From: Martin KaFai Lau <martin.lau@linux.dev>
To: "Hudson, Nick" <nhudson@akamai.com>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
"Tottenham, Max" <mtottenh@akamai.com>,
"Glasgall, Anna" <aglasgal@akamai.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 3/5] bpf: add helper masks for ADJ_ROOM flags and encap validation
Date: Thu, 26 Mar 2026 10:49:14 -0700 [thread overview]
Message-ID: <c0c453f9-28aa-462f-884d-0e9beb2fdf0a@linux.dev> (raw)
In-Reply-To: <9E9BE3BD-1640-49E7-8801-130945073B24@akamai.com>
On 3/26/26 10:02 AM, Hudson, Nick wrote:
>>> static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff,
>>> u64 flags)
>>> @@ -3502,6 +3513,11 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff,
>>> unsigned int gso_type = SKB_GSO_DODGY;
>>> int ret;
>>> + if (unlikely(flags & ~(BPF_F_ADJ_ROOM_ENCAP_MASK |
>>> + BPF_F_ADJ_ROOM_NO_CSUM_RESET |
>>> + BPF_F_ADJ_ROOM_FIXED_GSO)))
>> Under which case this new check will be hit?
> If a user supplies +ve len_diff and attempts to pass a DECAP flag.
>
> The commit message had
>
> Add flag validation to bpf_skb_net_grow() to reject invalid encap
> flags early.
There is DECAP_MASK check in bpf_skb_adjust_room() and then !shrink is
rejected. What am I missing?
next prev parent reply other threads:[~2026-03-26 17:49 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-18 13:42 [PATCH v2 0/5] bpf: skb_adjust_room helper refactor and tunnel decap flags Nick Hudson
2026-03-18 13:42 ` [PATCH v2 1/5] bpf: name the enum for BPF_FUNC_skb_adjust_room flags Nick Hudson
2026-03-21 0:39 ` Willem de Bruijn
2026-03-24 17:34 ` Martin KaFai Lau
2026-03-18 13:42 ` [PATCH v2 2/5] bpf: add BPF_F_ADJ_ROOM_DECAP_* flags for tunnel decapsulation Nick Hudson
2026-03-21 0:39 ` Willem de Bruijn
2026-03-18 13:42 ` [PATCH v2 3/5] bpf: add helper masks for ADJ_ROOM flags and encap validation Nick Hudson
2026-03-21 0:39 ` Willem de Bruijn
2026-03-24 18:12 ` Martin KaFai Lau
2026-03-26 17:02 ` Hudson, Nick
2026-03-26 17:49 ` Martin KaFai Lau [this message]
2026-03-27 10:55 ` Hudson, Nick
2026-03-27 19:02 ` Martin KaFai Lau
2026-03-18 13:42 ` [PATCH v2 4/5] bpf: allow new DECAP flags and add guard rails Nick Hudson
2026-03-18 20:02 ` Willem de Bruijn
2026-03-19 8:17 ` Hudson, Nick
2026-03-19 13:24 ` Willem de Bruijn
2026-03-21 0:40 ` Willem de Bruijn
2026-03-24 18:30 ` Martin KaFai Lau
2026-03-26 17:02 ` Hudson, Nick
2026-03-18 13:42 ` [PATCH v2 5/5] bpf: clear decap tunnel GSO state in skb_adjust_room Nick Hudson
2026-03-18 20:09 ` Willem de Bruijn
2026-03-18 20:01 ` [PATCH v2 0/5] bpf: skb_adjust_room helper refactor and tunnel decap flags Willem de Bruijn
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c0c453f9-28aa-462f-884d-0e9beb2fdf0a@linux.dev \
--to=martin.lau@linux.dev \
--cc=aglasgal@akamai.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mtottenh@akamai.com \
--cc=netdev@vger.kernel.org \
--cc=nhudson@akamai.com \
--cc=pabeni@redhat.com \
--cc=willemdebruijn.kernel@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.