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From:   =?utf-8?Q?Bj=C3=B8rn_Mork?= <bjorn@mork.no>
To:     Jouni =?utf-8?Q?Sepp=C3=A4nen?= <jks@iki.fi>
Cc:     Oliver Neukum <oliver@neukum.org>, linux-usb@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Enrico Mioso <mrkiko.rs@gmail.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net,stable] net: cdc_ncm: correct overhead in
 delayed_ndp_size
Organization: m
References: <20210103143602.95343-1-jks@iki.fi>
Date:   Sun, 03 Jan 2021 22:04:43 +0100
In-Reply-To: <20210103143602.95343-1-jks@iki.fi> ("Jouni =?utf-8?Q?Sepp?=
 =?utf-8?Q?=C3=A4nen=22's?= message
        of "Sun, 3 Jan 2021 16:36:02 +0200")
Message-ID: <87ft3henpw.fsf@miraculix.mork.no>
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Jouni Sepp=C3=A4nen <jks@iki.fi> writes:

> +		delayed_ndp_size =3D ctx->max_ndp_size +
> +			max(ctx->tx_ndp_modulus,
> +			    ctx->tx_modulus + ctx->tx_remainder) - 1;

You'll probably have to use something like

  max_t(u32, ctx->tx_ndp_modulus, ctx->tx_modulus + ctx->tx_remainder)
=20=20
here as the test robot already said.  Sorry for not seeing that earlier.
Otherwise this looks very good to me. The bug is real and severe, and
your patch appears to be the proper fix for it.

Thanks a lot for figuring this out and taking the time to fixup this
rather messy piece of code.

Reviewed-by: Bj=C3=B8rn Mork <bjorn@mork.no>