Quoting Dan Carpenter (2019-10-04 11:22:51)
The "used" variables here come from the user in the ioctl and it can be negative. It could result in an out of bounds write.
Signed-off-by: Dan Carpenter dan.carpenter@oracle.com
drivers/gpu/drm/i810/i810_dma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i810/i810_dma.c b/drivers/gpu/drm/i810/i810_dma.c index 2a77823b8e9a..e66c38332df4 100644 --- a/drivers/gpu/drm/i810/i810_dma.c +++ b/drivers/gpu/drm/i810/i810_dma.c @@ -728,7 +728,7 @@ static void i810_dma_dispatch_vertex(struct drm_device *dev, if (nbox > I810_NR_SAREA_CLIPRECTS) nbox = I810_NR_SAREA_CLIPRECTS;
if (used > 4 * 1024)
if (used < 0 || used > 4 * 1024) used = 0;
Yes, as passed to the GPU instruction, negative used is invalid.
Then it is used as an offset into a memblock, where a negative offset would be very bad.
Reviewed-by: Chris Wilson chris@chris-wilson.co.uk -Chris