CWE-479 - Signal Handler Use of a Non-reentrant Function
- 摘要：Variant
- 结构：Simple
- 状态：Draft
- 发布日期：2006-07-19
- 更新日期：2025-12-11
名称
Signal Handler Use of a Non-reentrant Function
描述
The product defines a signal handler that calls a non-reentrant function.
Non-reentrant functions are functions that cannot safely be called, interrupted, and then recalled before the first call has finished without resulting in memory corruption. This can lead to an unexpected system state and unpredictable results with a variety of potential consequences depending on context, including denial of service and code execution. Many functions are not reentrant, but some of them can result in the corruption of memory if they are used in a signal handler. The function call syslog() is an example of this. In order to perform its functionality, it allocates a small amount of memory as "scratch space." If syslog() is suspended by a signal call and the signal handler calls syslog(), the memory used by both of these functions enters an undefined, and possibly, exploitable state. Implementations of malloc() and free() manage metadata in global structures in order to track which memory is allocated versus which memory is available, but they are non-reentrant. Simultaneous calls to these functions can cause corruption of the metadata.
常见后果
范围：Integrity, Confidentiality, Availability
影响：Execute Unauthorized Code or Commands
注释：It may be possible to execute arbitrary code through the use of a write-what-where condition.
范围：Integrity
影响：Modify Memory, Modify Application Data
注释：Signal race conditions often result in data corruption.