Re: [PATCH 11/14] media: medkatek: vcodec: covert secure fd to secure handle

[Nicolas Dufresne]

Le lundi 11 septembre 2023 à 20:59 +0800, Yunfei Dong a écrit :
> User driver will fill or parse data in optee-os with secure handle,
> need to covert secure fd to secure handle in kernel.
> 
> Signed-off-by: Yunfei Dong <yunfei.dong@xxxxxxxxxxxx>
> ---
>  .../vcodec/decoder/mtk_vcodec_dec_drv.c       |  1 +
>  .../vcodec/decoder/mtk_vcodec_dec_stateless.c | 54 ++++++++++++++++++-
>  drivers/media/v4l2-core/v4l2-ctrls-defs.c     |  5 ++
>  include/uapi/linux/v4l2-controls.h            |  4 ++
>  4 files changed, 62 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c
> index 0a89ce452ac3..64e006820f43 100644
> --- a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c
> +++ b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c
> @@ -571,3 +571,4 @@ module_platform_driver(mtk_vcodec_dec_driver);
>  
>  MODULE_LICENSE("GPL v2");
>  MODULE_DESCRIPTION("Mediatek video codec V4L2 decoder driver");
> +MODULE_IMPORT_NS(DMA_BUF);
> diff --git a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c
> index 2ea517883a86..d2b09ce9f1cf 100644
> --- a/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c
> +++ b/drivers/media/platform/mediatek/vcodec/decoder/mtk_vcodec_dec_stateless.c
> @@ -426,6 +426,46 @@ static int mtk_vcodec_get_pic_info(struct mtk_vcodec_dec_ctx *ctx)
>  	return ret;
>  }
>  
> +static int mtk_dma_contig_get_secure_handle(struct mtk_vcodec_dec_ctx *ctx, int fd)
> +{
> +	int secure_handle = 0;
> +	struct dma_buf *buf;
> +	struct dma_buf_attachment *dba;
> +	struct sg_table *sgt;
> +	struct device *dev = &ctx->dev->plat_dev->dev;
> +
> +	buf = dma_buf_get(fd);
> +	if (IS_ERR(buf)) {
> +		mtk_v4l2_vdec_err(ctx, "dma_buf_get fail fd:%d", fd);
> +		return 0;
> +	}
> +
> +	dba = dma_buf_attach(buf, dev);
> +	if (IS_ERR(dba)) {
> +		mtk_v4l2_vdec_err(ctx, "dma_buf_attach fail fd:%d", fd);
> +		goto err_attach;
> +	}
> +
> +	sgt = dma_buf_map_attachment(dba, DMA_BIDIRECTIONAL);
> +	if (IS_ERR(sgt)) {
> +		mtk_v4l2_vdec_err(ctx, "dma_buf_map_attachment fail fd:%d", fd);
> +		goto err_map;
> +	}
> +	secure_handle = sg_dma_address(sgt->sgl);

Does it mean if your secure dmabuf is passed to a driver that didn't know it was
secure it will pick the handle as a memory address and program the HW with it ?
That seems unsafe, the handle should be stored in a dedicated place and mapping
should either fail, or provide a dummy buffer.

