From: Kees Cook <keescook@chromium.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
Thomas Garnier <thgarnie@google.com>,
Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, Borislav Petkov <bp@suse.de>,
Baoquan He <bhe@redhat.com>, Yinghai Lu <yinghai@kernel.org>,
Juergen Gross <jgross@suse.com>,
Matt Fleming <matt@codeblueprint.co.uk>,
Toshi Kani <toshi.kani@hpe.com>,
Andrew Morton <akpm@linux-foundation.org>,
Dan Williams <dan.j.williams@intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Xiao Guangrong <guangrong.xiao@linux.intel.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Alexander Kuleshov <kuleshovmail@gmail.com>,
Alexander Popov <alpopov@ptsecurity.com>,
Dave Young <dyoung@redhat.com>, Joerg Roedel <jroedel@suse.de>,
Lv Zheng <lv.zheng@intel.com>, Mark Salter <msalter@redhat.com>,
Dmitry Vyukov <dvyukov@google.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Jan Beulich <JBeulich@suse.com>,
linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com
Subject: [kernel-hardening] [PATCH v7 8/9] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
Date: Tue, 21 Jun 2016 17:47:05 -0700 [thread overview]
Message-ID: <1466556426-32664-9-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1466556426-32664-1-git-send-email-keescook@chromium.org>
From: Thomas Garnier <thgarnie@google.com>
Add vmemmap in the list of randomized memory regions.
The vmemmap region holds a representation of the physical memory (through
a struct page array). An attacker could use this region to disclose the
kernel memory layout (walking the page linked list).
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/include/asm/kaslr.h | 1 +
arch/x86/include/asm/pgtable_64_types.h | 4 +++-
arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
index 2674ee3de748..1052a797d71d 100644
--- a/arch/x86/include/asm/kaslr.h
+++ b/arch/x86/include/asm/kaslr.h
@@ -6,6 +6,7 @@ unsigned long kaslr_get_random_long(const char *purpose);
#ifdef CONFIG_RANDOMIZE_MEMORY
extern unsigned long page_offset_base;
extern unsigned long vmalloc_base;
+extern unsigned long vmemmap_base;
void kernel_randomize_memory(void);
#else
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 6fdef9eef2d5..3a264200c62f 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -57,11 +57,13 @@ typedef struct { pteval_t pte; } pte_t;
#define MAXMEM _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
#define VMALLOC_SIZE_TB _AC(32, UL)
#define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
-#define VMEMMAP_START _AC(0xffffea0000000000, UL)
+#define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
#ifdef CONFIG_RANDOMIZE_MEMORY
#define VMALLOC_START vmalloc_base
+#define VMEMMAP_START vmemmap_base
#else
#define VMALLOC_START __VMALLOC_BASE
+#define VMEMMAP_START __VMEMMAP_BASE
#endif /* CONFIG_RANDOMIZE_MEMORY */
#define VMALLOC_END (VMALLOC_START + _AC((VMALLOC_SIZE_TB << 40) - 1, UL))
#define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index c939cfe1b516..4f91dc273062 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -44,13 +44,22 @@
* ensure that this order is correct and won't be changed.
*/
static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
-static const unsigned long vaddr_end = VMEMMAP_START;
+
+#if defined(CONFIG_X86_ESPFIX64)
+static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
+#elif defined(CONFIG_EFI)
+static const unsigned long vaddr_end = EFI_VA_START;
+#else
+static const unsigned long vaddr_end = __START_KERNEL_map;
+#endif
/* Default values */
unsigned long page_offset_base = __PAGE_OFFSET_BASE;
EXPORT_SYMBOL(page_offset_base);
unsigned long vmalloc_base = __VMALLOC_BASE;
EXPORT_SYMBOL(vmalloc_base);
+unsigned long vmemmap_base = __VMEMMAP_BASE;
+EXPORT_SYMBOL(vmemmap_base);
/*
* Memory regions randomized by KASLR (except modules that use a separate logic
@@ -63,6 +72,7 @@ static __initdata struct kaslr_memory_region {
} kaslr_regions[] = {
{ &page_offset_base, 64/* Maximum */ },
{ &vmalloc_base, VMALLOC_SIZE_TB },
+ { &vmemmap_base, 1 },
};
/* Get size in bytes used by the memory region */
@@ -89,6 +99,18 @@ void __init kernel_randomize_memory(void)
struct rnd_state rand_state;
unsigned long remain_entropy;
+ /*
+ * All these BUILD_BUG_ON checks ensures the memory layout is
+ * consistent with the vaddr_start/vaddr_end variables.
