CWE-828

Signal Handler with Functionality that is not Asynchronous-Safe

Medium

Description

The product defines a signal handler that contains code sequences that are not asynchronous-safe, i.e., the functionality is not reentrant, or it can be interrupted.

Potential Impact

How to Fix

Implementation

Eliminate the usage of non-reentrant functionality inside of signal handlers. This includes replacing all non-reentrant library calls with reentrant calls. Note: This will not always be possible and may require large portions of the product to be rewritten or even redesigned. Sometimes reentrant-safe library alternatives will not be available. Sometimes non-reentrant interaction between the state of the system and the signal handler will be required by design.

Implementation

Where non-reentrant functionality must be leveraged within a signal handler, be sure to block or mask signals appropriately. This includes blocking other signals within the signal handler itself that may also leverage the functionality. It also includes blocking all signals reliant upon the functionality when it is being accessed or modified by the normal behaviors of the product.

Detection Methods

Related Weaknesses

References

View on MITRE CWE Database →

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