SEI CERT C Coding Standard

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changes.mady.by.user David Svoboda

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changes.mady.by.user Joerg Herter

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Recommendation

Severity

Likelihood

Detectable

Repairable

Priority

Level

ERR34-C

Medium

Unlikely

Yes

Yes

P6

L2

Automated Detection

Tool

Version

Checker

Description

Astrée
Include Page
Astrée_V
Astrée_V

bad-function-use
scanf-string-to-number

Partially checked
Axivion Bauhaus Suite

Include Page
Axivion Bauhaus Suite_V
Axivion Bauhaus Suite_V

CertC-ERR34
Clang
Include Page
Clang_39_V
Clang_39_V
cert-err34-cChecked by clang-tidy
CodeSonar
Include Page
CodeSonar_V
CodeSonar_V

BADFUNC.ATOF
BADFUNC.ATOI
BADFUNC.ATOL
BADFUNC.ATOLL

(customization)

Use of atof
Use of atoi
Use of atol
Use of atoll

Users can add custom checks for uses of other undesirable conversion functions.

Compass/ROSE



Can detect violations of this recommendation by flagging invocations of the following functions:

    • atoi()
    • scanf(), fscanf(), sscanf()
    • Others?
Helix QAC

Include Page
Helix QAC_V
Helix QAC_V

C5030

C++5016


Klocwork
Include Page
Klocwork_V
Klocwork_V

CERT.ERR.CONV.STR_TO_NUM
MISRA.STDLIB.ATOI
SV.BANNED.RECOMMENDED.SCANF


LDRA tool suite
Include Page
LDRA_V
LDRA_V

44 S

Fully implemented

Parasoft C/C++test
Include Page
Parasoft_V
Parasoft_V

CERT_C-ERR34-a

The 'atof', 'atoi', 'atol' and 'atoll' functions from the 'stdlib.h' or 'cstdlib' library should not be used
PC-lint Plus

Include Page
PC-lint Plus_V
PC-lint Plus_V

586

Assistance provided

Polyspace Bug Finder

Include Page
Polyspace Bug Finder_V
Polyspace Bug Finder_V

CERT C: Rule ERR34-CChecks for unsafe conversion from string to numeric value (rule fully covered)
RuleChecker

Include Page
RuleChecker_V
RuleChecker_V

bad-function-use
scanf-string-to-number		Partially checked
SonarQube C/C++ Plugin
Include Page
SonarQube C/C++ Plugin_V
SonarQube C/C++ Plugin_V
S989

Related Vulnerabilities

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

...

CWE-391 = Union( ERR34-C, list) where list =


  • Failure to errors outside of string-to-number conversion functions


CWE-676 and ERR34-C


  • Independent( ENV33-C, CON33-C, STR31-C, EXP33-C, MSC30-C, ERR34-C)



  • ERR34-C implies that string-parsing functions (eg atoi() and scanf()) are dangerous.



  • CWE-676 = Union( ERR34-C, list) where list =



  • Invocation of dangerous functions besides the following:



  • atoi(), atol(), atoll(), atof(), The scanf()family


CWE-758 and ERR34-C

Independent( INT34-C, INT36-C, MSC37-C, FLP32-C, EXP33-C, EXP30-C, ERR34-C, ARR32-C)

Intersection( CWE-758, ERR34-C) =


  • Undefined behavior arising from a non-representable numeric value being parsed by an ato*() or scanf() function


CWE-758 – ERR34-C =


  • Undefined behavior arising from using a function outside of the ato*() or scanf() family


ERR34-C – CWE-758 =


  • The ato*() or scanf() family receives input that is not a number when trying to parse one


Bibliography

[ISO/IEC 9899:2024]Subclause 7.24.1, "Numeric conversion functions"
[Klein 2002]

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