[Devel] [PATCH 14/39] x86_64: add KASan support
Andrey Ryabinin
aryabinin at odin.com
Mon Aug 24 03:19:04 PDT 2015
From: Andrey Ryabinin <a.ryabinin at samsung.com>
commit ef7f0d6a6ca8c9e4b27d78895af86c2fbfaeedb2 upstream.
This patch adds arch specific code for kernel address sanitizer.
16TB of virtual addressed used for shadow memory. It's located in range
[ffffec0000000000 - fffffc0000000000] between vmemmap and %esp fixup
stacks.
At early stage we map whole shadow region with zero page. Latter, after
pages mapped to direct mapping address range we unmap zero pages from
corresponding shadow (see kasan_map_shadow()) and allocate and map a real
shadow memory reusing vmemmap_populate() function.
Also replace __pa with __pa_nodebug before shadow initialized. __pa with
CONFIG_DEBUG_VIRTUAL=y make external function call (__phys_addr)
__phys_addr is instrumented, so __asan_load could be called before shadow
area initialized.
Signed-off-by: Andrey Ryabinin <a.ryabinin at samsung.com>
Cc: Dmitry Vyukov <dvyukov at google.com>
Cc: Konstantin Serebryany <kcc at google.com>
Cc: Dmitry Chernenkov <dmitryc at google.com>
Signed-off-by: Andrey Konovalov <adech.fo at gmail.com>
Cc: Yuri Gribov <tetra2005 at gmail.com>
Cc: Konstantin Khlebnikov <koct9i at gmail.com>
Cc: Sasha Levin <sasha.levin at oracle.com>
Cc: Christoph Lameter <cl at linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim at lge.com>
Cc: Dave Hansen <dave.hansen at intel.com>
Cc: Andi Kleen <andi at firstfloor.org>
Cc: Ingo Molnar <mingo at elte.hu>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: "H. Peter Anvin" <hpa at zytor.com>
Cc: Christoph Lameter <cl at linux.com>
Cc: Pekka Enberg <penberg at kernel.org>
Cc: David Rientjes <rientjes at google.com>
Cc: Jim Davis <jim.epost at gmail.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Andrey Ryabinin <aryabinin at odin.com>
---
Documentation/x86/x86_64/mm.txt | 3 +
arch/x86/Kconfig | 1 +
arch/x86/boot/Makefile | 2 +
arch/x86/boot/compressed/Makefile | 1 +
arch/x86/include/asm/kasan.h | 31 ++++++
arch/x86/kernel/Makefile | 2 +
arch/x86/kernel/dumpstack.c | 5 +-
arch/x86/kernel/head64.c | 9 +-
arch/x86/kernel/head_64.S | 29 ++++++
arch/x86/kernel/setup.c | 3 +
arch/x86/mm/Makefile | 3 +
arch/x86/mm/kasan_init_64.c | 199 ++++++++++++++++++++++++++++++++++++++
arch/x86/realmode/Makefile | 2 +-
arch/x86/realmode/rm/Makefile | 1 +
arch/x86/vdso/Makefile | 1 +
lib/Kconfig.kasan | 1 +
16 files changed, 289 insertions(+), 4 deletions(-)
create mode 100644 arch/x86/include/asm/kasan.h
create mode 100644 arch/x86/mm/kasan_init_64.c
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index c584a51..9bade83 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -12,6 +12,9 @@ ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space
ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole
ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
... unused hole ...
+ ... unused hole ...
+ffffec0000000000 - fffffc0000000000 (=44 bits) kasan shadow memory (16TB)
+... unused hole ...
ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0
ffffffffa0000000 - ffffffffff5fffff (=1525 MB) module mapping space
ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fc0d624..8ab367b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -78,6 +78,7 @@ config X86
select HAVE_CMPXCHG_LOCAL
select HAVE_CMPXCHG_DOUBLE
select HAVE_ARCH_KMEMCHECK
+ select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
select HAVE_USER_RETURN_NOTIFIER
select ARCH_BINFMT_ELF_RANDOMIZE_PIE
select HAVE_ARCH_JUMP_LABEL
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 379814b..5f9e79d 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -14,6 +14,8 @@
# Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.
