Thanks Pablo for clarification.
I will resend the patch.
regards
santosh
On Thu, Mar 1, 2012 at 6:33 PM, Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote:
> On Thu, Mar 01, 2012 at 04:15:05PM +0530, santosh prasad nayak wrote:
>> Hi Pablo.
>>
>> copy_to_user( dest, source, length)
>>
>> Normally, 'length' is equal to 'sizeof (source) '.
>>
>> In this case "length" = 32
>> "sizeof(source)" = 29.
>>
>> Is it intentional ?
>
> ebtables expects 32 bytes names.
>
>> Won't it copy extra 3 bytes of kernel data to userspace ?
>
> You're right. We have to copy 29 bytes but we have to fill the
> remaining bytes with zeroes. I think something like:
>
> char name[EBT_FUNCTION_MAXNAMELEN] = {};
>
> /* user-space ebtables expects 32 bytes-long names, but xt_match uses
> * 29 bytes for that. */
> sprintf(name, "%s", m->u.match->name);
> if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))
> ...
>
> will resolve this issue.
>
> Would you resend a new patch?
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