Re: [PATCH] drivers/amd/pm: fix a use-after-free in kv_parse_power_table

[Alex Deucher]

Applied.  Thanks!

On Thu, Dec 14, 2023 at 11:57 AM Zhipeng Lu <alexious@xxxxxxxxxx> wrote:
>
> When ps allocated by kzalloc equals to NULL, kv_parse_power_table
> frees adev->pm.dpm.ps that allocated before. However, after the control
> flow goes through the following call chains:
>
> kv_parse_power_table
>   |-> kv_dpm_init
>         |-> kv_dpm_sw_init
>               |-> kv_dpm_fini
>
> The adev->pm.dpm.ps is used in the for loop of kv_dpm_fini after its
> first free in kv_parse_power_table and causes a use-after-free bug.
>
> Fixes: a2e73f56fa62 ("drm/amdgpu: Add support for CIK parts")
> Signed-off-by: Zhipeng Lu <alexious@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
> index 5d28c951a319..5cb4725c773f 100644
> --- a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
> @@ -2735,10 +2735,8 @@ static int kv_parse_power_table(struct amdgpu_device *adev)
>                 non_clock_info = (struct _ATOM_PPLIB_NONCLOCK_INFO *)
>                         &non_clock_info_array->nonClockInfo[non_clock_array_index];
>                 ps = kzalloc(sizeof(struct kv_ps), GFP_KERNEL);
> -               if (ps == NULL) {
> -                       kfree(adev->pm.dpm.ps);
> +               if (ps == NULL)
>                         return -ENOMEM;
> -               }
>                 adev->pm.dpm.ps[i].ps_priv = ps;
>                 k = 0;
>                 idx = (u8 *)&power_state->v2.clockInfoIndex[0];
> --
> 2.34.1
>