Messages in this thread | | | Subject | Re: [PATCHv2 06/12] arm64: add basic pointer authentication support | From | Adam Wallis <> | Date | Tue, 22 May 2018 15:06:21 -0400 |
| |
On 11/27/2017 11:38 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.rutland@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/include/asm/mmu.h | 5 ++ > arch/arm64/include/asm/mmu_context.h | 25 +++++++++- > arch/arm64/include/asm/pointer_auth.h | 89 +++++++++++++++++++++++++++++++++++ > arch/arm64/include/uapi/asm/hwcap.h | 1 + > arch/arm64/kernel/cpufeature.c | 17 ++++++- > arch/arm64/kernel/cpuinfo.c | 1 + > 6 files changed, 134 insertions(+), 4 deletions(-) > create mode 100644 arch/arm64/include/asm/pointer_auth.h
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 <awallis@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.
| |