From: Jakub Kicinski <kuba@kernel.org>
To: Simon Horman <horms@kernel.org>
Cc: Xiang Mei <xmei5@asu.edu>,
andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
pabeni@redhat.com, netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, jakub@cloudflare.com,
stable@vger.kernel.org, co+0ea1ac045375cf05@bugs.sh
Subject: Re: [PATCH net] vlan: require the MAC header to be present in __vlan_insert_inner_tag()
Date: Sat, 19 Sep 2026 15:49:11 -0700 [thread overview]
Message-ID: <20260919154911.642616cf@kernel.org> (raw)
In-Reply-To: <20260919074535.GW51261@horms.kernel.org>
On Sat, 19 Sep 2026 08:45:35 +0100 Simon Horman wrote:
> > + if (unlikely(!pskb_may_pull(skb, mac_len)))
> > + return -EINVAL;
> > +
> > if (skb_cow_head(skb, meta_len + VLAN_HLEN) < 0)
> > return -ENOMEM;
>
> TBH I am surprised that we have a bug like this in this function.
> But your analysis matches my understanding of the code.
FWIW I suspect it's because non-ethernet packets shouldn't normally
reach ethernet helpers. But I'm not sure how practical it would be
to push mac_len checks to the callers or anything of the sort,
so we can as well check here..
next prev parent reply other threads:[~2026-09-19 22:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-15 8:31 [PATCH net] vlan: require the MAC header to be present in __vlan_insert_inner_tag() Xiang Mei
2026-09-19 7:45 ` Simon Horman
2026-09-19 22:49 ` Jakub Kicinski [this message]
2026-09-20 9:26 ` Simon Horman
2026-09-19 23:20 ` patchwork-bot+netdevbpf
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