releases/4.4.45/arm64-ptrace-preserve-previous-registers-for-short-regset-write-3.patch

   1 From a672401c00f82e4e19704aff361d9bad18003714 Mon Sep 17 00:00:00 2001
   2 From: Dave Martin <Dave.Martin@arm.com>
   3 Date: Wed, 18 Jan 2017 16:25:22 +0000
   4 Subject: arm64/ptrace: Preserve previous registers for short regset write - 3
   5
   6 From: Dave Martin <Dave.Martin@arm.com>
   7
   8 commit a672401c00f82e4e19704aff361d9bad18003714 upstream.
   9
  10 Ensure that if userspace supplies insufficient data to
  11 PTRACE_SETREGSET to fill all the registers, the thread's old
  12 registers are preserved.
  13
  14 Fixes: 5d220ff9420f ("arm64: Better native ptrace support for compat tasks")
  15 Signed-off-by: Dave Martin <Dave.Martin@arm.com>
  16 Acked-by: Will Deacon <Will.Deacon@arm.com>
  17 Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  19
  20 ---
  21  arch/arm64/kernel/ptrace.c |    2 +-
  22  1 file changed, 1 insertion(+), 1 deletion(-)
  23
  24 --- a/arch/arm64/kernel/ptrace.c
  25 +++ b/arch/arm64/kernel/ptrace.c
  26 @@ -849,7 +849,7 @@ static int compat_tls_set(struct task_st
  27                           const void __user *ubuf)
  28  {
  29         int ret;
  30 -       compat_ulong_t tls;
  31 +       compat_ulong_t tls = target->thread.tp_value;
  32
  33         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
  34         if (ret)