Non-final Nonfinal member methods that perform security checks can be compromised when a malicious subclass overrides the methods and omits the checks. Consequently, such methods must be declared private or final to prevent overriding.
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This noncompliant code example allows a subclass to override the readSensitiveFile() method and omit the required security check.:
| Code Block | ||
|---|---|---|
| ||
public void readSensitiveFile() {
try {
SecurityManager sm = System.getSecurityManager();
if (sm != null) { // Check for permission to read file
sm.checkRead("/temp/tempFile");
}
// Access the file
} catch (SecurityException se) {
// Log exception
}
}
|
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This compliant solution prevents overriding of the readSensitiveFile() method by declaring it final.:
| Code Block | ||
|---|---|---|
| ||
public final void readSensitiveFile() {
try {
SecurityManager sm = System.getSecurityManager();
if (sm != null) { // Check for permission to read file
sm.checkRead("/temp/tempFile");
}
// Access the file
} catch (SecurityException se) {
// Log exception
}
}
|
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This compliant solution prevents overriding of the readSensitiveFile() method by declaring it private.:
| Code Block | ||
|---|---|---|
| ||
private void readSensitiveFile() {
try {
SecurityManager sm = System.getSecurityManager();
if (sm != null) { // Check for permission to read file
sm.checkRead("/temp/tempFile");
}
// Access the file
} catch (SecurityException se) {
// Log exception
}
}
|
Exceptions
MET03-J-EX0: Classes that are declared final are exempt from this rule because their member methods cannot be overridden.
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Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
MET03-J | mediumMedium | probableProbable | mediumMedium | P8 | L2 |
Android Implementation Details
On Android, System.getSecurityManager() is not used, and the use of a Security Manager security manager is not exercised. However, an Android developer can implement security-sensitive methods, so the principle may be applicable on Android.
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IH.2.b.b. Declare methods that enforce |
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