# The number is the same as you would ordinarily press at bootup.
+KASAN_SANITIZE := n
+
SVGA_MODE := -DSVGA_MODE=NORMAL_VGA
targets := vmlinux.bin setup.bin setup.elf bzImage
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 5ef205c..3e40e93 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -17,6 +17,7 @@ KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector)
KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
GCOV_PROFILE := n
+KASAN_SANITIZE := n
LDFLAGS := -m elf_$(UTS_MACHINE)
LDFLAGS_vmlinux := -T
diff --git a/arch/x86/include/asm/kasan.h b/arch/x86/include/asm/kasan.h
new file mode 100644
index 0000000..8b22422
--- /dev/null
+++ b/arch/x86/include/asm/kasan.h
@@ -0,0 +1,31 @@
+#ifndef _ASM_X86_KASAN_H
+#define _ASM_X86_KASAN_H
+
+/*
+ * Compiler uses shadow offset assuming that addresses start
+ * from 0. Kernel addresses don't start from 0, so shadow
+ * for kernel really starts from compiler's shadow offset +
+ * 'kernel address space start' >> KASAN_SHADOW_SCALE_SHIFT
+ */
+#define KASAN_SHADOW_START (KASAN_SHADOW_OFFSET + \
+ (0xffff800000000000ULL >> 3))
+/* 47 bits for kernel address -> (47 - 3) bits for shadow */
+#define KASAN_SHADOW_END (KASAN_SHADOW_START + (1ULL << (47 - 3)))
+
+#ifndef __ASSEMBLY__
+
+extern pte_t kasan_zero_pte[];
+extern pte_t kasan_zero_pmd[];
+extern pte_t kasan_zero_pud[];
+
+#ifdef CONFIG_KASAN
+void __init kasan_map_early_shadow(pgd_t *pgd);
+void __init kasan_init(void);
+#else
+static inline void kasan_map_early_shadow(pgd_t *pgd) { }
+static inline void kasan_init(void) { }
+#endif
+
+#endif
+
+#endif
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index ead9d71..102a138 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -16,6 +16,8 @@ CFLAGS_REMOVE_ftrace.o = -pg
CFLAGS_REMOVE_early_printk.o = -pg
endif
+KASAN_SANITIZE_head$(BITS).o := n
+
CFLAGS_irq.o := -I$(src)/../include/asm/trace
obj-y := process_$(BITS).o signal.o entry_$(BITS).o
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index deb6421..b10f70a 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -258,7 +258,10 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err)
printk("SMP ");
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
- printk("DEBUG_PAGEALLOC");
+ printk("DEBUG_PAGEALLOC ");
+#endif
+#ifdef CONFIG_KASAN
+ printk("KASAN");
#endif
printk("\n");
if (notify_die(DIE_OOPS, str, regs, err,
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 0ffaa57..67df086 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -27,6 +27,7 @@
#include <asm/bios_ebda.h>
#include <asm/bootparam_utils.h>
#include <asm/microcode.h>
+#include <asm/kasan.h>
/*
* Manage page tables very early on.
@@ -46,7 +47,7 @@ static void __init reset_early_page_tables(void)
next_early_pgt = 0;
- write_cr3(__pa(early_level4_pgt));
+ write_cr3(__pa_nodebug(early_level4_pgt));
}
/* Create a new PMD entry */
@@ -59,7 +60,7 @@ int __init early_make_pgtable(unsigned long address)
pmdval_t pmd, *pmd_p;
/* Invalid address or early pgt is done ? */
- if (physaddr >= MAXMEM || read_cr3() != __pa(early_level4_pgt))
+ if (physaddr >= MAXMEM || read_cr3() != __pa_nodebug(early_level4_pgt))
return -1;
again:
@@ -158,6 +159,8 @@ void __init x86_64_start_kernel(char * real_mode_data)
/* Kill off the identity-map trampoline */
reset_early_page_tables();
+ kasan_map_early_shadow(early_level4_pgt);
+
/* clear bss before set_intr_gate with early_idt_handler */
clear_bss();
@@ -179,6 +182,8 @@ void __init x86_64_start_kernel(char * real_mode_data)
/* set init_level4_pgt kernel high mapping*/
init_level4_pgt[511] = early_level4_pgt[511];
+ kasan_map_early_shadow(init_level4_pgt);
+
x86_64_start_reservations(real_mode_data);
}
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 1681c4c..4178929 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -514,6 +514,22 @@ ENTRY(phys_base)
/* This must match the first entry in level2_kernel_pgt */
.quad 0x0000000000000000
+#ifdef CONFIG_KASAN
+#define FILL(VAL, COUNT) \
+ .rept (COUNT) ; \
+ .quad (VAL) ; \
+ .endr
+
+NEXT_PAGE(kasan_zero_pte)
+ FILL(kasan_zero_page - __START_KERNEL_map + _KERNPG_TABLE, 512)
+NEXT_PAGE(kasan_zero_pmd)
+ FILL(kasan_zero_pte - __START_KERNEL_map + _KERNPG_TABLE, 512)
+NEXT_PAGE(kasan_zero_pud)
+ FILL(kasan_zero_pmd - __START_KERNEL_map + _KERNPG_TABLE, 512)
+
+#undef FILL
+#endif
+
#include "../../x86/xen/xen-head.S"
.section .bss, "aw", @nobits
@@ -534,3 +550,16 @@ ENTRY(trace_idt_table)
__PAGE_ALIGNED_BSS
NEXT_PAGE(empty_zero_page)
.skip PAGE_SIZE
+
+#ifdef CONFIG_KASAN
+/*
+ * This page used as early shadow. We don't use empty_zero_page
+ * at early stages, stack instrumentation could write some garbage
+ * to this page.
