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Date:   Tue, 29 Nov 2022 18:55:31 +0200
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Artem Chernyshev <artem.chernyshev@red-soft.ru>
Cc:     Woojung Huh <woojung.huh@microchip.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S . Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org,
        Arun Ramadoss <arun.ramadoss@microchip.com>
Subject: Re: [PATCH] net: dsa: ksz: Check proper trim in ksz_common_rcv()
Message-ID: <20221129165531.wgeyxgo5el2x43mj@skbuf>
References: <20221129140809.2755960-1-artem.chernyshev@red-soft.ru>
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In-Reply-To: <20221129140809.2755960-1-artem.chernyshev@red-soft.ru>
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Hi Artyom,

On Tue, Nov 29, 2022 at 05:08:09PM +0300, Artem Chernyshev wrote:
> Return NULL if we got unexpected value from skb_trim_rcsum()
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: bafe9ba7d908 ("net: dsa: ksz: Factor out common tag code")
> Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>

It looks like the same pattern exists in tag_hellcreek.c and in
tag_sja1105.c. Do you intend to patch those as well?

>  net/dsa/tag_ksz.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
> index 38fa19c1e2d5..429250298ac4 100644
> --- a/net/dsa/tag_ksz.c
> +++ b/net/dsa/tag_ksz.c
> @@ -21,7 +21,8 @@ static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
>  	if (!skb->dev)
>  		return NULL;
>  
> -	pskb_trim_rcsum(skb, skb->len - len);
> +	if (pskb_trim_rcsum(skb, skb->len - len))
> +		return NULL;
>  
>  	dsa_default_offload_fwd_mark(skb);
>  
> -- 
> 2.30.3
>