CWE-479 - Signal Handler Use of a Non-reentrant Function
CWE-479 Low
- Abstraction:
- Variant
- Structure:
- Simple
- Status:
- Draft
- Weakness Name
Signal Handler Use of a Non-reentrant Function
- Description
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.
- Common Consequences
Scope: Integrity, Confidentiality, Availability
Impact: Execute Unauthorized Code or Commands
Notes: It may be possible to execute arbitrary code through the use of a write-what-where condition.
Scope: Integrity
Impact: Modify Memory, Modify Application Data
Notes: Signal race conditions often result in data corruption.
- Related Weaknesses
- Release Date:
- 2006-07-19
- Latest Modification Date:
- 2023-10-26
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