Re: [PATCH v3,1/2] media: mediatek: vcodec: Fix possible invalid memory access for decoder

["Yunfei Dong (董云飞)" <Yunfei.Dong@mediatek.com>]

Hi hans,

Thanks for your test and review.

On Wed, 2023-08-02 at 10:51 +0200, Hans Verkuil wrote:
>  	 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>  Hi Yunfei,
> 
> On 29/07/2023 05:47, Yunfei Dong wrote:
> > The vpu maybe null pointer or unreasonable value when scp crash,
> need to
> > validate that the vpu pointer and the vpu instance within this
> context is
> > valid in case of leading to kernel reboot.
> > 
> > Fixes: 590577a4e525 ("[media] vcodec: mediatek: Add Mediatek V4L2
> Video Decoder Driver")
> > Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
> > Reported-by: Steve Cho <stevecho@google.com>
> > Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> > ---
> > - compared with v2:
> > - rewrite the commit message for patch 01 and 02.
> > - add Reported-by and Fixes tag.
> > - fix smatch fail for patch 02/2.
> > ---
> >  .../vcodec/decoder/mtk_vcodec_dec_drv.h       |  2 +
> >  .../mediatek/vcodec/decoder/vdec_vpu_if.c     | 77 ++++++++++++---
> ----
> >  2 files changed, 52 insertions(+), 27 deletions(-)
> > 
> > diff --git
> a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h
> b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h
> > index 6c318de25a55e..7e36b2c69b7d1 100644
> > ---
> a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h
> > +++
> b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h
> > @@ -161,6 +161,7 @@ struct mtk_vcodec_dec_pdata {
> >   * @hw_id: hardware index used to identify different hardware.
> >   *
> >   * @msg_queue: msg queue used to store lat buffer information.
> > + * @vpu_inst: vpu instance pointer.
> >   *
> >   * @is_10bit_bitstream: set to true if it's 10bit bitstream
> >   */
> > @@ -205,6 +206,7 @@ struct mtk_vcodec_dec_ctx {
> >  int hw_id;
> >  
> >  struct vdec_msg_queue msg_queue;
> > +void *vpu_inst;
> >  
> >  bool is_10bit_bitstream;
> >  };
> > diff --git
> a/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c
> b/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c
> > index 82c3dc8c41273..23cfe5c6c90b7 100644
> > --- a/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c
> > +++ b/drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c
> > @@ -72,6 +72,21 @@ static void handle_get_param_msg_ack(const
> struct vdec_vpu_ipi_get_param_ack *ms
> >  }
> >  }
> >  
> > +static bool vpu_dec_check_ap_inst(struct mtk_vcodec_dec_dev
> *dec_dev, struct vdec_vpu_inst *vpu)
> > +{
> > +struct mtk_vcodec_dec_ctx *ctx;
> > +int ret = false;
> > +
> > +list_for_each_entry(ctx, &dec_dev->ctx_list, list) {
> > +if (!IS_ERR_OR_NULL(ctx) && ctx->vpu_inst == vpu) {
> > +ret = true;
> > +break;
> > +}
> > +}
> > +
> > +return ret;
> > +}
> > +
> >  /*
> >   * vpu_dec_ipi_handler - Handler for VPU ipi message.
> >   *
> > @@ -84,44 +99,51 @@ static void handle_get_param_msg_ack(const
> struct vdec_vpu_ipi_get_param_ack *ms
> >   */
> >  static void vpu_dec_ipi_handler(void *data, unsigned int len, void
> *priv)
> >  {
> > +struct mtk_vcodec_dec_dev *dec_dev;
> >  const struct vdec_vpu_ipi_ack *msg = data;
> > -struct vdec_vpu_inst *vpu = (struct vdec_vpu_inst *)
> > -(unsigned long)msg->ap_inst_addr;
> > +struct vdec_vpu_inst *vpu;
> >  
> > -if (!vpu) {
> > +dec_dev = (struct mtk_vcodec_dec_dev *)priv;
> > +vpu = (struct vdec_vpu_inst *)(unsigned long)msg->ap_inst_addr;
> > +if (!priv || !vpu) {
> >  mtk_v4l2_vdec_err(vpu->ctx, "ap_inst_addr is NULL, did the SCP
> hang or crash?");
> >  return;
> >  }
> 
> This change results in a smatch error:
> 
> drivers/media/platform/mediatek/vcodec/decoder/vdec_vpu_if.c:109
> vpu_dec_ipi_handler() error: we previously assumed 'vpu' could be
> null (see line 108)
> 
> The same happens in the next patch for vpu_enc_ipi_handler.
> 
> Can you post a v4 fixing this?
> 
> Thank you!
> 
> Hans

Please help to review v4 again.

