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Message-Id: <20170903120757.14968-1-ard.biesheuvel@linaro.org>
Date: Sun, 3 Sep 2017 13:07:28 +0100
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-arm-kernel@...ts.infradead.org,
kernel-hardening@...ts.openwall.com
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Arnd Bergmann <arnd@...db.de>,
Nicolas Pitre <nico@...aro.org>,
Russell King <linux@...linux.org.uk>,
Kees Cook <keescook@...omium.org>,
Thomas Garnier <thgarnie@...gle.com>,
Marc Zyngier <marc.zyngier@....com>,
Mark Rutland <mark.rutland@....com>,
Tony Lindgren <tony@...mide.com>,
Matt Fleming <matt@...eblueprint.co.uk>,
Dave Martin <dave.martin@....com>
Subject: [PATCH v2 00/29] implement KASLR for ARM
This series implements randomization of the placement of the core ARM kernel
inside the lowmem region. It consists of the following parts:
- changes that allow us to build vmlinux as a PIE executable which retains
the metadata required to fix up all absolute symbol references at runtime
- changes that eliminate absolute references from low-level code that may
execute with the MMU off: this removes the need to perform explicit cache
maintenance after the absolute references have been fixed up at runtime with
the caches enabled
- changes to the core kernel startup code to take the physical offset into
account when creating the virtual mapping (the pa-to-va mapping remains
unchanged)
- changes to the decompressor to collect some pseudo-entropy, and randomize
the physical offset of the decompressed kernel, taking placement of DTB,
initrd and reserved regions into account
- changes to the UEFI stub code to choose the KASLR offset and communicate
it to the decompressor
To test these changes, boot a multi_v7_defconfig+CONFIG_RANDOMIZE_BASE=y
build and expect to see something like
[ 0.000000] Virtual kernel memory layout:
[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[ 0.000000] fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
[ 0.000000] vmalloc : 0xf0800000 - 0xff800000 ( 240 MB)
[ 0.000000] lowmem : 0xc0000000 - 0xf0000000 ( 768 MB)
[ 0.000000] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[ 0.000000] modules : 0xbf800000 - 0xbfe00000 ( 6 MB)
[ 0.000000] .text : 0xd4208000 - 0xd4c00000 (10208 kB) <----
[ 0.000000] .init : 0xd5200000 - 0xd5600000 (4096 kB) <----
[ 0.000000] .data : 0xd5600000 - 0xd5776f28 (1500 kB) <----
[ 0.000000] .bss : 0xd57805e0 - 0xd57e60ac ( 407 kB) <----
v2: - make adr_l/ldr_l/str_l macros work in .arm sections under Thumb2 builds,
and remove support for conditional execution, which is finicky when
building for Thumb2 with -mimplicit-it=always
- work around a section mismatch warning resulting from using the -fpic
switch
- drop bogus patch to reserve initrd memory in the UEFI stub
- add support to the decompressor to perform the randomization
autonomously; this also removes the need for the extended zImage
header, since the UEFI stub doesn't need it, and other bootloaders
no longer have to do anything to enable KASLR.
