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Noncompliant Code Example
The following This noncompliant code example accepts user data without first validating it:
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The following table shows the value of currentBalance returned for various arguments:
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As this example demonstrates, the user can enter the exceptional values infinity and NaN, as well as force a float's value to be infinite, by entering out-of-range floats. These entries subsequently corrupt the value of currentBalance. So by entering exceptional floats, an attacker can corrupt the program data, possibly leading to a crash.
Compliant Solution
The following code This compliant solution first validates the input float before using it. The value is tested to ensure that it is neither an infinity nor a NaN.
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Inappropriate floating-point inputs can result in invalid calculations and unexpected results, possibly leading to crashing and providing a denial-of-service opportunity.
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
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FLP04-C |
Low |
Probable |
High | P2 | L3 |
Automated Detection
Tool | Version | Checker | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Astrée |
| Supported: Astrée reports potential runtime error resulting from missing checks for exceptional values. |
Related Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this recommendation on the CERT website.
Related Guidelines
| SEI CERT C++ |
| Coding Standard | FLP04-CPP. Check floating-point inputs for exceptional values |
| CERT Oracle Secure Coding Standard for Java | FLP06-J. Check floating-point inputs for exceptional values |
Bibliography
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