From: Arnd Bergmann <arnd@xxxxxxxx>
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@xxxxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Applied and queued up for -stable, thanks everyone.
