||
| 21 | $ PATH=~/third_party/llvm-build/Release+Asserts/bin/:$PATH | |
| 22 | ||
| 23 | Get and build libFuzzer (there is a git mirror at | |
| 24 | https://github.com/llvm-mirror/llvm/tree/master/lib/Fuzzer if you prefer): | |
| 25 | ||
| 26 | $ cd | |
| 27 | $ sudo apt-get install subversion | |
| 28 | $ mkdir svn-work | |
| 29 | $ cd svn-work | |
| 30 | $ svn co http://llvm.org/svn/llvm-project/llvm/trunk/lib/Fuzzer | |
| 31 | $ cd Fuzzer | |
| 32 | $ clang++ -c -g -O2 -std=c++11 *.cpp | |
| 33 | $ ar r libFuzzer.a *.o | |
| 34 | $ ranlib libFuzzer.a | |
| 35 | ||
| 36 | Configure for fuzzing: | |
| 37 | ||
| f59d0131 KR |
38 | $ CC=clang ./config enable-fuzz-libfuzzer \ |
| 39 | --with-fuzzer-include=../../svn-work/Fuzzer \ | |
| 40 | --with-fuzzer-lib=../../svn-work/Fuzzer/libFuzzer \ | |
| 3a9b9b2d | 41 | -DPEDANTIC enable-asan enable-ubsan no-shared \ |
| 0282aeb6 | 42 | -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION \ |
| e104d01d KR |
43 | -fsanitize-coverage=edge,indirect-calls,8bit-counters \ |
| 44 | enable-ec_nistp_64_gcc_128 -fno-sanitize=alignment enable-tls1_3 \ | |
| 45 | enable-weak-ssl-ciphers enable-rc5 enable-md2 \ | |
| 46 | enable-ssl3 enable-ssl3-method enable-nextprotoneg | |
| c38bb727 BL |
47 | $ sudo apt-get install make |
| 48 | $ LDCMD=clang++ make -j | |
| 31b15b9b | 49 | $ fuzz/helper.py $FUZZER |
| c38bb727 | 50 | |
| 31b15b9b | 51 | Where $FUZZER is one of the executables in `fuzz/`. |
| c38bb727 BL |
52 | |
| 53 | If you get a crash, you should find a corresponding input file in | |
| 31b15b9b | 54 | `fuzz/corpora/$FUZZER-crash/`. You can reproduce the crash with |
| c38bb727 | 55 | |
| 31b15b9b | 56 | $ fuzz/$FUZZER <crashfile> |
| f59d0131 KR |
57 | |
| 58 | AFL | |
| 59 | === | |
| 60 | ||
| 61 | Configure for fuzzing: | |
| 62 | ||
| 63 | $ sudo apt-get install afl-clang | |
| e104d01d KR |
64 | $ CC=afl-clang-fast ./config enable-fuzz-afl no-shared -DPEDANTIC \ |
| 65 | enable-tls1_3 enable-weak-ssl-ciphers enable-rc5 enable-md2 \ | |
| 66 | enable-ssl3 enable-ssl3-method enable-nextprotoneg \ | |
| 67 | enable-ec_nistp_64_gcc_128 | |
| f59d0131 KR |
68 | $ make |
| 69 | ||
| e104d01d KR |
70 | The following options can also be enabled: enable-asan, enable-ubsan, enable-msan |
| 71 | ||
| f59d0131 KR |
72 | Run one of the fuzzers: |
| 73 | ||
| 31b15b9b | 74 | $ afl-fuzz -i fuzz/corpora/$FUZZER -o fuzz/corpora/$FUZZER/out fuzz/$FUZZER |
| f59d0131 | 75 | |
| 31b15b9b | 76 | Where $FUZZER is one of the executables in `fuzz/`. |