can I input a gate service to kernel to get kernel data to user ?

can I input a gate service to kernel to get kernel data to user ?

[horse_rivers]

is there method for doing this work? take kernel data to user?


thanks!

can I input a gate service to kernel to get kernel data to user ?

[Daniel Baluta]

On Thu, Dec 13, 2012 at 5:17 AM, horse_rivers <horse_rivers@126.com> wrote:
> is there method for doing this work? take kernel data to user?

Check copy_to_user [1].

thanks,
Daniel.

[1] http://lxr.linux.no/#linux+v3.7/arch/x86/lib/usercopy_32.c#L715

can I input a gate service to kernel to get kernel data to user ?

[Matthias Brugger]

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

Cheers,
Matthias

>
>
> thanks!
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

can I input a gate service to kernel to get kernel data to user ?

[horse_rivers]

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 ?

BestRegards!

>Cheers,
>Matthias
>
>>
>>
>>?thanks!
>>
>>?_______________________________________________
>>?Kernelnewbies?mailing?list
>>?Kernelnewbies at kernelnewbies.org
>>?http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
>
>_______________________________________________
>Kernelnewbies?mailing?list
>Kernelnewbies at kernelnewbies.org
>http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

can I input a gate service to kernel to get kernel data to user ?

[horse_rivers]

At?2012-12-13?18:11:24,"Daniel?Baluta"?<daniel.baluta@gmail.com>?wrote:
>On?Thu,?Dec?13,?2012?at?5:17?AM,?horse_rivers?<horse_rivers@126.com>?wrote:
>>?is?there?method?for?doing?this?work??take?kernel?data?to?user?
>
>Check?copy_to_user?[1].

how can user application achive to getting data from kernel , I have no idea about ?procedure for implementing this quest

is there some advice ?

BestRegards!
?
>
>thanks,
>Daniel.
>
>[1]?http://lxr.linux.no/#linux+v3.7/arch/x86/lib/usercopy_32.c#L715
>
>_______________________________________________
>Kernelnewbies?mailing?list
>Kernelnewbies at kernelnewbies.org
>http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

can I input a gate service to kernel to get kernel data to user ?

[Matthias Brugger]

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!
>>>
>>>   _______________________________________________
>>>   Kernelnewbies mailing list
>>>   Kernelnewbies at kernelnewbies.org
>>>   http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>

Re: can I input a gate service to kernel to get kernel data to user ?

[jeshkumar555]

Hello  :),

Refer this doc for user and kernel communication methods. Hope it helps :).

people.ee.ethz.ch/~arkeller/linux/multi/kernel_user_space_howto.html#toc2

Sent from my HTC
Excuse for typo.

----- Reply message -----
From: "horse_rivers" <horse_rivers@126.com>
Date: Fri, Dec 14, 2012 6:29 am
Subject: can I input a gate service to kernel to get kernel data to user ?
To: "kernelnewbies at kernelnewbies.org" <kernelnewbies@kernelnewbies.org>

At?2012-12-13?18:11:24,"Daniel?Baluta"?<daniel.baluta@gmail.com>?wrote:
>On?Thu,?Dec?13,?2012?at?5:17?AM,?horse_rivers?<horse_rivers@126.com>?wrote:
>>?is?there?method?for?doing?this?work??take?kernel?data?to?user?
>
>Check?copy_to_user?[1].

how can user application achive to getting data from kernel , I have no idea about ?procedure for implementing this quest

is there some advice ?

BestRegards!
?
>
>thanks,
>Daniel.
>
>[1]?http://lxr.linux.no/#linux+v3.7/arch/x86/lib/usercopy_32.c#L715
>
>_______________________________________________
>Kernelnewbies?mailing?list
>Kernelnewbies at kernelnewbies.org
>http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

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Kernelnewbies mailing list
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