Re: [PATCH 4.4 041/241] cifs: fix strcat buffer overflow and reduce raciness in smb21_set_oplock_level()

From: Greg Kroah-Hartman
Date: Tue Jun 11 2019 - 03:24:58 EST


On Mon, Jun 10, 2019 at 07:13:24PM +0000, Pavel Shilovskiy wrote:
>
> -----Original Message-----
> From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Sent: Sunday, June 9, 2019 9:40 AM
> To: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx; Christoph Probst <kernel@xxxxxxxxx>; Pavel Shilovskiy <pshilov@xxxxxxxxxxxxx>; Steven French <Steven.French@xxxxxxxxxxxxx>
> Subject: [PATCH 4.4 041/241] cifs: fix strcat buffer overflow and reduce raciness in smb21_set_oplock_level()
>
> From: Christoph Probst <kernel@xxxxxxxxx>
>
> commit 6a54b2e002c9d00b398d35724c79f9fe0d9b38fb upstream.
>
> Change strcat to strncpy in the "None" case to fix a buffer overflow when cinode->oplock is reset to 0 by another thread accessing the same cinode. It is never valid to append "None" to any other message.
>
> Consolidate multiple writes to cinode->oplock to reduce raciness.
>
> Signed-off-by: Christoph Probst <kernel@xxxxxxxxx>
> Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
> CC: Stable <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> --------------------------------
>
> Hi Greg,
>
> This patch has been queued for 4.4.y and has already been merged into
> 5.1.y (5.1.5). Are you going to apply it to other stable kernels: 4.9,
> 4.14, 4.19?

It is already in the 4.9.179, 4.14.122, 4.19.46, 5.0.19, and 5.1.5
released kernels. So I don't think I can merge it into them again :)

thanks,

greg k-h