Re: [PATCH] drm/radeon/r600_cs: Fix possible int overflows in r600_cs_check_reg()

[Alex Deucher]

Applied.  Thanks!

On Wed, Nov 29, 2023 at 10:28 AM Nikita Zhandarovich
<n.zhandarovich@xxxxxxxxxx> wrote:
>
> While improbable, there may be a chance of hitting integer
> overflow when the result of radeon_get_ib_value() gets shifted
> left.
>
> Avoid it by casting one of the operands to larger data type (u64).
>
> Found by Linux Verification Center (linuxtesting.org) with static
> analysis tool SVACE.
>
> Fixes: 1729dd33d20b ("drm/radeon/kms: r600 CS parser fixes")
> Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/radeon/r600_cs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/r600_cs.c b/drivers/gpu/drm/radeon/r600_cs.c
> index 638f861af80f..6cf54a747749 100644
> --- a/drivers/gpu/drm/radeon/r600_cs.c
> +++ b/drivers/gpu/drm/radeon/r600_cs.c
> @@ -1275,7 +1275,7 @@ static int r600_cs_check_reg(struct radeon_cs_parser *p, u32 reg, u32 idx)
>                         return -EINVAL;
>                 }
>                 tmp = (reg - CB_COLOR0_BASE) / 4;
> -               track->cb_color_bo_offset[tmp] = radeon_get_ib_value(p, idx) << 8;
> +               track->cb_color_bo_offset[tmp] = (u64)radeon_get_ib_value(p, idx) << 8;
>                 ib[idx] += (u32)((reloc->gpu_offset >> 8) & 0xffffffff);
>                 track->cb_color_base_last[tmp] = ib[idx];
>                 track->cb_color_bo[tmp] = reloc->robj;
> @@ -1302,7 +1302,7 @@ static int r600_cs_check_reg(struct radeon_cs_parser *p, u32 reg, u32 idx)
>                                         "0x%04X\n", reg);
>                         return -EINVAL;
>                 }
> -               track->htile_offset = radeon_get_ib_value(p, idx) << 8;
> +               track->htile_offset = (u64)radeon_get_ib_value(p, idx) << 8;
>                 ib[idx] += (u32)((reloc->gpu_offset >> 8) & 0xffffffff);
>                 track->htile_bo = reloc->robj;
>                 track->db_dirty = true;
> --
> 2.25.1
>