Re: [PATCH][next] acpi/hmat: fix uninitialized pointer dereference on pointer 'target'

[Nathan Chancellor <natechancellor@gmail.com>]

On Fri, Apr 05, 2019 at 03:12:15PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> The pointer 'target' is not initialized and is only assigned when the
> ACPI_HMAT_MEMORY_PD_VALID bit in p->flags is set.  There is a later null
> check on target that leads to an uninitialized pointer read and
> dereference when assigning target->processor_pxm when target contains a
> non-null garbage value.  Fix this by initializing targer to null.
> 
> Fixes: 665ac7e92757 ("acpi/hmat: Register processor domain to its memory")
> Addresses-Coverity: ("Uninitialized pointer read")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>

> ---
>  drivers/acpi/hmat/hmat.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/hmat/hmat.c b/drivers/acpi/hmat/hmat.c
> index b7824a0309f7..b275016ff648 100644
> --- a/drivers/acpi/hmat/hmat.c
> +++ b/drivers/acpi/hmat/hmat.c
> @@ -366,7 +366,7 @@ static int __init hmat_parse_proximity_domain(union acpi_subtable_headers *heade
>  					      const unsigned long end)
>  {
>  	struct acpi_hmat_proximity_domain *p = (void *)header;
> -	struct memory_target *target;
> +	struct memory_target *target = NULL;
>  
>  	if (p->header.length != sizeof(*p)) {
>  		pr_notice("HMAT: Unexpected address range header length: %d\n",
> -- 
> 2.20.1
>