CWE-188 依赖数据/内存布局

Reliance on Data/Memory Layout

结构: Simple

Abstraction: Base

状态: Draft

被利用可能性: Low

基本描述

The software makes invalid assumptions about how protocol data or memory is organized at a lower level, resulting in unintended program behavior.

扩展描述

When changing platforms or protocol versions, in-memory organization of data may change in unintended ways. For example, some architectures may place local variables A and B right next to each other with A on top; some may place them next to each other with B on top; and others may add some padding to each. The padding size may vary to ensure that each variable is aligned to a proper word size.

In protocol implementations, it is common to calculate an offset relative to another field to pick out a specific piece of data. Exceptional conditions, often involving new protocol versions, may add corner cases that change the data layout in an unusual way. The result can be that an implementation accesses an unintended field in the packet, treating data of one type as data of another type.

相关缺陷

• cwe_Nature: ChildOf cwe_CWE_ID: 1105 cwe_View_ID: 1000 cwe_Ordinal: Primary

• cwe_Nature: ChildOf cwe_CWE_ID: 435 cwe_View_ID: 1000

适用平台

Language: [{'cwe_Name': 'C', 'cwe_Prevalence': 'Undetermined'}, {'cwe_Name': 'C++', 'cwe_Prevalence': 'Undetermined'}]

常见的影响

可能的缓解方案

['Implementation', 'Architecture and Design']

策略:

In flat address space situations, never allow computing memory addresses as offsets from another memory address.

Architecture and Design

策略:

Fully specify protocol layout unambiguously, providing a structured grammar (e.g., a compilable yacc grammar).

Testing

策略:

Testing: Test that the implementation properly handles each case in the protocol grammar.

示例代码

例

In this example function, the memory address of variable b is derived by adding 1 to the address of variable a. This derived address is then used to assign the value 0 to b.

bad C

Here, b may not be one byte past a. It may be one byte in front of a. Or, they may have three bytes between them because they are aligned on 32-bit boundaries.

分类映射

引用

• REF-62 The Art of Software Security Assessment

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