Cc: Alexander Oleinik <alxndr@bu.edu>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20211007130829.632254-2-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The timeout mechanism won't work if SIGALRM is blocked. This changes
unmasks SIGALRM when the timer is installed. This doesn't completely
solve the problem, as the fuzzer could trigger some device activity that
re-masks SIGALRM. However, there are currently no inputs on OSS-Fuzz
that re-mask SIGALRM and timeout. If that turns out to be a real issue,
we could try to hook sigmask-type calls, or use a separate timer thread.
Based-on: <20210713150037.9297-1-alxndr@bu.edu>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Using ITIMER_VIRTUAL is a bad idea, if the fuzzer hits a blocking
syscall - e.g. ppoll with a NULL timespec. This causes timeout issues
while fuzzing some block-device code. Fix that by using wall-clock time.
This might cause inputs to timeout sometimes due to scheduling
effects/ambient load, but it is better than bringing the entire fuzzing
process to a halt.
Based-on: <20210713150037.9297-1-alxndr@bu.edu>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
We have some configs for devices such as the AC97 and ES1370 that were
not matching memory-regions correctly, because the configs provided
lowercase names. To resolve these problems and prevent them from
occurring again in the future, convert both the pattern and names to
lower-case, prior to checking for a match.
Suggested-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Using a custom timeout is useful to continue fuzzing complex devices,
even after we run into some slow code-path. However, simply adding a
fixed timeout to each input effectively caps the maximum input
length/number of operations at some artificial value. There are two
major problems with this:
1. Some code might only be reachable through long IO sequences.
2. Longer inputs can actually be _better_ for performance. While the
raw number of fuzzer executions decreases with larger inputs, the
number of MMIO/PIO/DMA operation/second actually increases, since
were are speding proportionately less time fork()ing.
With this change, we keep the custom-timeout, but we renew it, prior to
each MMIO/PIO/DMA operation. Thus, we time-out only when a specific
operation takes a long time.
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
The code mistakenly relied on address_space_translate to store the
length remaining until the next memory-region. We care about this
because when there is RAM or sparse-memory neighboring on an MMIO
region, we should only write up to the border, to prevent inadvertently
invoking MMIO handlers within the DMA callback.
However address_space_translate_internal only stores the length until
the end of the MemoryRegion if memory_region_is_ram(mr). Otherwise
the *len is left unmodified. This caused some false-positive issues,
where the fuzzer found a way to perform a nested MMIO write through a
DMA callback on an [address, length] that started within sparse memory
and spanned some device MMIO regions.
To fix this, write to sparse memory in small chunks of
memory_access_size (similar to the underlying address_space_write code),
which will prevent accidentally hitting MMIO handlers through large
writes.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Use memory_region_size() to get the MemoryRegion size,
and display it with the '0x' prefix.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210612195842.1595999-1-f4bug@amsat.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Leading underscores followed by a capital letter or underscore are
reserved by the C standard.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/369
Signed-off-by: Ahmed Abouzied <email@aabouzied.com>
Message-Id: <20210605174938.13782-1-email@aabouzied.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
On Fedora 32, using clang (version 10.0.1-3.fc32) we get:
tests/qtest/fuzz/fuzz.c:237:5: error: implicit declaration of function 'qemu_init' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
qemu_init(result.we_wordc, result.we_wordv, NULL);
^
qemu_init() is declared in "sysemu/sysemu.h", include this
header to fix.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210513162008.3922223-1-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stop including exec/address-spaces.h in files that don't need it.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210416171314.2074665-5-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Stop including sysemu/sysemu.h in files that don't need it.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210416171314.2074665-2-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
The function flatview_for_each_range() calls a callback for each
range in a FlatView. Currently the callback gets the start and
length of the range and the MemoryRegion involved, but not the offset
within the MemoryRegion. Add this to the callback's arguments; we're
going to want it for a new use in the next commit.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210318174823.18066-4-peter.maydell@linaro.org
The return value of the flatview_cb callback passed to the
flatview_for_each_range() function is zero if the iteration through
the ranges should continue, or non-zero to break out of it. Use a
bool for this rather than int.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210318174823.18066-2-peter.maydell@linaro.org
qemu-fuzz-i386-target-generic-fuzz-sdhci-v3 uses -drive=sd where it
should use -drive if=none instead. This prints a deprecation warning:
$ ./build-oss-fuzz/DEST_DIR/qemu-fuzz-i386-target-generic-fuzz-sdhci-v3 -runs=1 -seed=1
[ASan warnings snipped...]
