[PATCH 3.16.y-ckt 033/118] drm: add a check for x/y in drm_mode_setcrtc

From: Luis Henriques
Date: Wed Aug 12 2015 - 05:34:48 EST

3.16.7-ckt16 -stable review patch. If anyone has any objections, please let me know.


From: Zhao Junwang <zhjwpku@xxxxxxxxx>

commit 01447e9f04ba1c49a9534ae6a5a6f26c2bb05226 upstream.

legacy setcrtc ioctl does take a 32 bit value which might indeed

the checks of crtc_req->x > INT_MAX and crtc_req->y > INT_MAX aren't
needed any more with this

v2: -polish the annotation according to Daniel's comment

Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Zhao Junwang <zhjwpku@xxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/gpu/drm/drm_crtc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index fe94cc10cd35..ee96912e0824 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -2382,8 +2382,11 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EINVAL;

- /* For some reason crtc x/y offsets are signed internally. */
- if (crtc_req->x > INT_MAX || crtc_req->y > INT_MAX)
+ /*
+ * Universal plane src offsets are only 16.16, prevent havoc for
+ * drivers using universal plane code internally.
+ */
+ if (crtc_req->x & 0xffff0000 || crtc_req->y & 0xffff0000)
return -ERANGE;

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