media: vivid: s_fbuf: add more sanity checks

[ Upstream commit f8bcaf714abfc94818dff8c0db84d750433984f4 ]

VIDIOC_S_FBUF is by definition a scary ioctl, which is why only root
can use it. But at least check if the framebuffer parameters match that
of one of the framebuffer created by vivid, and reject anything else.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Fixes: ef834f7836ec ([media] vivid: add the video capture and output parts)
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/media/test-drivers/vivid/vivid-core.c b/drivers/media/test-drivers/vivid/vivid-core.c
index 1e356dc65d3184483362eb3c24c7a317fbe68506..f69c64e5a1496ca132f63c2c7d8748a9665c44c7 100644 (file)
--- a/drivers/media/test-drivers/vivid/vivid-core.c
+++ b/drivers/media/test-drivers/vivid/vivid-core.c
@@ -330,6 +330,28 @@ static int vidioc_g_fbuf(struct file *file, void *fh, struct v4l2_framebuffer *a
        return vivid_vid_out_g_fbuf(file, fh, a);
 }
 
+/*
+ * Only support the framebuffer of one of the vivid instances.
+ * Anything else is rejected.
+ */
+bool vivid_validate_fb(const struct v4l2_framebuffer *a)
+{
+       struct vivid_dev *dev;
+       int i;
+
+       for (i = 0; i < n_devs; i++) {
+               dev = vivid_devs[i];
+               if (!dev || !dev->video_pbase)
+                       continue;
+               if ((unsigned long)a->base == dev->video_pbase &&
+                   a->fmt.width <= dev->display_width &&
+                   a->fmt.height <= dev->display_height &&
+                   a->fmt.bytesperline <= dev->display_byte_stride)
+                       return true;
+       }
+       return false;
+}
+
 static int vidioc_s_fbuf(struct file *file, void *fh, const struct v4l2_framebuffer *a)
 {
        struct video_device *vdev = video_devdata(file);

diff --git a/drivers/media/test-drivers/vivid/vivid-core.h b/drivers/media/test-drivers/vivid/vivid-core.h
index 99e69b8f770f00570369048b26ccff303a9f9799..6aa32c8e6fb5cd401de1133750219aaa569097eb 100644 (file)
--- a/drivers/media/test-drivers/vivid/vivid-core.h
+++ b/drivers/media/test-drivers/vivid/vivid-core.h
@@ -609,4 +609,6 @@ static inline bool vivid_is_hdmi_out(const struct vivid_dev *dev)
        return dev->output_type[dev->output] == HDMI;
 }
 
+bool vivid_validate_fb(const struct v4l2_framebuffer *a);
+
 #endif

diff --git a/drivers/media/test-drivers/vivid/vivid-vid-cap.c b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
index eadf28ab1e393d77da83684a637fd460c93adce2..d4e30cf64e5f2ab3d7032ddef617e5304fb5e061 100644 (file)
--- a/drivers/media/test-drivers/vivid/vivid-vid-cap.c
+++ b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
@@ -1276,7 +1276,14 @@ int vivid_vid_cap_s_fbuf(struct file *file, void *fh,
                return -EINVAL;
        if (a->fmt.bytesperline < (a->fmt.width * fmt->bit_depth[0]) / 8)
                return -EINVAL;
-       if (a->fmt.height * a->fmt.bytesperline < a->fmt.sizeimage)
+       if (a->fmt.bytesperline > a->fmt.sizeimage / a->fmt.height)
+               return -EINVAL;
+
+       /*
+        * Only support the framebuffer of one of the vivid instances.
+        * Anything else is rejected.
+        */
+       if (!vivid_validate_fb(a))
                return -EINVAL;
 
        dev->fb_vbase_cap = phys_to_virt((unsigned long)a->base);