ARM: xen: validate hypervisor compatible before parsing its version

ARM: xen: validate hypervisor compatible before parsing its version

fdt_find_hyper_node() reads the raw compatible property and then derives
hyper_node.version from a prefix match before later printing it with %s.
Flat DT properties are external boot input, and this path does not prove
that the first compatible entry is NUL-terminated within the returned
property length.

Keep the existing flat-DT lookup path, but verify that the first
compatible entry terminates within the returned property length before
deriving the version suffix from it.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20260405094005.5-arm-xen-v2-pengpeng@iscas.ac.cn>