[PATCH] nvme-fc: Prevent null pointer dereference in nvme_fc_io_getuuid()

[James Smart]

On 8/17/2023 12:43 PM, Nigel Kirkland wrote:
> The nvme_fc_fcp_op structure describing an AEN operation is initialized with a
> null request structure pointer. An FC LLDD may make a call to
> nvme_fc_io_getuuid passing a pointer to an nvmefc_fcp_req for an AEN operation.
> 
> Add validation of the request structure pointer before dereference.
> 
> Signed-off-by: Nigel Kirkland <nkirkland2304 at gmail.com>
> ---
>   drivers/nvme/host/fc.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> 
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 1cd2bf8..a15b377 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -1924,7 +1924,7 @@ char *nvme_fc_io_getuuid(struct nvmefc_fcp_req *req)
>       struct nvme_fc_fcp_op *op = fcp_req_to_fcp_op(req);
>       struct request *rq = op->rq;
> 
> -    if (!IS_ENABLED(CONFIG_BLK_CGROUP_FC_APPID) || !rq->bio)
> +    if (!IS_ENABLED(CONFIG_BLK_CGROUP_FC_APPID) || !rq || !rq->bio)
>           return NULL;
>       return blkcg_get_fc_appid(rq->bio);
>   }

Looks good

Reviewed-by: James Smart <jsmart2021 at gmail.com>

-- james