Java: Detecting flow through throw - catch statements

Hello,

I'm having a confusing issue trying to track the data flow from a throw to a catch statement. I had similar queries working just fine. However, I was messing around with my qlpack last week and I think I may have messed something up. To give you some context, I am using CLI version `2.20.3` and here is my

`qlpack.yml`

```yml
---
library: false
warnOnImplicitThis: false
name: custom-codeql-queries
version: 0.0.1
dependencies:
# codeql/java-queries: ^0.8.9
codeql/java-all: 6.1.0
libraries:
- name: SensitiveInfo
path: /SensitiveInfo
dataExtensions:
- SensitiveInfo/*.yml
```

Along with my `codeql-pack.lock.yml`

```yml
---
lockVersion: 1.0.0
dependencies:
codeql/dataflow:
version: 1.1.9
codeql/java-all:
version: 6.1.0
codeql/mad:
version: 1.0.15
codeql/rangeanalysis:
version: 1.0.15
codeql/regex:
version: 1.0.15
codeql/ssa:
version: 1.0.15
codeql/threat-models:
version: 1.0.15
codeql/tutorial:
version: 1.0.15
codeql/typeflow:
version: 1.0.15
codeql/typetracking:
version: 1.0.15
codeql/util:
version: 2.0.2
codeql/xml:
version: 1.0.15
compiled: false
```

I don't fully understand all of the dependency versions needed to work with my CLI version so I would appriacte it if someones could point out if this looks wrong.

On to my specific issue.

I am trying to detect this toy example.

```java
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.ejb.EJBException;
import java.io.IOException;

public class BAD_AuthenticationFailureServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
try {
authenticateUser(username, password);
} catch (EJBException e) {
response.getWriter().write("Authentication failed: " + e.getMessage());
}
}

private void authenticateUser(String username, String password) throws EJBException {
if (username == null || password == null) {
throw new EJBException("Username or password is null. Provided username: " + username + ", password: " + password);
}
throw new EJBException("Invalid credentials provided for user " + username + ". Attempted password: " + password);
}
}
```

With this query

```codeql
/**
* @name CWE-550: Exposure of sensitive information through servlet responses
* @description Detects flows of the `password` parameter into EJBException messages that are written back to HTTP clients.
* @kind path-problem
* @problem.severity warning
* @id java/servlet-info-exposure/550
* @tags security
* external/cwe/cwe-550
* external/cwe/cwe-200
* @cwe CWE-550
*/

import java
import semmle.code.java.dataflow.TaintTracking
import semmle.code.java.dataflow.DataFlow

// Define flow states
private newtype MyFlowState =
State1() or
State2() or
State3()

module ServerGeneratedErrorMessageConfig implements DataFlow::StateConfigSig {
class FlowState = MyFlowState;

// Source: the `password` servlet parameter
predicate isSource(DataFlow::Node source, FlowState state) {
state instanceof State1 and
exists(VarAccess va |
va.getVariable().getName() = "password" and
source.asExpr() = va
)
}


// Sink: explicit HTTP response sinks that expose the message
predicate isSink(DataFlow::Node sink, FlowState state) {
state instanceof State3 and (
// response.getWriter().write(msg)
exists(MethodCall mc |
mc.getMethod().getName() = "write" and
exists(MethodCall getWriter |
getWriter.getMethod().getName() = "getWriter" and
getWriter = mc.getQualifier() and
getWriter.getQualifier().getType().(RefType).hasQualifiedName("javax.servlet.http", "HttpServletResponse")
) and
mc.getArgument(0) = sink.asExpr()
)
)
}

// Transitions between flow states
predicate isAdditionalFlowStep(
DataFlow::Node node1, FlowState state1,
DataFlow::Node node2, FlowState state2
) {
// State1->State2: flows into EJBException constructor
state1 instanceof State1 and state2 instanceof State2 and
exists(ConstructorCall cc |
cc.getAnArgument() = node1.asExpr() and
cc.getConstructor().getDeclaringType().(RefType)
.getASupertype+().hasQualifiedName("javax.ejb", "EJBException") and
node2.asExpr() = cc
)
or
// State2->State3: flows from throw to catch capturing e or e.getMessage()
state1 instanceof State2 and state2 instanceof State3 and
exists(ThrowStmt t, CatchClause cc, Expr use |
t.getExpr() = node1.asExpr() and
cc.getEnclosingCallable() = t.getEnclosingCallable() and
(
use = cc.getVariable().getAnAccess()
or
exists(MethodCall mc2 |
mc2.getQualifier() = cc.getVariable().getAnAccess() and
mc2.getMethod().getName() = "getMessage" and
use = mc2
)
) and
node2.asExpr() = use
)
}
}

module SensitiveInfoInErrorMsgFlow =
TaintTracking::GlobalWithState;
import SensitiveInfoInErrorMsgFlow::PathGraph

from SensitiveInfoInErrorMsgFlow::PathNode source, SensitiveInfoInErrorMsgFlow::PathNode sink
where SensitiveInfoInErrorMsgFlow::flowPath(source, sink)
select sink, source, sink,
"CWE-550: password parameter is exposed via server error message."
```

I have confirmed that the `isSource` and `isSink` do work. So the issue is likely in the flow between them. I have used a few queries in the past that follow this similar structure. However, they are also missing some cases randomly at the moment. Which is leading me to believe it has something to do with my qlpack.

As always, thank you for the help.

Start with qlpack.yml and codeql-pack.lock.yml, then inspect the query's isSource, isSink, and isAdditionalFlowStep entry points against the toy Java example. Run the query with the stated CLI version and verify whether the throw-to-catch flow is detected; done means identifying the dependency or query behavior responsible for the missing flow.

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