2017-12-09 06:38:06

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH] drm/i915/gvt/fb_decoder: Fix out-of-bounds read

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 <[email protected]>
---
drivers/gpu/drm/i915/gvt/fb_decoder.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/fb_decoder.c b/drivers/gpu/drm/i915/gvt/fb_decoder.c
index 72f4217..aed578b 100644
--- 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(struct intel_vgpu *vgpu,
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 {
--
2.7.4


2017-12-11 09:27:05

by Zhenyu Wang

[permalink] [raw]
Subject: Re: [PATCH] drm/i915/gvt/fb_decoder: Fix out-of-bounds read

On 2017.12.09 00:37:59 -0600, Gustavo A. R. Silva wrote:
> 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 <[email protected]>
> ---
> drivers/gpu/drm/i915/gvt/fb_decoder.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gvt/fb_decoder.c b/drivers/gpu/drm/i915/gvt/fb_decoder.c
> index 72f4217..aed578b 100644
> --- 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(struct intel_vgpu *vgpu,
> 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 {
> --

Applied this, thanks!

--
Open Source Technology Center, Intel ltd.

$gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827


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2017-12-12 20:56:15

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH] drm/i915/gvt/fb_decoder: Fix out-of-bounds read

Hi Zhenyu,

Quoting Zhenyu Wang <[email protected]>:

> On 2017.12.09 00:37:59 -0600, Gustavo A. R. Silva wrote:
>> 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 <[email protected]>
>> ---
>> drivers/gpu/drm/i915/gvt/fb_decoder.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/gvt/fb_decoder.c
>> b/drivers/gpu/drm/i915/gvt/fb_decoder.c
>> index 72f4217..aed578b 100644
>> --- 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(struct
>> intel_vgpu *vgpu,
>> 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 {
>> --
>
> Applied this, thanks!
>

Glad to help. :)

Thanks
--
Gustavo A. R. Silva