handshake: Add pmksa setter & stealer

The majority of this patch was authored by Denis Kenzior, but
I have appended setting the PMK inside handshake_state_set_pmksa
as well as checking if the pmkid exists in
handshake_state_steal_pmkid.

Authored-by: Denis Kenzior <denkenz@gmail.com>
Authored-by: James Prestwood <prestwoj@gmail.com>

Makefile.am

@@ -458,6 +458,7 @@ unit_test_eap_sim_SOURCES = unit/test-eap-sim.c \
 		src/eapol.h src/eapol.c \
 		src/eapolutil.h src/eapolutil.c \
 		src/handshake.h src/handshake.c \
+		src/pmksa.h src/pmksa.c \
 		src/eap.h src/eap.c src/eap-private.h \
 		src/util.h src/util.c \
 		src/simauth.h src/simauth.c \
@@ -517,6 +518,7 @@ unit_test_eapol_SOURCES = unit/test-eapol.c \
 				src/eapol.h src/eapol.c \
 				src/eapolutil.h src/eapolutil.c \
 				src/handshake.h src/handshake.c \
+				src/pmksa.h src/pmksa.c \
 				src/eap.h src/eap.c src/eap-private.h \
 				src/eap-tls.c src/eap-ttls.c \
 				src/eap-md5.c src/util.c \
@@ -547,6 +549,7 @@ unit_test_wsc_SOURCES = unit/test-wsc.c src/wscutil.h src/wscutil.c \
 				src/eapol.h src/eapol.c \
 				src/eapolutil.h src/eapolutil.c \
 				src/handshake.h src/handshake.c \
+				src/pmksa.h src/pmksa.c \
 				src/eap.h src/eap.c src/eap-private.h \
 				src/util.h src/util.c \
 				src/erp.h src/erp.c \
@@ -565,6 +568,7 @@ unit_test_sae_SOURCES = unit/test-sae.c \
 				src/crypto.h src/crypto.c \
 				src/ie.h src/ie.c \
 				src/handshake.h src/handshake.c \
+				src/pmksa.h src/pmksa.c \
 				src/erp.h src/erp.c \
 				src/band.h src/band.c \
 				src/util.h src/util.c \

src/handshake.c

@@ -43,6 +43,7 @@
 #include "src/handshake.h"
 #include "src/erp.h"
 #include "src/band.h"
+#include "src/pmksa.h"
 
 static inline unsigned int n_ecc_groups(void)
 {
@@ -138,6 +139,9 @@ void handshake_state_unref(struct handshake_state *s)
 	l_free(s->fils_ip_resp_ie);
 	l_free(s->vendor_ies);
 
+	if (s->have_pmksa)
+		l_free(s->pmksa);
+
 	if (s->erp_cache)
 		erp_cache_put(s->erp_cache);
 
@@ -701,6 +705,11 @@ void handshake_state_install_ptk(struct handshake_state *s)
 {
 	s->ptk_complete = true;
 
+	if (!s->have_pmksa && IE_AKM_IS_SAE(s->akm_suite)) {
+		l_debug("Adding PMKSA expiration");
+		s->expiration = l_time_now() + pmksa_lifetime();
+	}
+
 	if (install_tk) {
 		uint32_t cipher = ie_rsn_cipher_suite_to_cipher(
 							s->pairwise_cipher);
@@ -1203,3 +1212,71 @@ done:
 
 	return r;
 }
+
+bool handshake_state_set_pmksa(struct handshake_state *s,
+					struct pmksa *pmksa)
+{
+	/* checks for both expiration || pmksa being set */
+	if (s->expiration)
+		return false;
+
+	s->pmksa = pmksa;
+	s->have_pmksa = true;
+
+	handshake_state_set_pmkid(s, pmksa->pmkid);
+	handshake_state_set_pmk(s, pmksa->pmk, pmksa->pmk_len);
+
+	return true;
+}
+
+static struct pmksa *handshake_state_steal_pmksa(struct handshake_state *s)
+{
+	struct pmksa *pmksa;
+	uint64_t now = l_time_now();
+
+	if (s->have_pmksa) {
+		pmksa = l_steal_ptr(s->pmksa);
+		s->have_pmksa = false;
+
+		if (l_time_after(now, pmksa->expiration)) {
+			l_free(pmksa);
+			pmksa = NULL;
+		}
+
+		return pmksa;
+	}
+
+	if (s->expiration && l_time_after(now, s->expiration)) {
+		s->expiration = 0;
+		return NULL;
+	}
+
+	if (!s->have_pmkid)
+		return NULL;
+
+	pmksa = l_new(struct pmksa, 1);
+	pmksa->expiration = s->expiration;
+	memcpy(pmksa->spa, s->spa, sizeof(s->spa));
+	memcpy(pmksa->aa, s->aa, sizeof(s->aa));
+	memcpy(pmksa->ssid, s->ssid, s->ssid_len);
+	pmksa->ssid_len = s->ssid_len;
+	pmksa->akm = s->akm_suite;
+	memcpy(pmksa->pmkid, s->pmkid, sizeof(s->pmkid));
+	pmksa->pmk_len = s->pmk_len;
+	memcpy(pmksa->pmk, s->pmk, s->pmk_len);
+
+	return pmksa;
+}
+
+void handshake_state_cache_pmksa(struct handshake_state *s)
+{
+	struct pmksa *pmksa = handshake_state_steal_pmksa(s);
+
+	l_debug("%p", pmksa);
+
+	if (!pmksa)
+		return;
+
+	if (L_WARN_ON(pmksa_cache_put(pmksa) < 0))
+		l_free(pmksa);
+}

src/handshake.h

@@ -29,6 +29,7 @@
 struct handshake_state;
 enum crypto_cipher;
 struct eapol_frame;
+struct pmksa;
 
 enum handshake_kde {
 	/* 802.11-2020 Table 12-9 in section 12.7.2 */
@@ -141,6 +142,11 @@ struct handshake_state {
 	bool supplicant_ocvc : 1;
 	bool ext_key_id_capable : 1;
 	bool force_default_ecc_group : 1;
+	bool have_pmksa : 1;
+	union {
+		struct pmksa *pmksa;
+		uint64_t expiration;
+	};
 	uint8_t ssid[SSID_MAX_SIZE];
 	size_t ssid_len;
 	char *passphrase;
@@ -302,6 +308,9 @@ void handshake_state_set_chandef(struct handshake_state *s,
 int handshake_state_verify_oci(struct handshake_state *s, const uint8_t *oci,
 				size_t oci_len);
 
+bool handshake_state_set_pmksa(struct handshake_state *s, struct pmksa *pmksa);
+void handshake_state_cache_pmksa(struct handshake_state *s);
+
 bool handshake_util_ap_ie_matches(const struct ie_rsn_info *msg_info,
 					const uint8_t *scan_ie, bool is_wpa);