[PATCH v9 00/23] Add virtual device fuzzing support

[Alexander Bulekov]

Hello,

This series adds a framework for coverage-guided fuzzing of
virtual-devices. Fuzzing targets are based on qtest and can make use of
the libqos abstractions.

V9:
 * Fix bug in the virtio-scsi fuzzer. Virtqueues were being kicked only
   if free_head != 0 (which it never was).
 * Move vl.c and main.c into a new directory: softmmu/
 * virtio-net-fuzz: refactor the looop over used descriptor.
 * Improve comments for i440fx and virtio-scsi fuzzers.

V8:
 * Small fixes to the virtio-net.
 * Keep rcu_atfork when not using qtest.

V7:
 * virtio-net: add virtio-net-check-used which waits for inputs on
 the tx/ctrl vq by watching the used vring.
 * virtio-net: add virtio-net-socket which uses the socket backend and can
 exercise the rx components of virtio-net.
 * virtio-net: add virtio-net-slirp which uses the user backend and exercises
 slirp. This may lead to real traffic emitted by qemu so it is best to
 run in an isolated network environment.
 * build should succeed after each commit

V5/V6:
 * added virtio-scsi fuzzer
 * add support for using fork-based fuzzers with multiple libfuzzer
   workers
 * misc fixes addressing V4 comments
 * cleanup in-process handlers/globals in libqtest.c
 * small fixes to fork-based fuzzing and support for multiple workers
 * changes to the virtio-net fuzzer to kick after each vq add

V4:
 * add/transfer license headers to new files
 * restructure the added QTestClientTransportOps struct
 * restructure the FuzzTarget struct and fuzzer skeleton
 * fork-based fuzzer now directly mmaps shm over the coverage bitmaps
 * fixes to i440 and virtio-net fuzz targets
 * undo the changes to qtest_memwrite
 * possible to build /fuzz and /all in the same build-dir
 * misc fixes to address V3 comments

V3:
 * rebased onto v4.1.0+
 * add the fuzzer as a new build-target type in the build-system
 * add indirection to qtest client/server communication functions
 * remove ramfile and snapshot-based fuzzing support
 * add i440fx fuzz-target as a reference for developers.
 * add linker-script to assist with fork-based fuzzer

V2:
 * split off changes to qos virtio-net and qtest server to other patches
 * move vl:main initialization into new func: qemu_init
 * moved useful functions from qos-test.c to a separate object
 * use struct of function pointers for add_fuzz_target(), instead of
   arguments
 * move ramfile to migration/qemu-file
 * rewrite fork-based fuzzer pending patch to libfuzzer
 * pass check-patch

Alexander Bulekov (23):
  checkpatch: replace vl.c in the top of repo check
  softmmu: move vl.c to softmmu/
  softmmu: split off vl.c:main() into main.c
  module: check module wasn't already initialized
  fuzz: add FUZZ_TARGET module type
  qtest: add qtest_server_send abstraction
  libqtest: add a layer of abstraction to send/recv
  libqtest: make bufwrite rely on the TransportOps
  qtest: add in-process incoming command handler
  libqos: rename i2c_send and i2c_recv
  libqos: split qos-test and libqos makefile vars
  libqos: move useful qos-test funcs to qos_external
  fuzz: add fuzzer skeleton
  exec: keep ram block across fork when using qtest
  main: keep rcu_atfork callback enabled for qtest
  fuzz: support for fork-based fuzzing.
  fuzz: add support for qos-assisted fuzz targets
  fuzz: add target/fuzz makefile rules
  fuzz: add configure flag --enable-fuzzing
  fuzz: add i440fx fuzz targets
  fuzz: add virtio-net fuzz target
  fuzz: add virtio-scsi fuzz target
  fuzz: add documentation to docs/devel/

 Makefile                            |  15 +-
 Makefile.objs                       |   2 -
 Makefile.target                     |  19 ++-
 configure                           |  39 +++++
 docs/devel/fuzzing.txt              | 116 ++++++++++++++
 exec.c                              |  12 +-
 include/qemu/module.h               |   4 +-
 include/sysemu/qtest.h              |   4 +
 include/sysemu/sysemu.h             |   4 +
 qtest.c                             |  31 +++-
 scripts/checkpatch.pl               |   2 +-
 softmmu/Makefile.objs               |   3 +
 softmmu/main.c                      |  53 +++++++
 vl.c => softmmu/vl.c                |  48 +++---
 tests/qtest/Makefile.include        |  72 ++++-----
 tests/qtest/fuzz/Makefile.include   |  18 +++
 tests/qtest/fuzz/fork_fuzz.c        |  55 +++++++
 tests/qtest/fuzz/fork_fuzz.h        |  23 +++
 tests/qtest/fuzz/fork_fuzz.ld       |  37 +++++
 tests/qtest/fuzz/fuzz.c             | 179 +++++++++++++++++++++
 tests/qtest/fuzz/fuzz.h             |  95 +++++++++++
 tests/qtest/fuzz/i440fx_fuzz.c      | 193 +++++++++++++++++++++++
 tests/qtest/fuzz/qos_fuzz.c         | 234 ++++++++++++++++++++++++++++
 tests/qtest/fuzz/qos_fuzz.h         |  33 ++++
 tests/qtest/fuzz/virtio_net_fuzz.c  | 198 +++++++++++++++++++++++
 tests/qtest/fuzz/virtio_scsi_fuzz.c | 214 +++++++++++++++++++++++++
 tests/qtest/libqos/i2c.c            |  10 +-
 tests/qtest/libqos/i2c.h            |   4 +-
 tests/qtest/libqos/qos_external.c   | 168 ++++++++++++++++++++
 tests/qtest/libqos/qos_external.h   |  28 ++++
 tests/qtest/libqtest.c              | 119 ++++++++++++--
 tests/qtest/libqtest.h              |   4 +
 tests/qtest/pca9552-test.c          |  10 +-
 tests/qtest/qos-test.c              | 132 +---------------
 util/module.c                       |   7 +
 35 files changed, 1958 insertions(+), 227 deletions(-)
 create mode 100644 docs/devel/fuzzing.txt
 create mode 100644 softmmu/Makefile.objs
 create mode 100644 softmmu/main.c
 rename vl.c => softmmu/vl.c (99%)
 create mode 100644 tests/qtest/fuzz/Makefile.include
 create mode 100644 tests/qtest/fuzz/fork_fuzz.c
 create mode 100644 tests/qtest/fuzz/fork_fuzz.h
 create mode 100644 tests/qtest/fuzz/fork_fuzz.ld
 create mode 100644 tests/qtest/fuzz/fuzz.c
 create mode 100644 tests/qtest/fuzz/fuzz.h
 create mode 100644 tests/qtest/fuzz/i440fx_fuzz.c
 create mode 100644 tests/qtest/fuzz/qos_fuzz.c
 create mode 100644 tests/qtest/fuzz/qos_fuzz.h
 create mode 100644 tests/qtest/fuzz/virtio_net_fuzz.c
 create mode 100644 tests/qtest/fuzz/virtio_scsi_fuzz.c
 create mode 100644 tests/qtest/libqos/qos_external.c
 create mode 100644 tests/qtest/libqos/qos_external.h

-- 
2.25.0