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False Negative:ArrayIndexOutOfBounds.ql

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描述

Version
codeql 2.23.9

When I detect the code like this using Likely Bugs/Collections/ArrayIndexOutOfBounds.ql, the problem is reported normally:
```java
package scensct.core.pos;
public class PosCase1 {
public static void main(String[] args) {
int[] arr = new int[5];
int index = 10; // Unbounded index, no constraint check before access
int value = arr[index]; // Direct access with potentially out-of-bounds index // [REPORTED LINE]
}
}
```

However, when I use a mediator variable or call a mediator function, ArrayIndexOutOfBounds.ql fails to detect the problem:
```java
package scensct.var.pos;

public class PosCase1_Var4 {
public static void main(String[] args) {
int[] arr = createArray();
int index = getIndex();
int value = arr[index]; // Access with index from method
}

private static int[] createArray() {
return new int[5];
}

private static int getIndex() {
return 10;
}
}

```
```java
package scensct.var.pos;

public class PosCase2_Var4 {
public static void main(String[] args) {
int[] arr = new int[5];
int K = 5;
// Introduce an alias reference
int[] alias = arr;
int index = K;
int value = alias[index];
}
}

```

```java
package scensct.var.pos;

public class PosCase2_Var5 {
private static int getIndex(int k) {
return k;
}

public static void main(String[] args) {
int[] arr = new int[5];
int K = 5;
// Move index computation to a helper method
int index = getIndex(K);
int value = arr[index];
}
}
```

```java
package scensct.core.pos;

public class PosCase3 {
public static void main(String[] args) {
int[] arr = new int[5];
int K = -1; // Negative bound
int index = K + 0; // Index bounded below by negative K
int value = arr[index]; // Access with potentially negative index
}
}
```

貢獻指南

開啟貢獻指南

研究方向

Start with Likely Bugs/Collections/ArrayIndexOutOfBounds.ql and compare how it handles direct array access with accesses using helper methods, aliases, and computed indices. Reproduce the Java examples from the issue, then verify that the query reports each out-of-bounds access, including negative indices.

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評估

技術堆疊
java
領域
security
Issue 類型
缺陷
難度
4/5
預估耗時
3-5 天
活躍度
冷清
描述清晰度
基本清楚
新手友好度
45/100

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