rework ieee80211_recv_4way_msg2() function.

add some RSNA authenticator state machine bits.

3 files changed, 101 insertions, 49 deletions

diff --git a/sys/net80211/ieee80211_input.c b/sys/net80211/ieee80211_input.c
index 714a1711918..3734c26d48a 100644
--- a/sys/net80211/ieee80211_input.c
+++ b/sys/net80211/ieee80211_input.c
@@ -1,5 +1,5 @@
 /*	$NetBSD: ieee80211_input.c,v 1.24 2004/05/31 11:12:24 dyoung Exp $	*/
-/*	$OpenBSD: ieee80211_input.c,v 1.68 2007/08/27 18:53:27 damien Exp $	*/
+/*	$OpenBSD: ieee80211_input.c,v 1.69 2007/08/27 20:14:21 damien Exp $	*/
 /*-
  * Copyright (c) 2001 Atsushi Onoe
  * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
@@ -102,11 +102,14 @@ void	ieee80211_recv_disassoc(struct ieee80211com *, struct mbuf *,
 void	ieee80211_recv_4way_msg1(struct ieee80211com *,
 	    struct ieee80211_eapol_key *, struct ieee80211_node *);
 void	ieee80211_recv_4way_msg2(struct ieee80211com *,
-	    struct ieee80211_eapol_key *, struct ieee80211_node *);
+	    struct ieee80211_eapol_key *, struct ieee80211_node *,
+	    const u_int8_t *);
 void	ieee80211_recv_4way_msg3(struct ieee80211com *,
 	    struct ieee80211_eapol_key *, struct ieee80211_node *);
 void	ieee80211_recv_4way_msg4(struct ieee80211com *,
 	    struct ieee80211_eapol_key *, struct ieee80211_node *);
+void	ieee80211_recv_4way_msg2or4(struct ieee80211com *,
+	    struct ieee80211_eapol_key *, struct ieee80211_node *);
 void	ieee80211_recv_rsn_group_msg1(struct ieee80211com *,
 	    struct ieee80211_eapol_key *, struct ieee80211_node *);
 void	ieee80211_recv_wpa_group_msg1(struct ieee80211com *,
@@ -2012,50 +2015,18 @@ ieee80211_recv_4way_msg1(struct ieee80211com *ic,
  */
 void
 ieee80211_recv_4way_msg2(struct ieee80211com *ic,
-    struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
+    struct ieee80211_eapol_key *key, struct ieee80211_node *ni,
+    const u_int8_t *rsn)
 {
-	const u_int8_t *frm, *efrm;
-	const u_int8_t *rsn;
 	const u_int8_t *pmk;
 	size_t pmk_len;
 
-	if (ic->ic_opmode != IEEE80211_M_HOSTAP &&
-	    ic->ic_opmode != IEEE80211_M_IBSS)
-		return;
-
-	if (BE_READ_8(key->replaycnt) != ni->ni_replaycnt)
+	/* discard if we're not expecting this message */
+	if (ni->ni_rsn_state != RSNA_PTKSTART &&
+	    ni->ni_rsn_state != RSNA_PTKCALCNEGOTIATING)
 		return;
 
-	/* parse key data field (shall contain an RSN IE) */
-	frm = (const u_int8_t *)&key[1];
-	efrm = frm + BE_READ_2(key->paylen);
-
-	rsn = NULL;
-	while (frm + 2 <= efrm) {
-		if (frm + 2 + frm[1] > efrm)
-			break;
-		switch (frm[0]) {
-		case IEEE80211_ELEMID_RSN:
-			rsn = frm;
-			break;
-		case IEEE80211_ELEMID_VENDOR:
-			if (frm[1] < 4)
-				break;
-			if (memcmp(&frm[2], MICROSOFT_OUI, 3) == 0) {
-				switch (frm[5]) {
-				case 1:	/* WPA */
-					rsn = frm;
-					break;
-				}
-			}
-		}
-		frm += 2 + frm[1];
-	}
-	if (rsn == NULL) {
-		/* no RSN/WPA IE, must be message 4 of the 4-Way Handshake */
-		ieee80211_recv_4way_msg4(ic, key, ni);
-		return;
-	}
+	ni->ni_rsn_state = RSNA_PTKCALCNEGOTIATING;
 
