IO.NEGFD : Negative file descriptor

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CodeSonar^® 9.2p0

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CodeSecure Inc

IO.NEGFD : Negative file descriptor

Summary

Properties

MisraC2025

MisraC2025:D.4.1

Run-time failures shall be minimized

MisraC2023

MisraC2023:D.4.1

Run-time failures shall be minimized

Misra2012

Misra2012:D.4.1

Run-time failures shall be minimized

MisraC++2023

MisraC++2023:0.3.2

A function call shall not violate the function's preconditions

CWE

CWE:687

Function Call With Incorrectly Specified Argument Value

Insecure design

Insecure Design

CWE:252	Unchecked Return Value

Example

#include <fcntl.h>
#include <unistd.h>

int negfd_nocheck(void){
  return close(open("myfile.txt",O_RDONLY)); /* 'Negative file descriptor' warning issued here
                                              *  - open() returns -1 on error
                                              */
}

int negfd_check(void){
  int rv;
  rv = open("myfile.txt",O_RDONLY);
  if (rv < 0){
    return -1;
  }
  return close(rv);
}

Triggering Functions

CodeSonar ships with library models that allow it to recognize a large number of functions that take a file descriptor or socket descriptor argument. Some examples are shown in the table below. If one of these functions is called with a negative value in the file/socket descriptor parameter position, a warning will be issued.

If you have created a custom library model for some function f() in terms of one of these existing models, calls to f() will also be capable of triggering Negative file descriptor warnings.

	Functions that can trigger warnings include...
libc	dup(), fdopen(), sendmsg(),
Win32	_dup(), _fstat64(), _write()

Functions that can trigger warnings include...

libc

dup(), fdopen(), sendmsg(),

Win32

_dup(), _fstat64(), _write()

Relevant Configuration File Parameters

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