CVE-2023-53487 powerpc/rtas_flash: allow user copy to flash block cache objects

In the Linux kernel, the following vulnerability has been resolved: powerpc/rtasflash: allow user copy to flash block cache objects With hardened usercopy enabled CONFIGHARDENEDUSERCOPY=y, using the /proc/powerpc/rtas/firmwareupdate interface to prepare a system firmware update yields a BUG: kern...