xplist: Convert nested {CF$UID:<int>} dicts to PLIST_UID safely

Convert single-entry { "CF$UID" : <integer> } dictionaries to PLIST_UID
nodes when closing a dict in the XML parser.

Refactor node cleanup logic:
- Split plist_free_data() into internal _plist_free_data()
- Introduce plist_free_children() to release child nodes separately
- Update plist_set_element_val() to free children before changing
  container node types
- Ensure PLIST_DICT hashtables do not free values (assert + force
  free_func = NULL)

This avoids in-place container mutation issues and ensures child
nodes and container metadata are released correctly before
changing node type.

Co-authored-by: Sami Kortelainen <sami.kortelainen@piceasoft.com>
Co-authored-by: Nikias Bassen <nikias@gmx.li>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/xplist.c b/src/xplist.c
index 73e2b9f..a445dc5 100644
--- a/src/xplist.c
+++ b/src/xplist.c
@@ -1562,6 +1562,26 @@ handle_closing:
                     ctx->err = PLIST_ERR_PARSE;
                     goto err_out;
                 }
+
+                /* When closing a dictionary, convert a single-entry
+                   { "CF$UID" : <integer> } dictionary into a PLIST_UID node.
+                   Perform the conversion before moving to the parent node. */
+                if (!strcmp(node_path->type, XPLIST_DICT) && parent && plist_get_node_type(parent) == PLIST_DICT) {
+                    if (plist_dict_get_size(parent) == 1) {
+                        plist_t uid = plist_dict_get_item(parent, "CF$UID");
+                        if (uid) {
+                            uint64_t val = 0;
+                            if (plist_get_node_type(uid) != PLIST_INT) {
+                                ctx->err = PLIST_ERR_PARSE;
+                                PLIST_XML_ERR("Invalid node type for CF$UID dict entry (must be PLIST_INT)\n");
+                                goto err_out;
+                            }
+                            plist_get_uint_val(uid, &val);
+                            plist_set_uid_val(parent, val);
+                        }
+                    }
+                }
+
                 if (depth > 0) depth--;
                 struct node_path_item *path_item = node_path;
                 node_path = (struct node_path_item*)node_path->prev;