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From: Andy Lutomirski <luto@amacapital.net>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>, Oleg Nesterov <oleg@redhat.com>,
	Mark Mossberg <mark.mossberg@gmail.com>,
	Ingo Molnar <mingo@redhat.com>, X86 ML <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>, Jann Horn <jannh@google.com>,
	kyin@redhat.com
Subject: Re: [PATCH v2] x86/dumpstack: Fix misleading instruction pointer error message
Date: Mon, 16 Nov 2020 15:04:02 -0800	[thread overview]
Message-ID: <CALCETrW+Jek_t51RyqxO=HUA_PJ4APwS9hJQWsXyc426cgf0wA@mail.gmail.com> (raw)
In-Reply-To: <87blfxx8ps.fsf@nanos.tec.linutronix.de>

On Mon, Nov 16, 2020 at 2:01 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>  arch/x86/kernel/dumpstack.c |   23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
>
> --- a/arch/x86/kernel/dumpstack.c
> +++ b/arch/x86/kernel/dumpstack.c
> @@ -78,6 +78,9 @@ static int copy_code(struct pt_regs *reg
>         if (!user_mode(regs))
>                 return copy_from_kernel_nofault(buf, (u8 *)src, nbytes);
>
> +       /* The user space code from other tasks cannot be accessed. */
> +       if (regs != task_pt_regs(current))
> +               return -EPERM;

Depending on exactly where this gets called, this may not be
sufficient.  You should also check nmi_uaccess_okay().

--Andy

  reply	other threads:[~2020-11-16 23:04 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-02  4:29 [PATCH v2] x86/dumpstack: Fix misleading instruction pointer error message Mark Mossberg
2020-10-02 10:26 ` [tip: x86/core] " tip-bot2 for Mark Mossberg
2020-11-03 12:50 ` [PATCH v2] " Oleg Nesterov
2020-11-03 17:15   ` Borislav Petkov
2020-11-03 17:47     ` Oleg Nesterov
2020-11-03 17:52       ` Borislav Petkov
2020-11-03 18:11         ` Oleg Nesterov
2020-11-03 18:20           ` Borislav Petkov
2020-11-16 22:01             ` Thomas Gleixner
2020-11-16 23:04               ` Andy Lutomirski [this message]
2020-11-16 23:37                 ` Thomas Gleixner
2020-11-17  3:29                   ` Andy Lutomirski
2020-11-17  9:54               ` Borislav Petkov
2020-11-17 17:31               ` Oleg Nesterov

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