From: Tadeusz Struk <tadeusz.struk@linaro.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] usb: mon: make mmapped memory read only
Date: Mon, 19 Sep 2022 07:53:52 -0700 [thread overview]
Message-ID: <75180d8c-235d-cdfa-2dff-01e0b8a24691@linaro.org> (raw)
In-Reply-To: <20220919042533.2688081-1-dvyukov@google.com>
Hi Dmitry,
On 9/18/22 21:25, Dmitry Vyukov wrote:
> Hi Tadeusz,
>
> Looking at places like these:
> https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/infiniband/hw/qib/qib_file_ops.c#L736
> https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/infiniband/hw/mlx5/main.c#L2088
> I think we also need to remove VM_MAYWRITE, otherwise it's still
> possible to turn it into a writable mapping with mprotect.
>
> It's also probably better to return an error if VM_WRITE (or VM_EXEC?) is set
> rather than silently fix it up.
Yes, I think that returning an error will make more sense here.
I don't think we need to worry about VM_EXEC. Even if userspace will try to execute
from the mmaped location it won't work. It will probably crash the application without
causing any harm to the kernel.
I will update the patch and send a v2 soon.
--
Thanks,
Tadeusz
next prev parent reply other threads:[~2022-09-19 14:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 22:47 [PATCH] usb: mon: make mmapped memory read only Tadeusz Struk
2022-09-17 4:14 ` Tadeusz Struk
2022-09-19 4:25 ` Dmitry Vyukov
2022-09-19 11:21 ` Dmitry Vyukov
2022-09-19 14:53 ` Tadeusz Struk [this message]
2022-09-19 21:59 ` [PATCH v2] " Tadeusz Struk
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