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Comment: Updated references from C11->C23

The C Standard, 6.2.5, paragraph 9 11 [ISO/IEC 9899:20112024], states

A computation involving unsigned operands can never produce an overflow, because a result that cannot be represented by the resulting unsigned integer type is reduced modulo the number that is one greater than the largest value that can be represented by the resulting typearithmetic for the unsigned type is performed modulo 2^N .

This behavior is more informally called unsigned integer wrapping. Unsigned integer operations can wrap if the resulting value cannot be represented by the underlying representation of the integer. The following table indicates which operators can result in wrapping:

...

Rule

Severity

Likelihood

Remediation Cost

Priority

Level

INT30-C

High

Likely

High

P9

L2

Automated Detection

Tool

Version

Checker

Description

Astrée
Include Page
Astrée_V
Astrée_V
integer-overflowFully checked
CodeSonar
Axivion Bauhaus Suite

Include Page

CodeSonar

cplusplus:Axivion Bauhaus Suite_V

CodeSonar

cplusplus:Axivion Bauhaus Suite_V

ALLOC.
CertC-INT30Implemented
CodeSonar
Include Page
CodeSonar_V
CodeSonar_V

ALLOC.SIZE.ADDOFLOW
ALLOC.SIZE.IOFLOW
ALLOC.SIZE.MULOFLOW
ALLOC.SIZE.SUBUFLOW
MISC.MEM.SIZE.ADDOFLOW
MISC.MEM.SIZE.BAD
MISC.MEM.SIZE.MULOFLOW
MISC.MEM.SIZE.SUBUFLOW

Addition overflow of allocation size
Integer overflow of allocation size
Multiplication overflow of allocation size
Subtraction underflow of allocation size
Addition overflow of size
Unreasonable size argument
Multiplication overflow of size
Subtraction underflow of size

Compass/ROSE



Can detect violations of this rule by ensuring that operations are checked for overflow before being performed (Be mindful of exception INT30-EX2 because it excuses many operations from requiring validation, including all the operations that would validate a potentially dangerous operation. For instance, adding two unsigned ints together requires validation involving subtracting one of the numbers from UINT_MAX, which itself requires no validation because it cannot wrap.)

Coverity
Include Page
Coverity_V
Coverity_V
INTEGER_OVERFLOWImplemented
Klocwork
Cppcheck Premium

Include Page

Klocwork

Cppcheck Premium_V

Klocwork

Cppcheck Premium_V

NUM.OVERFLOW
CWARN.NOEFFECT.OUTOFRANGELDRA tool suite
premium-cert-int30-cPartially implemented
Helix QAC

Include Page

LDRA

Helix QAC_V

LDRA

Helix QAC_V

493 S, 494 SPartially implementedParasoft C/C++test Include PageParasoft_VParasoft_VBD-PB-INTOVERF, PB-66_a, PB-66_bImplementedPolyspace Bug FinderR2016aUnsigned integer overflowOverflow from operation between unsigned integersPRQA QA-C Include PagePRQA QA-C_vPRQA QA-C_v

2910 (C)
2911 (D)
2912 (A)
2913 (S)

Partially implementedPRQA QA-C++ Include Pagecplusplus:PRQA QA-C++_Vcplusplus:PRQA QA-C++_V2910, 2911, 2912, 2913

C2910, C3383, C3384, C3385, C3386

C++2910

DF2911, DF2912, DF2913,


Klocwork
Include Page
Klocwork_V
Klocwork_V

NUM.OVERFLOW
CWARN.NOEFFECT.OUTOFRANGE
NUM.OVERFLOW.DF


LDRA tool suite
Include Page
LDRA_V
LDRA_V
493 S, 494 SPartially implemented
Parasoft C/C++test

Include Page
Parasoft_V
Parasoft_V

CERT_C-INT30-a
CERT_C-INT30-b
CERT_C-INT30-c

Avoid wraparounds when performing arithmetic integer operations
Integer overflow or underflow in constant expression in '+', '-', '*' operator
Integer overflow or underflow in constant expression in '<<' operator

Polyspace Bug Finder

Include Page
Polyspace Bug Finder_V
Polyspace Bug Finder_V

CERT C: Rule INT30-C

Checks for:

  • Unsigned integer overflow
  • Unsigned integer constant overflow

Rule partially covered.

PVS-Studio

Include Page
PVS-Studio_V
PVS-Studio_V

V658, V1012V1028, V5005, V5011 

TrustInSoft Analyzer

Include Page
TrustInSoft Analyzer_V
TrustInSoft Analyzer_V

unsigned overflowExhaustively verified.
PVS-Studio6.22V658RuleChecker Include PageRuleChecker_VRuleChecker_Vinteger-overflowFully checked

Related Vulnerabilities

CVE-2009-1385 results from a violation of this rule. The value performs an unchecked subtraction on the length of a buffer and then adds those many bytes of data to another buffer [xorl 2009]. This can cause a buffer overflow, which allows an attacker to execute arbitrary code.

...

[Bailey 2014]Raising Lazarus - The 20 Year Old Bug that Went to Mars
[Dowd 2006]Chapter 6, "C Language Issues" ("Arithmetic Boundary Conditions," pp. 211–223)
[ISO/IEC 9899:20112024]Subclause 6.2.5, "Types"
[Seacord 2013b]Chapter 5, "Integer Security"
[Viega 2005]Section 5.2.7, "Integer Overflow"
[VU#551436]
[Warren 2002]Chapter 2, "Basics"
[Wojtczuk 2008]
[xorl 2009]"CVE-2009-1385: Linux Kernel E1000 Integer Underflow"

...