From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Tadeusz Struk <tadeusz.struk@linaro.org>,
David Miller <davem@davemloft.net>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
David Ahern <dsahern@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Network Development <netdev@vger.kernel.org>,
bpf <bpf@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
stable <stable@vger.kernel.org>,
syzbot+e223cf47ec8ae183f2a0@syzkaller.appspotmail.com,
Willem de Bruijn <willemb@google.com>
Subject: Re: [PATCH v2] net: ipv6: fix skb_over_panic in __ip6_append_data
Date: Thu, 10 Mar 2022 17:43:20 -0500 [thread overview]
Message-ID: <CAF=yD-LrVjvY8wAqZtUTFS8V9ng2AD3jB1DOZvkagPOp3Sbq-g@mail.gmail.com> (raw)
In-Reply-To: <20220310143011.00c21f53@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On Thu, Mar 10, 2022 at 5:30 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Thu, 10 Mar 2022 14:13:28 -0800 Tadeusz Struk wrote:
> > diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
> > index 4788f6b37053..6d45112322a0 100644
> > --- a/net/ipv6/ip6_output.c
> > +++ b/net/ipv6/ip6_output.c
> > @@ -1649,6 +1649,16 @@ static int __ip6_append_data(struct sock *sk,
> > skb->protocol = htons(ETH_P_IPV6);
> > skb->ip_summed = csummode;
> > skb->csum = 0;
> > +
> > + /*
> > + * Check if there is still room for payload
> > + */
>
> TBH I think the check is self-explanatory. Not worth a banner comment,
> for sure.
>
> > + if (fragheaderlen >= mtu) {
> > + err = -EMSGSIZE;
> > + kfree_skb(skb);
> > + goto error;
> > + }
>
> Not sure if Willem prefers this placement, but seems like we can lift
> this check out of the loop, as soon as fragheaderlen and mtu are known.
>
> > /* reserve for fragmentation and ipsec header */
> > skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
> > dst_exthdrlen);
Just updating this boundary check will do?
if (mtu < fragheaderlen ||
((mtu - fragheaderlen) & ~7) + fragheaderlen <
sizeof(struct frag_hdr))
goto emsgsize;
next prev parent reply other threads:[~2022-03-10 22:44 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-08 0:01 [PATCH] net: ipv6: fix invalid alloclen in __ip6_append_data Tadeusz Struk
2022-03-08 2:58 ` David Laight
2022-03-08 15:43 ` Tadeusz Struk
2022-03-08 18:18 ` David Ahern
2022-03-08 19:46 ` Tadeusz Struk
2022-03-09 5:01 ` David Ahern
2022-03-09 21:37 ` Tadeusz Struk
2022-03-10 14:39 ` Willem de Bruijn
2022-03-10 16:06 ` Tadeusz Struk
2022-03-10 17:32 ` Willem de Bruijn
2022-03-10 21:14 ` Tadeusz Struk
2022-03-10 22:13 ` [PATCH v2] net: ipv6: fix skb_over_panic " Tadeusz Struk
2022-03-10 22:18 ` David Laight
2022-03-10 22:30 ` Jakub Kicinski
2022-03-10 22:42 ` Tadeusz Struk
2022-03-10 22:43 ` Willem de Bruijn [this message]
2022-03-10 23:04 ` Tadeusz Struk
2022-03-10 23:05 ` David Laight
2022-03-10 23:25 ` [PATCH v3] " Tadeusz Struk
2022-03-11 1:49 ` Willem de Bruijn
2022-03-11 3:43 ` Tadeusz Struk
2022-03-12 1:40 ` patchwork-bot+netdevbpf
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='CAF=yD-LrVjvY8wAqZtUTFS8V9ng2AD3jB1DOZvkagPOp3Sbq-g@mail.gmail.com' \
--to=willemdebruijn.kernel@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kpsingh@kernel.org \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=songliubraving@fb.com \
--cc=stable@vger.kernel.org \
--cc=syzbot+e223cf47ec8ae183f2a0@syzkaller.appspotmail.com \
--cc=tadeusz.struk@linaro.org \
--cc=willemb@google.com \
--cc=yhs@fb.com \
--cc=yoshfuji@linux-ipv6.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).