From: Tadeusz Struk <tadeusz.struk@linaro.org>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
Jakub Kicinski <kuba@kernel.org>
Cc: 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 15:04:14 -0800 [thread overview]
Message-ID: <77a44185-c9cd-21f5-125f-b8eec7a66537@linaro.org> (raw)
In-Reply-To: <CAF=yD-LrVjvY8wAqZtUTFS8V9ng2AD3jB1DOZvkagPOp3Sbq-g@mail.gmail.com>
On 3/10/22 14:43, Willem de Bruijn wrote:
> 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;
Yes, it will. v3 on its way.
--
Thanks,
Tadeusz
next prev parent reply other threads:[~2022-03-10 23:04 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
2022-03-10 23:04 ` Tadeusz Struk [this message]
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
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