Do not clear PMKSA entry or EAP session cache if config does not change

This avoids unnecessary flushing of the PMKSA cache entry and EAP
session data when processing SET_NETWORK commands that set a network
profile parameter to the same value that the parameter already has.

Introduce a new wpa_config_set() and wpa_config_set_quoted() return
value (==1) signifying that the new value being set for the
corresponding field equals to the already configured one so that the
caller can determine that nothing changed in the profile.

For now, this does not cover all the network profile parameters, but
number of the most commonly used parameters are included to cover the
Android use cases where the framework may have issued SET_NETWORK
commands that would have unnecessarily prevented use of PMKSA caching or
EAP fast reauthentication.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

wpa_supplicant/config.c

@@ -32,7 +32,11 @@ struct parse_data {
 	/* Configuration variable name */
 	char *name;
 
-	/* Parser function for this variable */
+	/* Parser function for this variable. The parser functions return 0 or 1
+	 * to indicate success. Value 0 indicates that the parameter value may
+	 * have changed while value 1 means that the value did not change.
+	 * Error cases (failure to parse the string) are indicated by returning
+	 * -1. */
 	int (*parser)(const struct parse_data *data, struct wpa_ssid *ssid,
 		      int line, const char *value);
 
@@ -59,7 +63,7 @@ static int wpa_config_parse_str(const struct parse_data *data,
 				struct wpa_ssid *ssid,
 				int line, const char *value)
 {
-	size_t res_len, *dst_len;
+	size_t res_len, *dst_len, prev_len;
 	char **dst, *tmp;
 
 	if (os_strcmp(value, "NULL") == 0) {
@@ -105,6 +109,21 @@ static int wpa_config_parse_str(const struct parse_data *data,
 set:
 	dst = (char **) (((u8 *) ssid) + (long) data->param1);
 	dst_len = (size_t *) (((u8 *) ssid) + (long) data->param2);
+
+	if (data->param2)
+		prev_len = *dst_len;
+	else if (*dst)
+		prev_len = os_strlen(*dst);
+	else
+		prev_len = 0;
+	if ((*dst == NULL && tmp == NULL) ||
+	    (*dst && tmp && prev_len == res_len &&
+	     os_memcmp(*dst, tmp, res_len) == 0)) {
+		/* No change to the previously configured value */
+		os_free(tmp);
+		return 1;
+	}
+
 	os_free(*dst);
 	*dst = tmp;
 	if (data->param2)
@@ -190,6 +209,9 @@ static int wpa_config_parse_int(const struct parse_data *data,
 			   line, value);
 		return -1;
 	}
+
+	if (*dst == val)
+		return 1;
 	*dst = val;
 	wpa_printf(MSG_MSGDUMP, "%s=%d (0x%x)", data->name, *dst, *dst);
 
@@ -457,8 +479,10 @@ static int wpa_config_parse_psk(const struct parse_data *data,
 		wpa_hexdump_ascii_key(MSG_MSGDUMP, "PSK (ASCII passphrase)",
 				      (u8 *) value, len);
 		if (ssid->passphrase && os_strlen(ssid->passphrase) == len &&
-		    os_memcmp(ssid->passphrase, value, len) == 0)
-			return 0;
+		    os_memcmp(ssid->passphrase, value, len) == 0) {
+			/* No change to the previously configured value */
+			return 1;
+		}
 		ssid->psk_set = 0;
 		str_clear_free(ssid->passphrase);
 		ssid->passphrase = dup_binstr(value, len);
@@ -569,6 +593,8 @@ static int wpa_config_parse_proto(const struct parse_data *data,
 		errors++;
 	}
 
+	if (!errors && ssid->proto == val)
+		return 1;
 	wpa_printf(MSG_MSGDUMP, "proto: 0x%x", val);
 	ssid->proto = val;
 	return errors ? -1 : 0;
@@ -705,6 +731,8 @@ static int wpa_config_parse_key_mgmt(const struct parse_data *data,
 		errors++;
 	}
 
+	if (!errors && ssid->key_mgmt == val)
+		return 1;
 	wpa_printf(MSG_MSGDUMP, "key_mgmt: 0x%x", val);
 	ssid->key_mgmt = val;
 	return errors ? -1 : 0;
@@ -953,6 +981,8 @@ static int wpa_config_parse_pairwise(const struct parse_data *data,
 		return -1;
 	}
 
+	if (ssid->pairwise_cipher == val)
+		return 1;
 	wpa_printf(MSG_MSGDUMP, "pairwise: 0x%x", val);
 	ssid->pairwise_cipher = val;
 	return 0;
@@ -989,6 +1019,8 @@ static int wpa_config_parse_group(const struct parse_data *data,
 		return -1;
 	}
 
