network: Generate the PSK as soon as we have a passphrase

In the name of failing earlier try to generate the PSK from the
passphrase as soon as we receive the passphrase or read it from the
file, mainly to validate it has the right number of characters.
The passphrase length currently gets validates inside
crypto_psk_from_passphrase which will be called when we receive a new
passphrase from the agent or when the config file has no PSK in it.  We
do not do this when there's already both the PSK and the passphrase
available in the settings -- we can add that separately if needed.

src/network.c

@@ -314,28 +314,7 @@ enum security network_get_security(const struct network *network)
 
 const uint8_t *network_get_psk(struct network *network)
 {
-	int r;
+	return network->psk;
-
-	if (network->psk)
-		return network->psk;
-
-	if (!network->passphrase)
-		return NULL;
-
-	network->psk = l_malloc(32);
-	r = crypto_psk_from_passphrase(network->passphrase,
-					(uint8_t *) network->info->ssid,
-					strlen(network->info->ssid),
-					network->psk);
-	if (!r)
-		return network->psk;
-
-	l_free(network->psk);
-	network->psk = NULL;
-	l_error("PMK generation failed: %s.  "
-		"Ensure Crypto Engine is properly configured",
-		strerror(-r));
-	return NULL;
 }
 
 const char *network_get_passphrase(const struct network *network)
@@ -427,19 +406,52 @@ static int network_load_psk(struct network *network, bool need_passphrase)
 						"Security", "PreSharedKey");
 	char *passphrase = l_settings_get_string(network->settings,
 						"Security", "Passphrase");
+	struct network_info *info = network->info;
+	int r;
 
+	/* PSK can be generated from the passphrase but not the other way */
 	if ((!psk || need_passphrase) && !passphrase)
 		return -ENOKEY;
 
 	l_free(network->passphrase);
 	network->passphrase = passphrase;
 	l_free(network->psk);
-	network->psk = l_util_from_hexstring(psk, &len);
+
-	if (network->psk && len == 32)
+	if (psk) {
+		char *path;
+
+		network->psk = l_util_from_hexstring(psk, &len);
+		if (network->psk && len == 32)
+			return 0;
+
+		path = storage_get_network_file_path(info->type, info->ssid);
+		l_error("%s: invalid PreSharedKey format", path);
+		l_free(path);
+
+		if (!passphrase)
+			goto reset_psk;
+
+		l_free(network->psk);
+	}
+
+	network->psk = l_malloc(32);
+	r = crypto_psk_from_passphrase(passphrase, (uint8_t *) info->ssid,
+					strlen(info->ssid), network->psk);
+	if (!r) {
+		network->update_psk = true;
 		return 0;
+	}
+
+	if (r == -ERANGE || r == -EINVAL)
+		l_error("PSK generation failed: invalid passphrase format");
+	else
+		l_error("PSK generation failed: %s.  "
+			"Ensure Crypto Engine is properly configured",
+			strerror(-r));
 
 	l_free(network->passphrase);
 	network->passphrase = NULL;
+reset_psk:
 	l_free(network->psk);
 	network->psk = NULL;
 	return -EINVAL;
@@ -677,6 +689,7 @@ static void passphrase_callback(enum agent_result result,
 	struct network *network = user_data;
 	struct station *station = network->station;
 	struct scan_bss *bss;
+	int r;
 
 	l_debug("result %d", result);
 
@@ -703,7 +716,30 @@ static void passphrase_callback(enum agent_result result,
 	}
 
 	l_free(network->psk);
-	network->psk = NULL;
+	network->psk = l_malloc(32);
+	r = crypto_psk_from_passphrase(passphrase,
+					(uint8_t *) network->info->ssid,
+					strlen(network->info->ssid),
+					network->psk);
+	if (r) {
+		struct l_dbus_message *error;
+
+		l_free(network->psk);
+		network->psk = NULL;
+
+		if (r == -ERANGE || r == -EINVAL)
+			error = dbus_error_invalid_format(message);
+		else {
+			l_error("PSK generation failed: %s.  "
+				"Ensure Crypto Engine is properly configured",
+				strerror(-r));
+			error = dbus_error_failed(message);
+		}
+
+		dbus_pending_reply(&message, error);
+		goto err;
+	}
+
 	l_free(network->passphrase);
 	network->passphrase = l_strdup(passphrase);