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Date:   Tue, 23 Oct 2018 09:02:47 -0700
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Subject: Re: [PATCH stable v2 1/2] termios, tty/tty_baudrate.c: fix buffer overrun
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
        Jiri Slaby <jslaby@suse.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Richard Henderson <rth@twiddle.net>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Eugene Syromiatnikov <esyr@redhat.com>,
        linux-alpha@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>,
        stable@vger.kernel.org
From:   hpa@zytor.com
Message-ID: <DD4A5EC1-E0A8-4DB0-907F-F334C27CE54D@zytor.com>
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On October 23, 2018 7:53:51 AM PDT, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
>On Mon, Oct 22, 2018 at 09:19:04AM -0700, H. Peter Anvin (Intel) wrote:
>> From: "H. Peter Anvin" <hpa@zytor.com>
>> 
>> On architectures with CBAUDEX == 0 (Alpha and PowerPC), the code in
>tty_baudrate.c does
>> not do any limit checking on the tty_baudrate[] array, and in fact a
>> buffer overrun is possible on both architectures. Add a limit check
>to
>> prevent that situation.
>> 
>> This will be followed by a much bigger cleanup/simplification patch.
>> 
>> Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
>> Requested-by: Cc: Johan Hovold <johan@kernel.org>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Jiri Slaby <jslaby@suse.com>
>> Cc: Al Viro <viro@zeniv.linux.org.uk>
>> Cc: Richard Henderson <rth@twiddle.net>
>> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
>> Cc: Matt Turner <mattst88@gmail.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Kate Stewart <kstewart@linuxfoundation.org>
>> Cc: Philippe Ombredanne <pombredanne@nexb.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Eugene Syromiatnikov <esyr@redhat.com>
>> Cc: <linux-alpha@vger.kernel.org>
>> Cc: <linux-serial@vger.kernel.org>
>> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
>> Cc: <stable@vger.kernel.org>
>> ---
>>  drivers/tty/tty_baudrate.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>
>As I think Al's big termios cleanups are going to be hitting Linus's
>tree soon, do you know how these patches interact with that?
>
>This patch seems like it will not, so I'll be glad to queue that up
>after my first round of patches get merged to Linus later this week,
>but
>the second one worries me.
>
>thanks,
>
>greg k-h

I have been working with Al; we had approached much the same problems but from different directions. Mine ended up being a bit more comprehensive as a result, so I think we're going to end up using my code with Al's reviews.

So bottom line is that it should be all good.
-- 
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