Messages in this thread | | | Date | Wed, 5 Sep 2018 11:40:12 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 2/3] x86/speculation: apply IBPB more strictly to avoid cross-process data leak |
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On Wed, Sep 05, 2018 at 10:02:41AM +0200, Jiri Kosina wrote: > Yeah, I did more or less that earlier today; my series currently has
Excellent, maybe add a wee comment like so?
> +static bool ibpb_needed(struct task_struct *tsk, u64 last_ctx_id) > +{ /* * Check if the current (previous) task has access to the memory * of the @tsk (next) task. If access is denied, make sure to * issue a IBPB to stop user->user Spectre-v2 attacks. * * Note: __ptrace_may_access() returns 0 or -ERRNO. */ > + return (tsk && tsk->mm && tsk->mm->context.ctx_id != last_ctx_id && > + __ptrace_may_access(tsk, PTRACE_MODE_IBPB)); > +}
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