diff options
Diffstat (limited to 'docs/INSTALL')
| -rw-r--r-- | docs/INSTALL | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/docs/INSTALL b/docs/INSTALL new file mode 100644 index 00000000..2e24724f --- /dev/null +++ b/docs/INSTALL @@ -0,0 +1,183 @@ +========================= +Installation instructions +========================= + + This document provides basic installation instructions and discusses known + issues for a variety of platforms. See README for the general instruction + manual. + +1) Linux on x86 +--------------- + +This platform is expected to work well. Compile the program with: + +$ make + +You can start using the fuzzer without installation, but it is also possible to +install it with: + +# make install + +There are no special dependencies to speak of; you will need GNU make and a +working compiler (gcc or clang). Some of the optional scripts bundled with the +program may depend on bash, gdb, and similar basic tools. + +If you are using clang, please review llvm_mode/README.llvm; the LLVM +integration mode can offer substantial performance gains compared to the +traditional approach. + +You may have to change several settings to get optimal results (most notably, +disable crash reporting utilities and switch to a different CPU governor), but +afl-fuzz will guide you through that if necessary. + +2) OpenBSD, FreeBSD, NetBSD on x86 +---------------------------------- + +Similarly to Linux, these platforms are expected to work well and are +regularly tested. Compile everything with GNU make: + +$ gmake + +Note that BSD make will *not* work; if you do not have gmake on your system, +please install it first. As on Linux, you can use the fuzzer itself without +installation, or install it with: + +# gmake install + +Keep in mind that if you are using csh as your shell, the syntax of some of the +shell commands given in the README and other docs will be different. + +The llvm_mode requires a dynamically linked, fully-operational installation of +clang. At least on FreeBSD, the clang binaries are static and do not include +some of the essential tools, so if you want to make it work, you may need to +follow the instructions in llvm_mode/README.llvm. + +Beyond that, everything should work as advertised. + +The QEMU mode is currently supported only on Linux. I think it's just a QEMU +problem, I couldn't get a vanilla copy of user-mode emulation support working +correctly on BSD at all. + +3) MacOS X on x86 +----------------- + +MacOS X should work, but there are some gotchas due to the idiosyncrasies of +the platform. On top of this, I have limited release testing capabilities +and depend mostly on user feedback. + +To build AFL, install Xcode and follow the general instructions for Linux. + +The Xcode 'gcc' tool is just a wrapper for clang, so be sure to use afl-clang +to compile any instrumented binaries; afl-gcc will fail unless you have GCC +installed from another source (in which case, please specify AFL_CC and +AFL_CXX to point to the "real" GCC binaries). + +Only 64-bit compilation will work on the platform; porting the 32-bit +instrumentation would require a fair amount of work due to the way OS X +handles relocations, and today, virtually all MacOS X boxes are 64-bit. + +The crash reporting daemon that comes by default with MacOS X will cause +problems with fuzzing. You need to turn it off by following the instructions +provided here: http://goo.gl/CCcd5u + +The fork() semantics on OS X 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 + considerable performance gains by running the jobs inside a Linux VM on + MacOS X. + + - Some non-portable, platform-specific code may be incompatible with the + AFL forkserver. If you run into any problems, set AFL_NO_FORKSRV=1 in the + environment before starting afl-fuzz. + +User emulation mode of QEMU does not appear to be supported on MacOS X, so +black-box instrumentation mode (-Q) will not work. + +The llvm_mode requires a fully-operational installation of clang. The one that +comes with Xcode is missing some of the essential headers and helper tools. +See llvm_mode/README.llvm for advice on how to build the compiler from scratch. + +4) Linux or *BSD on non-x86 systems +----------------------------------- + +Standard build will fail on non-x86 systems, but you should be able to +leverage two other options: + + - The LLVM mode (see llvm_mode/README.llvm), which does not rely on + x86-specific assembly shims. It's fast and robust, but requires a + complete installation of clang. + + - The QEMU mode (see qemu_mode/README.qemu), which can be also used for + fuzzing cross-platform binaries. It's slower and more fragile, but + can be used even when you don't have the source for the tested app. + +If you're not sure what you need, you need the LLVM mode. To get it, try: + +$ AFL_NO_X86=1 gmake && gmake -C llvm_mode + +...and compile your target program with afl-clang-fast or afl-clang-fast++ +instead of the traditional afl-gcc or afl-clang wrappers. + +5) Solaris on x86 +----------------- + +The fuzzer reportedly works on Solaris, but I have not tested this first-hand, +and the user base is fairly small, so I don't have a lot of feedback. + +To get the ball rolling, you will need to use GNU make and GCC or clang. I'm +being told that the stock version of GCC that comes with the platform does not +work properly due to its reliance on a hardcoded location for 'as' (completely +ignoring the -B parameter or $PATH). + +To fix this, you may want to build stock GCC from the source, like so: + +$ ./configure --prefix=$HOME/gcc --with-gnu-as --with-gnu-ld \ + --with-gmp-include=/usr/include/gmp --with-mpfr-include=/usr/include/mpfr +$ make +$ sudo make install + +Do *not* specify --with-as=/usr/gnu/bin/as - this will produce a GCC binary that +ignores the -B flag and you will be back to square one. + +Note that Solaris reportedly comes with crash reporting enabled, which causes +problems with crashes being misinterpreted as hangs, similarly to the gotchas +for Linux and MacOS X. AFL does not auto-detect crash reporting on this +particular platform, but you may need to run the following command: + +$ coreadm -d global -d global-setid -d process -d proc-setid \ + -d kzone -d log + +User emulation mode of QEMU is not available on Solaris, so black-box +instrumentation mode (-Q) will not work. + +6) Everything else +------------------ + +You're on your own. On POSIX-compliant systems, you may be able to compile and +run the fuzzer; and the LLVM mode may offer a way to instrument non-x86 code. + +The fuzzer will not run on Windows. It will also not work under Cygwin. It +could be ported to the latter platform fairly easily, but it's a pretty bad +idea, because Cygwin is extremely slow. It makes much more sense to use +VirtualBox or so to run a hardware-accelerated Linux VM; it will run around +20x faster or so. If you have a *really* compelling use case for Cygwin, let +me know. + +Although Android on x86 should theoretically work, the stock kernel may have +SHM support compiled out, and if so, you may have to address that issue first. +It's possible that all you need is this workaround: + + https://github.com/pelya/android-shmem + +Joshua J. Drake notes that the Android linker adds a shim that automatically +intercepts SIGSEGV and related signals. To fix this issue and be able to see +crashes, you need to put this at the beginning of the fuzzed program: + + signal(SIGILL, SIG_DFL); + signal(SIGABRT, SIG_DFL); + signal(SIGBUS, SIG_DFL); + signal(SIGFPE, SIG_DFL); + signal(SIGSEGV, SIG_DFL); + +You may need to #include <signal.h> first. |