Re: [PATCH v3 1/3] drm/framebuffer: Check for valid formats

2023-01-13 Thread Simon Ser
On Friday, January 13th, 2023 at 17:59, Maíra Canal  wrote:

> + /* Verify that the modifier is supported. */
> + if (r->modifier[0] && drm_drv_uses_atomic_modeset(dev) &&
> + !drm_any_plane_has_format(dev, r->pixel_format, r->modifier[0])) {
> + drm_dbg_kms(dev, "Unsupported pixel format %p4cc / modifier 
> 0x%llx\n",
> + >pixel_format, r->modifier[0]);
> + return -EINVAL;
> + }

User-space indicates whether there is a modifier in the IOCTL data by supplying
the DRM_MODE_FB_MODIFIERS flag. I believe we need to check that flag instead of
r->modifier[0]: the zero modifier is a valid modifier (LINEAR).


[PATCH v3 1/3] drm/framebuffer: Check for valid formats

2023-01-13 Thread Maíra Canal
Currently, framebuffer_check() doesn't check if the pixel format is
supported, which can lead to the acceptance of invalid pixel formats
e.g. the acceptance of invalid modifiers. Therefore, add a check for
valid formats on framebuffer_check(), so that the ADDFB2 IOCTL rejects
calls with invalid formats.

Moreover, note that this check is only valid for atomic drivers,
because, for non-atomic drivers, checking drm_any_plane_has_format() is
not possible since the format list for the primary plane is fake, and
we'd therefore reject valid formats.

Reviewed-by: Daniel Vetter 
Signed-off-by: Maíra Canal 
---
 Documentation/gpu/todo.rst| 9 -
 drivers/gpu/drm/drm_framebuffer.c | 8 
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 1f8a5ebe188e..3a79c26c5cc7 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -276,11 +276,10 @@ Various hold-ups:
 - Need to switch to drm_fbdev_generic_setup(), otherwise a lot of the custom fb
   setup code can't be deleted.
 
-- Many drivers wrap drm_gem_fb_create() only to check for valid formats. For
-  atomic drivers we could check for valid formats by calling
-  drm_plane_check_pixel_format() against all planes, and pass if any plane
-  supports the format. For non-atomic that's not possible since like the format
-  list for the primary plane is fake and we'd therefor reject valid formats.
+- Need to switch to drm_gem_fb_create(), as now framebuffer_check() checks for
+  valid formats for atomic drivers.
+
+- Add an addfb format validation for non-atomic drivers.
 
 - Many drivers subclass drm_framebuffer, we'd need a embedding compatible
   version of the varios drm_gem_fb_create functions. Maybe called
diff --git a/drivers/gpu/drm/drm_framebuffer.c 
b/drivers/gpu/drm/drm_framebuffer.c
index aff3746dedfb..0afc9e39188a 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -280,6 +280,14 @@ static int framebuffer_check(struct drm_device *dev,
}
}
 
+   /* Verify that the modifier is supported. */
+   if (r->modifier[0] && drm_drv_uses_atomic_modeset(dev) &&
+   !drm_any_plane_has_format(dev, r->pixel_format, r->modifier[0])) {
+   drm_dbg_kms(dev, "Unsupported pixel format %p4cc / modifier 
0x%llx\n",
+   >pixel_format, r->modifier[0]);
+   return -EINVAL;
+   }
+
return 0;
 }
 
-- 
2.39.0