NAME

fuzz - stress test programs

SYNOPSIS

DESCRIPTION

fuzz is a program designed to find bugs in other programs. It does this by doing a form of black box testing. It does this by running the target program multiple times and passing it random input. Right now this can come from one of two places, stdin and the command line arguments. Testing completes whenever the program either the requested number of runs finishes successufully or the program crashes.

Any arguments following the target program are passed directly to the target program.

OPTIONS

-t, --timeout TIME: This sets the number of seconds that the fuzz will wait for the other program before it assumes that the program is hung. The default value is 120 seconds. This is sensing of when a program is hung is not entirely reliable. See the BUGS section.
-p, --printable: This limits both the stdin and the command line arguments to only printable characters. By default fuzz passes fully random bytes into the target program.
-n, --newlines: Include random newlines in the input stream.
-l, --length LENGTH: The length in bytes of the data stream to pass through stdin into the target program. The default length is 100K.
-m, --maxline MAXLINELEN: Specify the maximum line length within the random data stream passed into stdin.
-r, --runcount RUNCOUNT: The number of times to run the target program. The default is 10,000.
-b, --bytes: In addition to counting through the number of runs. Count through the bytes being sent through stdin to the program. This option really serves no purpose other than making something interesting to watch.
-c, --chroot: Since there is no telling what a program will do when given random input. this allows a program to be sort of caged while it is run so that the damage that it may be able to do is minimized. This requires that the fuzz be run as root. It will drop privlages before it runs the test program. This option is best used in conjunction with the --user option. This often times requires that a program is statically linked.
-u, --user USERNAME: Since there is no telling what a program will do when given random input, this specifies what user the target program will be run as so that it is easy to find and repair anything that may have been scribbled across your file system. This option was designed to be used in conjuntion with the --chroot option and will only work if fuzz is run as root.
-a, --args: In addition to passing random data via stdin, pass random command line arguments. This simply sets the number or random arguments to be passed to 256. See the BUGS section.
-o, --omitdata: Some programs don't take input from stdin. They only take input from the command line arguments. If this is the case simply use the --omitdata option.
-x. --maxargs NUMARGS: This is to set the maximum number of arguments that are passed to each invocation of the target program.
-y, --maxarglen ARGLEN: Sets the maximum length of an arguments passed to the target program.
-V, --version: Print the version of fuzz and exit.
-i, --priority: Run at a specified priority.
-d, --dontask: In the cases where the target program is for sure part of a package and the packaging information will provide the needed version information then you can use this option to avoid being asked what the version is.

EXAMPLES

fuzz grep foo

fuzz -c -u nobody cpio -i

BUGS

The random arg functions doesn't work very well right now. The arguments passed are so random that the program usually just prints out the usage message and then terminates. This will become much more useful later when we are mating data sets with the intention of maximizing code coverage.

AUTHORS

Ben Woodard <ben@valinux.com>