Am 2021-01-11 um 4:05 p.m. schrieb Jeremy Cline:
> KASAN reported a slab-out-of-bounds read of size 1 in
> kdf_create_vcrat_image_cpu().
>
> This occurs when, for example, when on an x86_64 with a single NUMA node
> because kfd_fill_iolink_info_for_cpu() is a no-op, but afterwards the
> sub_type_hdr->length, which is out-of-bounds, is read and multiplied by
> entries. Fortunately, entries is 0 in this case so the overall
> crat_table->length is still correct.
>
> Check if there were any entries before de-referencing sub_type_hdr which
> may be pointing to out-of-bounds memory.
>
> Fixes: b7b6c38529c9 ("drm/amdkfd: Calculate CPU VCRAT size dynamically (v2)")
> Suggested-by: Felix Kuehling <felix.kuehl...@amd.com>
> Signed-off-by: Jeremy Cline <jcl...@redhat.com>
Thanks. I'll apply this patch.
Reviewed-by: Felix Kuehling <felix.kuehl...@amd.com>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> index 8cac497c2c45..a5640a6138cf 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> @@ -1040,11 +1040,14 @@ static int kfd_create_vcrat_image_cpu(void
> *pcrat_image, size_t *size)
> (struct crat_subtype_iolink *)sub_type_hdr);
> if (ret < 0)
> return ret;
> - crat_table->length += (sub_type_hdr->length * entries);
> - crat_table->total_entries += entries;
>
> - sub_type_hdr = (typeof(sub_type_hdr))((char *)sub_type_hdr +
> - sub_type_hdr->length * entries);
> + if (entries) {
> + crat_table->length += (sub_type_hdr->length * entries);
> + crat_table->total_entries += entries;
> +
> + sub_type_hdr = (typeof(sub_type_hdr))((char
> *)sub_type_hdr +
> + sub_type_hdr->length * entries);
> + }
> #else
> pr_info("IO link not available for non x86 platforms\n");
> #endif
