[PATCH] media: hantro: Harden MPEG-2 control access against NULL

[Tharit Tangkijwanichakul]

The MPEG-2 sequence and picture controls are validated
before a job is queued, so hantro_get_ctrl() is not expected to return
NULL in hantro_g1_mpeg2_dec_run(). The controls are nonetheless
dereferenced unconditionally.

Harden the invariant by checking the sequence and picture controls with
WARN_ON().

Found by code inspection.

Fixes: f329e21e9dad ("media: uapi: mpeg2: Split sequence and picture parameters")
Signed-off-by: Tharit Tangkijwanichakul <tharitt97@xxxxxxxxx>
---
Tested on a Rockchip RK3588 (Rock 5B) board with Fluster:
  MPEG-2 (MPEG2_VIDEO-MAIN): 23/43, unchanged

 drivers/media/platform/verisilicon/hantro_g1_mpeg2_dec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/media/platform/verisilicon/hantro_g1_mpeg2_dec.c b/drivers/media/platform/verisilicon/hantro_g1_mpeg2_dec.c
index e0d6bd0a6e44..6a942f4b8a2d 100644
--- a/drivers/media/platform/verisilicon/hantro_g1_mpeg2_dec.c
+++ b/drivers/media/platform/verisilicon/hantro_g1_mpeg2_dec.c
@@ -161,8 +161,13 @@ int hantro_g1_mpeg2_dec_run(struct hantro_ctx *ctx)
 
 	seq = hantro_get_ctrl(ctx,
 			      V4L2_CID_STATELESS_MPEG2_SEQUENCE);
+	if (WARN_ON(!seq))
+		return -EINVAL;
+
 	pic = hantro_get_ctrl(ctx,
 			      V4L2_CID_STATELESS_MPEG2_PICTURE);
+	if (WARN_ON(!pic))
+		return -EINVAL;
 
 	reg = G1_REG_DEC_AXI_RD_ID(0) |
 	      G1_REG_DEC_TIMEOUT_E(1) |
-- 
2.47.3