Calculating the visible size of the system framebuffer can result in truncation of the result. The calculation uses 32-bit arithmetics, which can overflow if the values for height and stride are large. Fix the issue by multiplying with mul_u32_u32().
Signed-off-by: Thomas Zimmermann <[email protected]> Fixes: 32ae90c66fb6 ("drm/sysfb: Add efidrm for EFI displays") Fixes: a84eb6abe2b6 ("drm/sysfb: Add vesadrm for VESA displays") Reported-by: Sashiko <[email protected]> Closes: https://lore.kernel.org/dri-devel/[email protected]/ Cc: Thomas Zimmermann <[email protected]> Cc: Javier Martinez Canillas <[email protected]> Cc: [email protected] Cc: <[email protected]> # v6.16+ --- I've added Reported-by and Closes tags because this is a pre-existing issue. --- drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c b/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c index 361b7233600c..8b14eaa304c0 100644 --- a/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c +++ b/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c @@ -2,6 +2,7 @@ #include <linux/export.h> #include <linux/limits.h> +#include <linux/math64.h> #include <linux/minmax.h> #include <linux/screen_info.h> @@ -67,7 +68,7 @@ EXPORT_SYMBOL(drm_sysfb_get_stride_si); u64 drm_sysfb_get_visible_size_si(struct drm_device *dev, const struct screen_info *si, unsigned int height, unsigned int stride, u64 size) { - u64 vsize = height * stride; + u64 vsize = mul_u32_u32(height, stride); return drm_sysfb_get_validated_size0(dev, "visible size", vsize, size); } -- 2.54.0
