CWE-609 Detail

The product uses double-checked locking to access a resource without the overhead of explicit synchronization, but the locking is insufficient.

Double-checked locking refers to the situation where a programmer checks to see if a resource has been initialized, grabs a lock, checks again to see if the resource has been initialized, and then performs the initialization if it has not occurred yet. This should not be done, as it is not guaranteed to work in all languages and on all architectures. In summary, other threads may not be operating inside the synchronous block and are not guaranteed to see the operations execute in the same order as they would appear inside the synchronous block.

Modes Of Introduction

Implementation

Applicable Platforms

Language

Name: Java (Undetermined)

Common Consequences

Potential Mitigations

Phases : Implementation
While double-checked locking can be achieved in some languages, it is inherently flawed in Java before 1.5, and cannot be achieved without compromising platform independence. Before Java 1.5, only use of the synchronized keyword is known to work. Beginning in Java 1.5, use of the "volatile" keyword allows double-checked locking to work successfully, although there is some debate as to whether it achieves sufficient performance gains. See references.

Vulnerability Mapping Notes

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

References

REF-490

The "Double-Checked Locking is Broken" Declaration
David Bacon et al.
http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html

REF-491

JSR 133 (Java Memory Model) FAQ
Jeremy Manson and Brian Goetz.
http://www.cs.umd.edu/~pugh/java/memoryModel/jsr-133-faq.html#dcl

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

Submission

Modifications