If you have to do a v5, the correct word is generic not general. :)
Otherwise looks great.
Paolo
On 15/10/20 15:41, Alexander Bulekov wrote:
> v4:
> - Replace yaml + c template-based oss-fuzz configs, with C code to
> register a FuzzTarget for each config (as suggested by Paolo)
> - Replicate the functionality of address_space_write_rom to ensure
> matching behavior when QTEST_LOG is enabled
> - Improve code documentation/comments
> - Small formatting changes
> v3:
> - Use flatviews to help select regions for fuzzing
> - Meson-related changes
> - Add some documentation
> - Improve minimalization script to trim write{bwlq} commands
> v2:
> - Remove QOS dependency.
> - Add a custom crossover function
> - Fix broken minimization scripts
> - Fixes to the IO region and DMA handling code
>
> This is a general virtual-device fuzzer, designed to fuzz devices over Port
> IO,
> MMIO, and DMA.
>
> To get started with this:
> 1. Build the fuzzers (see docs/devel/fuzzing.txt)
> Note: Build with --enable-sanitizers, or create a "dictionary file":
> echo kw1=\"FUZZ\" > dict
> and pass it as an argument to libFuzzer with -dict=./dict
> This magic value is a command separator that lets the fuzzer perform
> multiple IO actions with a single input.
>
> 2. Pick the qemu arguments you wish to fuzz:
> export QEMU_FUZZ_ARGS="-M q35 -device virtio-balloon"
>
> 3. Tell the fuzzer which QOM objects or MemoryRegion names to fuzz. I find
> the
> "info qom-tree", "info qtree" and "info mtree" commands useful for
> identifying
> these. Supports globbing. Here I will try to simultaneously fuzz(for no good
> reason) virtio-balloon and e1000e, which is included by default in the q35:
> export QEMU_FUZZ_OBJECTS='virtio* e1000*'
> You can also try to fuzz the whole machine:
> export QEMU_FUZZ_OBJECTS='*'
>
> 4. Run the fuzzer for 0 inputs. The fuzzer should output a list of
> MemoryRegions/PCI Devices it will try to fuzz. Confirm that these match your
> expectations.
> ./i386-softmmu/qemu-fuzz-i386 --fuzz-target=general-fuzz -runs=0
>
> 5. Run the fuzzer:
> ./i386-softmmu/qemu-fuzz-i386 --fuzz-target=general-fuzz
>
>
> Basically, at the core, this fuzzer is an interpreter that splits the input
> into a series of commands, such as mmio_write, pio_write, etc. We structure
> these commands to hit only MemoryRegions that are associated with the devices
> specified in QEMU_FUZZ_OBJECTS. Additionally, these patches add "hooks" to
> functions that are typically used by virtual-devices to read from RAM (DMA).
> These hooks attempt to populate these DMA regions with fuzzed data, just in
> time.
>
> Some of the issues I have found or reproduced with this fuzzer:
> https://bugs.launchpad.net/bugs/1525123
> https://bugs.launchpad.net/bugs/1681439
> https://bugs.launchpad.net/bugs/1777315
> https://bugs.launchpad.net/bugs/1878034
> https://bugs.launchpad.net/bugs/1878043
> https://bugs.launchpad.net/bugs/1878054
> https://bugs.launchpad.net/bugs/1878057
> https://bugs.launchpad.net/bugs/1878067
> https://bugs.launchpad.net/bugs/1878134
> https://bugs.launchpad.net/bugs/1878136
> https://bugs.launchpad.net/bugs/1878253
> https://bugs.launchpad.net/bugs/1878255
> https://bugs.launchpad.net/bugs/1878259
> https://bugs.launchpad.net/bugs/1878263
> https://bugs.launchpad.net/bugs/1878323
> https://bugs.launchpad.net/bugs/1878641
> https://bugs.launchpad.net/bugs/1878642
> https://bugs.launchpad.net/bugs/1878645
> https://bugs.launchpad.net/bugs/1878651
> https://bugs.launchpad.net/bugs/1879223
> https://bugs.launchpad.net/bugs/1879227
> https://bugs.launchpad.net/bugs/1879531
> https://bugs.launchpad.net/bugs/1880355
> https://bugs.launchpad.net/bugs/1880539
> https://bugs.launchpad.net/bugs/1884693
> https://bugs.launchpad.net/bugs/1886362
> https://bugs.launchpad.net/bugs/1887303
> https://bugs.launchpad.net/bugs/1887309
> https://bugs.launchpad.net/bugs/697510
>
> Alexander Bulekov (16):
> memory: Add FlatView foreach function
> fuzz: Add general virtual-device fuzzer
> fuzz: Add PCI features to the general fuzzer
> fuzz: Add DMA support to the generic-fuzzer
> fuzz: Declare DMA Read callback function
> fuzz: Add fuzzer callbacks to DMA-read functions
> fuzz: Add support for custom crossover functions
> fuzz: add a DISABLE_PCI op to general-fuzzer
> fuzz: add a crossover function to generic-fuzzer
> scripts/oss-fuzz: Add script to reorder a general-fuzzer trace
> scripts/oss-fuzz: Add crash trace minimization script
> fuzz: Add instructions for using general-fuzz
> fuzz: add an "opaque" to the FuzzTarget struct
> fuzz: add general-fuzz configs for oss-fuzz
> fuzz: register predefined general-fuzz configs
> scripts/oss-fuzz: remove the general-fuzz target
>
> docs/devel/fuzzing.txt | 39 +
> include/exec/memory.h | 21 +
> include/exec/memory_ldst_cached.h.inc | 3 +
> memory_ldst.c.inc | 4 +
> scripts/oss-fuzz/build.sh | 6 +
> scripts/oss-fuzz/minimize_qtest_trace.py | 157 +++
> .../oss-fuzz/reorder_fuzzer_qtest_trace.py | 103 ++
> softmmu/memory.c | 23 +
> softmmu/physmem.c | 2 +
> tests/qtest/fuzz/fuzz.c | 13 +
> tests/qtest/fuzz/fuzz.h | 28 +
> tests/qtest/fuzz/general_fuzz.c | 948 ++++++++++++++++++
> tests/qtest/fuzz/general_fuzz_configs.c | 140 +++
> tests/qtest/fuzz/general_fuzz_configs.h | 24 +
> tests/qtest/fuzz/meson.build | 1 +
> 15 files changed, 1512 insertions(+)
> create mode 100755 scripts/oss-fuzz/minimize_qtest_trace.py
> create mode 100755 scripts/oss-fuzz/reorder_fuzzer_qtest_trace.py
> create mode 100644 tests/qtest/fuzz/general_fuzz.c
> create mode 100644 tests/qtest/fuzz/general_fuzz_configs.c
> create mode 100644 tests/qtest/fuzz/general_fuzz_configs.h
>
