CKAN out of memory error when submitting the dataset form with a specially-crafted field

@@ -25,7 +25,8 @@
 from ckan.types import (
     Action, ChainedAction,
     ChainedAuthFunction, DataDict, ErrorDict, Context, FlattenDataDict,
-    Schema, Validator, ValidatorFactory)
+    FlattenKey, Schema, Validator, ValidatorFactory
+)
 
 Decorated = TypeVar("Decorated")
 
@@ -255,7 +256,35 @@ def tuplize_dict(data_dict: dict[str, Any]) -> FlattenDataDict:
                 except ValueError:
                     raise df.DataError('Bad key')
         tuplized_dict[tuple(key_list)] = value
-    return tuplized_dict
+
+    # Sanitize key indexes to make sure they are sequential
+    seq_tuplized_dict: FlattenDataDict = {}
+    # sequential field indexes grouped by common prefix
+    groups: dict[FlattenKey, dict[FlattenKey, int]] = defaultdict(dict)
+    for key in sorted(tuplized_dict.keys()):
+        new_key = key
+
+        # iterate over even(numeric) parts of the key
+        for idx in range(1, len(key), 2):
+            # narrow down scope by common prefix
+            group = groups[key[:idx]]
+
+            # if the identifier(i.e `(extra, 123)`, `(resource, 9)`) is met for
+            # the first time, generate for it next number in the index
+            # sequence. Index of the latest added item is always equals to the
+            # number of unique identifiers minus one(because list indexation
+            # starts from 0 in Python). If identifier already present(i.e, we
+            # process `(extra, 10, VALUE)` after processing `(extra, 10,
+            # KEY)`), reuse sequential index of this identifier
+            seq_index = group.setdefault(key[idx-1:idx+1], len(group))
+
+            # replace the currently processed key segment with computed
+            # sequential index
+            new_key = new_key[:idx] + (seq_index,) + new_key[idx+1:]
+
+        seq_tuplized_dict[new_key] = tuplized_dict[key]
+
+    return seq_tuplized_dict
 
 
 def untuplize_dict(tuplized_dict: FlattenDataDict) -> dict[str, Any]:

@@ -3,6 +3,8 @@
 from unittest import mock
 import pytest
 from ckan import logic, model
+import ckan.lib.navl.dictization_functions as df
+
 from ckan.types import Context
 import ckan.tests.factories as factories
 
@@ -100,3 +102,87 @@ def test_check_access_auth_user_for_different_objects():
     with pytest.raises(logic.NotAuthorized):
         for dataset in dataset3:
             logic.check_access("package_show", context, {'id': dataset["id"]})
+
+
+def test_tuplize_dict():
+
+    data_dict = {
+        "author": "Test Author",
+        "extras__0__key": "extra1",
+        "extras__0__value": "value1",
+        "extras__1__key": "extra2",
+        "extras__1__value": "value2",
+        "extras__2__key": "extra3",
+        "extras__2__value": "value3",
+        "extras__3__key": "",
+        "extras__3__value": "",
+        "groups__0__id": "5a65eae8-ef2b-4a85-8022-d9e5a71ad074",
+        "name": "test-title",
+        "notes": "Test desc",
+        "owner_org": "5a65eae8-ef2b-4a85-8022-d9e5a71ad074",
+        "private": "True",
+        "tag_string": "economy,climate",
+        "title": "Test title",
+    }
+
+    expected = {
+        ("author",): "Test Author",
+        ("extras", 0, "key"): "extra1",
+        ("extras", 0, "value"): "value1",
+        ("extras", 1, "key"): "extra2",
+        ("extras", 1, "value"): "value2",
+        ("extras", 2, "key"): "extra3",
+        ("extras", 2, "value"): "value3",
+        ("extras", 3, "key"): "",
+        ("extras", 3, "value"): "",
+        ("groups", 0, "id"): "5a65eae8-ef2b-4a85-8022-d9e5a71ad074",
+        ("name",): "test-title",
+        ("notes",): "Test desc",
+        ("owner_org",): "5a65eae8-ef2b-4a85-8022-d9e5a71ad074",
+        ("private",): "True",
+        ("tag_string",): "economy,climate",
+        ("title",): "Test title",
+    }
+
+    assert logic.tuplize_dict(data_dict) == expected
+
+
+def test_tuplize_dict_random_indexes():
+
+    data_dict = {
+        "extras__22__key": "extra2",
+        "extras__22__value": "value2",
+        "extras__1__key": "extra1",
+        "extras__1__value": "value1",
+        "extras__245566546__key": "extra3",
+        "extras__245566546__value": "value3",
+        "groups__13__id": "group2",
+        "groups__1__id": "group1",
+        "groups__13__nested__7__name": "latter",
+        "groups__13__nested__2__name": "former",
+
+    }
+
+    expected = {
+        ("extras", 0, "key"): "extra1",
+        ("extras", 0, "value"): "value1",
+        ("extras", 1, "key"): "extra2",
+        ("extras", 1, "value"): "value2",
+        ("extras", 2, "key"): "extra3",
+        ("extras", 2, "value"): "value3",
+        ("groups", 0, "id"): "group1",
+        ("groups", 1, "id"): "group2",
+        ("groups", 1, "nested", 0, "name"): "former",
+        ("groups", 1, "nested", 1, "name"): "latter",
+    }
+
+    assert logic.tuplize_dict(data_dict) == expected
+
+
+def test_tuplize_dict_wrong_index():
+
+    with pytest.raises(df.DataError):
+        data_dict = {
+            "extras__2a__key": "extra",
+        }
+        logic.tuplize_dict(data_dict)