Module cwe_checker_lib::checkers::cwe_789

This module implements a check for CWE-789: Memory Allocation with Excessive Size Value.

Stack memory allocation and function calls like malloc are covered in this module. Excessive allocation of memory might destabilize programs on machines with limited resources.

See https://cwe.mitre.org/data/definitions/789.html for a detailed description.

How the check works

Every instruction is checked if it assigns a new value to the stack pointer. If this is the case, the value range of the assignment is checked and if it exceeds the defined stack_threshold defined in config.json, a warning is generated. For calls like malloc, the provided argument is checked, if its value exceeds the defined heap_threshold. The covered function calls are defined in config.json. The defined thresholds are provided in bytes.

False Positives

False Negatives

• At most one warning for stack memory allocation is created for each Function. This means multiple weaknesses are not detected individually.

Structs

• Config
  The configuration struct. If a threshold is exceeded, the warning is generated.

Statics

• CWE_MODULE
  The module name and version

Functions

• check_cwe
  Run the CWE check. For each function, we check calls of the defined functions and instructions that assign a value to the stackpointer.