From 461bd6227ede277138bf33c2156b6ebd1fba04c2 Mon Sep 17 00:00:00 2001
From: "Gustavo A. R. Silva" <garsilva@embeddedor.com>
Date: Sat, 9 Dec 2017 00:37:59 -0600
Subject: [PATCH] drm/i915/gvt/fb_decoder: Fix out-of-bounds read
Git-commit: 461bd6227ede277138bf33c2156b6ebd1fba04c2
Patch-mainline: v4.16-rc1
References: FATE#322643 bsc#1055900

In case function skl_format_to_drm returns -EINVAL, fmt turns into a huge
number as fmt is of type u32, hence there is an out-of-bounds read when
using fmt as an index for array skl_pixel_formats at line 225:
plane->bpp = skl_pixel_formats[fmt].bpp;

Fix this by comparing the value returned by function skl_format_to_drm
against the size of array skl_pixel_formats, so in case it is greater than
or equal to the number of items contained in skl_pixel_formats, print an
error message and return -EINVAL.

Addresses-coverity-id: 1462495
Addresses-coverity-id: 1462502 ("Out-of-bounds read")
Fixes: 9f31d1063b43 ("drm/i915/gvt: Add framebuffer decoder support")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/gvt/fb_decoder.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/gpu/drm/i915/gvt/fb_decoder.c
+++ b/drivers/gpu/drm/i915/gvt/fb_decoder.c
@@ -222,6 +222,12 @@ int intel_vgpu_decode_primary_plane(stru
 			val & PLANE_CTL_ORDER_RGBX,
 			val & PLANE_CTL_ALPHA_MASK,
 			val & PLANE_CTL_YUV422_ORDER_MASK);
+
+		if (fmt >= ARRAY_SIZE(skl_pixel_formats)) {
+			gvt_vgpu_err("Out-of-bounds pixel format index\n");
+			return -EINVAL;
+		}
+
 		plane->bpp = skl_pixel_formats[fmt].bpp;
 		plane->drm_format = skl_pixel_formats[fmt].drm_format;
 	} else {