Re: [PATCH v2] platform: uv: fix missing checks for kcalloc

[Kees Cook]

On Mon, Mar 25, 2019 at 1:29 PM Kangjie Lu <kjlu@xxxxxxx> wrote:
>
> In case kcalloc fails, the patch return an error to avoid
> potential NULL pointer dereference.
>
> Signed-off-by: Kangjie Lu <kjlu@xxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

>
> ---
> v2: reuse existing error path as suggested by
> Borislav Petkov <bp@xxxxxxxxx>
> ---
>  arch/x86/platform/uv/tlb_uv.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
> index 2c53b0f19329..7b41b51b9a86 100644
> --- a/arch/x86/platform/uv/tlb_uv.c
> +++ b/arch/x86/platform/uv/tlb_uv.c
> @@ -2133,14 +2133,18 @@ static int __init summarize_uvhub_sockets(int nuvhubs,
>   */
>  static int __init init_per_cpu(int nuvhubs, int base_part_pnode)
>  {
> -       unsigned char *uvhub_mask;
>         struct uvhub_desc *uvhub_descs;
> +       unsigned char *uvhub_mask = NULL;
>
>         if (is_uv3_hub() || is_uv2_hub() || is_uv1_hub())
>                 timeout_us = calculate_destination_timeout();
>
>         uvhub_descs = kcalloc(nuvhubs, sizeof(struct uvhub_desc), GFP_KERNEL);
> +       if (!uvhub_descs)
> +               goto fail;
>         uvhub_mask = kzalloc((nuvhubs+7)/8, GFP_KERNEL);
> +       if (!uvhub_mask)
> +               goto fail;
>
>         if (get_cpu_topology(base_part_pnode, uvhub_descs, uvhub_mask))
>                 goto fail;
> --
> 2.17.1
>


-- 
Kees Cook