 	/* derive PTK from PMK */
 	ieee80211_derive_ptk(pmk, pmk_len, ic->ic_myaddr, ni->ni_macaddr,
@@ -2078,6 +2049,9 @@ ieee80211_recv_4way_msg2(struct ieee80211com *ic,
 		return;
 	}
 
+	ni->ni_rsn_state = RSNA_PTKCALCNEGOTIATING_2;
+	ni->ni_rsn_tocnt = 0;
+
 	if (ic->ic_if.if_flags & IFF_DEBUG)
 		printf("%s: received msg %d/%d of the %s handshake from %s\n",
 		    ic->ic_if.if_xname, 2, 4, "4-way",
@@ -2242,15 +2216,16 @@ ieee80211_recv_4way_msg4(struct ieee80211com *ic,
 {
 	struct ieee80211_key *k;
 
-	/*
-	 * ic->ic_opmode and key->replaycnt have already been validated by
-	 * ieee80211_recv_4way_msg2() from where we're called.
-	 */
+	/* discard if we're not expecting this message */
+	if (ni->ni_rsn_state != RSNA_PTKINITNEGOTIATING)
+		return;
 
 	/* check Key MIC field using KCK */
 	if (ieee80211_eapol_key_check_mic(key, ni->ni_ptk.kck) != 0)
 		return;
 
+	ni->ni_rsn_state = RSNA_PTKINITDONE;
+
 	/* empty key data field */
 
 	/* install the PTK */
@@ -2277,6 +2252,51 @@ ieee80211_recv_4way_msg4(struct ieee80211com *ic,
 }
 
 /*
+ * Differentiate Message 2 from Message 4 of the 4-Way Handshake based on
+ * the presence of an RSN or WPA Information Element.
+ */
+void
+ieee80211_recv_4way_msg2or4(struct ieee80211com *ic,
+    struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
+{
+	const u_int8_t *frm, *efrm;
+	const u_int8_t *rsn;
+
+	if (BE_READ_8(key->replaycnt) != ni->ni_replaycnt)
+		return;
+
+	/* parse key data field (check if an RSN IE is present) */
+	frm = (const u_int8_t *)&key[1];
+	efrm = frm + BE_READ_2(key->paylen);
+
+	rsn = NULL;
+	while (frm + 2 <= efrm) {
+		if (frm + 2 + frm[1] > efrm)
+			break;
+		switch (frm[0]) {
+		case IEEE80211_ELEMID_RSN:
+			rsn = frm;
+			break;
+		case IEEE80211_ELEMID_VENDOR:
+			if (frm[1] < 4)
+				break;
+			if (memcmp(&frm[2], MICROSOFT_OUI, 3) == 0) {
+				switch (frm[5]) {
+				case 1:	/* WPA */
+					rsn = frm;
+					break;
+				}
+			}
+		}
+		frm += 2 + frm[1];
+	}
+	if (rsn != NULL)
+		ieee80211_recv_4way_msg2(ic, key, ni, rsn);
+	else
+		ieee80211_recv_4way_msg4(ic, key, ni);
+}
+
+/*
  * Group Key Handshake Message 1 is sent by the authenticator to the
  * supplicant (see 8.5.4.1).
  */
@@ -2565,7 +2585,7 @@ ieee80211_recv_eapol(struct ieee80211com *ic, struct mbuf *m0,
 			if (info & EAPOL_KEY_KEYACK)
 				ieee80211_recv_4way_msg3(ic, key, ni);
 			else
-				ieee80211_recv_4way_msg2(ic, key, ni);
+				ieee80211_recv_4way_msg2or4(ic, key, ni);
 		} else
 			ieee80211_recv_4way_msg1(ic, key, ni);
 	} else {
diff --git a/sys/net80211/ieee80211_node.h b/sys/net80211/ieee80211_node.h
index 790fb4606ec..ebb61be724d 100644
--- a/sys/net80211/ieee80211_node.h
+++ b/sys/net80211/ieee80211_node.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_node.h,v 1.22 2007/08/27 18:53:27 damien Exp $	*/
+/*	$OpenBSD: ieee80211_node.h,v 1.23 2007/08/27 20:14:21 damien Exp $	*/
 /*	$NetBSD: ieee80211_node.h,v 1.9 2004/04/30 22:57:32 dyoung Exp $	*/
 