+ * Latter we reuse it as zero shadow for large ranges of memory
+ * that allowed to access, but not instrumented by kasan
+ * (vmalloc/vmemmap ...).
+ */
+NEXT_PAGE(kasan_zero_page)
+ .skip PAGE_SIZE
+#endif
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 6445e02..2f14f46 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -91,6 +91,7 @@
#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/bugs.h>
+#include <asm/kasan.h>
#include <asm/vsyscall.h>
#include <asm/cpu.h>
@@ -1229,6 +1230,8 @@ void __init setup_arch(char **cmdline_p)
x86_init.paging.pagetable_init();
+ kasan_init();
+
if (boot_cpu_data.cpuid_level >= 0) {
/* A CPU has %cr4 if and only if it has CPUID */
mmu_cr4_features = read_cr4();
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index e0a96cd..ac9ca65 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -20,6 +20,9 @@ obj-$(CONFIG_HIGHMEM) += highmem_32.o
obj-$(CONFIG_KMEMCHECK) += kmemcheck/
+KASAN_SANITIZE_kasan_init_$(BITS).o := n
+obj-$(CONFIG_KASAN) += kasan_init_$(BITS).o
+
obj-$(CONFIG_MMIOTRACE) += mmiotrace.o
mmiotrace-y := kmmio.o pf_in.o mmio-mod.o
obj-$(CONFIG_MMIOTRACE_TEST) += testmmiotrace.o
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
new file mode 100644
index 0000000..cf3190a
--- /dev/null
+++ b/arch/x86/mm/kasan_init_64.c
@@ -0,0 +1,199 @@
+#include <linux/bootmem.h>
+#include <linux/kasan.h>
+#include <linux/kdebug.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/vmalloc.h>
+
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+
+extern pgd_t early_level4_pgt[PTRS_PER_PGD];
+extern struct range pfn_mapped[E820_X_MAX];
+
+extern unsigned char kasan_zero_page[PAGE_SIZE];
+
+static int __init map_range(struct range *range)
+{
+ unsigned long start;
+ unsigned long end;
+
+ start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start));
+ end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end));
+
+ /*
+ * end + 1 here is intentional. We check several shadow bytes in advance
+ * to slightly speed up fastpath. In some rare cases we could cross
+ * boundary of mapped shadow, so we just map some more here.
+ */
+ return vmemmap_populate(start, end + 1, pfn_to_nid(range->start));
+}
+
+static void __init clear_pgds(unsigned long start,
+ unsigned long end)
+{
+ for (; start < end; start += PGDIR_SIZE)
+ pgd_clear(pgd_offset_k(start));
+}
+
+void __init kasan_map_early_shadow(pgd_t *pgd)
+{
+ int i;
+ unsigned long start = KASAN_SHADOW_START;
+ unsigned long end = KASAN_SHADOW_END;
+
+ for (i = pgd_index(start); start < end; i++) {
+ pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud)
+ | _KERNPG_TABLE);
+ start += PGDIR_SIZE;
+ }
+}
+
+static int __init zero_pte_populate(pmd_t *pmd, unsigned long addr,
+ unsigned long end)
+{
+ pte_t *pte = pte_offset_kernel(pmd, addr);
+
+ while (addr + PAGE_SIZE <= end) {
+ WARN_ON(!pte_none(*pte));
+ set_pte(pte, __pte(__pa_nodebug(kasan_zero_page)
+ | __PAGE_KERNEL_RO));
+ addr += PAGE_SIZE;
+ pte = pte_offset_kernel(pmd, addr);
+ }
+ return 0;
+}
+
+static int __init zero_pmd_populate(pud_t *pud, unsigned long addr,
+ unsigned long end)
+{
+ int ret = 0;
+ pmd_t *pmd = pmd_offset(pud, addr);
+
+ while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) {
+ WARN_ON(!pmd_none(*pmd));
+ set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte)
+ | __PAGE_KERNEL_RO));
+ addr += PMD_SIZE;
+ pmd = pmd_offset(pud, addr);
+ }
+ if (addr < end) {
+ if (pmd_none(*pmd)) {
+ void *p = vmemmap_alloc_block(PAGE_SIZE, 0);
+ if (!p)
+ return -ENOMEM;
+ set_pmd(pmd, __pmd(__pa_nodebug(p) | _KERNPG_TABLE));
+ }
+ ret = zero_pte_populate(pmd, addr, end);
+ }
+ return ret;
+}
+
+
