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From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>,  Qi Tang <tpluszz77@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
	 David Ahern <dsahern@kernel.org>,
	 Eric Dumazet <edumazet@google.com>,
	 Paolo Abeni <pabeni@redhat.com>,
	 Simon Horman <horms@kernel.org>,
	 netdev@vger.kernel.org,  linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v4] ipv6: validate extension header length before copying to cmsg
Date: Sat, 16 May 2026 09:41:07 -0400	[thread overview]
Message-ID: <willemdebruijn.kernel.1c02e791312d@gmail.com> (raw)
In-Reply-To: <20260515175522.0aafbfb4@kernel.org>

Jakub Kicinski wrote:
> On Thu, 14 May 2026 11:58:02 +0800 Qi Tang wrote:
> > +	return (ptr + len <= skb_tail_pointer(skb)) ? len : 0;
> 
> This is probably better written as:
> 
> 	return (len <= skb_tail_pointer(skb) - ptr) ? len : 0;
> 
> ? len can't be too large so unlikely to matter in practice
> but technically ptr + len may overflow and wrap on 32b?

If making changes, also time to replace the open coded offset with
sizeof ipv6_opt_hdr and opt_hdr->hdrlen?

Or perhaps better left for net-next.

      reply	other threads:[~2026-05-16 13:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-14  3:58 [PATCH net v4] ipv6: validate extension header length before copying to cmsg Qi Tang
2026-05-16  0:55 ` Jakub Kicinski
2026-05-16 13:41   ` Willem de Bruijn [this message]

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