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Commit 18a86221 authored by Suresh Siddha's avatar Suresh Siddha Committed by Ingo Molnar
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x86, i387: fix ptrace leakage using init_fpu() 



This bug got introduced by the recent i387 merge:

  commit 44210111
  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: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 976dde01

arch/x86/kernel/i387.c

+4 −4
Original line number Diff line number Diff line
@@ -132,7 +132,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, 
	if (!cpu_has_fxsr)

		return -ENODEV;



	unlazy_fpu(target);

	init_fpu(target);



	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,

				   &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)

		return -ENODEV;



	unlazy_fpu(target);

	init_fpu(target);

	set_stopped_child_used_math(target);



	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)

		return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);



	unlazy_fpu(target);

	init_fpu(target);



	if (!cpu_has_fxsr)

		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)

		return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);



	unlazy_fpu(target);

	init_fpu(target);

	set_stopped_child_used_math(target);



	if (!cpu_has_fxsr)