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| -rw-r--r-- | docs/INSTALL.md | 100 |
1 files changed, 37 insertions, 63 deletions
diff --git a/docs/INSTALL.md b/docs/INSTALL.md index 5260a65c..3089aab2 100644 --- a/docs/INSTALL.md +++ b/docs/INSTALL.md @@ -21,7 +21,7 @@ If you want to build AFL++ yourself, you have many options. The easiest choice is to build and install everything: NOTE: depending on your Debian/Ubuntu/Kali/... release, replace `-14` with -whatever llvm version is available. We recommend llvm 13, 14, 15 or 16. +whatever llvm version is available. We recommend llvm 13 or newer. ```shell sudo apt-get update @@ -67,7 +67,7 @@ These build targets exist: * unit: perform unit tests (based on cmocka) * help: shows these build options -[Unless you are on Mac OS X](https://developer.apple.com/library/archive/qa/qa1118/_index.html), +[Unless you are on macOS](https://developer.apple.com/library/archive/qa/qa1118/_index.html), you can also build statically linked versions of the AFL++ binaries by passing the `PERFORMANCE=1` argument to make: @@ -77,10 +77,10 @@ make PERFORMANCE=1 These build options exist: -* PERFORMANCE - compile with performance options that make the binary not transferable to other systems. Recommended! -* STATIC - compile AFL++ static -* CODE_COVERAGE - compile the target for code coverage (see docs/instrumentation/README.llvm.md) -* ASAN_BUILD - compiles AFL++ with memory sanitizer for debug purposes +* PERFORMANCE - compile with performance options that make the binary not transferable to other systems. Recommended (except on macOS)! +* STATIC - compile AFL++ static (does not work on macOS) +* CODE_COVERAGE - compile the target for code coverage (see [README.llvm.md](../instrumentation/README.llvm.md)) +* ASAN_BUILD - compiles AFL++ with address sanitizer for debug purposes * UBSAN_BUILD - compiles AFL++ tools with undefined behaviour sanitizer for debug purposes * DEBUG - no optimization, -ggdb3, all warnings and -Werror * LLVM_DEBUG - shows llvm deprecation warnings @@ -92,7 +92,7 @@ These build options exist: * NO_NYX - disable building nyx mode dependencies * NO_CORESIGHT - disable building coresight (arm64 only) * NO_UNICORN_ARM64 - disable building unicorn on arm64 -* AFL_NO_X86 - if compiling on non-intel/amd platforms +* AFL_NO_X86 - if compiling on non-Intel/AMD platforms * LLVM_CONFIG - if your distro doesn't use the standard name for llvm-config (e.g., Debian) e.g.: `make LLVM_CONFIG=llvm-config-14` @@ -101,8 +101,19 @@ e.g.: `make LLVM_CONFIG=llvm-config-14` macOS has some gotchas due to the idiosyncrasies of the platform. -To build AFL, install llvm (and perhaps gcc) from brew and follow the general -instructions for Linux. If possible, avoid Xcode at all cost. +macOS supports SYSV shared memory used by AFL++'s instrumentation, but the +default settings aren't sufficient. Before even building, increase +them by running the provided script: + +```shell +sudo afl-system-config +``` + +See +[https://www.spy-hill.com/help/apple/SharedMemory.html](https://www.spy-hill.com/help/apple/SharedMemory.html) +for documentation for the shared memory settings and how to make them permanent. + +Next, to build AFL++, install the following packages from brew: ```shell brew install wget git make cmake llvm gdb coreutils @@ -113,38 +124,37 @@ You can check with `brew info llvm` to know where, then create a variable for it ```shell export HOMEBREW_BASE="/opt/homebrew/opt" -# or +``` + +or + +```shell export HOMEBREW_BASE="/usr/local/opt" ``` -Be sure to setup `PATH` to point to the correct clang binaries and use the -freshly installed clang, clang++, llvm-config, gmake and coreutils, e.g.: +Set `PATH` to point to the brew clang, clang++, llvm-config, gmake and coreutils. +Also use the brew clang compiler; the Xcode clang compiler must not be used. ```shell export PATH="$HOMEBREW_BASE/coreutils/libexec/gnubin:/usr/local/bin:$HOMEBREW_BASE/llvm/bin:$PATH" export CC=clang export CXX=clang++ -gmake -cd frida_mode -gmake -cd .. -sudo gmake install ``` -`afl-gcc` will fail unless you have GCC installed, but that is using outdated -instrumentation anyway. `afl-clang` might fail too depending on your PATH setup. -But you don't want neither, you want `afl-clang-fast` anyway :) Note that -`afl-clang-lto`, `afl-gcc-fast` and `qemu_mode` are not working on macOS. +Then build following the general Linux instructions. -The crash reporting daemon that comes by default with macOS will cause -problems with fuzzing. You need to turn it off: +If everything worked, you should then have `afl-clang-fast` installed, which you can check with: -``` -launchctl unload -w /System/Library/LaunchAgents/com.apple.ReportCrash.plist -sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.ReportCrash.Root.plist +```shell +which afl-clang-fast ``` -The `fork()` semantics on OS X are a bit unusual compared to other unix systems +Note that `afl-clang-lto`, `afl-gcc-fast` and `qemu_mode` are not working on macOS. + +The crash reporting daemon that comes by default with macOS will cause +problems with fuzzing. You need to turn it off, which you can do with `afl-system-config`. + +The `fork()` semantics on macOS are a bit unusual compared to other unix systems and definitely don't look POSIX-compliant. This means two things: - Fuzzing will be probably slower than on Linux. In fact, some folks report @@ -157,39 +167,3 @@ and definitely don't look POSIX-compliant. This means two things: User emulation mode of QEMU does not appear to be supported on macOS, so black-box instrumentation mode (`-Q`) will not work. However, FRIDA mode (`-O`) works on both x86 and arm64 macOS boxes. - -macOS supports SYSV shared memory used by AFL's instrumentation, but the -default settings aren't usable with AFL++. The default settings on 10.14 seem to -be: - -```bash -$ ipcs -M -IPC status from <running system> as of XXX -shminfo: - shmmax: 4194304 (max shared memory segment size) - shmmin: 1 (min shared memory segment size) - shmmni: 32 (max number of shared memory identifiers) - shmseg: 8 (max shared memory segments per process) - shmall: 1024 (max amount of shared memory in pages) -``` - -To temporarily change your settings to something minimally usable with AFL++, -run these commands as root: - -```bash -sysctl kern.sysv.shmmax=8388608 -sysctl kern.sysv.shmall=4096 -``` - -If you're running more than one instance of AFL, you likely want to make -`shmall` bigger and increase `shmseg` as well: - -```bash -sysctl kern.sysv.shmmax=8388608 -sysctl kern.sysv.shmseg=48 -sysctl kern.sysv.shmall=98304 -``` - -See -[http://www.spy-hill.com/help/apple/SharedMemory.html](http://www.spy-hill.com/help/apple/SharedMemory.html) -for documentation for these settings and how to make them permanent. |