libfuzzer supports a "custom crossover function". Libfuzzer often tries
to blend two inputs to create a new interesting input. Sometimes, we
have a better idea about how to blend inputs together. This change
allows fuzzers to specify a custom function for blending two inputs
together.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201023150746.107063-8-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
In the initial FuzzTarget, get_init_cmdline returned a char *. With this
API, we had no guarantee about where the string came from. For example,
i440fx-qtest-reboot-fuzz simply returned a pointer to a string literal,
while the QOS-based targets build the arguments out in a GString an
return the gchar *str pointer. Since we did not try to free the cmdline,
we have a leak for any targets that do not simply return string
literals. Clean up this mess by forcing fuzz-targets to return
a GString, that we can free.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200714174616.20709-1-alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
The QTest server usually parses ASCII commands from clients. Since we
fuzz within the QEMU process, skip the QTest serialization and server
for most QTest commands. Leave the option to use the ASCII protocol, to
generate readable traces for crash reproducers.
Inspired-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200529221450.26673-2-alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
tests/fuzz/fuzz.c serves as the entry point for the virtual-device
fuzzer. Namely, libfuzzer invokes the LLVMFuzzerInitialize and
LLVMFuzzerTestOneInput functions, both of which are defined in this
file. This change adds a "FuzzTarget" struct, along with the
fuzz_add_target function, which should be used to define new fuzz
targets.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-id: 20200220041118.23264-13-alxndr@bu.edu
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
