source: zzuf/trunk/doc/zzuf.1 @ 1539

Last change on this file since 1539 was 1539, checked in by Sam Hocevar, 14 years ago
  • Totally reworked webpage.
File size: 7.5 KB
Line 
1.TH zzuf 1 "2006-12-22" "zzuf"
2.SH NAME
3zzuf \- multiple purpose fuzzer
4.SH SYNOPSIS
5\fBzzuf\fR [\fB\-cdiqS\fR] [\fB\-r\fR \fIratio\fR] [\fB\-s\fR \fIseed\fR | \fB\-s\fR \fIstart:stop\fR]
6.br
7              [\fB\-F\fR \fIchildren\fR] [\fB\-B\fR \fIbytes\fR] [\fB\-T\fR \fIseconds\fR]
8.br
9              [\fB\-I\fR \fIinclude\fR] [\fB\-E\fR \fIexclude\fR] \fICOMMAND\fR [\fIARGS\fR]...
10.br
11\fBzzuf \-h\fR | \fB\-\-help\fR
12.br
13\fBzzuf \-v\fR | \fB\-\-version\fR
14.SH DESCRIPTION
15.PP
16\fBZzuf\fR is a transparent application input fuzzer. It works by intercepting
17file operations and changing random bits in the program's input. \fBZzuf\fR's
18behaviour is deterministic, making it easy to reproduce bugs.
19.SH USAGE
20.PP
21\fBZzuf\fR will run an application specified on its command line, one or
22several times, with optional arguments, and will report the application's
23behaviour on the standard output.
24.PP
25If you want to specify arguments for your application, put a \fB\-\-\fR
26marker before them on the command line, or \fBzzuf\fR will try to interpret
27them as arguments for itself.
28.SH OPTIONS
29.TP
30\fB\-B\fR, \fB\-\-max\-bytes\fR=\fIn\fR
31Automatically terminate child processes that output more than \fIn\fR bytes
32on the standard output and standard error channels. This is useful to detect
33infinite loops. See also the \fB\-T\fR flag.
34.TP
35\fB\-c\fR, \fB\-\-cmdline\fR
36Only fuzz files whose name is specified in the target application's command
37line. This is mostly a shortcut to avoid specifiying twice the argument:
38\fBzzuf \-c cat file.txt\fR has the same effect as \fBzzuf \-I
39\(dq^file\\.txt$\(dq cat file.txt\fR. See the \fB\-I\fR flag for more
40information.
41.TP
42\fB\-d\fR, \fB\-\-debug\fR
43Activate the display of debug messages.
44.TP
45\fB\-E\fR, \fB\-\-exclude\fR=\fIregex\fR
46Do not fuzz files whose name matches the \fIregex\fR regular expression. This
47option supersedes anything that is specified by the \fB\-I\fR flag. Use this
48for instance if you are unsure of what files your application is going to read
49and do not want it to fuzz files in the \fB/etc\fR directory.
50
51Multiple \fB\-E\fR flags can be specified, in which case files matching any one
52of the regular expressions will be ignored.
53.TP
54\fB\-F\fR, \fB\-\-fork\fR=\fIchildren\fR
55Specify the number of simultaneous children that can be run. This option is
56only useful if the \fB\-s\fR flag is used with an interval argument.
57.TP
58\fB\-h\fR, \fB\-\-help\fR
59Display a short help message and exit.
60.TP
61\fB\-i\fR, \fB\-\-stdin\fR
62Fuzz the application's standard input. By default \fBzzuf\fR only fuzzes files.
63.TP
64\fB\-I\fR, \fB\-\-include\fR=\fIregex\fR
65Only fuzz files whose name matches the \fIregex\fR regular expression. Use
66this for instance if your application reads configuration files at startup
67and you only want specific files to be fuzzed.
68
69Multiple \fB\-I\fR flags can be specified, in which case files matching any one
70of the regular expressions will be fuzzed. See also the \fB\-c\fR flag.
71.TP
72\fB\-q\fR, \fB\-\-quiet\fR
73Hide the output of the fuzzed application. This is useful if the application
74is very verbose but only its exit code or signaled status is really useful to
75you.
76.TP
77\fB\-r\fR, \fB\-\-ratio\fR=\fIratio\fR
78Specify the amount of bits that will be randomly fuzzed. A value of 0
79will not fuzz anything. A value of 0.05 will fuzz 5% of the open files'
80bits. A value of 1.0 or more will fuzz all the bytes, theoretically making
81the input files undiscernible from random data. The default fuzzing ratio
82is 0.004 (fuzz 0.4% of the files' bits).
83.TP
84\fB\-s\fR, \fB\-\-seed\fR=\fIseed\fR
85.PD 0
86.TP
87\fB\-s\fR, \fB\-\-seed\fR=\fIstart:stop\fR
88.PD
89Specify the random seed to use for fuzzing, or an interval of random seeds.
90Running \fBzzuf\fR twice with the same random seed will fuzz the files exactly
91the same way, even with a different target application. The purpose of this is
92to use simple utilities such as \fBcat\fR or \fBcp\fR to generate a file that
93causes the target application to crash.
