Static array access may cause overflow¶
ID: cpp/static-buffer-overflow
Kind: problem
Security severity: 9.3
Severity: warning
Precision: high
Tags:
- reliability
- security
- external/cwe/cwe-119
- external/cwe/cwe-131
Query suites:
- cpp-code-scanning.qls
- cpp-security-extended.qls
- cpp-security-and-quality.qls
Click to see the query in the CodeQL repository
When you use static arrays you must ensure that you do not exceed the size of the array during write and access operations. If an operation attempts to write to or access an element that is outside the range of the array then this results in a buffer overflow. Buffer overflows can lead to anything from a segmentation fault to a security vulnerability.
Recommendation¶
Check the offsets and sizes used in the highlighted operations to ensure that a buffer overflow will not occur.
Example¶
#define SIZE 30
int f(char * s) {
char buf[20]; //buf not set to use SIZE macro
strncpy(buf, s, SIZE); //wrong: copy may exceed size of buf
for (int i = 0; i < SIZE; i++) { //wrong: upper limit that is higher than array size
cout << array[i];
}
}