+ */
+ BUILD_BUG_ON(vaddr_start >= vaddr_end);
+ BUILD_BUG_ON(config_enabled(CONFIG_X86_ESPFIX64) &&
+ vaddr_end >= EFI_VA_START);
+ BUILD_BUG_ON((config_enabled(CONFIG_X86_ESPFIX64) ||
+ config_enabled(CONFIG_EFI)) &&
+ vaddr_end >= __START_KERNEL_map);
+ BUILD_BUG_ON(vaddr_end > __START_KERNEL_map);
+
if (!kaslr_memory_enabled())
return;
--
2.7.4
next prev parent reply other threads:[~2016-06-22 0:47 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 0:46 [kernel-hardening] [PATCH v7 0/9] x86/mm: memory area address KASLR Kees Cook
2016-06-22 0:46 ` [kernel-hardening] [PATCH v7 1/9] x86/mm: Refactor KASLR entropy functions Kees Cook
2016-06-22 0:46 ` [kernel-hardening] [PATCH v7 2/9] x86/mm: Update physical mapping variable names (x86_64) Kees Cook
2016-06-22 0:47 ` [kernel-hardening] [PATCH v7 3/9] x86/mm: PUD VA support for physical mapping (x86_64) Kees Cook
2016-06-22 0:47 ` [kernel-hardening] [PATCH v7 4/9] x86/mm: Separate variable for trampoline PGD (x86_64) Kees Cook
2016-06-22 0:47 ` [kernel-hardening] [PATCH v7 5/9] x86/mm: Implement ASLR for kernel memory regions (x86_64) Kees Cook
2016-06-22 0:47 ` [kernel-hardening] [PATCH v7 6/9] x86/mm: Enable KASLR for physical mapping memory region (x86_64) Kees Cook
2016-06-22 0:47 ` [kernel-hardening] [PATCH v7 7/9] x86/mm: Enable KASLR for vmalloc " Kees Cook
2016-06-22 0:47 ` Kees Cook [this message]
2016-06-22 0:47 ` [kernel-hardening] [PATCH v7 9/9] x86/mm: Memory hotplug support for KASLR memory randomization (x86_64) Kees Cook
2016-06-22 12:47 ` [kernel-hardening] [PATCH v7 0/9] x86/mm: memory area address KASLR Jason Cooper
2016-06-22 15:59 ` Thomas Garnier
2016-06-22 17:05 ` Kees Cook
2016-06-23 19:33 ` Jason Cooper
2016-06-23 19:45 ` Sandy Harris
2016-06-23 19:59 ` Kees Cook
2016-06-23 20:19 ` Jason Cooper
2016-06-23 20:16 ` Jason Cooper
2016-06-23 19:58 ` Kees Cook
2016-06-23 20:05 ` Ard Biesheuvel
2016-06-24 1:11 ` Jason Cooper
2016-06-24 10:54 ` Ard Biesheuvel
2016-06-24 16:02 ` [kernel-hardening] devicetree random-seed properties, was: "Re: [PATCH v7 0/9] x86/mm: memory area address KASLR" Jason Cooper
2016-06-24 19:04 ` [kernel-hardening] " Kees Cook
2016-06-24 20:40 ` Andy Lutomirski
2016-06-30 21:48 ` Jason Cooper
2016-06-30 21:56 ` Thomas Garnier
2016-06-30 21:48 ` Jason Cooper
2016-07-07 22:24 ` [kernel-hardening] Re: [PATCH v7 0/9] x86/mm: memory area address KASLR Kees Cook
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