--> i386: -drive if=sd,index=0,file=null-co://,format=raw,id=mydrive: warning: bogus if=sd is deprecated, use if=none
INFO: Seed: 1
[More normal output snipped...]
Support for this usage will be gone soon. Adjust the test.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210319132008.1830950-1-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
The generic-fuzzer often provides randomized DMA addresses to
virtual-devices. For a 64-bit address-space, the chance of these
randomized addresses coinciding with RAM regions, is fairly small. Even
though the fuzzer's instrumentation eventually finds valid addresses,
this can take some-time, and slows-down fuzzing progress (especially,
when multiple DMA buffers are involved). To work around this, create
"fake" sparse-memory that spans all of the 64-bit address-space. Adjust
the DMA call-back to populate this sparse memory, correspondingly
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
I noticed that with a sufficiently small timeout, the fuzzer fork-server
sometimes locks up. On closer inspection, the issue appeared to be
caused by entering our SIGALRM handler, while libfuzzer is in it's crash
handlers. Because libfuzzer relies on pipe communication with an
external child process to print out stack-traces, we shouldn't exit
early, and leave an orphan child. Check for children in the SIGALRM
handler to avoid this issue.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Acked-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The device-type names for the pro100 network cards, are i8255.. We were
matching "eepro", which catches the PCI PIO/MMIO regions for those
devices, however misses the actual PCI device, which we use to map the
BARs, before fuzzing. Fix that
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
virtio-9p devices are often used to expose a virtual-filesystem to the
guest. There have been some bugs reported in this device, such as
CVE-2018-19364, and CVE-2021-20181. We should fuzz this device
This patch adds two virtio-9p configurations:
* One with the widely used -fsdev local driver. This driver leaks some
state in the form of files/directories created in the shared dir.
* One with the synth driver. While it is not used in the real world, this
driver won't leak leak state between fuzz inputs.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210117230924.449676-4-alxndr@bu.edu>
For some device configurations, it is useful to configure some
resources, and adjust QEMU arguments at runtime, prior to fuzzing. This
patch adds an "argfunc" to generic the generic_fuzz_config. When
specified, it is responsible for configuring the resources and returning
a string containing the corresponding QEMU arguments. This can be useful
for targets that rely on e.g.:
* a temporary qcow2 image
* a temporary directory
* an unused TCP port used to bind the VNC server
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210117230924.449676-2-alxndr@bu.edu>
This is useful for building reproducers. Instead checking the code or
the QEMU_FUZZ_ARGS, the arguments are at the top of the crash log.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210117201014.271610-3-alxndr@bu.edu>
Disks work differently depending on the x86 machine type (SATA vs PATA).
Additionally, we should fuzz the atapi code paths, which might contain
vulnerabilities such as CVE-2020-29443. This patch adds hard-disk and
cdrom generic-fuzzer configs for both the pc (PATA) and q35 (SATA)
machine types.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Acked-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210120152211.109782-1-alxndr@bu.edu>
We passed an is_write flag to the fuzz_dma_read_cb function to
differentiate between the mapped DMA regions that need to be populated
with fuzzed data, and those that don't. We simply passed through the
address_space_map is_write parameter. The goal was to cut down on
unnecessarily populating mapped DMA regions, when they are not read
from.
Unfortunately, nothing precludes code from reading from regions mapped
with is_write=true. For example, see:
https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg04729.html
This patch removes the is_write parameter to fuzz_dma_read_cb. As a
result, we will fill all mapped DMA regions with fuzzed data, ignoring
the specified transfer direction.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210120060255.558535-1-alxndr@bu.edu>
Prior to this patch, the fuzzer found inputs to map PCI device BARs and
enable the device. While it is nice that the fuzzer can do this, it
added significant overhead, since the fuzzer needs to map all the
BARs (regenerating the memory topology), at the start of each input.
