xplist: Enforce single root value inside <plist>HEADmaster

Ensure that XML property lists contain exactly one root value inside the <plist> element and reject any additional value nodes before </plist>.

Add tests covering root value handling and nested CF$UID conversion behavior.

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

3 files changed, 176 insertions, 2 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index a4191c4..f9f21e4 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -13,7 +13,8 @@ noinst_PROGRAMS = \
 	integer_set_test \
 	plist_btest \
 	plist_jtest \
-	plist_otest
+	plist_otest \
+	xml_behavior_test
 
 plist_cmp_SOURCES = plist_cmp.c
 plist_cmp_LDADD = \
@@ -38,6 +39,9 @@ plist_jtest_LDADD = $(top_builddir)/src/libplist-2.0.la
 plist_otest_SOURCES = plist_otest.c
 plist_otest_LDADD = $(top_builddir)/src/libplist-2.0.la
 
+xml_behavior_test_SOURCES = xml_behavior_test.c
+xml_behavior_test_LDADD = $(top_builddir)/src/libplist-2.0.la
+
 TESTS = \
 	empty.test \
 	small.test \
@@ -79,7 +83,8 @@ TESTS = \
 	ostep2.test \
 	ostep-strings.test \
 	ostep-comments.test \
-	ostep-invalid-types.test
+	ostep-invalid-types.test \
+	xml_behavior.test
 
 EXTRA_DIST = \
 	$(TESTS) \
diff --git a/test/xml_behavior.test b/test/xml_behavior.test
new file mode 100755
index 0000000..81d8dd0
--- /dev/null
+++ b/test/xml_behavior.test
@@ -0,0 +1,2 @@
+## -*- sh -*-
+$top_builddir/test/xml_behavior_test
diff --git a/test/xml_behavior_test.c b/test/xml_behavior_test.c
new file mode 100644
index 0000000..94d8a7f
--- /dev/null
+++ b/test/xml_behavior_test.c
@@ -0,0 +1,167 @@
+/*
+ * xml_behavior_test.c
+ *
+ * Tests XML parser behavior for correctness and specification compliance:
+ *
+ * 1) A <plist> element must contain exactly one root value node.
+ *    Any additional value nodes after the first root object must
+ *    cause parsing to fail.
+ *
+ * 2) Dictionaries of the form:
+ *        <dict>
+ *          <key>CF$UID</key>
+ *          <integer>...</integer>
+ *        </dict>
+ *    must be converted to PLIST_UID nodes during XML parsing,
+ *    including when they appear nested inside other containers.
+ *
+ * These tests ensure proper root handling and UID node conversion
+ * when parsing XML property lists.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <inttypes.h>
+
+#include "plist/plist.h"
+
+static int test_nested_cfuid_converts_to_uid(void)
+{
+    const char *xml =
+        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
+        "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" "
+        "\"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">"
+        "<plist version=\"1.0\">"
+        "  <dict>"
+        "    <key>obj</key>"
+        "    <dict>"
+        "      <key>CF$UID</key>"
+        "      <integer>7</integer>"
+        "    </dict>"
+        "  </dict>"
+        "</plist>";
+
+    plist_t root = NULL;
+    plist_err_t err = plist_from_xml(xml, (uint32_t)strlen(xml), &root);
+    if (err != PLIST_ERR_SUCCESS || !root) {
+        fprintf(stderr, "nested CF$UID: plist_from_xml failed (err=%d)\n", err);
+        plist_free(root);
+        return 0;
+    }
+
+    if (plist_get_node_type(root) != PLIST_DICT) {
+        fprintf(stderr, "nested CF$UID: root is not dict\n");
+        plist_free(root);
+        return 0;
+    }
+
+    plist_t obj = plist_dict_get_item(root, "obj");
+    if (!obj) {
+        fprintf(stderr, "nested CF$UID: missing key 'obj'\n");
+        plist_free(root);
+        return 0;
+    }
+
+    if (plist_get_node_type(obj) != PLIST_UID) {
+        fprintf(stderr, "nested CF$UID: expected PLIST_UID, got %d\n",
+                plist_get_node_type(obj));
+        plist_free(root);
+        return 0;
+    }
+
+    uint64_t uid = 0;
+    plist_get_uid_val(obj, &uid);
+    if (uid != 7) {
+        fprintf(stderr, "nested CF$UID: expected uid=7, got %" PRIu64 "\n", uid);
+        plist_free(root);
+        return 0;
+    }
+
+    plist_free(root);
+    return 1;
+}
+
+static int test_extra_root_value_is_rejected(void)
+{
+    /* Two root values inside <plist> must be rejected */
+    const char *xml =
+        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
+        "<plist version=\"1.0\">"
+        "  <string>one</string>"
+        "  <string>two</string>"
+        "</plist>";
+
+    plist_t root = NULL;
+    plist_err_t err = plist_from_xml(xml, (uint32_t)strlen(xml), &root);
+
+    /* Must fail, and root must be NULL (consistent with other parsers) */
+    if (err == PLIST_ERR_SUCCESS || root != NULL) {
+        fprintf(stderr, "extra root value: expected failure, got err=%d root=%p\n",
+                err, (void*)root);
+        plist_free(root);
+        return 0;
+    }
+    return 1;
+}
+
+static int test_scalar_then_extra_node_is_rejected(void)
+{
+    /* Scalar root followed by another node must be rejected */
+    const char *xml =
+        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
+        "<plist version=\"1.0\">"
+        "  <true/>"
+        "  <dict><key>A</key><string>x</string></dict>"
+        "</plist>";
+
+    plist_t root = NULL;
+    plist_err_t err = plist_from_xml(xml, (uint32_t)strlen(xml), &root);
+
+    if (err == PLIST_ERR_SUCCESS || root != NULL) {
+        fprintf(stderr, "scalar then extra node: expected failure, got err=%d root=%p\n",
+                err, (void*)root);
+        plist_free(root);
+        return 0;
+    }
+    return 1;
+}
+
+static int test_scalar_with_comment_is_ok(void)
+{
+    /* Comment after the single root value is not an extra value node */
+    const char *xml =
+        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
+        "<plist version=\"1.0\">"
+        "  <string>ok</string>"
+        "  <!-- trailing comment -->"
+        "</plist>";
+
+    plist_t root = NULL;
+    plist_err_t err = plist_from_xml(xml, (uint32_t)strlen(xml), &root);
+    if (err != PLIST_ERR_SUCCESS || !root) {
+        fprintf(stderr, "scalar + comment: expected success, got err=%d\n", err);
+        plist_free(root);
+        return 0;
+    }
+    if (plist_get_node_type(root) != PLIST_STRING) {
+        fprintf(stderr, "scalar + comment: expected root string, got %d\n",
+                plist_get_node_type(root));
+        plist_free(root);
+        return 0;
+    }
+    plist_free(root);
+    return 1;
+}
+
+int main(void)
+{
+    int ok = 1;
+
+    ok &= test_nested_cfuid_converts_to_uid();
+    ok &= test_extra_root_value_is_rejected();
+    ok &= test_scalar_then_extra_node_is_rejected();
+    ok &= test_scalar_with_comment_is_ok();
+
+    return ok ? 0 : 1;
+}