From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Kunbo Zhang <absoler@smail.nju.edu.cn>,
tiwai@suse.de, wsa+renesas@sang-engineering.com,
linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
security@kernel.org
Subject: Re: [PATCH] input: i8042 - fix a double-fetch vulnerability introduced by GCC
Date: Fri, 4 Nov 2022 11:23:17 -0700 [thread overview]
Message-ID: <Y2VYlc8RxOsKxbmm@google.com> (raw)
In-Reply-To: <Y2TtXAW1LhOwlE64@kroah.com>
Hi Greg,
On Fri, Nov 04, 2022 at 11:45:48AM +0100, Greg KH wrote:
> On Fri, Nov 04, 2022 at 03:23:47PM +0800, Kunbo Zhang wrote:
> > As in the source code, the global variable is tested (at line 408) before three assignments of irq_bit, disable_bit and port_name.
> > However, as shown in the following disassembly of i8042_port_close(),
> > the variable (0x0(%rip)) is fetched and tested three times for each
> > assignment of irq_bit, disable_bit and port_name.
>
> There should not be any problem with this as that value does not ever
> change except in rare cases (shutdown or init).
We use this chunk only to establish identity of the port, we do not
expect instances to change while driver operates, so I do not think
there is any concern with re-fetching/re-checking the port while it is
being closed.
Thanks.
--
Dmitry
prev parent reply other threads:[~2022-11-04 18:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-04 7:23 [PATCH] input: i8042 - fix a double-fetch vulnerability introduced by GCC Kunbo Zhang
2022-11-04 8:04 ` Bagas Sanjaya
2022-11-04 10:45 ` Greg KH
2022-11-04 18:23 ` Dmitry Torokhov [this message]
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