 /*-
@@ -65,6 +65,29 @@ enum ieee80211_node_state {
 		(__ni)->ni_state = (__state);	\
 	} while (0)
 
+/* RSNA Authenticator state machine (see 8.5.6). */
+enum {
+	RSNA_AUTHENTICATION,
+	RSNA_AUTHENTICATION_2,
+	RSNA_INITPMK,
+	RSNA_INITPSK,
+	RSNA_PTKSTART,
+	RSNA_PTKCALCNEGOTIATING,
+	RSNA_PTKCALCNEGOTIATING_2,
+	RSNA_PTKINITNEGOTIATING,
+	RSNA_PTKINITDONE,
+	RSNA_DISCONNECT,
+	RSNA_DISCONNECTED,
+	RSNA_INITIALIZE,
+	RSNA_IDLE,
+	RSNA_REKEYNEGOTIATING,
+	RSNA_KEYERROR,
+	RSNA_REKEYESTABLISHED,
+	RSNA_GTK_INIT,
+	RSNA_SETKEYSDONE,
+	RSNA_SETKEYS
+};
+
 /*
  * Node specific information.  Note that drivers are expected
  * to derive from this structure to add device-specific per-node
@@ -113,6 +136,8 @@ struct ieee80211_node {
 	struct ifqueue		ni_savedq;	/* packets queued for pspoll */
 
 	/* RSN */
+	u_int			ni_rsn_state;
+	u_int			ni_rsn_tocnt;
 	u_int			ni_group_cipher;
 	enum ieee80211_cipher	ni_pairwise_cipher;
 	u_int			ni_pairwise_cipherset;
diff --git a/sys/net80211/ieee80211_output.c b/sys/net80211/ieee80211_output.c
index 31e8a3a15a5..6523e409cf8 100644
--- a/sys/net80211/ieee80211_output.c
+++ b/sys/net80211/ieee80211_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_output.c,v 1.57 2007/08/27 18:53:27 damien Exp $	*/
+/*	$OpenBSD: ieee80211_output.c,v 1.58 2007/08/27 20:14:21 damien Exp $	*/
 /*	$NetBSD: ieee80211_output.c,v 1.13 2004/05/31 11:02:55 dyoung Exp $	*/
 
 /*-
@@ -1627,6 +1627,10 @@ ieee80211_send_4way_msg1(struct ieee80211com *ic, struct ieee80211_node *ni)
 	u_int8_t *pmkid;
 	u_int8_t *frm;
 
+	ni->ni_rsn_state = RSNA_PTKSTART;
+	if (++ni->ni_rsn_tocnt == 3)
+		return 0;	/* XXX move to RSNA_DISCONNECT */
+
 	m = ieee80211_get_eapol_key(M_DONTWAIT, MT_DATA,
 	    (ni->ni_eapol_desc == EAPOL_KEY_DESC_IEEE80211) ? 2 + 20 : 0);
 	if (m == NULL)
@@ -1637,8 +1641,7 @@ ieee80211_send_4way_msg1(struct ieee80211com *ic, struct ieee80211_node *ni)
 	info = EAPOL_KEY_PAIRWISE | EAPOL_KEY_KEYACK;
 	BE_WRITE_2(key->info, info);
 
-	/* generate a new nonce ANonce */
-	get_random_bytes(ni->ni_nonce, EAPOL_KEY_NONCE_LEN);
+	/* copy the authenticator's nonce (ANonce) */
 	memcpy(key->nonce, ni->ni_nonce, EAPOL_KEY_NONCE_LEN);
 
 	keylen = ieee80211_cipher_keylen(ni->ni_pairwise_cipher);
@@ -1724,6 +1727,10 @@ ieee80211_send_4way_msg3(struct ieee80211com *ic, struct ieee80211_node *ni)
 	u_int16_t info, keylen;
 	u_int8_t *frm;
 
+	ni->ni_rsn_state = RSNA_PTKINITNEGOTIATING;
+	if (++ni->ni_rsn_tocnt == 3)
+		return 0;	/* XXX move to RSNA_KEYERROR */
+
 	m = ieee80211_get_eapol_key(M_DONTWAIT, MT_DATA,
 	    2 + 48 +
 	    ((ni->ni_eapol_desc == EAPOL_KEY_DESC_IEEE80211) ?