數組邊界檢查可能被錯誤地進行了優化。
如果數組邊界檢查涉及計算非法指針,然后確定該指針超出邊界,那么一些編譯器將優化檢查,假設程序員絕不會故意創建非法指針。
例:
char *buf;
int len;
...
len = 1<<30;
if (buf+len < buf) //wrap check
[handle overflow]
buf + len 大于 2^32,因此生成的值小于 buf。但由于指針上的運算溢出是 undefined behavior,因此一些編譯器將假設 buf + len >= buf,并優化封裝檢查。此優化的結果是,跟蹤此數據塊的代碼會產生 buffer overflow 漏洞。
[1] Standards Mapping - OWASP Top 10 2004 - (OWASP 2004) A5 Buffer Overflow
[2] Standards Mapping - Security Technical Implementation Guide Version 3 - (STIG 3) APP3590.1 CAT I
[3] Standards Mapping - Security Technical Implementation Guide Version 3.4 - (STIG 3.4) APP3590.1 CAT I
[4] Standards Mapping - Common Weakness Enumeration - (CWE) CWE ID 733
[5] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 - (PCI 2.0) Requirement 6.5.2
[6] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 - (PCI 1.1) Requirement 6.5.5
[7] Vulnerability Note VU#162289 CERT