drm/i810: Prevent underflow in ioctl (4f69851f) · Commits · 戴 / test

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:

drivers/gpu/drm/i810/i810_dma.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;

		if (sarea_priv->dirty)
		@@ -1048,7 +1048,7 @@ static void i810_dma_dispatch_mc(struct drm_device dev, struct drm_buf buf, in
		if (u != I810_BUF_CLIENT)
		DRM_DEBUG("MC found buffer that isn't mine!\n");

		if (used > 4 * 1024)
		if (used < 0 \|\| used > 4 * 1024)
		used = 0;

		sarea_priv->dirty = 0x7f;