Re: [patch] eicon: make buffer larger

[Armin Schindler]

On Wed, 6 Oct 2010, Dan Carpenter wrote:
> On Wed, Oct 06, 2010 at 10:21:02AM +0200, Armin Schindler wrote:
> > On Wed, 6 Oct 2010, Dan Carpenter wrote:
> > > 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    }
> >
> > this is tmp with a bigger size. It seems you are mixing the sizes of
> > drvName and tmp.
>
> What I mean is that later on we use strcpy() to copy "tmp" into
> "clients[id].Dbg.drvName"
>
>   927    strcpy (clients[id].drvName,     tmp);
>   928    strcpy (clients[id].Dbg.drvName, tmp);
>                               ^
>                    this buffer is only 16 chars

Now I understand. You are right. So the fix would be to change these 
strcpy() to e.g. strncpy() or similar.

Armin

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