From 18a8622101154277df97e24097ed17aace84fa3a Mon Sep 17 00:00:00 2001
From: Suresh Siddha <suresh.b.siddha@intel.com>
Date: Mon, 3 Mar 2008 13:01:08 -0800
Subject: [PATCH] x86, i387: fix ptrace leakage using init_fpu()
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>
---
arch/x86/kernel/i387.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 763dfc407232b..60fe801575696 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -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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