[lvc-project] [PATCH] ACPICA: Fix dereference in acpi_ev_address_space_dispatch()

[Fedor Pchelkin]

On Thu, 31. Oct 20:31, George Rurikov wrote:
> When support for  PCC Opregion was added, validation of field_obj
> was missed.
> Based on the acpi_ev_address_space_dispatch function description,
> field_obj can be NULL, and also when acpi_ev_address_space_dispatch
> is called in the acpi_ex_region_read() NULL is passed as field_obj.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 0acf24ad7e10 ("ACPICA: Add support for PCC Opregion special context data")
> Cc: stable at vger.kernel.org
> Signed-off-by: George Rurikov <grurikov at gmail.com>
> ---
>  drivers/acpi/acpica/evregion.c | 18 +++++++++++-------

Hi George,

ACPICA patches go first via a separate Github project [1].
[1]: https://github.com/acpica/acpica

Please see [2] and [3] for more info:
[2]: https://lore.kernel.org/acpica-devel/CAJZ5v0i7LYzF13M0qdeYWXZ7uO6HUpAS7pE5RJnOAJtKB8o88A@mail.gmail.com/
[3]: https://docs.kernel.org/driver-api/acpi/linuxized-acpica.html

>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c
> index cf53b9535f18..03e8b6f186af 100644
> --- a/drivers/acpi/acpica/evregion.c
> +++ b/drivers/acpi/acpica/evregion.c
> @@ -164,13 +164,17 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
>  		}
>  
>  		if (region_obj->region.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
> -			struct acpi_pcc_info *ctx =
> -			    handler_desc->address_space.context;
> -
> -			ctx->internal_buffer =
> -			    field_obj->field.internal_pcc_buffer;
> -			ctx->length = (u16)region_obj->region.length;
> -			ctx->subspace_id = (u8)region_obj->region.address;
> +			if (field_obj != NULL) {
> +				struct acpi_pcc_info *ctx =
> +					handler_desc->address_space.context;
> +
> +				ctx->internal_buffer =
> +					field_obj->field.internal_pcc_buffer;
> +				ctx->length = (u16)region_obj->region.length;
> +				ctx->subspace_id = (u8)region_obj->region.address;
> +			} else {
> +				return_ACPI_STATUS(AE_ERROR);
> +			}
>  		}
>  
>  		if (region_obj->region.space_id ==
> -- 
> 2.34.1