Buffer overflow from unbounded string input
The string copy function is used to copy a string of characters to a buffer of memory. The strcpy function has no argument to limit the size of the written data, so a buffer overflow may result.
The SV.UNBOUND_STRING_INPUT.CIN checker looks for code calling string copy functions that don't specify a buffer size-either getwd() or a function that uses C++ input.
Vulnerability and risk
If the string copy function is called without a size parameter, a buffer overrun error can result. This can lead to application instability or, with a carefully constructed attack, code injection, or other vulnerabilities.
Mitigation and prevention
To avoid this vulnerability, make sure you use functions that have buffer size as an input parameter, or use a function like strlen() to determine the buffer size you need.
- CERT ARR00-C: Understand how arrays work
- CERT STR50-CPP: Guarantee that storage for strings has sufficient space for character data and the null terminator
- CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
- CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
- CWE-125: Out-of-bounds Read
- CWE-242: Use of Inherently Dangerous Function
- CWE-787: Out-of-bounds Write