netdev - Re: [PATCH net-next 09/11] tcp: Check for filled TCP option space before SACK

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Message-ID: <47545b88-94db-e9cd-2f9f-2c6d665246e2@gmail.com>
Date:   Fri, 13 Dec 2019 15:22:38 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Mat Martineau <mathew.j.martineau@...ux.intel.com>,
        netdev@...r.kernel.org, mptcp@...ts.01.org
Subject: Re: [PATCH net-next 09/11] tcp: Check for filled TCP option space
 before SACK



On 12/13/19 3:00 PM, Mat Martineau wrote:
> The SACK code would potentially add four bytes to the expected
> TCP option size even if all option space was already used.
> 
> Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
> ---
>  net/ipv4/tcp_output.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
> index 9e04d45bc0e4..710ab45badfa 100644
> --- a/net/ipv4/tcp_output.c
> +++ b/net/ipv4/tcp_output.c
> @@ -748,6 +748,9 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
>  		size += TCPOLEN_TSTAMP_ALIGNED;
>  	}
>  
> +	if (size + TCPOLEN_SACK_BASE_ALIGNED >= MAX_TCP_OPTION_SPACE)
> +		return size;
> +
>  	eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
>  	if (unlikely(eff_sacks)) {
>  		const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
> 


Hmmm... I thought I already fixed this issue ?

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9424e2e7ad93ffffa88f882c9bc5023570904b55

Please do not mix fixes (targeting net tree) in a patch series targeting net-next