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Message-ID: <1d19be1f21d579b529231882d761554d758db5b4.camel@collabora.com>
Date: Tue, 19 Sep 2023 19:03:31 -0400
From: Nicolas Dufresne <nicolas.dufresne@...labora.com>
To: Jeffrey Kardatzke <jkardatzke@...gle.com>
Cc: Yunfei Dong <yunfei.dong@...iatek.com>,
Nícolas "F . R . A . Prado"
<nfraprado@...labora.com>, Hans Verkuil <hverkuil-cisco@...all.nl>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>,
Benjamin Gaignard <benjamin.gaignard@...labora.com>,
Nathan Hebert <nhebert@...omium.org>,
Chen-Yu Tsai <wenst@...omium.org>,
Hsin-Yi Wang <hsinyi@...omium.org>,
Fritz Koenig <frkoenig@...omium.org>,
Daniel Vetter <daniel@...ll.ch>,
Steve Cho <stevecho@...omium.org>, linux-media@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org,
Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH 11/14] media: medkatek: vcodec: covert secure fd to
secure handle
Le mardi 19 septembre 2023 à 15:38 -0700, Jeffrey Kardatzke a écrit :
> On Tue, Sep 19, 2023 at 12:43 PM Nicolas Dufresne
> <nicolas.dufresne@...labora.com> wrote:
> >
> > 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@...iatek.com>
> > > ---
> > > .../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.
>
> Since the secure dmabufs don't support any mmap/cpu access to them and
> return -EPERM in those cases; wouldn't that prevent misuse of them in
> other places? (so the mmap operation and CPU access will fail, but
> getting the SG list from the dmabuf succeeds)
My impression is that if userspace can pass this FD to a driver without telling
the driver it is secure memory, the driver may potentially crash trying to use
the handle as an memory address.
In my opinion, sg_dma_address() should return addresses, like its name state. If
you want to get something else, you should find another way to obtain it.
Nicolas
>
> >
> > > +
> > > + 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)
> >
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