C and C++

LANG.STRUCT.PARITH : Pointer Arithmetic

Summary

A +, -, +=, or -= operator is applied to an expression of pointer type.

Exception: pointer subtraction between two pointers will not trigger a warning of this class.

Properties

Class Name Pointer Arithmetic
Significance style
Mnemonic LANG.STRUCT.PARITH
Categories
MisraC2023 MisraC2023:18.1 A pointer resulting from arithmetic on a pointer operand shall address an element of the same array as that pointer operand
  MisraC2023:18.2 Subtraction between pointers shall only be applied to pointers that address elements of the same array
  MisraC2023:18.4 The +, -, += and -= operators should not be applied to an expression of pointer type
Misra2012 Misra2012:18.1 A pointer resulting from arithmetic on a pointer operand shall address an element of the same array as that pointer operand
  Misra2012:18.2 Subtraction between pointers shall only be applied to pointers that address elements of the same array
  Misra2012:18.4 The +, -, += and -= operators should not be applied to an expression of pointer type
Misra2004 Misra2004:17.1 Pointer arithmetic shall only be applied to pointers that address an array or array element
  Misra2004:17.2 Pointer subtraction shall only be applied to pointers that address elements of the same array
  Misra2004:17.4 Array indexing shall be the only allowed form of pointer arithmetic
AUTOSARC++14 AUTOSARC++14:A5-0-4 Pointer arithmetic shall not be used with pointers to non-final classes.
  AUTOSARC++14:M5-0-15 Array indexing shall be the only form of pointer arithmetic.
  AUTOSARC++14:M5-0-16 A pointer operand and any pointer resulting from pointer arithmetic using that operand shall both address elements of the same array.
MisraC++2008 MisraC++2008:5-0-15 Array indexing shall be the only form of pointer arithmetic.
  MisraC++2008:5-0-16 A pointer operand and any pointer resulting from pointer arithmetic using that operand shall both address elements of the same array.
MisraC++2023 MisraC++2023:8.7.1 Pointer arithmetic shall not form an invalid pointer
CWE CWE:823 Use of Out-of-range Pointer Offset
CERT-C CERT-C:ARR30-C Do not form or use out-of-bounds pointers or array subscripts
  CERT-C:ARR37-C Do not add or subtract an integer to a pointer to a non-array object
  CERT-C:ARR39-C Do not add or subtract a scaled integer to a pointer
  CERT-C:EXP08-C Ensure pointer arithmetic is used correctly
  CERT-C:MEM35-C Allocate sufficient memory for an object
CERT-CPP CERT-CPP:CTR50-CPP Guarantee that container indices and iterators are within the valid range
  CERT-CPP:CTR56-CPP Do not use pointer arithmetic on polymorphic objects
JSF++ JSF++:211 Algorithms shall not assume that shorts, ints, longs, floats, doubles or long doubles begin at particular addresses.
  JSF++:215 Pointer arithmetic will not be used.
OWASP-2017 OWASP-2017:A8 Insecure deserialization
OWASP-2021 OWASP-2021:A8 Software and data integrity failures
Availability Available for C and C++.
Enabling Checks for this warning class are disabled by default, and require the unnormalized C ASTs for the project. To enable them, add the following WARNING_FILTER rule and RETAIN_UNNORMALIZED_C_AST specification to the project configuration file. 
RETAIN_UNNORMALIZED_C_AST = Yes
WARNING_FILTER += allow class="Pointer Arithmetic"
Note that retaining the unnormalized ASTs will increase the disk space used to store the project representation, and may make the analysis take longer.

Example 

void * use_pointers(int *ptra, int *ptrb, int *ptrc);
void * use_ints(int x, int y);

void lang_struct_parith(int *p, int i)
{
    int *p1, *p2, *p3;
    int a, b;
        
    p1 = p + i;    /* 'Pointer Arithmetic' warning issued here */
    p2 = i + p;    /* 'Pointer Arithmetic' warning issued here */
    p2 += i;       /* 'Pointer Arithmetic' warning issued here */
    p2++;                      /* operator is not -, +, +=, or -= */
    p3 = *(p - 5); /* 'Pointer Arithmetic' warning issued here */
    p3 -= 4;       /* 'Pointer Arithmetic' warning issued here */
    a = *p - 5;                /* '-' operands are not pointers */                 
    b = p1 - p;                /* exception case: subtraction between two pointers */
    b += 5;                    /* '+=' operands are not pointers */

    use_ints(a,b);
    use_pointers(p1, p2, p3);
}

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.