[PATCH 0/6] media: v4l2-ctrls: bound stateless HEVC/AV1 tile counts

[Michael Bommarito]

The stateless HEVC and AV1 V4L2 controls carry tile counts that several SoC
decoder drivers consume as loop bounds and divisors when laying out
fixed-size hardware descriptor buffers, but std_validate_compound() does not
bound them. A process with access to a /dev/videoN stateless decoder (on a
typical desktop or SBC, the active-seat local user via the logind/udev
uaccess ACL, no extra capability) can set a HEVC PPS or AV1 frame control
with a tile count far beyond the array capacity the drivers assume, making
them loop past their fixed buffers.

Patch 1 caps the HEVC and AV1 tile counts to the uAPI array capacity in the
core. Patches 2-5 add matching bounds in the consuming driver loops (and
bound the driver-interpreted HEVC pic_parameter_set_id / AV1
context_update_tile_id indices the core does not reject). Patch 6 adds
KUnit tests for the core validation.

I did my best to reproduce these with the hardware I have, but apologies
in advance if I missed something because the soft repro.

Test matrix: patch 1 + patch 6 run the real std_validate_compound() under
KASAN on x86_64 (rejects out-of-range counts, in-range pass, stock and
patched); all objects build clean W=1; the ARM SoC decoders are not
reachable on the x86 host, so the per-driver writes are not reproduced here.

Michael Bommarito (6):
  media: v4l2-ctrls: validate HEVC and AV1 tile counts
  media: rkvdec: bound HEVC tile loops and PPS id to the array capacity
  media: verisilicon: hantro: bound G2 HEVC tile loop to the buffer
    capacity
  media: verisilicon: rockchip: bound VPU981 AV1 tile loop and guard
    divisor
  media: mediatek: vcodec: bound AV1 tile-start copy to the array
    capacity
  media: v4l2-ctrls: add KUnit tests for compound control tile
    validation

 .../vcodec/decoder/vdec/vdec_av1_req_lat_if.c |   5 +-
 .../rockchip/rkvdec/rkvdec-hevc-common.c      |  22 +++-
 .../platform/rockchip/rkvdec/rkvdec-hevc.c    |   8 +-
 .../rockchip/rkvdec/rkvdec-vdpu381-hevc.c     |   2 +
 .../platform/verisilicon/hantro_g2_hevc_dec.c |   6 +
 .../verisilicon/rockchip_vpu981_hw_av1_dec.c  |  29 +++--
 drivers/media/v4l2-core/Kconfig               |  12 ++
 .../media/v4l2-core/v4l2-ctrls-core-test.c    | 119 ++++++++++++++++++
 drivers/media/v4l2-core/v4l2-ctrls-core.c     |  27 ++++
 9 files changed, 213 insertions(+), 17 deletions(-)
 create mode 100644 drivers/media/v4l2-core/v4l2-ctrls-core-test.c

base-commit: 5200f5f493f79f14bbdc349e402a40dfb32f23c8
-- 
2.53.0