x86, i387: fix ptrace leakage using init_fpu() (18a86221) · Commits · 戴 / test

This bug got introduced by the recent i387 merge: commit 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>

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)

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