[PATCH 4.14 083/159] x86/kasan/64: Teach KASAN about the cpu_entry_area

Greg Kroah-Hartman
2017-12-22T09:02:25Z

From: Andy Lutomirski <luto@kernel.org>

commit 21506525fb8ddb0342f2a2370812d47f6a1f3833 upstream.

The cpu_entry_area will contain stacks. Make sure that KASAN has
appropriate shadow mappings for them.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: kasan-dev@googlegroups.com
Cc: keescook@google.com
Link: https://lkml.kernel.org/r/20171204150605.642806442@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/mm/kasan_init_64.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)

--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -277,6 +277,7 @@ void __init kasan_early_init(void)
void __init kasan_init(void)
{
int i;
+ void *shadow_cpu_entry_begin, *shadow_cpu_entry_end;

#ifdef CONFIG_KASAN_INLINE
register_die_notifier(&kasan_die_notifier);
@@ -329,8 +330,23 @@ void __init kasan_init(void)
(unsigned long)kasan_mem_to_shadow(_end),
early_pfn_to_nid(__pa(_stext)));

+ shadow_cpu_entry_begin = (void *)__fix_to_virt(FIX_CPU_ENTRY_AREA_BOTTOM);
+ shadow_cpu_entry_begin = kasan_mem_to_shadow(shadow_cpu_entry_begin);
+ shadow_cpu_entry_begin = (void *)round_down((unsigned long)shadow_cpu_entry_begin,
+ PAGE_SIZE);
+
+ shadow_cpu_entry_end = (void *)(__fix_to_virt(FIX_CPU_ENTRY_AREA_TOP) + PAGE_SIZE);
+ shadow_cpu_entry_end = kasan_mem_to_shadow(shadow_cpu_entry_end);
+ shadow_cpu_entry_end = (void *)round_up((unsigned long)shadow_cpu_entry_end,
+ PAGE_SIZE);
+
kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
- (void *)KASAN_SHADOW_END);
+ shadow_cpu_entry_begin);
+
+ kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
+ (unsigned long)shadow_cpu_entry_end, 0);
+
+ kasan_populate_zero_shadow(shadow_cpu_entry_end, (void *)KASAN_SHADOW_END);

load_cr3(init_top_pgt);
__flush_tlb_all();