diff options
| author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2016-01-11 15:51:19 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-02-09 13:33:14 +0100 |
| commit | 063fb3e56f6dd29b2633b678b837e1d904200e6f (patch) | |
| tree | ffe61cc04b53f7a3b9f41f80e5f0a2c4acaabc35 /arch | |
| parent | 69e0210fd01ff157d332102219aaf5c26ca8069b (diff) | |
| download | linux-063fb3e56f6dd29b2633b678b837e1d904200e6f.tar.bz2 | |
x86/kasan: Write protect kasan zero shadow
After kasan_init() executed, no one is allowed to write to kasan_zero_page,
so write protect it.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1452516679-32040-3-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/kasan_init_64.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 303e47045864..1b1110fa0057 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -125,10 +125,16 @@ void __init kasan_init(void) /* * kasan_zero_page has been used as early shadow memory, thus it may - * contain some garbage. Now we can clear it, since after the TLB flush - * no one should write to it. + * contain some garbage. Now we can clear and write protect it, since + * after the TLB flush no one should write to it. */ memset(kasan_zero_page, 0, PAGE_SIZE); + for (i = 0; i < PTRS_PER_PTE; i++) { + pte_t pte = __pte(__pa(kasan_zero_page) | __PAGE_KERNEL_RO); + set_pte(&kasan_zero_pte[i], pte); + } + /* Flush TLBs again to be sure that write protection applied. */ + __flush_tlb_all(); init_task.kasan_depth = 0; pr_info("KernelAddressSanitizer initialized\n"); |