nvmet: Don't overflow subsysnqn

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: nvmet: Don't overflow subsysnqn nvmet_root_discovery_nqn_store treats the subsysnqn string like a fixed size buffer, even though it is dynamically allocated to the size of the string. Create a new string with kstrndup instead of using the old buffer.

References

• https://git.kernel.org/stable/c/86645d8d062af3fdcbdaa0a289b95de55bca827d
• https://git.kernel.org/stable/c/4db3d750ac7e894278ef1cb1c53cc7d883060496