Re: [patch] eicon: make buffer larger

walter harms
2010-10-06T08:16:15Z

Dan Carpenter schrieb:
> On Wed, Oct 06, 2010 at 09:25:44AM +0200, Armin Schindler wrote:
>> On Mon, 4 Oct 2010, Dan Carpenter wrote:
>>> In diva_mnt_add_xdi_adapter() we do this:
>>> strcpy (clients[id].drvName, tmp);
>>> strcpy (clients[id].Dbg.drvName, tmp);
>>>
>>> The "clients[id].drvName" is a 128 character buffer and
>>> "clients[id].Dbg.drvName" was originally a 16 character buffer but I've
>>> changed it to 128 as well. We don't actually use 128 characters but we
>>> do use more than 16.
>> I don't see any reason for that change. The driver names here do not use
>> more than 16 characters and when filled, the length is checked anyway.
>> Please avoid changing the size of that structure.
>>
>
> drivers/isdn/hardware/eicon/debug.c diva_mnt_add_xdi_adapter()
> 874 sprintf (tmp, "ADAPTER:%d SN:%u-%d",
> 12345678 90123 45 67
>
> That's a minimum 17 characters.
>
> 875 (int)logical,
> 876 serial & 0x00ffffff,
> 877 (byte)(((serial & 0xff000000) >> 24) + 1));
> 878 } else {
> 879 sprintf (tmp, "ADAPTER:%d SN:%u", (int)logical, serial);
> 880 }
>

for that reason i am a fan of kasprintf().
Maybe this a solution here also ? samething like:

kasprintf (&buf, "ADAPTER:%d SN:%u-%d",12345678,90123,45,67):
...
kstrncpy(tmp,buf,sizeof(buf));
....
free(buf);

that would keep overflows away until the changes in the structure are ready.

re,
wh