From: Nicolas Dichtel <nicolas.dichtel@6wind•com>
To: Thomas Graf <tgraf@suug•ch>
Cc: bhutchings@solarflare•com, netdev@vger•kernel.org,
davem@davemloft•net, David.Laight@ACULAB•COM
Subject: Re: [PATCH v2] netlink: align attributes on 64-bits
Date: Wed, 19 Dec 2012 19:07:11 +0100 [thread overview]
Message-ID: <50D2024F.9070604@6wind.com> (raw)
In-Reply-To: <20121219170912.GB6975@casper.infradead.org>
Le 19/12/2012 18:09, Thomas Graf a écrit :
> On 12/19/12 at 12:22pm, Nicolas Dichtel wrote:
>> Here padlen will return 4, which is wrong: padlen + NLA_HDRLEN = 8,
>> alignment is the same than before. Here is a proposal fix:
>>
>> diff --git a/lib/nlattr.c b/lib/nlattr.c
>> index e4f0329..1556313 100644
>> --- a/lib/nlattr.c
>> +++ b/lib/nlattr.c
>> @@ -338,7 +338,10 @@ struct nlattr *__nla_reserve(struct sk_buff
>> *skb, int attrtype, int attrlen)
>> struct nlattr *pad;
>> size_t padlen;
>>
>> - padlen = nla_total_size(offset) - offset - NLA_HDRLEN;
>> + /* We need to remove NLA_HDRLEN two times: one time for the
>> + * attribute hdr and one time for the pad attribute hdr.
>> + */
>> + padlen = nla_total_size(offset) - offset - 2 * NLA_HDRLEN;
>> pad = (struct nlattr *) skb_put(skb, nla_attr_size(padlen));
>> pad->nla_type = 0;
>> pad->nla_len = nla_attr_size(padlen);
>>
>> With this patch, it seems goods. attribute are always aligned on 8 bytes. Also
>> I did not notice any problem with size calculation (I try some ip
>> link, ip xfrm, ip [m]route).
>>
>> Do you want to make more tests? Or will your repost the full patch?
>> I can do it if you don't have time.
>
> Thanks.
>
> I would like to do some testing as well. I do expect some fallout from
> this. There is likely some interface abuse that will now be exposed
> due to this.
>
> We'll have to wait for the next merge window to open anyway. I'd
> consider this a new feature and not a bugfix based on the possible
> regression impact it could have.
>
> I'll post a new version of the patch integrating your fix above so
> others (especially subsystem maintainers depending on netlink) can run
> the patch as well.
>
Ok, sounds good.
next prev parent reply other threads:[~2012-12-19 18:08 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-04 11:13 [PATCH net-next 0/7] Allow to monitor multicast cache event via rtnetlink Nicolas Dichtel
2012-12-04 11:13 ` [PATCH net-next 1/7] netconf: advertise mc_forwarding status Nicolas Dichtel
2012-12-04 11:13 ` [PATCH net-next 2/7] ip6mr: use nla_nest_* helpers Nicolas Dichtel
2012-12-04 11:13 ` [PATCH net-next 3/7] ipmr/ip6mr: advertise mfc stats via rtnetlink Nicolas Dichtel
2012-12-04 11:13 ` [PATCH net-next 4/7] ipmr/ip6mr: report origin of mfc entry into rtnl msg Nicolas Dichtel
2012-12-04 11:13 ` [PATCH net-next 5/7] ipmr/ip6mr: allow to get unresolved cache via netlink Nicolas Dichtel
2012-12-04 11:13 ` [PATCH net-next 6/7] ipmr: advertise new mfc entries via rtnl Nicolas Dichtel
2012-12-04 11:13 ` [PATCH net-next 7/7] ip6mr: " Nicolas Dichtel
2012-12-04 18:09 ` [PATCH net-next 0/7] Allow to monitor multicast cache event via rtnetlink David Miller
2012-12-04 20:02 ` Nicolas Dichtel
2012-12-05 11:02 ` Nicolas Dichtel
2012-12-05 11:41 ` David Laight
2012-12-05 17:54 ` David Miller
2012-12-06 8:43 ` Nicolas Dichtel
2012-12-06 17:49 ` Thomas Graf
2012-12-06 21:49 ` Nicolas Dichtel
2012-12-07 10:38 ` David Laight
2012-12-07 10:58 ` Thomas Graf
2012-12-11 15:03 ` Nicolas Dichtel
2012-12-11 18:40 ` Thomas Graf
2012-12-12 17:30 ` Nicolas Dichtel
2012-12-14 13:16 ` [PATCH] netlink: align attributes on 64-bits Nicolas Dichtel
2012-12-14 15:49 ` Ben Hutchings
2012-12-14 16:04 ` Nicolas Dichtel
2012-12-17 16:49 ` [PATCH v2] " Nicolas Dichtel
2012-12-17 17:06 ` David Laight
2012-12-17 17:35 ` Nicolas Dichtel
2012-12-18 9:19 ` David Laight
2012-12-18 10:18 ` Nicolas Dichtel
2012-12-18 12:57 ` Thomas Graf
2012-12-18 16:23 ` Nicolas Dichtel
2012-12-18 16:50 ` David Laight
2012-12-18 17:11 ` Thomas Graf
2012-12-19 9:17 ` David Laight
2012-12-19 17:20 ` Thomas Graf
2012-12-20 9:37 ` David Laight
2012-12-20 9:40 ` David Laight
2012-12-18 17:08 ` Thomas Graf
2012-12-18 22:07 ` Nicolas Dichtel
2012-12-19 11:22 ` Nicolas Dichtel
2012-12-19 17:09 ` Thomas Graf
2012-12-19 18:07 ` Nicolas Dichtel [this message]
2012-12-17 9:59 ` [PATCH] " David Laight
2012-12-17 16:53 ` Nicolas Dichtel
2012-12-05 17:53 ` [PATCH net-next 0/7] Allow to monitor multicast cache event via rtnetlink David Miller
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