The APIs tabulated below perform tasks using the immediate caller's class loader.
APIs |
---|
java.lang.Class.forName |
java.lang.Package.getPackage(s) |
java.lang.Runtime.load |
java.lang.Runtime.loadLibrary |
java.lang.System.load |
java.lang.System.loadLibrary |
java.sql.DriverManager.getConnection |
java.sql.DriverManager.getDriver(s) |
java.sql.DriverManager.deregisterDriver |
java.util.ResourceBundle.getBundle |
Non-Compliant Code Example
The untrustedCode
method invokes loadLibrary
method in this non-compliant example. This is dangerous as the library gets loaded on behalf of the untrusted code. The acceptance of tainted inputs from the untrusted code further exacerbates this issue. In essence, untrusted code's class loader may be able to load the intended library even if it does not have sufficient permissions.
public static void untrustedCode() { loadLibrary("/com/foo/MyLib.so"); } public static void loadLibrary() { System.loadLibrary(lib); }
Compliant Solution
Ensure that untrusted code cannot invoke the affected APIs directly or indirectly (that is, via a call to an invoking method). Do not operate on tainted inputs and make sure that internal objects are not returned to untrusted code.
public static void loadLibrary() { System.loadLibrary("/com/foo/HardcodedLib.so"); }
References
Sun Secure Coding Guidelines