mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 05:08:09 +07:00
11bf9b8658
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>
35 lines
972 B
ArmAsm
35 lines
972 B
ArmAsm
/*
|
|
* Adapted from arm64 version.
|
|
*
|
|
* Copyright (C) 2012 ARM Limited
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* Author: Will Deacon <will.deacon@arm.com>
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/linkage.h>
|
|
#include <linux/const.h>
|
|
#include <asm/page.h>
|
|
|
|
.globl vdso_start, vdso_end
|
|
.section .data..ro_after_init
|
|
.balign PAGE_SIZE
|
|
vdso_start:
|
|
.incbin "arch/arm/vdso/vdso.so"
|
|
.balign PAGE_SIZE
|
|
vdso_end:
|
|
|
|
.previous
|