[PATCH 5.12 182/242] drm/i915/display: Do not zero past infoframes.vsc

[Greg Kroah-Hartman]

From: Kees Cook <keescook@xxxxxxxxxxxx>

commit 07b72960d2b4a087ff2445e286159e69742069cc upstream.

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@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20210617213301.1824728-1-keescook@xxxxxxxxxxxx
(cherry picked from commit c88e2647c5bb45d04dc4302018ebe6ebbf331823)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/i915/display/intel_dp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3913,7 +3913,7 @@ static int intel_dp_vsc_sdp_unpack(struc
 	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;