buffer: fix value check for writeUInt{B,L}E

Fixes: #3497
PR-URL: #3500
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

Author: trevnorris

lib/buffer.js

@@ -836,8 +836,10 @@ Buffer.prototype.writeUIntLE = function(value, offset, byteLength, noAssert) {
 value=+value;
 offset=offset>>>0;
 byteLength=byteLength>>>0;
-if(!noAssert)
-checkInt(this,value,offset,byteLength,Math.pow(2,8*byteLength),0);
+if(!noAssert){
+constmaxBytes=Math.pow(2,8*byteLength)-1;
+checkInt(this,value,offset,byteLength,maxBytes,0);
+}
 
 varmul=1;
 vari=0;
@@ -853,8 +855,10 @@ Buffer.prototype.writeUIntBE = function(value, offset, byteLength, noAssert) {
 value=+value;
 offset=offset>>>0;
 byteLength=byteLength>>>0;
-if(!noAssert)
-checkInt(this,value,offset,byteLength,Math.pow(2,8*byteLength),0);
+if(!noAssert){
+constmaxBytes=Math.pow(2,8*byteLength)-1;
+checkInt(this,value,offset,byteLength,maxBytes,0);
+}
 
 vari=byteLength-1;
 varmul=1;

test/parallel/test-writeuint.js

@@ -122,6 +122,25 @@ function test32(clazz) {
 }
 
 
+functiontestUint(clazz){
+constdata=newclazz(8);
+varval=1;
+
+// Test 0 to 5 bytes.
+for(vari=0;i<=5;i++){
+consterrmsg=`byteLength: ${i}`;
+ASSERT.throws(function(){
+data.writeUIntBE(val,0,i);
+},/valueisoutofbounds/,errmsg);
+ASSERT.throws(function(){
+data.writeUIntLE(val,0,i);
+},/valueisoutofbounds/,errmsg);
+val*=0x100;
+}
+}
+
+
 test8(Buffer);
 test16(Buffer);
 test32(Buffer);
+testUint(Buffer);