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x86, i387: fix ptrace leakage using init_fpu()

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This bug got introduced by the recent i387 merge:

  commit 4421011120b2304e5c248ae4165a2704588aedf1
  Author: Roland McGrath <roland@redhat.com>
  Date:   Wed Jan 30 13:31:50 2008 +0100

      x86: x86 i387 user_regset

Current usage of unlazy_fpu() in ptrace specific routines is wrong.
unlazy_fpu() will not init fpu if the task never used math. So the
ptrace calls can expose the parent tasks FPU data in some cases.

Replace it with the init_fpu() which will init the math state, if the
task never used math before.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Suresh Siddha 2008-03-03 13:01:08 -08:00 committed by Ingo Molnar
parent 976dde010e
commit 18a8622101
1 changed files with 4 additions and 4 deletions
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8
arch/x86/kernel/i387.c
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@ -132,7 +132,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_fxsr) if (!cpu_has_fxsr)
return -ENODEV; return -ENODEV;
unlazy_fpu(target); init_fpu(target);
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.i387.fxsave, 0, -1); &target->thread.i387.fxsave, 0, -1);
@ -147,7 +147,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_fxsr) if (!cpu_has_fxsr)
return -ENODEV; return -ENODEV;
unlazy_fpu(target); init_fpu(target);
set_stopped_child_used_math(target); set_stopped_child_used_math(target);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
@ -307,7 +307,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
if (!HAVE_HWFP) if (!HAVE_HWFP)
return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf); return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
unlazy_fpu(target); init_fpu(target);
if (!cpu_has_fxsr) if (!cpu_has_fxsr)
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
@ -332,7 +332,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
if (!HAVE_HWFP) if (!HAVE_HWFP)
return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf); return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
unlazy_fpu(target); init_fpu(target);
set_stopped_child_used_math(target); set_stopped_child_used_math(target);
if (!cpu_has_fxsr) if (!cpu_has_fxsr)