From: Wang Chen <wangchen@cn.fujitsu.com>
To: "YOSHIFUJI Hideaki / 吉藤英明" <yoshfuji@linux-ipv6.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: Re: [2.6 PATCH] IPV6: Check length of optval provided by user in setsockopt()
Date: Mon, 31 Mar 2008 19:04:54 +0800 [thread overview]
Message-ID: <47F0C556.8090109@cn.fujitsu.com> (raw)
In-Reply-To: <20080331.195323.83430743.yoshfuji@linux-ipv6.org>
YOSHIFUJI Hideaki / 吉藤英明 said the following on 2008-3-31 18:53:
>>>> Check length of setsockopt's optval, which provided by user, before copy it
>>>> from user space.
>>> Please use "<" not "==".
>>>
>> There are two reasons that why I only check whether
>> len of optval is equal to that one in user space.
>> 1. We currently copy the entire structure from user
>> to kernel.
>> 2. In other cases, such as IPV6_LEAVE/JOIN_ANYCAST,
>> we check whether the len is equal to struct's len.
>>
>> So, Yoshifuji-san, can you tell me more about why we
>> should use "<"? :)
>
> POSIX, as we have some comments in that file ;-).
> If it is shorter than expected, -EINVAL, otherwise, no error.
> We need to fix other sites as well.
>
ooh, I see.
I will take a business trip to Japan tomorrow and I will finish
this patch since I come back weekend.
Thank you for your explanation.
--WCN
next prev parent reply other threads:[~2008-03-31 11:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-31 9:08 [2.6 PATCH] IPV6: Check length of optval provided by user in setsockopt() Wang Chen
2008-03-31 9:15 ` YOSHIFUJI Hideaki / 吉藤英明
2008-03-31 10:46 ` Wang Chen
2008-03-31 10:53 ` YOSHIFUJI Hideaki / 吉藤英明
2008-03-31 11:04 ` Wang Chen [this message]
2008-04-07 1:42 ` Wang Chen
2008-04-11 7:15 ` YOSHIFUJI Hideaki / 吉藤英明
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