drm/i915/gem: Detect overflow in calculating dumb buffer size

To multiply 2 u32 numbers to generate a u64 in C requires a bit of
forewarning for the compiler.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200123125934.1401755-1-chris@chris-wilson.co.uk
(cherry picked from commit 0f8f8a64300092852b9361cd835395ee71e6a7d6)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 94f993e4c12f5cb687513efee0a2822afd20d734..c2de2f45b459b85e428b2e11f7984a417158ae5f 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -265,7 +265,10 @@ i915_gem_dumb_create(struct drm_file *file,
                                                    DRM_FORMAT_MOD_LINEAR))
                args->pitch = ALIGN(args->pitch, 4096);
 
-       args->size = args->pitch * args->height;
+       if (args->pitch < args->width)
+               return -EINVAL;
+
+       args->size = mul_u32_u32(args->pitch, args->height);
 
        mem_type = INTEL_MEMORY_SYSTEM;
        if (HAS_LMEM(to_i915(dev)))