patches/kernel/0195-x86-mm-pti-Populate-user-PGD.patch

   1 From 3bc42412073e1c559266e2b07bc1fbce154d92dc Mon Sep 17 00:00:00 2001
   2 From: Dave Hansen <dave.hansen@linux.intel.com>
   3 Date: Mon, 4 Dec 2017 15:07:40 +0100
   4 Subject: [PATCH 195/241] x86/mm/pti: Populate user PGD
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 CVE-2017-5754
  10
  11 In clone_pgd_range() copy the init user PGDs which cover the kernel half of
  12 the address space, so a process has all the required kernel mappings
  13 visible.
  14
  15 [ tglx: Split out from the big kaiser dump and folded Andys simplification ]
  16
  17 Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
  18 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  19 Reviewed-by: Borislav Petkov <bp@suse.de>
  20 Cc: Andy Lutomirski <luto@kernel.org>
  21 Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
  22 Cc: Borislav Petkov <bp@alien8.de>
  23 Cc: Brian Gerst <brgerst@gmail.com>
  24 Cc: David Laight <David.Laight@aculab.com>
  25 Cc: Denys Vlasenko <dvlasenk@redhat.com>
  26 Cc: Eduardo Valentin <eduval@amazon.com>
  27 Cc: Greg KH <gregkh@linuxfoundation.org>
  28 Cc: H. Peter Anvin <hpa@zytor.com>
  29 Cc: Josh Poimboeuf <jpoimboe@redhat.com>
  30 Cc: Juergen Gross <jgross@suse.com>
  31 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  32 Cc: Peter Zijlstra <peterz@infradead.org>
  33 Cc: Will Deacon <will.deacon@arm.com>
  34 Cc: aliguori@amazon.com
  35 Cc: daniel.gruss@iaik.tugraz.at
  36 Cc: hughd@google.com
  37 Cc: keescook@google.com
  38 Signed-off-by: Ingo Molnar <mingo@kernel.org>
  39 (cherry picked from commit fc2fbc8512ed08d1de7720936fd7d2e4ce02c3a2)
  40 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  41 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  42 (cherry picked from commit 26c08c52162e1079cbb3e9ce8e1346a100ea7ccc)
  43 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  44 ---
  45  arch/x86/include/asm/pgtable.h | 9 ++++++++-
  46  1 file changed, 8 insertions(+), 1 deletion(-)
  47
  48 diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
  49 index 3ef8415b2358..25604b8a251a 100644
  50 --- a/arch/x86/include/asm/pgtable.h
  51 +++ b/arch/x86/include/asm/pgtable.h
  52 @@ -1104,7 +1104,14 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
  53   */
  54  static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
  55  {
  56 -       memcpy(dst, src, count * sizeof(pgd_t));
  57 +       memcpy(dst, src, count * sizeof(pgd_t));
  58 +#ifdef CONFIG_PAGE_TABLE_ISOLATION
  59 +       if (!static_cpu_has(X86_FEATURE_PTI))
  60 +               return;
  61 +       /* Clone the user space pgd as well */
  62 +       memcpy(kernel_to_user_pgdp(dst), kernel_to_user_pgdp(src),
  63 +              count * sizeof(pgd_t));
  64 +#endif
  65  }
  66
  67  #define PTE_SHIFT ilog2(PTRS_PER_PTE)
  68 --
  69 2.14.2
  70