Type Mismatch: Signed to Unsigned

C/C++

Abstract

無符號變數獲指派了一個有符號數。

Explanation

依賴於有符號和無符號值之間的隱式轉換是危險的，因為結果可能是一個不可預料的值，並且違反程式設計師在別處的假設。

範例 1：在此範例中，視 accecssmainframe() 的回傳值而定，變數 amount 可能在傳回時帶負值。由於函數被宣告為傳回一個無符號值，所以 amount 將間接轉換為一個無符號的數值。


unsigned int readdata () {
	int amount = 0;
    ...
    amount = accessmainframe();
    ...
	return amount;
}

如果 accessmainframe() 的回傳值為 -1，那麼 readdata() 回傳值在 32 位元整數的系統上將會是 4,294,967,295。

在有符號和無符號值之間轉換會引起許多錯誤，但是從安全的觀點來看，最常見的情況是 Integer Overflow 和 Buffer overflow 弱點。

References

[1] Standards Mapping - CIS Azure Kubernetes Service Benchmark 1

[2] Standards Mapping - CIS Amazon Elastic Kubernetes Service Benchmark 4

[3] Standards Mapping - CIS Amazon Web Services Foundations Benchmark 1

[4] Standards Mapping - CIS Google Kubernetes Engine Benchmark normal

[5] Standards Mapping - Common Weakness Enumeration CWE ID 195

[6] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002824

[7] Standards Mapping - Motor Industry Software Reliability Association (MISRA) C Guidelines 2012 Rule 10.3

[8] Standards Mapping - Motor Industry Software Reliability Association (MISRA) C++ Guidelines 2008 Rule 5-0-3

[9] Standards Mapping - NIST Special Publication 800-53 Revision 4 SI-16 Memory Protection (P1)

[10] Standards Mapping - NIST Special Publication 800-53 Revision 5 SI-16 Memory Protection

[11] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.6

[12] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.6

[13] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.6

[14] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.6

[15] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4

[16] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 4.2 - Critical Asset Protection

[17] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 4.2 - Critical Asset Protection

[18] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 4.2 - Critical Asset Protection

[19] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3550 CAT I

[20] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3550 CAT I

[21] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3550 CAT I

[22] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3550 CAT I

[23] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3550 CAT I

[24] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3550 CAT I

[25] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3550 CAT I

[26] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002590 CAT I

[27] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002590 CAT I

[28] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002590 CAT I

[29] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002590 CAT I

[30] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002590 CAT I

[31] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002590 CAT I

[32] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002590 CAT I

[33] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002590 CAT I

[34] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002590 CAT I

[35] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002590 CAT I

[36] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002590 CAT I

[37] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002590 CAT I

[38] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002590 CAT I

[39] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002590 CAT I

desc.structural.cpp.type_mismatch_signed_to_unsigned