handshake: store PMK length

Non-802.11 AKMs can define their own key lengths. Currently only OWE does
this, and the MIC/KEK/KCK lengths will be determined by the PMK length so
we need to save it.

src/handshake.c

@@ -108,6 +108,7 @@ void handshake_state_set_pmk(struct handshake_state *s, const uint8_t *pmk,
 				size_t pmk_len)
 {
 	memcpy(s->pmk, pmk, pmk_len);
+	s->pmk_len = pmk_len;
 	s->have_pmk = true;
 }
 

src/handshake.h

@@ -87,6 +87,7 @@ struct handshake_state {
 	enum ie_rsn_cipher_suite group_management_cipher;
 	enum ie_rsn_akm_suite akm_suite;
 	uint8_t pmk[64];
+	size_t pmk_len;
 	uint8_t snonce[32];
 	uint8_t anonce[32];
 	uint8_t ptk[64];