From: matthias.bgg@gmail.com (Matthias Brugger)
To: kernelnewbies@lists.kernelnewbies.org
Subject: can I input a gate service to kernel to get kernel data to user ?
Date: Fri, 14 Dec 2012 10:28:35 +0100 [thread overview]
Message-ID: <50CAF143.6060604@gmail.com> (raw)
In-Reply-To: <1b46c269.bc6.13b96e666c5.Coremail.horse_rivers@126.com>
Hi,
On 12/14/2012 01:53 AM, horse_rivers wrote:
> At 2012-12-13 18:52:53,"Matthias Brugger" <matthias.bgg@gmail.com> wrote:
>> On 12/13/2012 04:17 AM, horse_rivers wrote:
>>> is there method for doing this work? take kernel data to user?
>>
>> I think copy_to_user is what you are looking for:
>> http://lxr.free-electrons.com/source/include/asm-generic/uaccess.h#L253
>>
>
> thanks !
>
> can this function run at user level ?
>
> when programme is at user level , can I use this function to get kernel text segment data ,and then analysis it ?
no you can't. Userspace programs can only access the kernel trough a
systemcall, otherwise userspace could read memory from other programs
which would be dangerous (think of passwords etc).
If you want to read certain parts of kernel memory from userspace, you
need a kernel module which uses copy_to_user, for example a character
driver using the read or ioctl function to call copy_to_user.
The userspace then would use that character device to invoke systemcalls.
Please refer to http://lwn.net/Kernel/LDD3/ about device driver
programing. Although the book is outdated it is a perfect point to start
understanding the concepts.
Best regards,
Matthias
>
> BestRegards!
>
>> Cheers,
>> Matthias
>>
>>>
>>>
>>> thanks!
>>>
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>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>
>>
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next prev parent reply other threads:[~2012-12-14 9:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-13 3:17 can I input a gate service to kernel to get kernel data to user ? horse_rivers
2012-12-13 10:11 ` Daniel Baluta
2012-12-14 0:59 ` horse_rivers
2012-12-13 10:52 ` Matthias Brugger
2012-12-14 0:53 ` horse_rivers
2012-12-14 9:28 ` Matthias Brugger [this message]
-- strict thread matches above, loose matches on Subject: below --
2012-12-14 1:50 jeshkumar555
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