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Date:   Tue, 12 Oct 2021 08:23:09 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Ralf Baechle <ralf@linux-mips.org>
Cc:     netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Thomas Osterried <thomas@osterried.de>,
        linux-hams@vger.kernel.org
Subject: Re: [PATCH] ax25: Fix use of copy_from_sockptr() in
 ax25_setsockopt()
Message-ID: <20211012062309.GD17407@lst.de>
References: <YVXkwzKZhPoD0Ods@linux-mips.org>
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On Thu, Sep 30, 2021 at 06:24:35PM +0200, Ralf Baechle wrote:
> The destination pointer passed to copy_from_sockptr() is an unsigned long *
> but the source in userspace is an unsigned int * resulting in an integer
> of the wrong size being copied from userspace.
> 
> This happens to work on 32 bit but breaks 64-bit where bytes 4..7 will not
> be initialized.  By luck it may work on little endian but on big endian
> where the userspace data is copied to the upper 32 bit of the destination
> it's most likely going to break.
> 
> A simple test case to demonstrate this setsockopt() issue is:

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>