Fix string injection vulnerability in FilterExpressionConverter imple…

spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/filter/FilterStringEscapeUtils.java

@@ -0,0 +1,227 @@
+/*
+ * Copyright 2023-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.ai.vectorstore.filter;
+
+/**
+ * Utility class for safely escaping strings in filter expressions to prevent injection
+ * attacks. This class provides methods to escape special characters that could be used to
+ * break filter expression syntax or cause security vulnerabilities.
+ *
+ * @author Spring AI Team
+ * @since 1.0.0
+ */
+public final class FilterStringEscapeUtils {
+
+	private FilterStringEscapeUtils() {
+		// Utility class - prevent instantiation
+		throw new IllegalStateException("Utility class");
+	}
+
+	/**
+	 * Escape characters for double-quoted strings (used in GraphQL, JSON, etc.). Escapes:
+	 * ", \, \n, \r, \t, \b, \f
+	 * @param input the string to escape
+	 * @return the escaped string safe for use in double-quoted contexts
+	 */
+	public static String escapeForDoubleQuotes(String input) {
+		if (input == null) {
+			return null;
+		}
+
+		StringBuilder result = new StringBuilder();
+		for (char c : input.toCharArray()) {
+			switch (c) {
+				case '"' -> result.append("\\\"");
+				case '\\' -> result.append("\\\\");
+				case '\n' -> result.append("\\n");
+				case '\r' -> result.append("\\r");
+				case '\t' -> result.append("\\t");
+				case '\b' -> result.append("\\b");
+				case '\f' -> result.append("\\f");
+				default -> result.append(c);
+			}
+		}
+		return result.toString();
+	}
+
+	/**
+	 * Escape characters for single-quoted strings (used in SQL, etc.). Escapes: ', \, \n,
+	 * \r, \t, \b, \f
+	 * @param input the string to escape
+	 * @return the escaped string safe for use in single-quoted contexts
+	 */
+	public static String escapeForSingleQuotes(String input) {
+		if (input == null) {
+			return null;
+		}
+
+		StringBuilder result = new StringBuilder();
+		for (char c : input.toCharArray()) {
+			switch (c) {
+				case '\'' -> result.append("\\'");
+				case '\\' -> result.append("\\\\");
+				case '\n' -> result.append("\\n");
+				case '\r' -> result.append("\\r");
+				case '\t' -> result.append("\\t");
+				case '\b' -> result.append("\\b");
+				case '\f' -> result.append("\\f");
+				default -> result.append(c);
+			}
+		}
+		return result.toString();
+	}
+
+	/**
+	 * Escape characters for SQL identifiers and values. This method handles both single
+	 * quotes and backslashes for SQL contexts.
+	 * @param input the string to escape
+	 * @return the escaped string safe for use in SQL contexts
+	 */
+	public static String escapeForSql(String input) {
+		if (input == null) {
+			return null;
+		}
+		// SQL standard: escape single quotes by doubling them
+		return input.replace("'", "''");
+	}
+
+	/**
+	 * Escape characters for GraphQL string values. This method handles double quotes and
+	 * escape sequences for GraphQL contexts.
+	 * @param input the string to escape
+	 * @return the escaped string safe for use in GraphQL contexts
+	 */
+	public static String escapeForGraphQL(String input) {
+		return escapeForDoubleQuotes(input);
+	}
+
+	/**
+	 * Escape characters for JSON string values. This method handles double quotes and
+	 * escape sequences for JSON contexts.
+	 * @param input the string to escape
+	 * @return the escaped string safe for use in JSON contexts
+	 */
+	public static String escapeForJson(String input) {
+		return escapeForDoubleQuotes(input);
+	}
+
+	/**
+	 * Escape characters for Redis search queries. Redis has specific escaping rules for
+	 * special characters.
+	 * @param input the string to escape
+	 * @return the escaped string safe for use in Redis search contexts
+	 */
+	public static String escapeForRedis(String input) {
+		if (input == null) {
+			return null;
+		}
+
+		StringBuilder result = new StringBuilder();
+		for (char c : input.toCharArray()) {
+			switch (c) {
+				case '\\' -> result.append("\\\\");
+				case '"' -> result.append("\\\"");
+				case '\'' -> result.append("\\'");
+				case ' ' -> result.append("\\ ");
+				case '\n' -> result.append("\\n");
+				case '\r' -> result.append("\\r");
+				case '\t' -> result.append("\\t");
+				case '\b' -> result.append("\\b");
+				case '\f' -> result.append("\\f");
+				default -> result.append(c);
+			}
+		}
+		return result.toString();
+	}
+
+	/**
+	 * Escape characters for Elasticsearch queries. Elasticsearch requires specific
+	 * escaping for special characters in query strings.
+	 * @param input the string to escape
+	 * @return the escaped string safe for use in Elasticsearch query contexts
+	 */
+	public static String escapeForElasticsearch(String input) {
+		if (input == null) {
+			return null;
+		}
+
+		StringBuilder result = new StringBuilder();
+		for (char c : input.toCharArray()) {
+			switch (c) {
+				case '\\' -> result.append("\\\\");
+				case '"' -> result.append("\\\"");
+				case '\'' -> result.append("\\'");
+				case '+' -> result.append("\\+");
+				case '-' -> result.append("\\-");
+				case '=' -> result.append("\\=");
+				case '&' -> result.append("\\&");
+				case '|' -> result.append("\\|");
+				case '!' -> result.append("\\!");
+				case '(' -> result.append("\\(");
+				case ')' -> result.append("\\)");
+				case '{' -> result.append("\\{");
+				case '}' -> result.append("\\}");
+				case '[' -> result.append("\\[");
+				case ']' -> result.append("\\]");
+				case '^' -> result.append("\\^");
+				case '~' -> result.append("\\~");
+				case '*' -> result.append("\\*");
+				case '?' -> result.append("\\?");
+				case ':' -> result.append("\\:");
+				case '/' -> result.append("\\/");
+				case ' ' -> result.append("\\ ");
+				case '\n' -> result.append("\\n");
+				case '\r' -> result.append("\\r");
+				case '\t' -> result.append("\\t");
+				default -> result.append(c);
+			}
+		}
+		return result.toString();
+	}
+
+	/**
+	 * Generic escape method that takes an escape type parameter.
+	 * @param input the string to escape
+	 * @param escapeType the type of escaping to apply
+	 * @return the escaped string
+	 */
+	public static String escape(String input, EscapeType escapeType) {
+		if (input == null) {
+			return null;
+		}
+
+		return switch (escapeType) {
+			case DOUBLE_QUOTES -> escapeForDoubleQuotes(input);
+			case SINGLE_QUOTES -> escapeForSingleQuotes(input);
+			case SQL -> escapeForSql(input);
+			case GRAPHQL -> escapeForGraphQL(input);
+			case JSON -> escapeForJson(input);
+			case REDIS -> escapeForRedis(input);
+			case ELASTICSEARCH -> escapeForElasticsearch(input);
+		};
+	}
+
+	/**
+	 * Enumeration of different escape types supported by this utility.
+	 */
+	public enum EscapeType {
+
+		DOUBLE_QUOTES, SINGLE_QUOTES, SQL, GRAPHQL, JSON, REDIS, ELASTICSEARCH
+
+	}
+
+}

spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/filter/converter/AbstractFilterExpressionConverter.java

@@ -24,7 +24,6 @@
 import org.springframework.ai.vectorstore.filter.Filter.Group;
 import org.springframework.ai.vectorstore.filter.Filter.Operand;
 import org.springframework.ai.vectorstore.filter.FilterExpressionConverter;
-import org.springframework.ai.vectorstore.filter.FilterHelper;
 
 /**
  * AbstractFilterExpressionConverter is an abstract class that implements the
@@ -99,7 +98,7 @@ protected void doNot(Filter.Expression expression, StringBuilder context) {
 		// equivalent negation expression.
 		// Effectively removing the NOT types form the boolean expression tree before
 		// passing it to the doExpression.
-		this.convertOperand(FilterHelper.negate(expression), context);
+		this.convertOperand(org.springframework.ai.vectorstore.filter.FilterHelper.negate(expression), context);
 	}
 
 	/**
@@ -145,7 +144,8 @@ protected void doValue(Filter.Value filterValue, StringBuilder context) {
 	 */
 	protected void doSingleValue(Object value, StringBuilder context) {
 		if (value instanceof String) {
-			context.append(String.format("\"%s\"", value));
+			context.append(String.format("\"%s\"", org.springframework.ai.vectorstore.filter.FilterStringEscapeUtils
+				.escapeForDoubleQuotes((String) value)));
 		}
 		else {
 			context.append(value);

spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/filter/converter/SimpleVectorStoreFilterExpressionConverter.java

@@ -26,6 +26,7 @@
 
 import org.springframework.ai.vectorstore.filter.Filter;
 import org.springframework.ai.vectorstore.filter.Filter.Expression;
+import org.springframework.ai.vectorstore.filter.FilterStringEscapeUtils;
 
 /**
  * Converts {@link Expression} into SpEL metadata filter expression format.
@@ -128,7 +129,7 @@ else if (value instanceof String text) {
 				}
 			}
 			else {
-				context.append(text);
+				context.append(FilterStringEscapeUtils.escapeForSingleQuotes(text));
 			}
 			context.append("'");
 		}