+	if (ssid->group_cipher == val)
+		return 1;
 	wpa_printf(MSG_MSGDUMP, "group: 0x%x", val);
 	ssid->group_cipher = val;
 	return 0;
@@ -1050,6 +1082,8 @@ static int wpa_config_parse_auth_alg(const struct parse_data *data,
 		errors++;
 	}
 
+	if (!errors && ssid->auth_alg == val)
+		return 1;
 	wpa_printf(MSG_MSGDUMP, "auth_alg: 0x%x", val);
 	ssid->auth_alg = val;
 	return errors ? -1 : 0;
@@ -1304,6 +1338,32 @@ static int wpa_config_parse_eap(const struct parse_data *data,
 	methods[num_methods].method = EAP_TYPE_NONE;
 	num_methods++;
 
+	if (!errors && ssid->eap.eap_methods) {
+		struct eap_method_type *prev_m;
+		size_t i, j, prev_methods, match = 0;
+
+		prev_m = ssid->eap.eap_methods;
+		for (i = 0; prev_m[i].vendor != EAP_VENDOR_IETF ||
+			     prev_m[i].method != EAP_TYPE_NONE; i++) {
+			/* Count the methods */
+		}
+		prev_methods = i + 1;
+
+		for (i = 0; prev_methods == num_methods && i < prev_methods;
+		     i++) {
+			for (j = 0; j < num_methods; j++) {
+				if (prev_m[i].vendor == methods[j].vendor &&
+				    prev_m[i].method == methods[j].method) {
+					match++;
+					break;
+				}
+			}
+		}
+		if (match == num_methods) {
+			os_free(methods);
+			return 1;
+		}
+	}
 	wpa_hexdump(MSG_MSGDUMP, "eap methods",
 		    (u8 *) methods, num_methods * sizeof(*methods));
 	os_free(ssid->eap.eap_methods);
@@ -1356,6 +1416,8 @@ static int wpa_config_parse_password(const struct parse_data *data,
 	u8 *hash;
 
 	if (os_strcmp(value, "NULL") == 0) {
+		if (!ssid->eap.password)
+			return 1; /* Already unset */
 		wpa_printf(MSG_DEBUG, "Unset configuration string 'password'");
 		bin_clear_free(ssid->eap.password, ssid->eap.password_len);
 		ssid->eap.password = NULL;
@@ -1419,6 +1481,12 @@ static int wpa_config_parse_password(const struct parse_data *data,
 
 	wpa_hexdump_key(MSG_MSGDUMP, data->name, hash, 16);
 
+	if (ssid->eap.password && ssid->eap.password_len == 16 &&
+	    os_memcmp(ssid->eap.password, hash, 16) == 0 &&
+	    (ssid->eap.flags & EAP_CONFIG_FLAGS_PASSWORD_NTHASH)) {
+		bin_clear_free(hash, 16);
+		return 1;
+	}
 	bin_clear_free(ssid->eap.password, ssid->eap.password_len);
 	ssid->eap.password = hash;
 	ssid->eap.password_len = 16;
@@ -2472,7 +2540,8 @@ void wpa_config_set_network_defaults(struct wpa_ssid *ssid)
  * @var: Variable name, e.g., "ssid"
  * @value: Variable value
  * @line: Line number in configuration file or 0 if not used
- * Returns: 0 on success, -1 on failure
+ * Returns: 0 on success with possible change in the value, 1 on success with
+ * no change to previously configured value, or -1 on failure
  *
  * This function can be used to set network configuration variables based on
  * both the configuration file and management interface input. The value
@@ -2493,7 +2562,8 @@ int wpa_config_set(struct wpa_ssid *ssid, const char *var, const char *value,
 		if (os_strcmp(var, field->name) != 0)
 			continue;
 
-		if (field->parser(field, ssid, line, value)) {
+		ret = field->parser(field, ssid, line, value);
+		if (ret < 0) {
 			if (line) {
 				wpa_printf(MSG_ERROR, "Line %d: failed to "
 					   "parse %s '%s'.", line, var, value);

wpa_supplicant/ctrl_iface.c

@@ -3003,11 +3003,16 @@ static int wpa_supplicant_ctrl_iface_update_network(
 	struct wpa_supplicant *wpa_s, struct wpa_ssid *ssid,
 	char *name, char *value)
 {
-	if (wpa_config_set(ssid, name, value, 0) < 0) {
+	int ret;
+
+	ret = wpa_config_set(ssid, name, value, 0);
+	if (ret < 0) {
 		wpa_printf(MSG_DEBUG, "CTRL_IFACE: Failed to set network "
 			   "variable '%s'", name);
 		return -1;
 	}
+	if (ret == 1)
+		return 0; /* No change to the previously configured value */
 
 	if (os_strcmp(name, "bssid") != 0 &&
 	    os_strcmp(name, "priority") != 0) {