SEI CERT C Coding Standard

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Comment: Added PC-lint Plus to Automated Detection Table

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A less portable but potentially more secure solution is to use the capabilities provided by the underlying implementation. If this approach is taken, the caveats of that system must be well understood. The following table provides a starting point for some common operating systems:

Operating System

How to Handle Floating-Point Errors

Linux
Solaris 10
AIX 5.3
HP-UX 11.31
Mac OS X 10.5

Use the C floating-point exception functions

Windows

Use either the C floating-point exception functions or structured exception handling through _fpieee_flt [MSDN]

Noncompliant Code Example

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Undetected floating-point errors may result in lower program efficiency, inaccurate results, or software vulnerabilities. Most processors stall for a significant duration when an operation incurs a NaN (not a number) value.

Recommendation

Severity

Likelihood

Remediation Cost

Priority

Level

FLP03-C

Low

Probable

High

P2

L3

Automated Detection

Tool

Version

Checker

Description

Astrée
Include Page
Astrée_V
Astrée_V
CERT.FLP.3
float-division-by-zeroPartially checked
Compass/ROSE

 

 



Could detect violations of this rule by ensuring that floating-point operations are surrounded by feclearexcept() and fetestexcept(). It would need to look for type conversions to float or double, divisions (by a number not known to be nonzero), and multiplication. It may be wisest to apply this to all floating-point operations in general

LDRA tool suite
Include Page
LDRA_V
LDRA_V
43 DPartially implemented
Parasoft C/C++test
9.5BD-PB-ZERO, MISRA2004-10_2_{b,c,d}
Include Page
Parasoft_V
Parasoft_V

CERT_C-FLP03-a
CERT_C-FLP03-b
CERT_C-FLP03-c
CERT_C-FLP03-d

Avoid division by zero
Avoid implicit conversions from wider to narrower floating type
Avoid implicit conversions from narrower to wider floating type
Avoid implicit conversions of floating point numbers from wider to narrower floating type

Partially implemented

Parasoft Insure++
  


Runtime analysis
PC-lint Plus

Include Page
PC-lint Plus_V
PC-lint Plus_V

736, 9120, 9227

Assistance provided

Polyspace Bug Finder

Include Page
Polyspace Bug Finder_V

Runtime analysis

Polyspace Bug Finder

R2016a

_V

CERT C: Rec. FLP03-C


Checks for:

  • Float conversion overflow
  • Float overflow
Invalid use of standard library floating point routineDividing floating point number by zero
  • Float division by zero

Overflow when converting between floating point data types

Overflow from operation between floating points

Wrong arguments to standard library function

Rec. partially covered.

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this recommendation on the CERT website.

Related Guidelines

SEI CERT C++ Coding StandardVOID FLP03-CPP. Detect and handle floating point errors
MITRE CWECWE-369, Divide by zero

Bibliography

[IEEE Std 1003.1:2013]XBD, Headers, <fenv.h>
[Intel 2001]
 

[ISO/IEC 9899:2011]Subclause 7.6.2, "Floating-Point Exceptions"
[Keil 2008]
 

[MSDN]"fpieee_flt (CRT)"
[SecurityFocus 2007]
 

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