Add a check if the framebuffer described by the provided drm_mode_fb_cmd2
structure fits into provided GEM buffers. Without this check it is
possible to create a framebuffer object from a small buffer and set it to
the hardware, what results in displaying system memory outside the
allocated GEM buffer.
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # v4.7+
---
This issue was there from the beggining, but the provided patch applies only
to v4.7+ kernels due to other changes in the fixed code.
---
drivers/gpu/drm/exynos/exynos_drm_fb.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
index d48fd7c918f8..73217c281c9a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
@@ -145,13 +145,19 @@ struct drm_framebuffer *
exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
const struct drm_mode_fb_cmd2 *mode_cmd)
{
+ const struct drm_format_info *info = drm_get_format_info(dev, mode_cmd);
struct exynos_drm_gem *exynos_gem[MAX_FB_BUFFER];
struct drm_gem_object *obj;
struct drm_framebuffer *fb;
int i;
int ret;
- for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
+ for (i = 0; i < info->num_planes; i++) {
+ unsigned int height = (i == 0) ? mode_cmd->height :
+ DIV_ROUND_UP(mode_cmd->height, info->vsub);
+ unsigned long size = height * mode_cmd->pitches[i] +
+ mode_cmd->offsets[i];
+
obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
if (!obj) {
DRM_ERROR("failed to lookup gem object\n");
@@ -160,6 +166,12 @@ struct drm_framebuffer *
}
exynos_gem[i] = to_exynos_gem(obj);
+
+ if (size > exynos_gem[i]->size) {
+ i++;
+ ret = -EINVAL;
+ goto err;
+ }
}
fb = exynos_drm_framebuffer_init(dev, mode_cmd, exynos_gem, i);
--
1.9.1