CWE-609 詳細資料

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.

引入方式

Implementation

適用平台

程式語言

名稱： Java (Undetermined)

常見後果

潛在緩解措施

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.

偵測方法

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

漏洞對應備注

理由說明 : 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.
備註 : 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.

參考資料

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.

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