linux/arch/arm64
Mark Rutland cff5b236fa arm64: Rework valid_user_regs
commit dbd4d7ca56 upstream.

We validate pstate using PSR_MODE32_BIT, which is part of the
user-provided pstate (and cannot be trusted). Also, we conflate
validation of AArch32 and AArch64 pstate values, making the code
difficult to reason about.

Instead, validate the pstate value based on the associated task. The
task may or may not be current (e.g. when using ptrace), so this must be
passed explicitly by callers. To avoid circular header dependencies via
sched.h, is_compat_task is pulled out of asm/ptrace.h.

To make the code possible to reason about, the AArch64 and AArch32
validation is split into separate functions. Software must respect the
RES0 policy for SPSR bits, and thus the kernel mirrors the hardware
policy (RAZ/WI) for bits as-yet unallocated. When these acquire an
architected meaning writes may be permitted (potentially with additional
validation).

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[ rebased for v4.1+
  This avoids a user-triggerable Oops() if a task is switched to a mode
  not supported by the kernel (e.g. switching a 64-bit task to AArch32).
]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com> [backport]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2016-07-27 09:47:33 -07:00
..
boot ls2080a/dts: Add little endian property for GPIO IP block 2015-12-11 16:13:03 -08:00
configs arm64 fixes and clean-ups: 2015-11-12 15:33:11 -08:00
crypto arm64: crypto: reduce priority of core AES cipher 2015-11-18 12:09:08 +00:00
include arm64: Rework valid_user_regs 2016-07-27 09:47:33 -07:00
kernel arm64: Rework valid_user_regs 2016-07-27 09:47:33 -07:00
kvm kvm: arm64: Fix EC field in inject_abt64 2016-06-01 12:15:48 -07:00
lib arm64: add KASAN support 2015-10-12 17:46:36 +01:00
mm arm64: mm: always take dirty state from new pte in ptep_set_access_flags 2016-06-24 10:18:19 -07:00
net arm64: bpf: add 'store immediate' instruction 2015-12-03 11:38:31 -05:00
xen arm: xen: implement multicall hypercall support. 2014-04-24 13:09:46 +01:00
Kconfig arm64 fixes: 2015-11-27 11:09:59 -08:00
Kconfig.debug arm64: remove redundant FRAME_POINTER kconfig option and force to select it 2015-11-10 10:36:00 +00:00
Kconfig.platforms ARM: DT updates for v4.4 2015-11-10 15:06:26 -08:00
Makefile arm64: errata: Add -mpc-relative-literal-loads to build flags 2016-03-03 15:07:08 -08:00