os: fix netmask format check condition in getCIDR function

Modified to check the format of the netmask instead
of just checking that each part of the netmask is even
PR-URL: #57324
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: HBSPS

lib/internal/util.js

@@ -8,6 +8,7 @@ const {
  Error,
  ErrorCaptureStackTrace,
  FunctionPrototypeCall,
+ NumberParseInt,
  ObjectDefineProperties,
  ObjectDefineProperty,
  ObjectFreeze,
@@ -33,7 +34,9 @@ const {
  SafeSet,
  SafeWeakMap,
  SafeWeakRef,
+ StringPrototypeIncludes,
  StringPrototypeReplace,
+ StringPrototypeSlice,
  StringPrototypeToLowerCase,
  StringPrototypeToUpperCase,
  Symbol,
@@ -806,6 +809,59 @@ function setupCoverageHooks(dir) {
 returncoverageDirectory;
 }
 
+// Returns the number of ones in the binary representation of the decimal
+// number.
+functioncountBinaryOnes(n){
+// Count the number of bits set in parallel, which is faster than looping
+n=n-((n>>>1)&0x55555555);
+n=(n&0x33333333)+((n>>>2)&0x33333333);
+return((n+(n>>>4)&0xF0F0F0F)*0x1010101)>>>24;
+}
+
+functiongetCIDR(address,netmask,family){
+letones=0;
+letsplit='.';
+letrange=10;
+letgroupLength=8;
+lethasZeros=false;
+letlastPos=0;
+
+if(family==='IPv6'){
+split=':';
+range=16;
+groupLength=16;
+}
+
+for(leti=0;i<netmask.length;i++){
+if(netmask[i]!==split){
+if(i+1<netmask.length){
+continue;
+}
+i++;
+}
+constpart=StringPrototypeSlice(netmask,lastPos,i);
+lastPos=i+1;
+if(part!==''){
+if(hasZeros){
+if(part!=='0'){
+returnnull;
+}
+}else{
+constbinary=NumberParseInt(part,range);
+constbinaryOnes=countBinaryOnes(binary);
+ones+=binaryOnes;
+if(binaryOnes!==groupLength){
+if(StringPrototypeIncludes(binary.toString(2),'01')){
+returnnull;
+}
+hasZeros=true;
+}
+}
+}
+}
+
+return`${address}/${ones}`;
+}
 
 consthandleTypes=['TCP','TTY','UDP','FILE','PIPE','UNKNOWN'];
 functionguessHandleType(fd){
@@ -872,6 +928,7 @@ module.exports = {
  filterDuplicateStrings,
  filterOwnProperties,
  getConstructorOf,
+ getCIDR,
  getCWDURL,
  getInternalGlobal,
  getStructuredStack,

lib/os.js

@@ -24,7 +24,6 @@
 const{
  ArrayPrototypePush,
  Float64Array,
- NumberParseInt,
  ObjectDefineProperties,
  StringPrototypeSlice,
  SymbolToPrimitive,
@@ -40,6 +39,7 @@ const {
 },
  hideStackFrames,
 }=require('internal/errors');
+const{ getCIDR }=require('internal/util');
 const{ validateInt32 }=require('internal/validators');
 
 const{
@@ -202,60 +202,6 @@ function endianness() {
 }
 endianness[SymbolToPrimitive]=()=>kEndianness;
 
-// Returns the number of ones in the binary representation of the decimal
-// number.
-functioncountBinaryOnes(n){
-// Count the number of bits set in parallel, which is faster than looping
-n=n-((n>>>1)&0x55555555);
-n=(n&0x33333333)+((n>>>2)&0x33333333);
-return((n+(n>>>4)&0xF0F0F0F)*0x1010101)>>>24;
-}
-
-functiongetCIDR(address,netmask,family){
-letones=0;
-letsplit='.';
-letrange=10;
-letgroupLength=8;
-lethasZeros=false;
-letlastPos=0;
-
-if(family==='IPv6'){
-split=':';
-range=16;
-groupLength=16;
-}
-
-for(leti=0;i<netmask.length;i++){
-if(netmask[i]!==split){
-if(i+1<netmask.length){
-continue;
-}
-i++;
-}
-constpart=StringPrototypeSlice(netmask,lastPos,i);
-lastPos=i+1;
-if(part!==''){
-if(hasZeros){
-if(part!=='0'){
-returnnull;
-}
-}else{
-constbinary=NumberParseInt(part,range);
-constbinaryOnes=countBinaryOnes(binary);
-ones+=binaryOnes;
-if(binaryOnes!==groupLength){
-if((binary&1)!==0){
-returnnull;
-}
-hasZeros=true;
-}
-}
-}
-}
-
-return`${address}/${ones}`;
-}
-
 /**
  * @returns {Record<string, Array<{
  * address: string,

test/parallel/test-internal-util-getCIDR.js

@@ -0,0 +1,23 @@
+// Flags: --expose-internals
+'use strict';
+require('../common');
+
+// These are tests that verify that the subnetmask is used
+// to create the correct CIDR address.
+// Tests that it returns null if the subnetmask is not in the correct format.
+// (ref: https://www.rfc-editor.org/rfc/rfc1878)
+
+constassert=require('node:assert');
+const{ getCIDR }=require('internal/util');
+
+assert.strictEqual(getCIDR('127.0.0.1','255.0.0.0','IPv4'),'127.0.0.1/8');
+assert.strictEqual(getCIDR('127.0.0.1','255.255.0.0','IPv4'),'127.0.0.1/16');
+
+// 242 = 11110010(2)
+assert.strictEqual(getCIDR('127.0.0.1','242.0.0.0','IPv4'),null);
+
+assert.strictEqual(getCIDR('::1','ffff:ffff:ffff:ffff::','IPv6'),'::1/64');
+assert.strictEqual(getCIDR('::1','ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff','IPv6'),'::1/128');
+
+// ff00:ffff = 11111111 00000000 : 11111111 11111111(2)
+assert.strictEqual(getCIDR('::1','ffff:ff00:ffff::','IPv6'),null);