CWE-469

Use of Pointer Subtraction to Determine Size
AI Translation Available

The product subtracts one pointer from another in order to determine size, but this calculation can be incorrect if the pointers do not exist in the same memory chunk.

Status
draft
Abstraction
base
Likelihood
medium
C C++

Common Consequences

access control integrity confidentiality availability
Impacts
modify memory read memory execute unauthorized code or commands gain privileges or assume identity

Detection Methods

fuzzing automated static analysis

Potential Mitigations

Phases:
implementation
Descriptions:
• Save an index variable. This is the recommended solution. Rather than subtract pointers from one another, use an index variable of the same size as the pointers in question. Use this variable to "walk" from one pointer to the other and calculate the difference. Always validate this number.