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From: Nicolas Dichtel <nicolas.dichtel@6wind•com>
To: Fan Du <fan.du@intel•com>, steffen.klassert@secunet•com
Cc: herbert@gondor•apana.org.au, davem@davemloft•net,
	netdev@vger•kernel.org, fengyuleidian0615@gmail•com
Subject: Re: [PATCHv3, ipsec-next] xfrm: Do not parse 32bits compiled xfrm netlink msg on 64bits host
Date: Thu, 29 Jan 2015 11:29:51 +0100	[thread overview]
Message-ID: <54CA0B9F.8080104@6wind.com> (raw)
In-Reply-To: <1422349230-17394-1-git-send-email-fan.du@intel.com>

Le 27/01/2015 10:00, Fan Du a écrit :
> structure like xfrm_usersa_info or xfrm_userpolicy_info
> has different sizeof when compiled as 32bits and 64bits
> due to not appending pack attribute in their definition.
> This will result in broken SA and SP information when user
> trying to configure them through netlink interface.
>
> Inform user land about this situation instead of keeping
> silent, the upper test scripts would behave accordingly.
>
> Quotes from: http://marc.info/?l=linux-netdev&m=142226348715503&w=2
>>
>> Before a clean solution show up, I think it's better to warn user in some way
>> like http://patchwork.ozlabs.org/patch/323842/ did. Otherwise, many people
>> who stuck there will always spend time and try to fix this issue in whatever way.
>
> Yes, this is the first thing we should do. I'm willing to accept a patch
>
> Signed-off-by: Fan Du <fan.du@intel•com>
A way to solve this problem was to provide to userland a xfrm compat header
file, which match the ABI of the kernel. Something like:

#include <linux/xfrm.h>

#define xfrm_usersa_info xfrm_usersa_info_64
#define xfrm_usersa_info_compat xfrm_usersa_info
struct xfrm_usersa_info_compat {
	struct xfrm_selector		sel;
	struct xfrm_id			id;
	xfrm_address_t			saddr;
	struct xfrm_lifetime_cfg	lft;
	struct xfrm_lifetime_cur	curlft;
	struct xfrm_stats		stats;
	__u32				seq;
	__u32				reqid;
	__u16				family;
	__u8				mode;
	__u8				replay_window;
	__u8				flags;
	__u8				hole1;
	__u32				hole2;
};

The point I try to make is that patching userland apps allows to use xfrm on a
32bits userland / 64bits kernel.

If I understand well your patch, it will not be possible anymore, all messages
will be rejected. And this may break existing apps.


Regards,
Nicolas

  parent reply	other threads:[~2015-01-29 10:29 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20150127.001226.711259930266409202.davem () davemloft ! net>
2015-01-27  9:00 ` [PATCHv3 ipsec-next] xfrm: Do not parse 32bits compiled xfrm netlink msg on 64bits host Fan Du
2015-01-27  9:46   ` David Laight
2015-01-27 11:04     ` Florian Westphal
2015-01-27 11:54       ` David Laight
2015-01-27 19:24     ` David Miller
2015-01-28  9:53       ` David Laight
2015-01-28  4:34     ` Fan Du
2015-01-29 10:29   ` Nicolas Dichtel [this message]
2015-01-29 13:56     ` [PATCHv3, " David Laight
2015-01-29 14:14       ` Nicolas Dichtel
2015-01-30  2:11     ` Fan Du
2015-02-02  8:44     ` Steffen Klassert
2015-02-02  9:02       ` Nicolas Dichtel
2015-02-02 19:45         ` David Miller
2015-02-03 12:24         ` Steffen Klassert
2015-02-03 14:02           ` Nicolas Dichtel
2015-03-06  6:13   ` [PATCHv3 " Steffen Klassert

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