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From: Christian Hopps <chopps@chopps•org>
To: Florian Westphal <fw@strlen•de>
Cc: Christian Hopps <chopps@chopps•org>,
	devel@linux-ipsec•org,
	Steffen Klassert <steffen.klassert@secunet•com>,
	netdev@vger•kernel.org, Christian Hopps <chopps@labn•net>
Subject: Re: [devel-ipsec] [PATCH ipsec-next v5 06/17] xfrm: add mode_cbs module functionality
Date: Fri, 19 Jul 2024 17:06:41 -0700	[thread overview]
Message-ID: <m2jzhgx6sg.fsf@chopps.org> (raw)
In-Reply-To: <20240719061413.GA29401@breakpoint.cc>

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Florian Westphal <fw@strlen•de> writes:

> Christian Hopps via Devel <devel@linux-ipsec•org> wrote:
>> +static struct xfrm_mode_cbs xfrm_mode_cbs_map[XFRM_MODE_MAX];
>
> Why not
> static struct xfrm_mode_cbs *xfrm_mode_cbs_map[XFRM_MODE_MAX];
> i.e., why does
>
>> +int xfrm_register_mode_cbs(u8 mode, const struct xfrm_mode_cbs *mode_cbs)
>> +{
>> +	if (mode >= XFRM_MODE_MAX)
>> +		return -EINVAL;
>> +
>> +	xfrm_mode_cbs_map[mode] = *mode_cbs;
>
> do a deep copy here rather than
> 	xfrm_mode_cbs_map[mode] = mode_cbs;
>
> ?
>
>> +	if (mode == XFRM_MODE_IPTFS && !xfrm_mode_cbs_map[mode].create_state)
>> +		request_module("xfrm-iptfs");
>> +	return &xfrm_mode_cbs_map[mode];
>
> Sabrina noticed that this looks weird, and I agree.
>
> This can, afaics, return a partially initialised structure or an
> all-zero structure.
>
> request_module() might load the module, it can fail to load the
> module, and, most importantly, there is no guarantee that the
> module is removed right after.
>
> Is there any locking scheme in place that prevents this from
> happening? If so, a comment should be added that explains this.

I've switched it to the more obvious array of pointers and storing the module provided pointer.

Thanks,
Chris.

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  reply	other threads:[~2024-07-20  0:10 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-14 20:22 [PATCH ipsec-next v5 00/17] Add IP-TFS mode to xfrm Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 01/17] xfrm: config: add CONFIG_XFRM_IPTFS Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 02/17] include: uapi: add ip_tfs_*_hdr packet formats Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 03/17] include: uapi: add IPPROTO_AGGFRAG for AGGFRAG in ESP Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 04/17] xfrm: sysctl: allow configuration of global default values Christian Hopps
2024-07-18 13:13   ` Sabrina Dubroca
2024-07-18 13:15     ` Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 05/17] xfrm: netlink: add config (netlink) options Christian Hopps
2024-07-18 13:45   ` Sabrina Dubroca
2024-07-18 14:08     ` [devel-ipsec] " Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 06/17] xfrm: add mode_cbs module functionality Christian Hopps
2024-07-19  6:14   ` [devel-ipsec] " Florian Westphal
2024-07-20  0:06     ` Christian Hopps [this message]
2024-07-25 13:32   ` Sabrina Dubroca
2024-07-30 21:29     ` Christian Hopps
2024-07-31 17:10       ` Sabrina Dubroca
2024-07-31 18:32         ` Christian Hopps
2024-07-31 18:41           ` Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 07/17] xfrm: add generic iptfs defines and functionality Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 08/17] xfrm: iptfs: add new iptfs xfrm mode impl Christian Hopps
2024-07-15 12:39   ` Simon Horman
2024-07-18  5:56     ` [devel-ipsec] " Christian Hopps
2024-07-19  6:16   ` Florian Westphal
2024-07-20  0:30     ` Christian Hopps
2024-07-25 13:33   ` Sabrina Dubroca
2024-07-25 14:56     ` Christian Hopps
2024-07-31 16:29     ` Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 09/17] xfrm: iptfs: add user packet (tunnel ingress) handling Christian Hopps
2024-07-15 12:55   ` Simon Horman
2024-07-18  5:35     ` [devel-ipsec] " Christian Hopps
2024-07-18  6:32       ` Christian Hopps
2024-07-16 14:00   ` kernel test robot
2024-07-14 20:22 ` [PATCH ipsec-next v5 10/17] xfrm: iptfs: share page fragments of inner packets Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 11/17] xfrm: iptfs: add fragmenting of larger than MTU user packets Christian Hopps
2024-07-15 13:12   ` Simon Horman
2024-07-18  5:57     ` [devel-ipsec] " Christian Hopps
2024-07-18  6:56       ` Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 12/17] xfrm: iptfs: add basic receive packet (tunnel egress) handling Christian Hopps
2024-07-15 13:16   ` Simon Horman
2024-07-18  6:14     ` [devel-ipsec] " Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 13/17] xfrm: iptfs: handle received fragmented inner packets Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 14/17] xfrm: iptfs: add reusing received skb for the tunnel egress packet Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 15/17] xfrm: iptfs: add skb-fragment sharing code Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 16/17] xfrm: iptfs: handle reordering of received packets Christian Hopps
2024-07-14 20:22 ` [PATCH ipsec-next v5 17/17] xfrm: iptfs: add tracepoint functionality Christian Hopps
2024-07-15 11:53   ` kernel test robot
2024-07-17  5:21   ` kernel test robot

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