On 5/3/2018 9:20 AM, Mark Rutland wrote: > This patch adds basic support for pointer authentication, allowing > userspace to make use of APIAKey. The kernel maintains an APIAKey value > for each process (shared by all threads within), which is initialised to > a random value at exec() time. > > To describe that address authentication instructions are available, the > ID_AA64ISAR0.{APA,API} fields are exposed to userspace. A new hwcap, > APIA, is added to describe that the kernel manages APIAKey. > > Instructions using other keys (APIBKey, APDAKey, APDBKey) are disabled, > and will behave as NOPs. These may be made use of in future patches. > > No support is added for the generic key (APGAKey), though this cannot be > trapped or made to behave as a NOP. Its presence is not advertised with > a hwcap. > > Signed-off-by: Mark Rutland <mark.rutl...@arm.com> > Cc: Catalin Marinas <catalin.mari...@arm.com> > Cc: Ramana Radhakrishnan <ramana.radhakrish...@arm.com> > Cc: Suzuki K Poulose <suzuki.poul...@arm.com> > Cc: Will Deacon <will.dea...@arm.com> > ---
Mark, I was able to verify that a buffer overflow exploit results in a segfault with these PAC patches. When I compile the same binary without "-msign-return-address=none", I am able to successfully overflow the stack and execute malicious code. Thanks Adam Tested-by: Adam Wallis <awal...@codeaurora.org> -- Adam Wallis Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.