From: =?UTF-8?B?dGlwLWJvdCBmb3IgRGF2aWQgQnJvd24gPHRpcGJvdEB6eXRvci5jb20+?=@zytor.com
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Cc: hpa@zytor.com, linux-arch@vger.kernel.org, bp@alien8.de,
re.emese@gmail.com, pageexec@freemail.hu, keescook@chromium.org,
tglx@linutronix.de, peterz@infradead.org, spender@grsecurity.net,
mpe@ellerman.id.au, mingo@kernel.org, dvlasenk@redhat.com,
nathan_lynch@mentor.com, linux@arm.linux.org.uk,
brgerst@gmail.com, minipli@googlemail.com,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
david.brown@linaro.org, luto@amacapital.net, arnd@arndb.de
Subject: [tip:mm/readonly] ARM/vdso: Mark the vDSO code read-only after init
Date: Mon, 22 Feb 2016 04:20:45 -0800 [thread overview]
Message-ID: <tip-11bf9b865898961cee60a41c483c9f27ec76e12e@git.kernel.org> (raw)
In-Reply-To: <1455748879-21872-8-git-send-email-keescook@chromium.org>
Commit-ID: 11bf9b865898961cee60a41c483c9f27ec76e12e
Gitweb: http://git.kernel.org/tip/11bf9b865898961cee60a41c483c9f27ec76e12e
Author: David Brown <david.brown@linaro.org>
AuthorDate: Wed, 17 Feb 2016 14:41:18 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 22 Feb 2016 08:51:39 +0100
ARM/vdso: Mark the vDSO code read-only after init
Although the ARM vDSO is cleanly separated by code/data with the code
being read-only in userspace mappings, the code page is still writable
from the kernel.
There have been exploits (such as http://itszn.com/blog/?p=21) that
take advantage of this on x86 to go from a bad kernel write to full
root.
Prevent this specific exploit class on ARM as well by putting the vDSO
code page in post-init read-only memory as well.
Before:
vdso: 1 text pages at base 80927000
root@Vexpress:/ cat /sys/kernel/debug/kernel_page_tables
---[ Modules ]---
---[ Kernel Mapping ]---
0x80000000-0x80100000 1M RW NX SHD
0x80100000-0x80600000 5M ro x SHD
0x80600000-0x80800000 2M ro NX SHD
0x80800000-0xbe000000 984M RW NX SHD
After:
vdso: 1 text pages at base 8072b000
root@Vexpress:/ cat /sys/kernel/debug/kernel_page_tables
---[ Modules ]---
---[ Kernel Mapping ]---
0x80000000-0x80100000 1M RW NX SHD
0x80100000-0x80600000 5M ro x SHD
0x80600000-0x80800000 2M ro NX SHD
0x80800000-0xbe000000 984M RW NX SHD
Inspired by https://lkml.org/lkml/2016/1/19/494 based on work by the
PaX Team, Brad Spengler, and Kees Cook.
Signed-off-by: David Brown <david.brown@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Lynch <nathan_lynch@mentor.com>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1455748879-21872-8-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/arm/vdso/vdso.S | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm/vdso/vdso.S b/arch/arm/vdso/vdso.S
index b2b97e3..a62a7b6 100644
--- a/arch/arm/vdso/vdso.S
+++ b/arch/arm/vdso/vdso.S
@@ -23,9 +23,8 @@
#include <linux/const.h>
#include <asm/page.h>
- __PAGE_ALIGNED_DATA
-
.globl vdso_start, vdso_end
+ .section .data..ro_after_init
.balign PAGE_SIZE
vdso_start:
.incbin "arch/arm/vdso/vdso.so"
next prev parent reply other threads:[~2016-02-22 12:20 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-17 22:41 [PATCH v5 0/7] introduce post-init read-only memory Kees Cook
2016-02-17 22:41 ` [PATCH v5 1/7] asm-generic: consolidate mark_rodata_ro() Kees Cook
2016-02-19 14:38 ` Will Deacon
2016-02-22 12:18 ` [tip:mm/readonly] asm-generic: Consolidate mark_rodata_ro() =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-22 12:18 ` =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-17 22:41 ` [PATCH v5 2/7] init: create cmdline param to disable readonly Kees Cook
2016-02-17 22:41 ` Kees Cook
2016-02-22 12:18 ` [tip:mm/readonly] mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-22 12:18 ` =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-17 22:41 ` [PATCH v5 3/7] x86: make CONFIG_DEBUG_RODATA non-optional Kees Cook
2016-02-17 22:41 ` Kees Cook
2016-02-22 12:19 ` [tip:mm/readonly] x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-22 12:19 ` =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-17 22:41 ` [PATCH v5 4/7] introduce post-init read-only memory Kees Cook
2016-02-17 22:41 ` Kees Cook
2016-02-22 12:19 ` [tip:mm/readonly] arch: Introduce " =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-22 12:19 ` =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-03-07 13:00 ` [PATCH v5 4/7] introduce " Christian Borntraeger
2016-03-08 0:16 ` Kees Cook
2016-03-08 0:16 ` Kees Cook
2016-03-08 0:23 ` Andy Lutomirski
2016-03-08 0:23 ` Andy Lutomirski
2016-02-17 22:41 ` [PATCH v5 5/7] lkdtm: verify that __ro_after_init works correctly Kees Cook
2016-02-17 22:41 ` Kees Cook
2016-02-22 12:19 ` [tip:mm/readonly] lkdtm: Verify that '__ro_after_init' " =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-22 12:19 ` =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-17 22:41 ` [PATCH v5 6/7] x86, vdso: mark vDSO read-only after init Kees Cook
2016-02-17 22:41 ` Kees Cook
2016-02-22 12:20 ` [tip:mm/readonly] x86/vdso: Mark the vDSO code " =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-22 12:20 ` =?UTF-8?B?dGlwLWJvdCBmb3IgS2VlcyBDb29rIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-17 22:41 ` [PATCH v5 7/7] ARM: vdso: Mark vDSO code as read-only Kees Cook
2016-02-17 22:41 ` Kees Cook
2016-02-22 12:20 ` =?UTF-8?B?dGlwLWJvdCBmb3IgRGF2aWQgQnJvd24gPHRpcGJvdEB6eXRvci5jb20+?= [this message]
2016-02-22 12:20 ` [tip:mm/readonly] ARM/vdso: Mark the vDSO code read-only after init =?UTF-8?B?dGlwLWJvdCBmb3IgRGF2aWQgQnJvd24gPHRpcGJvdEB6eXRvci5jb20+?=
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