On 2020/02/25 13:00, Stefan Sperling wrote:
> On Tue, Feb 25, 2020 at 10:40:47AM +0000, Stuart Henderson wrote:
> > On 2020/02/24 11:56, Stefan Sperling wrote:
> > > These functions will compute the wrong display width for input which is
> > > already a hex string. This bug doesn't trigger because we never actually
> > > pass an ASCII hex string in, but it is still a bug.
> > >
> > > ASCII hex strings are printable ASCII, so there's no reason to have a
> > > special case for them.
> > >
> > > This special case for "0x" was added in r1.60 of ifconfig.c ("Add support
> > > for
> > > nwkey and powersave; from NetBSD") by millert. At that time, the
> > > print_string
> > > function did not compute a length, and ifconfig was still using
> > > print_string
> > > to print WEP keys to stdout, which seems to be why the check for "0x"
> > > existed.
> > > WEP keys could be either printable ASCII or ASCII hex.
> > >
> > > Later on, phessler and I copied the same check to len_string which is
> > > based
> > > on print_string.
> > >
> > > We don't print keys nowadays, and these functions are used only to print
> > > binary data SSIDs (ASCII hex is an output, never an input).
> > >
> > > So we can simplify this.
> > >
> > > ok?
> >
> > We do still need the 0x special case otherwise the user won't be able
> > to figure out how to connect to networks with certain names without
> > referring to an ascii-hex table.
>
> I'm not sure I understand what you mean. Can you give an example?
>
> If we need to keep this then don't we still need to fix the return value?
>
Say you have an access point broadcasting these SSIDs (literally):
- 0xfoobar
without the 0x case in print_string it will be printed as 0xfoobar but
you need to use 0x666f6f626172 to connect.
- 0x6162616374c3a97269c3a96d69717565
- abactériémique
without the 0x case, they will both appear the same in the list.
with the 0x case they will both be encoded so can be distinguished (and
so you can copy-and-paste to ifconfig nwid).
