In the Linux kernel, the following vulnerability has been resolved:powerpc/pseries: Whitelist dtl slub object for copying to userspaceReading the dispatch trace log from /sys/kernel/debug/powerpc/dtl/cpu-*
results in a BUG() when the config CONFIG_HARDENED_USERCOPY is enabled as
shown below.Commit 6d07d1cd300f ("usercopy: Restrict non-usercopy caches to size 0")
requires that only whitelisted areas in slab/slub objects can be copied to
userspace when usercopy hardening is enabled using CONFIG_HARDENED_USERCOPY.
Dtl contains hypervisor dispatch events which are expected to be read by
privileged users. Hence mark this safe for user access.
Specify useroffset=0 and usersize=DISPATCH_LOG_BYTES to whitelist the
entire object.