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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 08/11] ARM: Implement __arch_rare_write_begin/end()
Date: Wed, 29 Mar 2017 11:16:00 -0700
Message-ID: <1490811363-93944-9-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1490811363-93944-1-git-send-email-keescook@chromium.org>

Based on grsecurity's ARM pax_{open,close}_kernel() implementation, this
allows HAVE_ARCH_RARE_WRITE to work on ARM.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm/Kconfig               |  1 +
 arch/arm/include/asm/domain.h  |  3 ++-
 arch/arm/include/asm/pgtable.h | 27 +++++++++++++++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 0d4e71b42c77..57b8aeaf501c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -45,6 +45,7 @@ config ARM
 	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
+	select HAVE_ARCH_RARE_WRITE if MMU && !ARM_LPAE && !CPU_USE_DOMAINS
 	select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARM_SMCCC if CPU_V7
diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h
index b5ca80ac823c..b3fb5c0a2efd 100644
--- a/arch/arm/include/asm/domain.h
+++ b/arch/arm/include/asm/domain.h
@@ -54,6 +54,7 @@
 #define DOMAIN_MANAGER	3
 #else
 #define DOMAIN_MANAGER	1
+#define DOMAIN_FORCE_MANAGER 3
 #endif
 
 #define domain_mask(dom)	((3) << (2 * (dom)))
@@ -118,7 +119,7 @@ static inline void set_domain(unsigned val)
 }
 #endif
 
-#ifdef CONFIG_CPU_USE_DOMAINS
+#if defined(CONFIG_CPU_USE_DOMAINS) || defined(CONFIG_HAVE_ARCH_RARE_WRITE)
 #define modify_domain(dom,type)					\
 	do {							\
 		unsigned int domain = get_domain();		\
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 1c462381c225..104923ea9eb5 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -57,6 +57,33 @@ extern void __pgd_error(const char *file, int line, pgd_t);
 #define pmd_ERROR(pmd)		__pmd_error(__FILE__, __LINE__, pmd)
 #define pgd_ERROR(pgd)		__pgd_error(__FILE__, __LINE__, pgd)
 
+#ifdef CONFIG_HAVE_ARCH_RARE_WRITE
+#include <asm/domain.h>
+#include <linux/preempt.h>
+
+static inline int test_domain(int domain, int domaintype)
+{
+	return (get_domain() & domain_val(domain, 3)) ==
+		domain_val(domain, domaintype);
+}
+
+static inline unsigned long __arch_rare_write_begin(void)
+{
+	preempt_disable();
+	BUG_ON(test_domain(DOMAIN_WR_RARE, DOMAIN_FORCE_MANAGER));
+	modify_domain(DOMAIN_WR_RARE, DOMAIN_FORCE_MANAGER);
+	return 0;
+}
+
+static inline unsigned long __arch_rare_write_end(void)
+{
+	BUG_ON(test_domain(DOMAIN_WR_RARE, DOMAIN_CLIENT));
+	modify_domain(DOMAIN_WR_RARE, DOMAIN_CLIENT);
+	preempt_enable_no_resched();
+	return 0;
+}
+#endif
+
 /*
  * This is the lowest virtual address we can permit any user space
  * mapping to be mapped at.  This is particularly important for
-- 
2.7.4

  parent reply index

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 ` [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() Kees Cook
2017-03-29 22:38   ` 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 ` Kees Cook [this message]
2017-04-07  9:36   ` [RFC v2][PATCH 08/11] ARM: Implement __arch_rare_write_begin/end() 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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