fix(checkpoint-sqlite): harden (#6565)

harden

libs/checkpoint-sqlite/langgraph/checkpoint/sqlite/__init__.py

@@ -329,8 +329,9 @@ class SqliteSaver(BaseCheckpointSaver[str]):
         FROM checkpoints
         {where}
         ORDER BY checkpoint_id DESC"""
-        if limit:
-            query += f" LIMIT {limit}"
+        if limit is not None:
+            query += " LIMIT ?"
+            param_values = (*param_values, limit)
         with self.cursor(transaction=False) as cur, closing(self.conn.cursor()) as wcur:
             cur.execute(query, param_values)
             for (

libs/checkpoint-sqlite/langgraph/checkpoint/sqlite/aio.py

@@ -425,8 +425,9 @@ class AsyncSqliteSaver(BaseCheckpointSaver[str]):
         FROM checkpoints
         {where}
         ORDER BY checkpoint_id DESC"""
-        if limit:
-            query += f" LIMIT {limit}"
+        if limit is not None:
+            query += " LIMIT ?"
+            params = (*params, limit)
         async with (
             self.lock,
             self.conn.execute(query, params) as cur,

libs/checkpoint-sqlite/langgraph/checkpoint/sqlite/utils.py

@@ -1,12 +1,32 @@
 from __future__ import annotations
 
 import json
+import re
 from collections.abc import Sequence
 from typing import Any
 
 from langchain_core.runnables import RunnableConfig
 from langgraph.checkpoint.base import get_checkpoint_id
 
+_FILTER_PATTERN = re.compile(r"^[a-zA-Z0-9_.-]+$")
+
+
+def _validate_filter_key(key: str) -> None:
+    """Validate that a filter key is safe for use in SQL queries.
+
+    Args:
+        key: The filter key to validate
+
+    Raises:
+        ValueError: If the key contains invalid characters that could enable SQL injection
+    """
+    # Allow alphanumeric characters, underscores, dots, and hyphens
+    # This covers typical JSON property names while preventing SQL injection
+    if not _FILTER_PATTERN.match(key):
+        raise ValueError(
+            f"Invalid filter key: '{key}'. Filter keys must contain only alphanumeric characters, underscores, dots, and hyphens."
+        )
+
 
 def _metadata_predicate(
     metadata_filter: dict[str, Any],
@@ -43,6 +63,7 @@ def _metadata_predicate(
 
     # process metadata query
     for query_key, query_value in metadata_filter.items():
+        _validate_filter_key(query_key)
         operator, param_value = _where_value(query_value)
         predicates.append(
             f"json_extract(CAST(metadata AS TEXT), '$.{query_key}') {operator}"