CVE-2024-50215

In the Linux kernel, the following vulnerability has been resolved:

nvmet-auth: assign dh_key to NULL after kfree_sensitive

ctrl->dh_key might be used across multiple calls to nvmet_setup_dhgroup()
for the same controller. So it's better to nullify it after release on
error path in order to avoid double free later in nvmet_destroy_auth().

Found by Linux Verification Center (linuxtesting.org) with Svace.