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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Yonghong Song <yhs@fb.com>, bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	kernel-team@fb.com, Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH bpf-next v3 09/15] bpf: add bpf_skc_to_udp6_sock() helper
Date: Tue, 23 Jun 2020 15:11:24 -0700	[thread overview]
Message-ID: <ca899dce-4eac-382d-538b-4cab1f5c249d@gmail.com> (raw)
In-Reply-To: <3e24b214-fc7e-d585-9c8d-98edd6202e70@fb.com>



On 6/23/20 10:03 AM, Yonghong Song wrote:
> 
> 
> On 6/23/20 9:27 AM, Eric Dumazet wrote:
>>
>>
>> On 6/22/20 7:22 PM, Yonghong Song wrote:
>>>
>>>
>>> On 6/22/20 6:47 PM, Eric Dumazet wrote:
>> &
>>>>
>>>> Why is the sk_fullsock(sk) needed ?
>>>
>>> The parameter 'sk' could be a sock_common. That is why the
>>> helper name bpf_skc_to_udp6_sock implies. The sock_common cannot
>>> access sk_protocol, hence we requires sk_fullsock(sk) here.
>>> Did I miss anything?
>>
>> OK, if arbitrary sockets can land here, you need also to check sk_type
> 
> The current check is:
>         if (sk_fullsock(sk) && sk->sk_protocol == IPPROTO_UDP &&
>             sk->sk_family == AF_INET6)
>                 return (unsigned long)sk;
> it checks to ensure it is full socket, it is a ipv6 socket and then check protocol.
> 
> Are you suggesting to add the following check?
>   sk->sk_type == SOCK_DGRAM
> 
> Not a networking expert. Maybe you can explain when we could have
> protocol is IPPROTO_UDP and sk_type not SOCK_DGRAM?


RAW sockets for instance.

Look at :

commit 940ba14986657a50c15f694efca1beba31fa568f
Author: Eric Dumazet <edumazet@google.com>
Date:   Tue Jan 21 23:17:14 2020 -0800

    gtp: make sure only SOCK_DGRAM UDP sockets are accepted
    
    A malicious user could use RAW sockets and fool
    GTP using them as standard SOCK_DGRAM UDP sockets.

  reply	other threads:[~2020-06-23 22:11 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-23  0:36 [PATCH bpf-next v3 00/15] implement bpf iterator for tcp and udp sockets Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 01/15] net: bpf: add bpf_seq_afinfo in tcp_iter_state Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 02/15] net: bpf: implement bpf iterator for tcp Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 03/15] bpf: support 'X' in bpf_seq_printf() helper Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 04/15] bpf: allow tracing programs to use bpf_jiffies64() helper Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 05/15] bpf: add bpf_skc_to_tcp6_sock() helper Yonghong Song
2020-06-23  5:46   ` kernel test robot
2020-06-23  5:53   ` kernel test robot
2020-06-23  6:39   ` Andrii Nakryiko
2020-06-23 14:52     ` Yonghong Song
2020-06-23 18:23       ` Andrii Nakryiko
2020-06-23 19:45         ` Yonghong Song
2020-06-23 20:11           ` Andrii Nakryiko
2020-06-23 20:46             ` Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 06/15] bpf: add bpf_skc_to_{tcp,tcp_timewait,tcp_request}_sock() helpers Yonghong Song
2020-06-23  5:18   ` kernel test robot
2020-06-23  6:39   ` kernel test robot
2020-06-23  0:36 ` [PATCH bpf-next v3 07/15] net: bpf: add bpf_seq_afinfo in udp_iter_state Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 08/15] net: bpf: implement bpf iterator for udp Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 09/15] bpf: add bpf_skc_to_udp6_sock() helper Yonghong Song
2020-06-23  1:47   ` Eric Dumazet
2020-06-23  2:22     ` Yonghong Song
2020-06-23 16:27       ` Eric Dumazet
2020-06-23 17:03         ` Yonghong Song
2020-06-23 22:11           ` Eric Dumazet [this message]
2020-06-23 22:44             ` Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 10/15] bpf/selftests: move newer bpf_iter_* type redefining to a new header file Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 11/15] tools/bpf: refactor some net macros to libbpf bpf_tracing_net.h Yonghong Song
2020-06-23  6:45   ` Andrii Nakryiko
2020-06-23 14:56     ` Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 12/15] tools/libbpf: add more common macros to bpf_tracing_net.h Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 13/15] tools/bpf: selftests: implement sample tcp/tcp6 bpf_iter programs Yonghong Song
2020-06-23  6:56   ` Andrii Nakryiko
2020-06-23 15:03     ` Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 14/15] tools/bpf: add udp4/udp6 bpf iterator Yonghong Song
2020-06-23  6:57   ` Andrii Nakryiko
2020-06-23 15:03     ` Yonghong Song
2020-06-23  0:36 ` [PATCH bpf-next v3 15/15] bpf/selftests: add tcp/udp iterator programs to selftests Yonghong Song
2020-06-23  6:59   ` Andrii Nakryiko

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