Messages in this thread |  | | From | Andy Lutomirski <> | Date | Sat, 22 May 2021 16:39:19 -0700 | Subject | Re: [PATCH v27 24/31] x86/cet/shstk: Handle thread shadow stack |
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On Fri, May 21, 2021 at 3:14 PM Yu-cheng Yu <yu-cheng.yu@intel.com> wrote: > diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c > index 5ea2b494e9f9..8e5f772181b9 100644 > --- a/arch/x86/kernel/shstk.c > +++ b/arch/x86/kernel/shstk.c > @@ -71,6 +71,53 @@ int shstk_setup(void) > return 0; > } > > +int shstk_alloc_thread_stack(struct task_struct *tsk, unsigned long clone_flags, > + unsigned long stack_size) > +{
...
> + state = get_xsave_addr(&tsk->thread.fpu.state.xsave, XFEATURE_CET_USER); > + if (!state) > + return -EINVAL; > +
The get_xsave_addr() API is horrible, and we already have one egregiously buggy instance in the kernel. Let's not add another dubious use case.
If state == NULL, this means that CET_USER is in its init state. CET_USER in the init state should behave identically regardless of whether XINUSE[CET_USER] is set. Can you please adjust this code accordingly?
Thanks, Andy
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