OWE: Reduce code duplication in OWE element parsing

Reduce the code-duplication for methods handling the OWE transition
mode.

Signed-off-by: David Bauer <mail@david-bauer.net>

wpa_supplicant/events.c

@@ -1139,30 +1139,20 @@ static void owe_trans_ssid(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 			   const u8 **ret_ssid, size_t *ret_ssid_len)
 {
 #ifdef CONFIG_OWE
-	const u8 *owe, *pos, *end, *bssid;
+	const u8 *owe, *bssid;
-	u8 ssid_len;
 
 	owe = wpa_bss_get_vendor_ie(bss, OWE_IE_VENDOR_TYPE);
 	if (!owe || !wpa_bss_get_rsne(wpa_s, bss, NULL, false))
 		return;
 
-	pos = owe + 6;
+	if (wpas_get_owe_trans_network(owe, &bssid, ret_ssid, ret_ssid_len))
-	end = owe + 2 + owe[1];
-
-	if (end - pos < ETH_ALEN + 1)
-		return;
-	bssid = pos;
-	pos += ETH_ALEN;
-	ssid_len = *pos++;
-	if (end - pos < ssid_len || ssid_len > SSID_MAX_LEN)
 		return;
 
 	/* Match the profile SSID against the OWE transition mode SSID on the
 	 * open network. */
 	wpa_dbg(wpa_s, MSG_DEBUG, "OWE: transition mode BSSID: " MACSTR
-		" SSID: %s", MAC2STR(bssid), wpa_ssid_txt(pos, ssid_len));
+		" SSID: %s", MAC2STR(bssid),
-	*ret_ssid = pos;
+		wpa_ssid_txt(*ret_ssid, *ret_ssid_len));
-	*ret_ssid_len = ssid_len;
 
 	if (!(bss->flags & WPA_BSS_OWE_TRANSITION)) {
 		struct wpa_ssid *ssid;
@@ -1170,8 +1160,8 @@ static void owe_trans_ssid(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 		for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
 			if (wpas_network_disabled(wpa_s, ssid))
 				continue;
-			if (ssid->ssid_len == ssid_len &&
+			if (ssid->ssid_len == *ret_ssid_len &&
-			    os_memcmp(ssid->ssid, pos, ssid_len) == 0) {
+			    os_memcmp(ssid->ssid, ret_ssid, *ret_ssid_len) == 0) {
 				/* OWE BSS in transition mode for a currently
 				 * enabled OWE network. */
 				wpa_dbg(wpa_s, MSG_DEBUG,

wpa_supplicant/scan.c

@@ -954,8 +954,7 @@ static void wpa_add_owe_scan_ssid(struct wpa_supplicant *wpa_s,
 		   wpa_ssid_txt(ssid->ssid, ssid->ssid_len));
 
 	dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
-		const u8 *owe, *pos, *end;
+		const u8 *owe, *owe_bssid, *owe_ssid;
-		const u8 *owe_ssid;
 		size_t owe_ssid_len;
 
 		if (bss->ssid_len != ssid->ssid_len ||
@@ -966,21 +965,9 @@ static void wpa_add_owe_scan_ssid(struct wpa_supplicant *wpa_s,
 		if (!owe || owe[1] < 4)
 			continue;
 
-		pos = owe + 6;
+		if (wpas_get_owe_trans_network(owe, &owe_bssid, &owe_ssid,
-		end = owe + 2 + owe[1];
+					       &owe_ssid_len))
-
+			continue;
-		/* Must include BSSID and ssid_len */
-		if (end - pos < ETH_ALEN + 1)
-			return;
-
-		/* Skip BSSID */
-		pos += ETH_ALEN;
-		owe_ssid_len = *pos++;
-		owe_ssid = pos;
-
-		if ((size_t) (end - pos) < owe_ssid_len ||
-		    owe_ssid_len > SSID_MAX_LEN)
-			return;
 
 		wpa_printf(MSG_DEBUG,
 			   "OWE: scan_ssids: transition mode OWE ssid=%s",

wpa_supplicant/wpa_supplicant.c

@@ -5504,8 +5504,8 @@ int wpa_supplicant_set_debug_params(struct wpa_global *global, int debug_level,
 static int owe_trans_ssid_match(struct wpa_supplicant *wpa_s, const u8 *bssid,
 				const u8 *entry_ssid, size_t entry_ssid_len)
 {
-	const u8 *owe, *pos, *end;
+	const u8 *owe, *owe_bssid, *owe_ssid;
-	u8 ssid_len;
+	size_t owe_ssid_len;
 	struct wpa_bss *bss;
 
 	/* Check network profile SSID aganst the SSID in the
@@ -5519,18 +5519,12 @@ static int owe_trans_ssid_match(struct wpa_supplicant *wpa_s, const u8 *bssid,
 	if (!owe)
 		return 0;
 
-	pos = owe + 6;
+	if (wpas_get_owe_trans_network(owe, &owe_bssid, &owe_ssid,
-	end = owe + 2 + owe[1];
+				       &owe_ssid_len))
-
-	if (end - pos < ETH_ALEN + 1)
-		return 0;
-	pos += ETH_ALEN;
-	ssid_len = *pos++;
-	if (end - pos < ssid_len || ssid_len > SSID_MAX_LEN)
 		return 0;
 
-	return entry_ssid_len == ssid_len &&
+	return entry_ssid_len == owe_ssid_len &&
-		os_memcmp(pos, entry_ssid, ssid_len) == 0;
+		os_memcmp(owe_ssid, entry_ssid, owe_ssid_len) == 0;
 }
 #endif /* CONFIG_OWE */
 
@@ -9714,3 +9708,34 @@ bool wpas_ap_supports_rsn_overriding_2(struct wpa_supplicant *wpa_s,
 
 	return false;
 }
+
+
+int wpas_get_owe_trans_network(const u8 *owe_ie, const u8 **bssid,
+			       const u8 **ssid, size_t *ssid_len)
+{
+#ifdef CONFIG_OWE
+	const u8 *pos, *end;
+	u8 ssid_len_tmp;
+
+	if (!owe_ie)
+		return -1;
+
+	pos = owe_ie + 6;
+	end = owe_ie + 2 + owe_ie[1];
+
+	if (end - pos < ETH_ALEN + 1)
+		return -1;
+	*bssid = pos;
+	pos += ETH_ALEN;
+	ssid_len_tmp = *pos++;
+	if (end - pos < ssid_len_tmp || ssid_len_tmp > SSID_MAX_LEN)
+		return -1;
+
+	*ssid = pos;
+	*ssid_len = ssid_len_tmp;
+
+	return 0;
+#else /* CONFIG_OWE */
+	return -1;
+#endif /* CONFIG_OWE */
+}

wpa_supplicant/wpa_supplicant_i.h

@@ -2017,5 +2017,7 @@ bool wpas_ap_supports_rsn_overriding(struct wpa_supplicant *wpa_s,
 				     struct wpa_bss *bss);
 bool wpas_ap_supports_rsn_overriding_2(struct wpa_supplicant *wpa_s,
 				       struct wpa_bss *bss);
+int wpas_get_owe_trans_network(const u8 *owe_ie, const u8 **bssid,
+			       const u8 **ssid, size_t *ssid_len);
 
 #endif /* WPA_SUPPLICANT_I_H */