From: Kees Cook <keescook@chromium.org>
To: kernel-hardening@lists.openwall.com
Cc: Kees Cook <keescook@chromium.org>,
Mark Rutland <mark.rutland@arm.com>,
Andy Lutomirski <luto@kernel.org>,
Hoeun Ryu <hoeun.ryu@gmail.com>, PaX Team <pageexec@freemail.hu>,
Emese Revfy <re.emese@gmail.com>,
Russell King <linux@armlinux.org.uk>,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap()
Date: Wed, 29 Mar 2017 11:15:56 -0700 [thread overview]
Message-ID: <1490811363-93944-5-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1490811363-93944-1-git-send-email-keescook@chromium.org>
Based on PaX's x86 pax_{open,close}_kernel() implementation, this
allows HAVE_ARCH_RARE_WRITE to work on x86.
There is missing work to sort out some header file issues where preempt.h
is missing, though it can't be included in pg_table.h unconditionally...
some other solution will be needed, perhaps an entirely separate header
file for rare_write()-related defines...
This patch is also missing paravirt support.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/pgtable.h | 31 +++++++++++++++++++++++++++++++
2 files changed, 32 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cc98d5a294ee..2d1d707aa036 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -106,6 +106,7 @@ config X86
select HAVE_ARCH_KMEMCHECK
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
+ select HAVE_ARCH_RARE_WRITE
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1cfb36b8c024..2e6bf661bb84 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -91,6 +91,37 @@ extern struct mm_struct *pgd_page_get_mm(struct page *page);
#endif /* CONFIG_PARAVIRT */
+/* TODO: Bad hack to deal with preempt macros being missing sometimes. */
+#ifndef preempt_disable
+#include <linux/preempt.h>
+#endif
+
+static __always_inline unsigned long __arch_rare_write_begin(void)
+{
+ unsigned long cr0;
+
+ preempt_disable();
+ barrier();
+ cr0 = read_cr0() ^ X86_CR0_WP;
+ BUG_ON(cr0 & X86_CR0_WP);
+ write_cr0(cr0);
+ barrier();
+ return cr0 ^ X86_CR0_WP;
+}
+
+static __always_inline unsigned long __arch_rare_write_end(void)
+{
+ unsigned long cr0;
+
+ barrier();
+ cr0 = read_cr0() ^ X86_CR0_WP;
+ BUG_ON(!(cr0 & X86_CR0_WP));
+ write_cr0(cr0);
+ barrier();
+ preempt_enable_no_resched();
+ return cr0 ^ X86_CR0_WP;
+}
+
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
--
2.7.4
next prev parent reply other threads:[~2017-03-29 18:19 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 18:15 [RFC v2] Introduce rare_write() infrastructure Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 01/11] " Kees Cook
2017-03-29 18:23 ` Kees Cook
2017-03-30 7:44 ` Ho-Eun Ryu
2017-03-30 17:02 ` Kees Cook
2017-04-07 8:09 ` Ho-Eun Ryu
2017-04-07 20:38 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 02/11] lkdtm: add test for " Kees Cook
2017-03-30 9:34 ` [kernel-hardening] " Ian Campbell
2017-03-30 16:16 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 03/11] net: switch sock_diag handlers to rare_write() Kees Cook
2017-03-29 18:15 ` Kees Cook [this message]
2017-03-29 22:38 ` [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() Andy Lutomirski
2017-03-30 1:41 ` Kees Cook
2017-04-05 23:57 ` Andy Lutomirski
2017-04-06 0:14 ` Kees Cook
2017-04-06 15:59 ` Andy Lutomirski
2017-04-07 8:34 ` [kernel-hardening] " Mathias Krause
2017-04-07 9:46 ` Thomas Gleixner
2017-04-07 10:51 ` Mathias Krause
2017-04-07 13:14 ` Thomas Gleixner
2017-04-07 13:30 ` Mathias Krause
2017-04-07 16:14 ` Andy Lutomirski
2017-04-07 16:22 ` Mark Rutland
2017-04-07 19:58 ` PaX Team
2017-04-08 4:58 ` Andy Lutomirski
2017-04-09 12:47 ` PaX Team
2017-04-10 0:10 ` Andy Lutomirski
2017-04-10 10:42 ` PaX Team
2017-04-10 16:01 ` Andy Lutomirski
2017-04-07 20:44 ` Thomas Gleixner
2017-04-07 21:20 ` Kees Cook
2017-04-08 4:12 ` Daniel Micay
2017-04-08 4:13 ` Daniel Micay
2017-04-08 4:21 ` Daniel Micay
2017-04-08 5:07 ` Andy Lutomirski
2017-04-08 7:33 ` Daniel Micay
2017-04-08 15:20 ` Andy Lutomirski
2017-04-09 10:53 ` Ingo Molnar
2017-04-10 10:22 ` Mark Rutland
2017-04-09 20:24 ` PaX Team
2017-04-10 0:31 ` Andy Lutomirski
2017-04-10 19:47 ` PaX Team
2017-04-10 20:27 ` Andy Lutomirski
2017-04-10 20:13 ` Kees Cook
2017-04-10 20:17 ` Andy Lutomirski
2017-04-07 19:25 ` Thomas Gleixner
2017-04-07 14:45 ` Peter Zijlstra
2017-04-10 10:29 ` Mark Rutland
2017-04-07 19:52 ` PaX Team
2017-04-10 8:26 ` Thomas Gleixner
2017-04-10 19:55 ` PaX Team
2017-04-07 9:37 ` Peter Zijlstra
2017-03-29 18:15 ` [RFC v2][PATCH 05/11] ARM: mm: dump: Add domain to output Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 06/11] ARM: domains: Extract common USER domain init Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 07/11] ARM: mm: set DOMAIN_WR_RARE for rodata Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 08/11] ARM: Implement __arch_rare_write_begin/end() Kees Cook
2017-04-07 9:36 ` Peter Zijlstra
2017-03-29 18:16 ` [RFC v2][PATCH 09/11] list: add rare_write() list helpers Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 10/11] gcc-plugins: Add constify plugin Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 11/11] cgroups: force all struct cftype const Kees Cook
2017-03-29 19:00 ` [RFC v2] Introduce rare_write() infrastructure Russell King - ARM Linux
2017-03-29 19:14 ` Kees Cook
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