With this patch, we do this once, before fuzzing, mitigating some of
this overhead.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20201221181203.1853-1-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
On the pc-i440fx machine, the floppy drive relies on the i8257 DMA
controller. Add this device to the floppy fuzzer config, and silence the
warning about a missing format specifier for the null-co:// drive.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201216203328.41112-1-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes, with the changes
to the following files manually reverted:
contrib/libvhost-user/libvhost-user-glib.h
contrib/libvhost-user/libvhost-user.c
contrib/libvhost-user/libvhost-user.h
contrib/plugins/hotblocks.c
contrib/plugins/hotpages.c
contrib/plugins/howvec.c
contrib/plugins/lockstep.c
linux-user/mips64/cpu_loop.c
linux-user/mips64/signal.c
linux-user/sparc64/cpu_loop.c
linux-user/sparc64/signal.c
linux-user/x86_64/cpu_loop.c
linux-user/x86_64/signal.c
target/s390x/gen-features.c
tests/fp/platform.h
tests/migration/s390x/a-b-bios.c
tests/plugin/bb.c
tests/plugin/empty.c
tests/plugin/insn.c
tests/plugin/mem.c
tests/test-rcu-simpleq.c
tests/test-rcu-slist.c
tests/test-rcu-tailq.c
tests/uefi-test-tools/UefiTestToolsPkg/BiosTablesTest/BiosTablesTest.c
contrib/plugins/, tests/plugin/, and tests/test-rcu-slist.c appear not
to include osdep.h intentionally. The remaining reverts are the same
as in commit bbfff19688.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201113061216.2483385-1-armbru@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Alexander Bulekov <alxndr@bu.edu>
The generic fuzzer can find double-fetch bugs. However:
* We currently have no good way of producing qemu-system reproducers for
double-fetch bugs. Even if we can get developers to run the binary-blob
reproducers with the qemu-fuzz builds, we currently don't have a minimizer for
these reproducers, so they are usually not easy to follow.
* Often times the fuzzer will provide a reproducer containing a
double-fetch for a bug that can be reproduced without double-fetching.
Until we find a way to build nice double-fetch reproducers that
developers are willing to look at, lets tell OSS-Fuzz to avoid
double-fetches.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201202164214.93867-1-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
The virtio-blk fuzz target sets up and fuzzes the available virtio-blk
queues. The implementation is based on two files:
- tests/qtest/fuzz/virtio_scsi_fuzz.c
- tests/qtest/virtio_blk_test.c
Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <e2405c459302ecaee2555405604975353bfa3837.1604920905.git.dimastep@yandex-team.ru>
Signed-off-by: Thomas Huth <thuth@redhat.com>
LLVM's linker, LLD, supports the keyword "INSERT AFTER", starting with
version 11.
However, when multiple sections are defined in the same "INSERT AFTER",
they are added in a reversed order, compared to BFD's LD.
This patch makes fork_fuzz.ld generic enough to work with both linkers.
Each section now has its own "INSERT AFTER" keyword, so proper ordering is
defined between the sections added.
Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
Message-Id: <20201105221905.1350-2-dbuono@linux.vnet.ibm.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
The code did not add offsets to FlatRange bases, so we did not fuzz
offsets within device MemoryRegions.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201029172901.534442-4-alxndr@bu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We should be checking that the device is trying to read from RAM, before
filling the region with data. Otherwise, we will try to populate
nonsensical addresses in RAM for callbacks on PIO/MMIO reads. We did
this originally, however the final version I sent had the line commented
out..
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201029172901.534442-3-alxndr@bu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This code had all sorts of issues. We used a loop similar to
address_space_write_rom, but I did not remove a "break" that only made
sense in the context of the switch statement in the original code. Then,
after the loop, we did a separate qtest_memwrite over the entire DMA
access range, defeating the purpose of the loop. Additionally, we
increment the buf pointer, and then try to g_free() it. Fix these
problems.
Reported-by: OSS-Fuzz (Issue 26725)
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reported-by: OSS-Fuzz (Issue 26691)
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201029172901.534442-2-alxndr@bu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In qos_build_main_args(), the pointer 'path' is dereferenced before
checking it is valid, which may lead to NULL pointer dereference.
So move the assignment to 'cmd_line' after checking 'path' is valid.
