linux-kernel - Re: data-race in do_compute_shiftstate / vt_get_shift

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Date:   Fri, 19 Aug 2022 09:06:03 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Abhishek Shah <abhishek.shah@...umbia.edu>
Cc:     jirislaby@...nel.org, linux-kernel@...r.kernel.org,
        changlianzhi@...ontech.com, dmitry.torokhov@...il.com,
        johan@...nel.org, Gabriel Ryan <gabe@...columbia.edu>
Subject: Re: data-race in do_compute_shiftstate / vt_get_shift_state

On Thu, Aug 18, 2022 at 08:25:00PM -0400, Abhishek Shah wrote:
> Hi all,
> 
> We found a data race involving the *shift_state * variable. Although we see
> that the race involves a function which has a comment about being racy
> <https://elixir.bootlin.com/linux/v5.18-rc5/source/drivers/tty/vt/vt.c#L3174>,
> we are unsure of its security implications as the remaining switch cases
> have a console_lock() call but this one
> <https://elixir.bootlin.com/linux/v5.18-rc5/source/drivers/tty/vt/vt.c#L3224>
> does not. Please let us know what you think.

Can you propose a patch that solves the problem for you in your testing
that we can review?

thanks,

greg k-h