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From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 24/30] ARM: decompressor: explicitly map decompressor binary cacheable
Date: Mon, 14 Aug 2017 13:54:05 +0100	[thread overview]
Message-ID: <20170814125411.22604-25-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20170814125411.22604-1-ard.biesheuvel@linaro.org>

When randomizing the kernel load address, there may be a large
distance in memory between the decompressor binary and its payload
and the destination area in memory. Ensure that the decompressor
itself is mapped cacheable in this case, by tweaking the existing
routine that takes care of this for XIP decompressors.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/boot/compressed/head.S | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 5884e8151376..583cc6899d98 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -706,20 +706,24 @@ __setup_mmu:	sub	r3, r4, #16384		@ Page directory size
 		teq	r0, r2
 		bne	1b
 /*
- * If ever we are running from Flash, then we surely want the cache
- * to be enabled also for our execution instance...  We map 2MB of it
- * so there is no map overlap problem for up to 1 MB compressed kernel.
- * If the execution is in RAM then we would only be duplicating the above.
+ * Make sure our entire executable image (including payload) is mapped
+ * cacheable, in case it is located outside the region we covered above.
+ * (This may be the case if running from flash or with randomization enabled)
+ * If the regions happen to overlap, we just duplicate some of the above.
  */
 		orr	r1, r6, #0x04		@ ensure B is set for this
 		orr	r1, r1, #3 << 10
 		mov	r2, pc
+		adr_l	r9, _end
 		mov	r2, r2, lsr #20
+		mov	r9, r9, lsr #20
 		orr	r1, r1, r2, lsl #20
 		add	r0, r3, r2, lsl #2
-		str	r1, [r0], #4
+		add	r9, r3, r9, lsl #2
+0:		str	r1, [r0], #4
 		add	r1, r1, #1048576
-		str	r1, [r0]
+		cmp	r0, r9
+		bls	0b
 		mov	pc, lr
 ENDPROC(__setup_mmu)
 
-- 
2.11.0

WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: kernel-hardening@lists.openwall.com
Cc: linux-arm-kernel@lists.infradead.org,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>, Nicolas Pitre <nico@linaro.org>,
	Russell King <linux@armlinux.org.uk>,
	Kees Cook <keescook@chromium.org>,
	Thomas Garnier <thgarnie@google.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Tony Lindgren <tony@atomide.com>,
	Matt Fleming <matt@codeblueprint.co.uk>,
	Dave Martin <dave.martin@arm.com>
Subject: [kernel-hardening] [PATCH 24/30] ARM: decompressor: explicitly map decompressor binary cacheable
Date: Mon, 14 Aug 2017 13:54:05 +0100	[thread overview]
Message-ID: <20170814125411.22604-25-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20170814125411.22604-1-ard.biesheuvel@linaro.org>

When randomizing the kernel load address, there may be a large
distance in memory between the decompressor binary and its payload
and the destination area in memory. Ensure that the decompressor
itself is mapped cacheable in this case, by tweaking the existing
routine that takes care of this for XIP decompressors.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/boot/compressed/head.S | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 5884e8151376..583cc6899d98 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -706,20 +706,24 @@ __setup_mmu:	sub	r3, r4, #16384		@ Page directory size
 		teq	r0, r2
 		bne	1b
 /*
- * If ever we are running from Flash, then we surely want the cache
- * to be enabled also for our execution instance...  We map 2MB of it
- * so there is no map overlap problem for up to 1 MB compressed kernel.
- * If the execution is in RAM then we would only be duplicating the above.
+ * Make sure our entire executable image (including payload) is mapped
+ * cacheable, in case it is located outside the region we covered above.
+ * (This may be the case if running from flash or with randomization enabled)
+ * If the regions happen to overlap, we just duplicate some of the above.
  */
 		orr	r1, r6, #0x04		@ ensure B is set for this
 		orr	r1, r1, #3 << 10
 		mov	r2, pc
+		adr_l	r9, _end
 		mov	r2, r2, lsr #20
+		mov	r9, r9, lsr #20
 		orr	r1, r1, r2, lsl #20
 		add	r0, r3, r2, lsl #2
-		str	r1, [r0], #4
+		add	r9, r3, r9, lsl #2
+0:		str	r1, [r0], #4
 		add	r1, r1, #1048576
-		str	r1, [r0]
+		cmp	r0, r9
+		bls	0b
 		mov	pc, lr
 ENDPROC(__setup_mmu)
 
-- 
2.11.0

  parent reply	other threads:[~2017-08-14 12:54 UTC|newest]

