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Date:   Tue, 30 Jul 2019 14:42:35 -0700 (PDT)
Message-Id: <20190730.144235.188879655867188705.davem@davemloft.net>
To:     arnd@arndb.de
Cc:     viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, g.nault@alphalink.fr,
        mostrows@earthlink.net, xeb@mail.ru, jchapman@katalix.com,
        netdev@vger.kernel.org
Subject: Re: [PATCH v5 09/29] compat_ioctl: pppoe: fix PPPOEIOCSFWD handling
From:   David Miller <davem@davemloft.net>
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        <20190730192552.4014288-10-arnd@arndb.de>
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From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 30 Jul 2019 21:25:20 +0200

> Support for handling the PPPOEIOCSFWD ioctl in compat mode was added in
> linux-2.5.69 along with hundreds of other commands, but was always broken
> sincen only the structure is compatible, but the command number is not,
> due to the size being sizeof(size_t), or at first sizeof(sizeof((struct
> sockaddr_pppox)), which is different on 64-bit architectures.
> 
> Guillaume Nault adds:
> 
>   And the implementation was broken until 2016 (see 29e73269aa4d ("pppoe:
>   fix reference counting in PPPoE proxy")), and nobody ever noticed. I
>   should probably have removed this ioctl entirely instead of fixing it.
>   Clearly, it has never been used.
> 
> Fix it by adding a compat_ioctl handler for all pppoe variants that
> translates the command number and then calls the regular ioctl function.
> 
> All other ioctl commands handled by pppoe are compatible between 32-bit
> and 64-bit, and require compat_ptr() conversion.
> 
> This should apply to all stable kernels.
> 
> Acked-by: Guillaume Nault <g.nault@alphalink.fr>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Applied and queued up for -stable, thanks everyone.