From: Suresh Siddha Date: Mon, 3 Mar 2008 21:01:08 +0000 (-0800) Subject: x86, i387: fix ptrace leakage using init_fpu() X-Git-Tag: v2.6.25-rc4~96^2~2 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=18a8622101154277df97e24097ed17aace84fa3a;p=linux-2.6 x86, i387: fix ptrace leakage using init_fpu() This bug got introduced by the recent i387 merge: commit 4421011120b2304e5c248ae4165a2704588aedf1 Author: Roland McGrath 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 Signed-off-by: Ingo Molnar Acked-by: Thomas Gleixner --- diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 763dfc4072..60fe801575 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)