- avoid macros in ALT_SMP() calls (#9)
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Nicolas Pitre <nico@...aro.org>
Cc: Russell King <linux@...linux.org.uk>
Cc: Kees Cook <keescook@...omium.org>
Cc: Thomas Garnier <thgarnie@...gle.com>
Cc: Marc Zyngier <marc.zyngier@....com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Tony Lindgren <tony@...mide.com>
Cc: Matt Fleming <matt@...eblueprint.co.uk>
Cc: Dave Martin <dave.martin@....com>
Ard Biesheuvel (29):
net/core: work around section mismatch warning for ptp_classifier
asm-generic: add .data.rel.ro sections to __ro_after_init
ARM: assembler: introduce adr_l, ldr_l and str_l macros
ARM: head-common.S: use PC-relative insn sequence for __proc_info
ARM: head-common.S: use PC-relative insn sequence for idmap creation
ARM: head.S: use PC-relative insn sequence for secondary_data
ARM: kernel: use relative references for UP/SMP alternatives
ARM: head: use PC-relative insn sequence for __smp_alt
ARM: sleep.S: use PC-relative insn sequence for
sleep_save_sp/mpidr_hash
ARM: head.S: use PC-relative insn sequences for __fixup_pv_table
ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET
ARM: kvm: replace open coded VA->PA calculations with adr_l call
arm-soc: exynos: replace open coded VA->PA conversions
arm-soc: mvebu: replace open coded VA->PA conversion
arm-soc: various: replace open coded VA->PA calculation of pen_release
ARM: kernel: switch to relative exception tables
ARM: kernel: use relative phys-to-virt patch tables
arm-soc: tegra: make sleep asm code runtime relocatable
ARM: kernel: make vmlinux buildable as a PIE executable
ARM: kernel: use PC-relative symbol references in MMU switch code
ARM: kernel: use PC relative symbol references in suspend/resume code
ARM: mm: export default vmalloc base address
ARM: kernel: refer to swapper_pg_dir via its symbol
ARM: kernel: implement randomization of the kernel load address
ARM: decompressor: explicitly map decompressor binary cacheable
ARM: decompressor: add KASLR support
efi/libstub: add 'max' parameter to efi_random_alloc()
efi/libstub: check for vmalloc= command line argument
efi/libstub: arm: implement KASLR
arch/arm/Kconfig | 19 +
arch/arm/Makefile | 5 +
arch/arm/boot/compressed/Makefile | 8 +-
arch/arm/boot/compressed/head.S | 125 ++++--
arch/arm/boot/compressed/kaslr.c | 398 ++++++++++++++++++++
arch/arm/include/asm/Kbuild | 1 -
arch/arm/include/asm/assembler.h | 86 ++++-
arch/arm/include/asm/extable.h | 19 +
arch/arm/include/asm/futex.h | 2 +-
arch/arm/include/asm/memory.h | 6 +-
arch/arm/include/asm/pgtable.h | 1 +
arch/arm/include/asm/processor.h | 2 +-
arch/arm/include/asm/uaccess.h | 8 +-
arch/arm/include/asm/word-at-a-time.h | 2 +-
arch/arm/kernel/entry-armv.S | 6 +-
arch/arm/kernel/head-common.S | 61 ++-
arch/arm/kernel/head.S | 217 ++++++-----
arch/arm/kernel/hyp-stub.S | 33 +-
arch/arm/kernel/sleep.S | 28 +-
arch/arm/kernel/swp_emulate.c | 4 +-
arch/arm/kernel/vmlinux.lds.S | 9 +
arch/arm/kvm/init.S | 8 +-
arch/arm/lib/backtrace.S | 8 +-
arch/arm/lib/getuser.S | 22 +-
arch/arm/lib/putuser.S | 12 +-
arch/arm/mach-exynos/headsmp.S | 9 +-
arch/arm/mach-exynos/sleep.S | 26 +-
arch/arm/mach-mvebu/coherency_ll.S | 8 +-
arch/arm/mach-prima2/headsmp.S | 11 +-
arch/arm/mach-spear/headsmp.S | 11 +-
arch/arm/mach-sti/headsmp.S | 10 +-
arch/arm/mach-tegra/sleep-tegra20.S | 22 +-
arch/arm/mach-tegra/sleep-tegra30.S | 6 +-
arch/arm/mach-tegra/sleep.S | 4 +-
arch/arm/mm/alignment.c | 14 +-
arch/arm/mm/extable.c | 2 +-
arch/arm/mm/mmu.c | 3 +-
arch/arm/nwfpe/entry.S | 2 +-
arch/arm/plat-versatile/headsmp.S | 9 +-
drivers/firmware/efi/libstub/arm32-stub.c | 47 ++-
drivers/firmware/efi/libstub/arm64-stub.c | 2 +-
drivers/firmware/efi/libstub/efi-stub-helper.c | 9 +
drivers/firmware/efi/libstub/efistub.h | 4 +-
drivers/firmware/efi/libstub/random.c | 11 +-
include/asm-generic/vmlinux.lds.h | 2 +-
include/linux/hidden.h | 20 +
net/core/ptp_classifier.c | 7 +-
scripts/module-common.lds | 1 +
scripts/sortextable.c | 2 +-
49 files changed, 982 insertions(+), 350 deletions(-)
create mode 100644 arch/arm/boot/compressed/kaslr.c
create mode 100644 arch/arm/include/asm/extable.h
create mode 100644 include/linux/hidden.h
--
2.11.0
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