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

[ Upstream commit 8ae5b3a685dc59a8cf7ccfe0e850999ba9727a3c ]

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@gmail.com>
Reviewed-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 6c3d469..177a365 100644 (file)
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1911,7 +1911,7 @@ 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);
 }