patches/kernel/0106-x86-entry-64-Shorten-TEST-instructions.patch

   1 From de4c79dbea1d23e58752c189586c5f5b751fa142 Mon Sep 17 00:00:00 2001
   2 From: Borislav Petkov <bp@suse.de>
   3 Date: Thu, 2 Nov 2017 13:09:26 +0100
   4 Subject: [PATCH 106/233] x86/entry/64: Shorten TEST instructions
   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 Convert TESTL to TESTB and save 3 bytes per callsite.
  12
  13 No functionality change.
  14
  15 Signed-off-by: Borislav Petkov <bp@suse.de>
  16 Cc: Andy Lutomirski <luto@kernel.org>
  17 Cc: Brian Gerst <brgerst@gmail.com>
  18 Cc: Dave Hansen <dave.hansen@intel.com>
  19 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  20 Cc: Peter Zijlstra <peterz@infradead.org>
  21 Cc: Thomas Gleixner <tglx@linutronix.de>
  22 Link: http://lkml.kernel.org/r/20171102120926.4srwerqrr7g72e2k@pd.tnic
  23 Signed-off-by: Ingo Molnar <mingo@kernel.org>
  24 (cherry picked from commit 1e4c4f610f774df6088d7c065b2dd4d22adba698)
  25 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  26 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  27 (cherry picked from commit 2b5cfca36261d4ce45ebfdf2602d65201fa3c780)
  28 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  29 ---
  30  arch/x86/entry/entry_64.S | 4 ++--
  31  1 file changed, 2 insertions(+), 2 deletions(-)
  32
  33 diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
  34 index 05501c781c20..2491b3b25b9a 100644
  35 --- a/arch/x86/entry/entry_64.S
  36 +++ b/arch/x86/entry/entry_64.S
  37 @@ -620,7 +620,7 @@ GLOBAL(retint_user)
  38  GLOBAL(swapgs_restore_regs_and_return_to_usermode)
  39  #ifdef CONFIG_DEBUG_ENTRY
  40         /* Assert that pt_regs indicates user mode. */
  41 -       testl   $3, CS(%rsp)
  42 +       testb   $3, CS(%rsp)
  43         jnz     1f
  44         ud2
  45  1:
  46 @@ -653,7 +653,7 @@ retint_kernel:
  47  GLOBAL(restore_regs_and_return_to_kernel)
  48  #ifdef CONFIG_DEBUG_ENTRY
  49         /* Assert that pt_regs indicates kernel mode. */
  50 -       testl   $3, CS(%rsp)
  51 +       testb   $3, CS(%rsp)
  52         jz      1f
  53         ud2
  54  1:
  55 --
  56 2.14.2
  57