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Alex Chen <alex.chen@huawei.com>
Message-Id: <5FA16ED5.4000203@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We call get_generic_fuzz_configs, which fills an array with
predefined {name, args, objects} triples. For each of these, we add a
new FuzzTarget, that uses a small wrapper to set
QEMU_FUZZ_{ARGS,OBJECTS} to the corresponding predefined values.
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201023150746.107063-16-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Predefine some generic-fuzz configs. For each of these, we will create a
separate FuzzTarget that can be selected through argv0 and, therefore,
fuzzed on oss-fuzz.
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201023150746.107063-15-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
It can be useful to register FuzzTargets that have nearly-identical
initialization handlers (e.g. for using the same fuzzing code, with
different configuration options). Add an opaque pointer to the
FuzzTarget struct, so that FuzzTargets can hold some data, useful for
storing target-specific configuration options, that can be read by the
get_init_cmdline function.
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201023150746.107063-14-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201023150746.107063-10-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This new operation is used in the next commit, which concatenates two
fuzzer-generated inputs. With this operation, we can prevent the second
input from clobbering the PCI configuration performed by the first.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201023150746.107063-9-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
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>
When a virtual-device tries to access some buffer in memory over DMA, we
add call-backs into the fuzzer(next commit). The fuzzer checks verifies
that the DMA request maps to a physical RAM address and fills the memory
with fuzzer-provided data. The patterns that we use to fill this memory
are specified using add_dma_pattern and clear_dma_patterns operations.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201023150746.107063-5-alxndr@bu.edu>
[thuth: Reformatted one comment according to the QEMU coding style]
Signed-off-by: Thomas Huth <thuth@redhat.com>
This patch compares TYPE_PCI_DEVICE objects against the user-provided
matching pattern. If there is a match, we use some hacks and leverage
QOS to map each possible BAR for that device. Now fuzzed inputs might be
converted to pci_read/write commands which target specific. This means
that we can fuzz a particular device's PCI configuration space,
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201023150746.107063-4-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This is a generic fuzzer designed to fuzz a virtual device's
MemoryRegions, as long as they exist within the Memory or Port IO (if it
exists) AddressSpaces. The fuzzer's input is interpreted into a sequence
of qtest commands (outb, readw, etc). The interpreted commands are
separated by a magic seaparator, which should be easy for the fuzzer to
guess. Without ASan, the separator can be specified as a "dictionary
value" using the -dict argument (see libFuzzer documentation).
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201023150746.107063-3-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Prior to this patch, the only way I found to terminate the fuzzer was
either to:
1. Explicitly specify the number of fuzzer runs with the -runs= flag
2. SIGKILL the process with "pkill -9 qemu-fuzz-*" or similar
In addition to being annoying to deal with, SIGKILLing the process skips
over any exit handlers(e.g. registered with atexit()). This is bad,
since some fuzzers might create temporary files that should ideally be
removed on exit using an exit handler. The only way to achieve a clean
exit now is to specify -runs=N , but the desired "N" is tricky to
identify prior to fuzzing.
Why doesn't the process exit with standard SIGINT,SIGHUP,SIGTERM
signals? QEMU installs its own handlers for these signals in
os-posix.c:os_setup_signal_handling, which notify the main loop that an
exit was requested. The fuzzer, however, does not run qemu_main_loop,
which performs the main_loop_should_exit() check. This means that the
fuzzer effectively ignores these signals. As we don't really care about
cleanly stopping the disposable fuzzer "VM", this patch uninstalls
QEMU's signal handlers. Thus, we can stop the fuzzer with
SIG{INT,HUP,TERM} and the fuzzing code can optionally use atexit() to
clean up temporary files/resources.
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201014142157.46028-1-alxndr@bu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make things consistent with how softmmu/vl.c uses os_find_datadir.
Initializing the path to the executables will also be needed for
get_relocatable_path to work.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Just return the directory without requiring the caller to free it.
This also removes a bogus check for NULL in os_find_datadir and
module_load_one; g_strdup of a static variable cannot return NULL.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Telling QTest to log to /dev/fd/2, essentially results in dup(2). This
is fine, if other code isn't logging to stderr. Otherwise, the order of
the logs is mixed due to buffering issues, since two file-descriptors
are used to write to the same file. We can avoid this, since just
specifying "-qtest" sets the log fd to stderr. If we want to disable
qtest logs, we can just add -qtest-log none.
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200819061110.1320568-2-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
