lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 25 Aug 2021 17:21:15 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Russell King <linux@...linux.org.uk>,
        Alexander Potapenko <glider@...gle.com>,
        Marco Elver <elver@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <kasan-dev@...glegroups.com>
CC:     Andrew Morton <akpm@...ux-foundation.org>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH 3/4] ARM: Support KFENCE for ARM

Add architecture specific implementation details for KFENCE and enable
KFENCE on ARM. In particular, this implements the required interface in
 <asm/kfence.h>.

KFENCE requires that attributes for pages from its memory pool can
individually be set. Therefore, force the kfence pool to be mapped
at page granularity.

Testing this patch using the testcases in kfence_test.c and all passed
with or without ARM_LPAE.

Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 arch/arm/Kconfig              |  1 +
 arch/arm/include/asm/kfence.h | 52 +++++++++++++++++++++++++++++++++++
 arch/arm/mm/fault.c           |  9 ++++--
 3 files changed, 60 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm/include/asm/kfence.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7a8059ff6bb0..3798f82a0c0d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -73,6 +73,7 @@ config ARM
 	select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT
 	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
 	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
+	select HAVE_ARCH_KFENCE if MMU
 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
 	select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
diff --git a/arch/arm/include/asm/kfence.h b/arch/arm/include/asm/kfence.h
new file mode 100644
index 000000000000..eae7a12ab2a9
--- /dev/null
+++ b/arch/arm/include/asm/kfence.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_ARM_KFENCE_H
+#define __ASM_ARM_KFENCE_H
+
+#include <linux/kfence.h>
+#include <asm/set_memory.h>
+#include <asm/pgalloc.h>
+
+static inline int split_pmd_page(pmd_t *pmd, unsigned long addr)
+{
+	int i;
+	unsigned long pfn = PFN_DOWN(__pa((addr & PMD_MASK)));
+	pte_t *pte = pte_alloc_one_kernel(&init_mm);
+
+	if (!pte)
+		return -ENOMEM;
+
+	for (i = 0; i < PTRS_PER_PTE; i++)
+		set_pte_ext(pte + i, pfn_pte(pfn + i, PAGE_KERNEL), 0);
+	pmd_populate_kernel(&init_mm, pmd, pte);
+
+	flush_tlb_kernel_range(addr, addr + PMD_SIZE);
+	return 0;
+}
+
+static inline bool arch_kfence_init_pool(void)
+{
+	unsigned long addr;
+	pmd_t *pmd;
+
+	for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
+	     addr += PAGE_SIZE) {
+		pmd = pmd_off_k(addr);
+
+		if (pmd_leaf(*pmd)) {
+			if (split_pmd_page(pmd, addr))
+				return false;
+		}
+	}
+
+	return true;
+}
+
+static inline bool kfence_protect_page(unsigned long addr, bool protect)
+{
+	set_memory_valid(addr, 1, !protect);
+
+	return true;
+}
+
+#endif /* __ASM_ARM_KFENCE_H */
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index f7ab6dabe89f..9fa221ffa1b9 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -17,6 +17,7 @@
 #include <linux/sched/debug.h>
 #include <linux/highmem.h>
 #include <linux/perf_event.h>
+#include <linux/kfence.h>
 
 #include <asm/system_misc.h>
 #include <asm/system_info.h>
@@ -131,10 +132,14 @@ __do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
 	/*
 	 * No handler, we'll have to terminate things with extreme prejudice.
 	 */
-	if (addr < PAGE_SIZE)
+	if (addr < PAGE_SIZE) {
 		msg = "NULL pointer dereference";
-	else
+	} else {
+		if (kfence_handle_page_fault(addr, is_write_fault(fsr), regs))
+			return;
+
 		msg = "paging request";
+	}
 
 	die_kernel_fault(msg, mm, addr, fsr, regs);
 }
-- 
2.26.2

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