[PATCH v2 06/20] WPA: Extend the fils_pmk_to_ptk() function to also derive KDK

[Peer, Ilan]

> -----Original Message-----
> From: Jouni Malinen <j at w1.fi>
> Sent: Monday, January 18, 2021 19:14
> To: Peer, Ilan <ilan.peer at intel.com>
> Cc: hostap at lists.infradead.org
> Subject: Re: [PATCH v2 06/20] WPA: Extend the fils_pmk_to_ptk() function
> to also derive KDK
> 
> On Wed, Dec 16, 2020 at 01:00:19PM +0200, Ilan Peer wrote:
> > Extend the fils_pmk_to_ptk() to also derive Key Derivation Key (KDK)
> > which can later be used for secure LTF measurements.
> 
> > diff --git a/src/common/wpa_common.c b/src/common/wpa_common.c
> @@
> > -682,9 +697,16 @@ int fils_pmk_to_ptk(const u8 *pmk, size_t pmk_len,
> const u8 *spa, const u8 *aa,
> >  	os_memcpy(ptk->tk, tmp + *ick_len + ptk->kek_len, ptk->tk_len);
> >  	wpa_hexdump_key(MSG_DEBUG, "FILS: TK", ptk->tk, ptk->tk_len);
> >
> > +	if (ptk->kdk_len) {
> > +		os_memcpy(ptk->kdk, tmp + *ick_len + ptk->kek_len +
> > +			  ptk->tk_len, ptk->kdk_len);
> > +		wpa_hexdump_key(MSG_DEBUG, "FILS: KDK", ptk->kdk,
> > +				ptk->kdk_len);
> > +	}
> > +
> >  	if (fils_ft && fils_ft_len) {
> > -		os_memcpy(fils_ft, tmp + *ick_len + ptk->kek_len + ptk-
> >tk_len,
> > -			  *fils_ft_len);
> > +		os_memcpy(fils_ft, tmp + *ick_len + ptk->kek_len + ptk-
> >tk_len +
> > +			  ptk->kdk_len, *fils_ft_len);
> >  		wpa_hexdump_key(MSG_DEBUG, "FILS: FILS-FT",
> >  				fils_ft, *fils_ft_len);
> >  	}
> 
> This is in incorrect order, i.e., FILS-FT, if derived, is before KDK in FILS-Key-
> Data. I've fixed this in my review version, so no need to send an updated
> patch.

Sure. 

Thanks,

Ilan.