Best Regards,
Yunfei Dong
> 
> >  
> > -mtk_vdec_debug(vpu->ctx, "+ id=%X", msg->msg_id);
> > +if (!vpu_dec_check_ap_inst(dec_dev, vpu) || msg->msg_id <
> VPU_IPIMSG_DEC_INIT_ACK ||
> > +    msg->msg_id > VPU_IPIMSG_DEC_GET_PARAM_ACK) {
> > +mtk_v4l2_vdec_err(vpu->ctx, "vdec msg id not correctly => 0x%x",
> msg->msg_id);
> > +vpu->failure = -EINVAL;
> > +goto error;
> > +}
> >  
> >  vpu->failure = msg->status;
> > -vpu->signaled = 1;
> > +if (msg->status != 0)
> > +goto error;
> >  
> > -if (msg->status == 0) {
> > -switch (msg->msg_id) {
> > -case VPU_IPIMSG_DEC_INIT_ACK:
> > -handle_init_ack_msg(data);
> > -break;
> > +switch (msg->msg_id) {
> > +case VPU_IPIMSG_DEC_INIT_ACK:
> > +handle_init_ack_msg(data);
> > +break;
> >  
> > -case VPU_IPIMSG_DEC_START_ACK:
> > -case VPU_IPIMSG_DEC_END_ACK:
> > -case VPU_IPIMSG_DEC_DEINIT_ACK:
> > -case VPU_IPIMSG_DEC_RESET_ACK:
> > -case VPU_IPIMSG_DEC_CORE_ACK:
> > -case VPU_IPIMSG_DEC_CORE_END_ACK:
> > -break;
> > +case VPU_IPIMSG_DEC_START_ACK:
> > +case VPU_IPIMSG_DEC_END_ACK:
> > +case VPU_IPIMSG_DEC_DEINIT_ACK:
> > +case VPU_IPIMSG_DEC_RESET_ACK:
> > +case VPU_IPIMSG_DEC_CORE_ACK:
> > +case VPU_IPIMSG_DEC_CORE_END_ACK:
> > +break;
> >  
> > -case VPU_IPIMSG_DEC_GET_PARAM_ACK:
> > -handle_get_param_msg_ack(data);
> > -break;
> > -default:
> > -mtk_vdec_err(vpu->ctx, "invalid msg=%X", msg->msg_id);
> > -break;
> > -}
> > +case VPU_IPIMSG_DEC_GET_PARAM_ACK:
> > +handle_get_param_msg_ack(data);
> > +break;
> > +default:
> > +mtk_vdec_err(vpu->ctx, "invalid msg=%X", msg->msg_id);
> > +break;
> >  }
> >  
> > -mtk_vdec_debug(vpu->ctx, "- id=%X", msg->msg_id);
> > +error:
> > +vpu->signaled = 1;
> >  }
> >  
> >  static int vcodec_vpu_send_msg(struct vdec_vpu_inst *vpu, void
> *msg, int len)
> > @@ -182,9 +204,10 @@ int vpu_dec_init(struct vdec_vpu_inst *vpu)
> >  
> >  init_waitqueue_head(&vpu->wq);
> >  vpu->handler = vpu_dec_ipi_handler;
> > +vpu->ctx->vpu_inst = vpu;
> >  
> >  err = mtk_vcodec_fw_ipi_register(vpu->ctx->dev->fw_handler, vpu-
> >id,
> > - vpu->handler, "vdec", NULL);
> > + vpu->handler, "vdec", vpu->ctx->dev);
> >  if (err) {
> >  mtk_vdec_err(vpu->ctx, "vpu_ipi_register fail status=%d", err);
> >  return err;
> > @@ -193,7 +216,7 @@ int vpu_dec_init(struct vdec_vpu_inst *vpu)
> >  if (vpu->ctx->dev->vdec_pdata->hw_arch ==
> MTK_VDEC_LAT_SINGLE_CORE) {
> >  err = mtk_vcodec_fw_ipi_register(vpu->ctx->dev->fw_handler,
> >   vpu->core_id, vpu->handler,
> > - "vdec", NULL);
> > + "vdec", vpu->ctx->dev);
> >  if (err) {
> >  mtk_vdec_err(vpu->ctx, "vpu_ipi_register core fail status=%d",
> err);
> >  return err;
> 
>