Re: [PATCH][next] drm/amdgpu/df: fix potential array out-of-bounds read

[Alex Deucher]

On Wed, May 30, 2018 at 12:41 PM, Colin King <colin.king@xxxxxxxxxxxxx> wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The comparison with the number of elements in array df_v3_7_channel_number
> is off-by-one and can produce an array out-of-bounds read if
> fb_channel_number is equal to the number of elements of the array. Fix
> this by changing the comparison to >= instead of >.
>
> Detected by CoverityScan, CID#1469489 ("Out-of-bounds read")
>
> Fixes: 13b581502d51 ("drm/amdgpu/df: implement df v3_6 callback functions (v2)")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Applied.  thanks!

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/df_v3_6.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/df_v3_6.c b/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> index 60608b3df881..d5ebe566809b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> +++ b/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> @@ -64,7 +64,7 @@ static u32 df_v3_6_get_hbm_channel_number(struct amdgpu_device *adev)
>         int fb_channel_number;
>
>         fb_channel_number = adev->df_funcs->get_fb_channel_number(adev);
> -       if (fb_channel_number > ARRAY_SIZE(df_v3_6_channel_number))
> +       if (fb_channel_number >= ARRAY_SIZE(df_v3_6_channel_number))
>                 fb_channel_number = 0;
>
>         return df_v3_6_channel_number[fb_channel_number];
> --
> 2.17.0
>
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