Re: [PATCH] drm/amdgpu: avoid out of bounds access on array interrupt_status_offsets

[Alex Deucher]

On Tue, Sep 20, 2016 at 11:16 AM, Colin King <colin.king@xxxxxxxxxxxxx> wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The check for an out of bound index into array interrupt_status_offsets
> is off-by-one. Fix this and also don't compared to a hard coded array
> size but use ARRAY_SIZE instead.
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/amd/amdgpu/dce_v6_0.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> index d3512f3..4ce4c1a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> @@ -2782,7 +2782,7 @@ static int dce_v6_0_hpd_irq(struct amdgpu_device *adev,
>         uint32_t disp_int, mask, int_control, tmp;
>         unsigned hpd;
>
> -       if (entry->src_data > 6) {
> +       if (entry->src_data >= ARRAY_SIZE(interrupt_status_offsets)) {

This should actually be adev->mode_info.num_hpd as some asic variants
may not have 6 hpd lines.  Thanks for catching this.

Alex

>                 DRM_DEBUG("Unhandled interrupt: %d %d\n", entry->src_id, entry->src_data);
>                 return 0;
>         }
> --
> 2.9.3
>
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