94
95If an interval is specified, \fBzzuf\fR will run the application several times,
96each time with a different seed, and report the behaviour of each run.
97.TP
98\fB\-S\fR, \fB\-\-signal\fR
99Prevent children from installing signal handlers for signals that usually
100cause coredumps. These signals are \fBSIGABRT\fR, \fBSIGFPE\fR, \fBSIGILL\fR,
101\fBSIGQUIT\fR, \fBSIGSEGV\fR, \fBSIGTRAP\fR and, if available on the running
102platform, \fBSIGSYS\fR, \fBSIGEMT\fR, \fBSIGBUS\fR, \fBSIGXCPU\fR and
103\fBSIGXFSZ\fR. Instead of calling the signal handler, the application will
104simply crash. If you do not want core dumps, you should set appropriate limits
105with the \fBlimit coredumpsize\fR command. See your shell's documentation on
106how to set such limits.
107.TP
108\fB\-T\fR, \fB\-\-max\-time\fR=\fIn\fR
109Automatically terminate child processes that run for more than \fIn\fR
110seconds. This is useful to detect infinite loops or processes stuck in other
111situations. See also the \fB\-B\fR flag.
112.TP
113\fB\-v\fR, \fB\-\-version\fR
114Output version information and exit.
115.SH EXAMPLES
116.PP
117Fuzz the input of the \fBcat\fR program using default settings:
118.PP
119.RS
120.nf
121\fB# zzuf cat /etc/motd\fR
122.fi
123.RE
124.PP
125Fuzz 1% of the input bits of the \fBcat\fR program using seed 94324:
126.PP
127.RS
128.nf
129\fB# zzuf -s 94324 -r 0.01 cat /etc/motd\fR
130.fi
131.RE
132.PP
133Fuzz the input of the \fBconvert\fR program, using file \fBfoo.jpeg\fR as the
134original input and excluding \fB.xml\fR files from fuzzing (because
135\fBconvert\fR will also open its own XML configuration files and we do not
136want \fBzzuf\fR to fuzz them):
137.PP
138.RS
139.nf
140\fB# zzuf -E \(dq\\.xml$\(dq convert -- foo.jpeg -format tga /dev/null\fR
141.fi
142.RE
143.PP
144Fuzz the input of \fBvlc\fR, using file \fBmovie.avi\fR as the original input
145and restricting fuzzing to filenames that appear on the command line
146(\fB\-c\fR), then generate \fBfuzzy-movie.avi\fR which is a file that can
147be read by \fBvlc\fR to reproduce the same behaviour without using \fBzzuf\fR:
148.PP
149.RS
150.nf
151\fB# zzuf -c -s 87423 -r 0.01 vlc movie.avi\fR
152\fB# zzuf -c -s 87423 -r 0.01 cp movie.avi fuzzy-movie.avi\fR
153\fB# vlc fuzzy-movie.avi\fR
154.fi
155.RE
156.PP
157Fuzz 2% of \fBmplayer\fR's input bits (\fB\-r 0.02\fR) with seeds 0 to 9999
158(\fB\-s 0:10000\fR), disabling its standard output messages (\fB\-q\fR),
159launching up to three simultaneous child processes (\fB\-F 3\fR), killing
160\fBmplayer\fR if it takes more than one minute to read the file (\fB\-T 60\fR)
161and disabling its \fBSIGSEGV\fR signal handler (\fB\-S\fR):
162.PP
163.RS
164.nf
165\fB# zzuf -c -q -s 0:10000 -F 3 -T 60 -r 0.02 \\\fR
166\fB    mplayer movie.avi -- -benchmark -vo null -fps 1000\fR
167.fi
168.RE
169.SH BUGS
170.PP
171Only the most common file operations are implemented as of now: \fBopen\fR(),
172\fBread\fR(), \fBfopen\fR(), \fBfseek\fR(), etc. One important unimplemented
173function is \fBfscanf\fR().
174.PP
175Network fuzzing is not implemented. It is not yet possible to insert or
176drop bytes from the input, to fuzz according to the file format, or to do
177all these complicated operations. They are planned, though.
178.PP
179Due to \fBzzuf\fR using \fBLD_PRELOAD\fR to run its child processes, it will
180fail in the presence of any mechanism that disables preloading. For instance
181setuid root binaries will not be fuzzed when run as an unprivileged user.
182.SH AUTHOR
183.PP
184Copyright \(co 2006, 2007 Sam Hocevar <sam@zoy.org>.
185.PP
186\fBZzuf\fR and this manual page are free software. They come without any
187warranty, to the extent permitted by applicable law. You can redistribute
188them and/or modify them under the terms of the Do What The Fuck You Want
189To Public License, Version 2, as published by Sam Hocevar. See
190\fBhttp://sam.zoy.org/wtfpl/COPYING\fR for more details.
191.PP
192\fBZzuf\fR's webpage can be found at \fBhttp://sam.zoy.org/zzuf/\fR.
Note: See TracBrowser for help on using the repository browser.