strongswan: stage the migration in the LuCI session through ubus

When LuCI passes a session id, migrate-ipsec-to-swanctl moves its uci
delta into /tmp/run/rpcd/uci-<session id>, rpcd's private save directory
of that session. rpcd stops naming this directory after the session id,
as the id is a bearer credential that leaked through directory listings,
so the migrated configuration would no longer show up as pending changes
in LuCI.

Stage the migration through rpcd's uci ubus API instead: revert the
session's ipsec changes, delete all sections and add the sections of the
migrated configuration. Then revert the changes of the uci command line
tool, which the old code moved away. This works with old and new rpcd
versions. If staging fails, both are reverted and the script exits with
an error.

Fixes: d5f33e6410 ("strongswan: support optional UCI session staging in migrate-ipsec-to-swanctl")
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

net/strongswan/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=strongswan
 PKG_VERSION:=6.0.7
-PKG_RELEASE:=8
+PKG_RELEASE:=9
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=https://download.strongswan.org/ https://download2.strongswan.org/

net/strongswan/files/usr/libexec/strongswan/migrate-ipsec-to-swanctl

@@ -1,6 +1,8 @@
 #!/bin/sh
 
 . /lib/functions.sh
+. /usr/share/libubox/jshn.sh
+
 migrate_ipsec() {
 	# Skip migration if the 'globals' section already exists
 	uci show ipsec.globals 1>/dev/null 2>/dev/null
@@ -569,14 +571,89 @@ migrate_child_subnet_to_ts() {
 	config_foreach migrate_subnet_to_ts child remote_subnet remote_ts
 }
 
-main() {
+session_uci() {
+	local session="$1"
+	local method="$2"
+
+	json_add_string config ipsec
+	json_add_string ubus_rpc_session "$session"
+	ubus call uci "$method" "$(json_dump)" 2>/dev/null
+}
+
+# Stage the migrated configuration as pending changes of the given LuCI
+# session. rpcd does not expose where it keeps the changes of a session,
+# so replace the configuration section by section through its uci ubus
+# API.
+stage_session() {
 	local session="$1"
 
-	#If LuCI provides a session ID, it can be marked 'staging,' allowing
-	# migration without an immediate restart.
-	[ -n "$session" ] && {
-		mkdir -p /tmp/run/rpcd/uci-${session}
-	}
+	local data section sections
+
+	# The migrated configuration including the changes staged above.
+	# Do not name anonymous sections, so that they stay anonymous.
+	data="$(uci -q -S -N export ipsec)" || return 1
+
+	json_init
+	session_uci "$session" revert >/dev/null || return 1
+
+	json_init
+	sections="$(session_uci "$session" get)" || return 1
+	json_load "$sections"
+	json_select values
+	json_get_keys sections
+
+	for section in $sections; do
+		json_init
+		json_add_string section "$section"
+		session_uci "$session" delete >/dev/null || return 1
+	done
+
+	# Add the sections of the migrated configuration. Run in a subshell,
+	# as the config, option and list handlers of /lib/functions.sh are
+	# replaced for evaluating the export.
+	(
+		sec_type=
+		cur_list=
+
+		add_section() {
+			[ -n "$sec_type" ] || return 0
+			[ -n "$cur_list" ] && json_close_array
+			json_close_object
+			session_uci "$session" add >/dev/null || exit 1
+		}
+
+		config() {
+			add_section
+			sec_type="$1"
+			cur_list=
+			json_init
+			json_add_string type "$1"
+			[ -n "$2" ] && json_add_string name "$2"
+			json_add_object values
+		}
+
+		option() {
+			[ -n "$cur_list" ] && json_close_array
+			cur_list=
+			json_add_string "$1" "$2"
+		}
+
+		list() {
+			[ "$cur_list" = "$1" ] || {
+				[ -n "$cur_list" ] && json_close_array
+				cur_list="$1"
+				json_add_array "$1"
+			}
+			json_add_string "" "$2"
+		}
+
+		eval "$data"
+		add_section
+	)
+}
+
+main() {
+	local session="$1"
 
 	[ -f /etc/config/ipsec ] || {
 		echo "File '/etc/config/ipsec' does not exists."
@@ -606,9 +683,19 @@ main() {
 	migrate_connections_local_remote
 	migrate_child_subnet_to_ts
 
-	# Move staged migration changes to LuCI
+	# If LuCI provides a session ID, hand the migration over to it as
+	# pending changes, allowing to review and apply it in LuCI without an
+	# immediate restart.
 	[ -n "$session" ] && {
-		mv /tmp/.uci/ipsec /tmp/run/rpcd/uci-${session}
+		if ! stage_session "$session"; then
+			json_init
+			session_uci "$session" revert >/dev/null
+			uci -q revert ipsec
+			echo "Failed to stage the migrated configuration in the LuCI session." >&2
+			exit 1
+		fi
+
+		uci -q revert ipsec
 	}
 
 	exit 0