> +
> +	dma_buf_unmap_attachment(dba, sgt, DMA_BIDIRECTIONAL);
> +	dma_buf_detach(buf, dba);
> +	dma_buf_put(buf);
> +
> +	return secure_handle;
> +err_map:
> +	dma_buf_detach(buf, dba);
> +err_attach:
> +	dma_buf_put(buf);
> +
> +	return 0;
> +}
> +
>  static int mtk_vdec_s_ctrl(struct v4l2_ctrl *ctrl)
>  {
>  	struct mtk_vcodec_dec_ctx *ctx = ctrl_to_dec_ctx(ctrl);
> @@ -436,7 +476,7 @@ static int mtk_vdec_s_ctrl(struct v4l2_ctrl *ctrl)
>  	struct v4l2_ctrl *hdr_ctrl;
>  	const struct mtk_vcodec_dec_pdata *dec_pdata = ctx->dev->vdec_pdata;
>  	const struct mtk_video_fmt *fmt;
> -	int i = 0, ret = 0;
> +	int i = 0, ret = 0, sec_fd;
>  
>  	hdr_ctrl = ctrl;
>  	if (!hdr_ctrl || !hdr_ctrl->p_new.p)
> @@ -489,6 +529,12 @@ static int mtk_vdec_s_ctrl(struct v4l2_ctrl *ctrl)
>  			return -EINVAL;
>  		}
>  		break;
> +	case V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE:
> +		sec_fd = ctrl->val;
> +
> +		ctrl->val = mtk_dma_contig_get_secure_handle(ctx, ctrl->val);
> +		mtk_v4l2_vdec_dbg(3, ctx, "get secure handle: %d => 0x%x", sec_fd, ctrl->val);
> +		break;
>  	default:
>  		mtk_v4l2_vdec_dbg(3, ctx, "Not supported to set ctrl id: 0x%x\n", hdr_ctrl->id);
>  		return ret;
> @@ -525,8 +571,9 @@ static const struct v4l2_ctrl_ops mtk_vcodec_dec_ctrl_ops = {
>  static int mtk_vcodec_dec_ctrls_setup(struct mtk_vcodec_dec_ctx *ctx)
>  {
>  	unsigned int i;
> +	struct v4l2_ctrl *ctrl;
>  
> -	v4l2_ctrl_handler_init(&ctx->ctrl_hdl, NUM_CTRLS);
> +	v4l2_ctrl_handler_init(&ctx->ctrl_hdl, NUM_CTRLS + 1);
>  	if (ctx->ctrl_hdl.error) {
>  		mtk_v4l2_vdec_err(ctx, "v4l2_ctrl_handler_init failed\n");
>  		return ctx->ctrl_hdl.error;
> @@ -543,6 +590,9 @@ static int mtk_vcodec_dec_ctrls_setup(struct mtk_vcodec_dec_ctx *ctx)
>  		}
>  	}
>  
> +	ctrl = v4l2_ctrl_new_std(&ctx->ctrl_hdl, &mtk_vcodec_dec_ctrl_ops,
> +				 V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE, 0, 65535, 1, 0);
> +
>  	v4l2_ctrl_handler_setup(&ctx->ctrl_hdl);
>  
>  	return 0;
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> index 8696eb1cdd61..d8cf01f76aab 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> @@ -1041,6 +1041,7 @@ const char *v4l2_ctrl_get_name(u32 id)
>  	case V4L2_CID_MPEG_VIDEO_HEVC_SIZE_OF_LENGTH_FIELD:	return "HEVC Size of Length Field";
>  	case V4L2_CID_MPEG_VIDEO_REF_NUMBER_FOR_PFRAMES:	return "Reference Frames for a P-Frame";
>  	case V4L2_CID_MPEG_VIDEO_PREPEND_SPSPPS_TO_IDR:		return "Prepend SPS and PPS to IDR";
> +	case V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE:		return "MediaTek Decoder get secure handle";
>  
>  	/* AV1 controls */
>  	case V4L2_CID_MPEG_VIDEO_AV1_PROFILE:			return "AV1 Profile";
> @@ -1437,6 +1438,10 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
>  	case V4L2_CID_MPEG_VIDEO_VPX_NUM_REF_FRAMES:
>  		*type = V4L2_CTRL_TYPE_INTEGER_MENU;
>  		break;
> +	case V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE:
> +		*type = V4L2_CTRL_TYPE_INTEGER;
> +		*flags |= V4L2_CTRL_FLAG_WRITE_ONLY;
> +		break;
>  	case V4L2_CID_USER_CLASS:
>  	case V4L2_CID_CAMERA_CLASS:
>  	case V4L2_CID_CODEC_CLASS:
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index c3604a0a3e30..7b3694985366 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -954,6 +954,10 @@ enum v4l2_mpeg_mfc51_video_force_frame_type {
>  #define V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC		(V4L2_CID_CODEC_MFC51_BASE+53)
>  #define V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P		(V4L2_CID_CODEC_MFC51_BASE+54)
>  
> +/*  MPEG-class control IDs specific to the MediaTek Decoder driver as defined by V4L2 */
> +#define V4L2_CID_MPEG_MTK_BASE			(V4L2_CTRL_CLASS_CODEC | 0x2000)
> +#define V4L2_CID_MPEG_MTK_GET_SECURE_HANDLE	(V4L2_CID_MPEG_MTK_BASE+8)
> +
>  /*  Camera class control IDs */
>  
>  #define V4L2_CID_CAMERA_CLASS_BASE	(V4L2_CTRL_CLASS_CAMERA | 0x900)