linux-kernel - Re: [PATCH] kprobe: safely access memory specified by userspace

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Message-ID: <20190214094447.0adeea8e@gandalf.local.home>
Date:   Thu, 14 Feb 2019 09:44:47 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Changbin Du <changbin.du@...il.com>
Cc:     mingo@...hat.com, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: Re: [PATCH] kprobe: safely access memory specified by userspace

On Thu, 14 Feb 2019 14:10:44 +0000
Changbin Du <changbin.du@...il.com> wrote:

> > No I didn't have the fix. I was running an older kernel actually. One
> > before commit 9da3f2b74054406f87dff7101a569217ffceb29b was added.
> > There's nothing actually wrong with that code, since kprobes is allowed
> > to poke at anything. But that commit considers the kernel using copy
> > from user to poke kernel address space is a security bug.
> >   
> Glade to know that. And I wonder wether all such cases have been
> disclosed. I noticed the uprobe code also uses some usercopy functions.

Well, uprobe shouldn't be poking at kernel addresses ;-)

-- Steve