Thread overview: 120+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-14 12:53 [PATCH 00/30] implement KASLR for ARM Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 01/30] asm-generic: add .data.rel.ro sections to __ro_after_init Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 14:26   ` Arnd Bergmann
2017-08-14 14:26     ` [kernel-hardening] " Arnd Bergmann
2017-08-14 12:53 ` [PATCH 02/30] ARM: assembler: introduce adr_l, ldr_l and str_l macros Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:29   ` Dave Martin
2017-08-14 15:29     ` [kernel-hardening] " Dave Martin
2017-08-14 15:38     ` Ard Biesheuvel
2017-08-14 15:38       ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:50       ` Dave Martin
2017-08-14 15:50         ` [kernel-hardening] " Dave Martin
2017-08-14 16:18         ` Nicolas Pitre
2017-08-14 16:18           ` [kernel-hardening] " Nicolas Pitre
2017-08-14 16:22           ` Ard Biesheuvel
2017-08-14 16:22             ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:33             ` Nicolas Pitre
2017-08-14 16:33               ` [kernel-hardening] " Nicolas Pitre
2017-08-14 16:42             ` Russell King - ARM Linux
2017-08-14 16:42               ` [kernel-hardening] " Russell King - ARM Linux
2017-08-14 16:56               ` Ard Biesheuvel
2017-08-14 16:56                 ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:32   ` Dave Martin
2017-08-14 15:32     ` [kernel-hardening] " Dave Martin
2017-08-14 15:40     ` Ard Biesheuvel
2017-08-14 15:40       ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:53       ` Dave Martin
2017-08-14 15:53         ` [kernel-hardening] " Dave Martin
2017-08-14 12:53 ` [PATCH 03/30] ARM: head-common.S: use PC-relative insn sequence for __proc_info Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 04/30] ARM: head-common.S: use PC-relative insn sequence for idmap creation Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 05/30] ARM: head.S: use PC-relative insn sequence for secondary_data Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 06/30] ARM: kernel: use relative references for UP/SMP alternatives Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 07/30] ARM: head: use PC-relative insn sequence for __smp_alt Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 08/30] ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 09/30] ARM: head.S: use PC-relative insn sequences for __fixup_pv_table Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 10/30] ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 11/30] ARM: kvm: replace open coded VA->PA calculations with adr_l call Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 12/30] arm-soc: exynos: replace open coded VA->PA conversions Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 13/30] arm-soc: mvebu: replace open coded VA->PA conversion Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 14/30] arm-soc: various: replace open coded VA->PA calculation of pen_release Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 15/30] ARM: kernel: switch to relative exception tables Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 16/30] ARM: kernel: use relative phys-to-virt patch tables Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:53 ` [PATCH 17/30] arm-soc: tegra: make sleep asm code runtime relocatable Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 14:42   ` Dave Martin
2017-08-14 14:42     ` [kernel-hardening] " Dave Martin
2017-08-14 14:49     ` Ard Biesheuvel
2017-08-14 14:49       ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:29       ` Dave Martin
2017-08-14 15:29         ` [kernel-hardening] " Dave Martin
2017-08-14 12:53 ` [PATCH 18/30] ARM: kernel: make vmlinux buildable as a PIE executable Ard Biesheuvel
2017-08-14 12:53   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 19/30] ARM: kernel: use PC-relative symbol references in MMU switch code Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 20/30] ARM: kernel: use PC relative symbol references in suspend/resume code Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:02   ` Nicolas Pitre
2017-08-14 16:02     ` [kernel-hardening] " Nicolas Pitre
2017-08-14 18:14     ` Ard Biesheuvel
2017-08-14 18:14       ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 18:37       ` Nicolas Pitre
2017-08-14 18:37         ` [kernel-hardening] " Nicolas Pitre
2017-08-14 12:54 ` [PATCH 21/30] ARM: mm: export default vmalloc base address Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 22/30] ARM: kernel: refer to swapper_pg_dir via its symbol Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 23/30] ARM: kernel: implement randomization of the kernel load address Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` Ard Biesheuvel [this message]
2017-08-14 12:54   ` [kernel-hardening] [PATCH 24/30] ARM: decompressor: explicitly map decompressor binary cacheable Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 25/30] ARM: compressed: factor out zImage header and make it extensible Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 26/30] ARM: decompressor: add KASLR support Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 27/30] efi/libstub: add 'max' parameter to efi_random_alloc() Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 28/30] efi/libstub: check for vmalloc= command line argument Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 29/30] efi/libstub: arm: reserve bootloader supplied initrd in memory map Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-18 11:48   ` Ard Biesheuvel
2017-08-18 11:48     ` [kernel-hardening] " Ard Biesheuvel
2017-08-21 10:37   ` Mark Rutland
2017-08-21 10:37     ` [kernel-hardening] " Mark Rutland
2017-08-21 10:39     ` Ard Biesheuvel
2017-08-21 10:39       ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 12:54 ` [PATCH 30/30] efi/libstub: arm: implement KASLR Ard Biesheuvel
2017-08-14 12:54   ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 15:30 ` [PATCH 00/30] implement KASLR for ARM Arnd Bergmann
2017-08-14 15:30   ` [kernel-hardening] " Arnd Bergmann
2017-08-14 15:49   ` Ard Biesheuvel
2017-08-14 15:49     ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:03     ` Arnd Bergmann
2017-08-14 16:03       ` [kernel-hardening] " Arnd Bergmann
2017-08-14 16:28       ` Nicolas Pitre
2017-08-14 16:28         ` [kernel-hardening] " Nicolas Pitre
2017-08-14 17:28         ` Ard Biesheuvel
2017-08-14 17:28           ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 18:01           ` Nicolas Pitre
2017-08-14 18:01             ` [kernel-hardening] " Nicolas Pitre
2017-08-14 18:08             ` Ard Biesheuvel
2017-08-14 18:08               ` [kernel-hardening] " Ard Biesheuvel
2017-08-14 16:16     ` Nicolas Pitre
2017-08-14 16:16       ` [kernel-hardening] " Nicolas Pitre

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