On Tue, Nov 27, 2012 at 03:28:25PM -0500, Tomas Hozza wrote:
>
>
> ----- Original Message -----
> > On Tue, 2012-11-27 at 08:56 +0100, Tomas Hozza wrote:
> > > kvp_get_if_name and kvp_mac_to_if_name copy strings into statically
> > > sized buffers which could be too small to store really long names.
> > >
> > > Buffer sizes have been changed to PATH_MAX, include "limits.h"
> > > where
> > > PATH_MAX is defined was added and length checks ware added via
> > > snprintf.
> > [...]
> >
> > PATH_MAX has nothing to do with any actual kernel limit; it's no more
> > meaningful than the current value of 256. Network interface names
> > are
> > limited to 15 characters, thus the current array is more than long
> > enough. So I think this is entirely unnecessary.
>
> This is just for sanity. The value PATH_MAX was chosen after discussion
> with K. Y. Srinivasan and Olaf Hering instead of some "magic" number like
> 256 or 512.
PATH_MAX is a magic name.
> > Using snprintf() is a good idea, but you need to check the return
> > value and handle the truncation case somehow.
>
> By using PATH_MAX sized buffer there is no need for handling the truncation
> case.
You are claiming two contradictory things: sprintf() may overrun the
buffer, so we need the length check provided by snprintf(), but there
is no need to check for truncation because we know the length is
sufficient.
Ben.
--
Ben Hutchings
We get into the habit of living before acquiring the habit of thinking.
- Albert Camus
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