+static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
+ unsigned long end)
+{
+ int ret = 0;
+ pud_t *pud = pud_offset(pgd, addr);
+
+ while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) {
+ WARN_ON(!pud_none(*pud));
+ set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd)
+ | __PAGE_KERNEL_RO));
+ addr += PUD_SIZE;
+ pud = pud_offset(pgd, addr);
+ }
+
+ if (addr < end) {
+ if (pud_none(*pud)) {
+ void *p = vmemmap_alloc_block(PAGE_SIZE, 0);
+ if (!p)
+ return -ENOMEM;
+ set_pud(pud, __pud(__pa_nodebug(p) | _KERNPG_TABLE));
+ }
+ ret = zero_pmd_populate(pud, addr, end);
+ }
+ return ret;
+}
+
+static int __init zero_pgd_populate(unsigned long addr, unsigned long end)
+{
+ int ret = 0;
+ pgd_t *pgd = pgd_offset_k(addr);
+
+ while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) {
+ WARN_ON(!pgd_none(*pgd));
+ set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud)
+ | __PAGE_KERNEL_RO));
+ addr += PGDIR_SIZE;
+ pgd = pgd_offset_k(addr);
+ }
+
+ if (addr < end) {
+ if (pgd_none(*pgd)) {
+ void *p = vmemmap_alloc_block(PAGE_SIZE, 0);
+ if (!p)
+ return -ENOMEM;
+ set_pgd(pgd, __pgd(__pa_nodebug(p) | _KERNPG_TABLE));
+ }
+ ret = zero_pud_populate(pgd, addr, end);
+ }
+ return ret;
+}
+
+
+static void __init populate_zero_shadow(const void *start, const void *end)
+{
+ if (zero_pgd_populate((unsigned long)start, (unsigned long)end))
+ panic("kasan: unable to map zero shadow!");
+}
+
+
+#ifdef CONFIG_KASAN_INLINE
+static int kasan_die_handler(struct notifier_block *self,
+ unsigned long val,
+ void *data)
+{
+ if (val == DIE_GPF) {
+ pr_emerg("CONFIG_KASAN_INLINE enabled");
+ pr_emerg("GPF could be caused by NULL-ptr deref or user memory access");
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block kasan_die_notifier = {
+ .notifier_call = kasan_die_handler,
+};
+#endif
+
+void __init kasan_init(void)
+{
+ int i;
+
+#ifdef CONFIG_KASAN_INLINE
+ register_die_notifier(&kasan_die_notifier);
+#endif
+
+ memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt));
+ load_cr3(early_level4_pgt);
+
+ clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
+
+ populate_zero_shadow((void *)KASAN_SHADOW_START,
+ kasan_mem_to_shadow((void *)PAGE_OFFSET));
+
+ for (i = 0; i < E820_X_MAX; i++) {
+ if (pfn_mapped[i].end == 0)
+ break;
+
+ if (map_range(&pfn_mapped[i]))
+ panic("kasan: unable to allocate shadow!");
+ }
+
+ populate_zero_shadow(kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
+ (void *)KASAN_SHADOW_END);
+
+ memset(kasan_zero_page, 0, PAGE_SIZE);
+
+ load_cr3(init_level4_pgt);
+}
diff --git a/arch/x86/realmode/Makefile b/arch/x86/realmode/Makefile
index 94f7fbe..e02c2c6 100644
--- a/arch/x86/realmode/Makefile
+++ b/arch/x86/realmode/Makefile
@@ -6,7 +6,7 @@
# for more details.
#
#
-
+KASAN_SANITIZE := n
subdir- := rm
obj-y += init.o
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 8869287..71c2c94 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -6,6 +6,7 @@
# for more details.
#
#
+KASAN_SANITIZE := n
always := realmode.bin realmode.relocs
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 1f3eb19..35bcad7 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -184,6 +184,7 @@ quiet_cmd_vdso = VDSO $@
VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
GCOV_PROFILE := n
+KASAN_SANITIZE := n
#
# Install the unstripped copy of vdso*.so listed in $(vdso-install-y).
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index e5b3fbe..0052b1b 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -15,6 +15,7 @@ config KASAN
config KASAN_SHADOW_OFFSET
hex
+ default 0xdffffc0000000000 if X86_64
choice
prompt "Instrumentation type"
--
2.4.6
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