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IAR Embedded Workbench for RH850 3.20.x

SEC-BUFFER-use-after-free-some

In this section:
Synopsis

A pointer is used after it has been freed, on some execution paths.

Enabled by default

Yes

Severity/Certainty

High/Low

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Full description

A pointer is used after it has been freed, on some execution paths. This might cause data corruption or an application crash. A pointer should be assigned to a different and valid memory location (either by aliasing another pointer, or by performing another allocation) before being used. This check is identical to MEM-use-free-some, MISRAC2012-Dir-4.13_e, MISRAC2012-Rule-1.3_p, CERT-MEM30-C_b.

Coding standards
CERT MEM30-C

Do not access freed memory

CWE 416

Use After Free

MISRA C:2012 Dir-4.13

(Advisory) Functions which are designed to provide operations on a resource should be called in an appropriate sequence

MISRA C:2012 Rule-1.3

(Required) There shall be no occurrence of undefined or critical unspecified behaviour

Code examples

The following code example fails the check and will give a warning:

#include <stdlib.h>

void example(void) {
  int *x;
  x = (int *)malloc(sizeof(int));
  free(x);
  if (rand()) {
    x = (int *)malloc(sizeof(int));
  }
  else {
    /* x not reallocated along this path */
  }
  (*x)++;
}

The following code example passes the check and will not give a warning about this issue:

#include <stdlib.h>

void example(void) {
  int *x;
  x = (int *)malloc(sizeof(int));
  free(x);
  x = (int *)malloc(sizeof(int));
  *x++;
}