CWE-762 不匹配的内存管理例程

Mismatched Memory Management Routines

结构: Simple

Abstraction: Variant

状态: Incomplete

被利用可能性: Low

基本描述

The application attempts to return a memory resource to the system, but it calls a release function that is not compatible with the function that was originally used to allocate that resource.

扩展描述

This weakness can be generally described as mismatching memory management routines, such as:

When the memory management functions are mismatched, the consequences may be as severe as code execution, memory corruption, or program crash. Consequences and ease of exploit will vary depending on the implementation of the routines and the object being managed.

相关缺陷

  • cwe_Nature: ChildOf cwe_CWE_ID: 763 cwe_View_ID: 1000 cwe_Ordinal: Primary

适用平台

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

常见的影响

范围 影响 注释
['Integrity', 'Availability', 'Confidentiality'] ['Modify Memory', 'DoS: Crash, Exit, or Restart', 'Execute Unauthorized Code or Commands']

可能的缓解方案

Implementation

策略:

Only call matching memory management functions. Do not mix and match routines. For example, when you allocate a buffer with malloc(), dispose of the original pointer with free().

MIT-41 Implementation

策略: Libraries or Frameworks

Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391]. To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

MIT-4.6 Architecture and Design

策略: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, glibc in Linux provides protection against free of invalid pointers.

Architecture and Design

策略:

Use a language that provides abstractions for memory allocation and deallocation.

Testing

策略:

Use a tool that dynamically detects memory management problems, such as valgrind.

示例代码

例

This example allocates a BarObj object using the new operator in C++, however, the programmer then deallocates the object using free(), which may lead to unexpected behavior.

bad C++

void foo(){
BarObj ptr = new BarObj()
/ do some work with ptr here */

...

free(ptr);
}

Instead, the programmer should have either created the object with one of the malloc family functions, or else deleted the object with the delete operator.

good C++

void foo(){
BarObj ptr = new BarObj()
/ do some work with ptr here */

...

delete ptr;
}

例

In this example, the program does not use matching functions such as malloc/free, new/delete, and new[]/delete[] to allocate/deallocate the resource.

bad C++

class A {
void foo();
};
void A::foo(){
int ptr;
ptr = (int)malloc(sizeof(int));
delete ptr;
}

例

In this example, the program calls the delete[] function on non-heap memory.

bad C++

class A{
void foo(bool);
};
void A::foo(bool heap) {
int localArray[2] = {
11,22
};
int *p = localArray;
if (heap){
p = new int[2];
}
delete[] p;
}

Notes

分类映射

映射的分类名 ImNode ID Fit Mapped Node Name
CERT C Secure Coding WIN30-C Exact Properly pair allocation and deallocation functions
Software Fault Patterns SFP12 Faulty Memory Release

引用