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IAR Embedded Workbench for RISC-V 3.40

SEC-BUFFER-strncpy-overrun

In this section:
Synopsis

A call to the strncpy function will overrun the target buffer.

Enabled by default

Yes

Severity/Certainty

High/High

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Full description

A call to the strncpy function will overrun the target buffer. If the supplied buffer length exceeds the actual length of the destination buffer, strncpy might write past the bounds of the destination buffer. Make sure the length passed to strncpy is correct. You might need to perform a comparison before calling strncpy.

Coding standards
CERT STR31-C

Guarantee that storage for strings has sufficient space for character data and the null terminator

CWE 119

Improper Restriction of Operations within the Bounds of a Memory Buffer

CWE 120

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CWE 121

Stack-based Buffer Overflow

CWE 122

Heap-based Buffer Overflow

CWE 124

Buffer Underwrite ('Buffer Underflow')

CWE 126

Buffer Over-read

CWE 127

Buffer Under-read

CWE 805

Buffer Access with Incorrect Length Value

Code examples

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

#include <string.h>
#include <stdlib.h>

void example(void)
{
  char *str1 = "Hello World!\n";
  char *str2 = (char *)malloc(13);
  strncpy(str2,str1,14);
}

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

#include <string.h>
#include <stdlib.h>

void example(void)
{
  char *str1 = "Hello World!\n";
  char *str2 = (char *)malloc(14);
  strncpy(str2, str1, 14);
}