This document describes the honggfuzz project.
Honggfuzz is a general-purpose fuzzing tool. Given an input corpus files, honggfuzz modifies input to a test program and utilize the ptrace() API/POSIX signal interface to detect and log crashes. It can also use software or hardware-based code coverage techniques to produce more and more interesting inputs
A POSIX compliant operating system (See the compatibility list for more) for static and ASAN code-coverage (SANCOV) modes
GNU/Linux with modern kernel (e.g. v4.0) for hardware-based code coverage guided fuzzing
A corpus of input files. Honggfuzz expects a set of files to use and modify as input to the application you're fuzzing. How you get or create these files is up to you, but you might be interested in the following sources:
It should work under the following operating systems:
| OS | Status | Notes |
|---|---|---|
| GNU/Linux | Works | ptrace() API (x86, x86-64 disassembly support) |
| FreeBSD | Works | POSIX signal interface |
| Mac OS X | Works | POSIX signal interface/Mac OS X crash reports (x86-64/x86 disassembly support) |
| MS Windows | Works | POSIX signal interface via CygWin |
| Other Unices | Depends* | POSIX signal interface |
*) It might work provided that a given operating system implements wait4() call
This document explains how to use an external command to create fuzzing input.
Usage: ./honggfuzz [options] -- path_to_command [args] Options: --help|-h Help plz.. --input|-f VALUE Path to the file corpus (file or a directory) --nullify_stdio|-q Null-ify children's stdin, stdout, stderr; make them quiet --timeout|-t VALUE Timeout in seconds (default: '10') --threads|-n VALUE Number of concurrent fuzzing threads (default: '2') --stdin_input|-s Provide fuzzing input on STDIN, instead of ___FILE___ --mutation_rate|-r VALUE Maximal mutation rate in relation to the file size, (default: '0.001') --logfile|-l VALUE Log file --verbose|-v Disable ANSI console; use simple log output --verifier|-V Enable crashes verifier --debug_level|-d VALUE Debug level (0 - FATAL ... 4 - DEBUG), (default: '3' [INFO]) --extension|-e VALUE Input file extension (e.g. 'swf'), (default: 'fuzz') --workspace|-W VALUE Workspace directory to save crashes & runtime files (default: '.') --covdir VALUE Output directory for coverage data (default: The same as workspace directory) --wordlist|-w VALUE Wordlist file (tokens delimited by NUL-bytes) --stackhash_bl|-B VALUE Stackhashes blacklist file (one entry per line) --mutate_cmd|-c VALUE External command providing fuzz files, instead of mutating the input corpus --iterations|-N VALUE Number of fuzzing iterations (default: '0' [no limit]) --rlimit_as VALUE Per process memory limit in MiB (default: '0' [no limit]) --report|-R VALUE Write report to this file (default: 'HONGGFUZZ.REPORT.TXT') --max_file_size|-F VALUE Maximal size of files processed by the fuzzer in bytes (default: '1048576') --clear_env Clear all environment variables before executing the binary --env|-E VALUE Pass this environment variable, can be used multiple times --save_all|-u Save all test-cases (not only the unique ones) by appending the current time-stamp to the filenames --sancov|-C Enable sanitizer coverage feedback --instr|-z Enable compile-time instrumentation (see libraries/instrument_func.c) --msan_report_umrs Report MSAN's UMRS (uninitialized memory access) --persistent|-P Enable persistent fuzzing (link with libraries/persistent.mode.main.o) --linux_pid|-p VALUE Attach to a pid (and its thread group) --linux_file_pid VALUE Attach to pid (and its thread group) read from file --linux_addr_low_limit VALUE Address limit (from si.si_addr) below which crashes are not reported, (default: '0') --linux_keep_aslr Don't disable ASLR randomization, might be useful with MSAN --linux_perf_ignore_above VALUE Ignore perf events which report IPs above this address --linux_perf_instr Use PERF_COUNT_HW_INSTRUCTIONS perf --linux_perf_branch Use PERF_COUNT_HW_BRANCH_INSTRUCTIONS perf --linux_perf_bts_block Use Intel BTS to count unique blocks --linux_perf_bts_edge Use Intel BTS to count unique edges --linux_perf_ipt_block Use Intel Processor Trace to count unique blocks --linux_perf_custom Custom counter (based on GS register for x86_64) Examples: Run the binary over a mutated file chosen from the directory honggfuzz -f input_dir -- /usr/bin/tiffinfo -D ___FILE___ As above, provide input over STDIN: honggfuzz -f input_dir -s -- /usr/bin/djpeg Use SANCOV to maximize code coverage: honggfuzz -f input_dir -C -- /usr/bin/tiffinfo -D ___FILE___ Use compile-time instrumentation (libhfuzz/instrument.c): honggfuzz -f input_dir -z -- /usr/bin/tiffinfo -D ___FILE___ Use persistent mode (libhfuzz/persistent.c): honggfuzz -f input_dir -P -- /usr/bin/tiffinfo_persistent Run the binary over a dynamic file, maximize total no. of instructions: honggfuzz --linux_perf_instr -- /usr/bin/tiffinfo -D ___FILE___ Run the binary over a dynamic file, maximize total no. of branches: honggfuzz --linux_perf_branch -- /usr/bin/tiffinfo -D ___FILE___ Run the binary over a dynamic file, maximize unique code blocks (coverage): honggfuzz --linux_perf_ip -- /usr/bin/tiffinfo -D ___FILE___ Run the binary over a dynamic file, maximize unique branches (edges): honggfuzz --linux_perf_ip_addr -- /usr/bin/tiffinfo -D ___FILE___ Run the binary over a dynamic file, maximize custom counters (experimental): honggfuzz --linux_perf_custom -- /usr/bin/tiffinfo -D ___FILE___
| Mode | Output file |
|---|---|
| Linux | SIGSEGV.PC.4ba1ae.STACK.13599d485.CODE.1.ADDR.0x10.INSTR.mov____0x10(%rbx),%rax.fuzz |
| POSIX signal interface | SIGSEGV.22758.2010-07-01.17.24.41.tif |
_t.si_addr (see man 2 signaction for more details) (most likely meaningless for SIGABRT)Q: Why the name honggfuzz?
A: The term honggfuzz was coined during a major and memorable event in the city of Zurich, where a Welsh security celebrity tried to reach Höngg in a cab while singing Another one bites the dust.
Q: Why do you prefer the ptrace() API to the POSIX signal interface?
A: The ptrace() API is more flexible when it comes to analyzing a process' crash. wait3/4() syscalls are only able to determine the type of signal which crashed an application and limited resource usage information (see man wait4).
Q: Why isn't there any support for the ptrace() API when compiling under FreeBSD or Mac OS X operating systems?
A: These operating systems lack some specific ptrace() operations, including PT_GETREGS (Mac OS X) and PT_GETSIGINFO, both of which honggfuzz depends on. If you have any ideas on how to get around this limitation, send us an email or patch.
This project is licensed under the Apache License, Version 2.0