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From: "Randy.Dunlap" <rddunlap@osdl.org>
To: Robert Hancock <hancockr@shaw.ca>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Taking strlen of buffers copied from userspace
Date: Tue, 15 Mar 2005 21:30:27 -0800	[thread overview]
Message-ID: <4237C473.2060205@osdl.org> (raw)
In-Reply-To: <4237C2F2.5010203@shaw.ca>

Robert Hancock wrote:
> Randy.Dunlap wrote:
> 
>> The latter one does (before the listed code):
>>
>>     memset(line, 0, LINE_SIZE);
>>     if (len > LINE_SIZE)
>>         len = LINE_SIZE;
>>     if (copy_from_user(line, buf, len - 1))
>>         return -EFAULT;
>>
>> so isn't line[LINE_SIZE - 1] always 0 ?
> 
> 
> In that case, yes (I hadn't looked at the surrounding code). Rather an 
> odd way of doing it, but shouldn't have that problem. Could still be 
> subject to problems if buf contains a null at the first character, 
> unless they're somehow preventing that too..

Yes, that's still a problem.

-- 
~Randy

  reply	other threads:[~2005-03-16  5:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <3IugU-2m4-11@gated-at.bofh.it>
     [not found] ` <3IugU-2m4-9@gated-at.bofh.it>
     [not found]   ` <3IykC-5x0-29@gated-at.bofh.it>
2005-03-16  5:24     ` Taking strlen of buffers copied from userspace Robert Hancock
2005-03-16  5:30       ` Randy.Dunlap [this message]
     [not found] <3Iphf-66y-15@gated-at.bofh.it>
2005-03-15 23:56 ` Robert Hancock
2005-03-16  4:20   ` Randy.Dunlap
2005-03-15 18:27 Artem Frolov

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