drm/i915/display: Do not zero past infoframes.vsc

intel_dp_vsc_sdp_unpack() was using a memset() size (36, struct dp_sdp)
larger than the destination (24, struct drm_dp_vsc_sdp), clobbering
fields in struct intel_crtc_state after infoframes.vsc. Use the actual
target size for the memset().

Fixes: 1b404b7dbb10 ("drm/i915/dp: Read out DP SDPs")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210617213301.1824728-1-keescook@chromium.org
(cherry picked from commit c88e2647c5bb45d04dc4302018ebe6ebbf331823)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 5c9222283044a89c37e949b6a90aca151dfe718e..6cc03b9e4321aa5376d8fa4de41e86ed507542b1 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2868,7 +2868,7 @@ static int intel_dp_vsc_sdp_unpack(struct drm_dp_vsc_sdp *vsc,
        if (size < sizeof(struct dp_sdp))
                return -EINVAL;
 
-       memset(vsc, 0, size);
+       memset(vsc, 0, sizeof(*vsc));
 
        if (sdp->sdp_header.HB0 != 0)
                return -EINVAL;