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DNS-SD, front-end debug
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@veniware
veniware committed Aug 13, 2024
1 parent 49716be commit 283baeb
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Showing 4 changed files with 131 additions and 68 deletions.
2 changes: 1 addition & 1 deletion Protest/Front/hexviewer.css
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Original file line number Diff line number Diff line change
Expand Up @@ -51,9 +51,9 @@
height: 20px;
font-size: large;
font-family: monospace;
line-height: 16px;
text-align: center;
border-radius: 2px;
margin: 1px 0px;
}

.hexviewer-hexbox > div > div:nth-child(16n + 8),
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147 changes: 97 additions & 50 deletions Protest/Front/hexviewer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@ class HexViewer extends Window {
16: "TXT",
28: "AAAA",
33: "SRV",
47: "NSEC",
255: "ANY",
};

Expand Down Expand Up @@ -375,7 +376,7 @@ class HexViewer extends Window {
}
}

PopulateLabel(label, indentation, hexContainer, charContainer, offset, length) {
PopulateLabel(label, indentation, hexContainer, charContainer, offset, length, isDnsPointers=false) {
const element = document.createElement("div");
element.style.paddingLeft = `${8 + indentation * 20}px`;
this.list.appendChild(element);
Expand Down Expand Up @@ -438,7 +439,7 @@ class HexViewer extends Window {
this.lastIndentationValue = indentation;
this.lastIndentationElement = element;

element.onclick = event=> {
element.onclick = ()=> {
const hexElements = hexContainer.childNodes;
const charElements = charContainer.childNodes;
const listElements = this.list.childNodes;
Expand Down Expand Up @@ -471,13 +472,25 @@ class HexViewer extends Window {
charElements[i].scrollIntoView({ block:"center", inline:"center" });
}

if (isDnsPointers) {
if (length === 2) {
const byteA = parseInt("0x"+hexElements[offset].textContent, 16);
const byteB = parseInt("0x"+hexElements[offset+1].textContent, 16);
if ((byteA & 0xC0) === 0xC0) {
let pointer = ((byteA & 0x3F) << 8) | byteB;
hexElements[pointer].style.color = "#000";
hexElements[pointer].style.backgroundColor = "var(--clr-warning)";
}
}
}

element.style.color = "#000";
element.style.backgroundColor = "var(--clr-select)";
};

return element;
}

PopulateDnsLabels(hexContainer, charContainer, stream) {
const transactionId = stream[0].toString(16).padStart(2,"0") + stream[1].toString(16).padStart(2,"0");
this.PopulateLabel(`Transaction ID: 0x${transactionId}`, 0, hexContainer, charContainer, 0, 2);
Expand Down Expand Up @@ -519,97 +532,104 @@ class HexViewer extends Window {
const adCount = stream[10] << 8 | stream[11];
this.PopulateLabel(`Additional RRs: ${adCount}`, 0, hexContainer, charContainer, 10, 2);

let offset = 12;
let index = 12;
let count = 0;

while (offset < stream.length && count < qCount) { //questions
const start = offset;
while (index < stream.length && count < qCount) { //questions
const start = index;

let end = start;
if (stream[offset] === 0xC0) { //pointer

if ((stream[index] & 0xC0) === 0xC0) { //pointer
end += 2;
}
else {
while (end < stream.length && stream[end] !== 0 && stream[end] !== 0xC0) {
while (end < stream.length && stream[end] !== 0 && (stream[end] & 0xC0) !== 0xC0) {
end++;
}

if (stream[end] === 0) { //null termination
end++;
}
else if (stream[end] === 0xC0) { //pointer
else if ((stream[end] & 0xC0) === 0xC0) { //pointer
end += 2;
}
}

const first = this.PopulateLabel("Name", 1, hexContainer, charContainer, start, end - start - 1);
offset = end;
const first = this.PopulateLabel("Name", 1, hexContainer, charContainer, start, end - start - 1, true);
index = end;

let type = (stream[index] << 8) | stream[index+1];
this.PopulateLabel(`Type: ${type} ${HexViewer.DNS_RECORD_TYPES[type] ? `(${HexViewer.DNS_RECORD_TYPES[type]})` : ""}`, 1, hexContainer, charContainer, index, 2);
index += 2;

let type = (stream[offset] << 8) | stream[offset+1];
this.PopulateLabel(`Type: ${type} ${HexViewer.DNS_RECORD_TYPES[type] ? `(${HexViewer.DNS_RECORD_TYPES[type]})` : ""}`, 1, hexContainer, charContainer, offset, 2);
offset += 2;
const cacheFlashFlag = stream[index] & 0x80;
if (cacheFlashFlag > 0) {
this.PopulateLabel(`Cache-flush: true`, 1, hexContainer, charContainer, index, 2);
}

let class_ = (stream[offset] << 8) | stream[offset+1];
this.PopulateLabel(`Class: ${class_} ${HexViewer.DNS_CLASSES[class_] ? `(${HexViewer.DNS_CLASSES[class_]})` : ""}`, 1, hexContainer, charContainer, offset, 2);
let class_ = stream[index+1];
this.PopulateLabel(`Class: ${class_} ${HexViewer.DNS_CLASSES[class_] ? `(${HexViewer.DNS_CLASSES[class_]})` : ""}`, 1, hexContainer, charContainer, index, 2);

offset += 2;
index += 2;

const element = this.PopulateLabel("Question:", 0, hexContainer, charContainer, start, offset - start);
const element = this.PopulateLabel("Question:", 0, hexContainer, charContainer, start, index - start, true);
this.list.insertBefore(element, first);

count++;
}

const totalRecords = qCount + anCount + auCount + adCount;
while (offset < stream.length && count < totalRecords) { //records
let start = offset;
let end = offset;
while (index < stream.length && count < totalRecords) { //records
let start = index;
let end = index;

if (stream[offset] === 0xC0) { //pointer
console.log(this.hexBox.childNodes[offset]);
if ((stream[index] & 0xC0) === 0xC0) { //pointer
end += 2;
}
else {
while (end < stream.length && stream[end] !== 0 && stream[end] !== 0xC0) {
while (end < stream.length && stream[end] !== 0 && (stream[end] & 0xC0) !== 0xC0) {
end++;
}

if (stream[end] === 0) { //null termination
end++;
}
else if (stream[end] === 0xC0) { //pointer
else if ((stream[end] & 0xC0) === 0xC0) { //pointer
end += 2;
}
}

console.log(offset.toString(16).padStart(2, "0"), end.toString(16).padStart(2, "0"));
const first = this.PopulateLabel("Name", 1, hexContainer, charContainer, start, end - start, true);
index = end;

const first = this.PopulateLabel("Name", 1, hexContainer, charContainer, start, end - start);
const type = (stream[index] << 8) | stream[index+1];
this.PopulateLabel(`Type: ${type} ${HexViewer.DNS_RECORD_TYPES[type] ? `(${HexViewer.DNS_RECORD_TYPES[type]})` : ""}`, 1, hexContainer, charContainer, index, 2);
index += 2;

offset = end;

let type = (stream[offset] << 8) | stream[offset+1];
this.PopulateLabel(`Type: ${type} ${HexViewer.DNS_RECORD_TYPES[type] ? `(${HexViewer.DNS_RECORD_TYPES[type]})` : ""}`, 1, hexContainer, charContainer, offset, 2);
offset += 2;
const cacheFlashFlag = stream[index] & 0x80;
if (cacheFlashFlag > 0) {
this.PopulateLabel(`Cache-flush: true`, 1, hexContainer, charContainer, index, 2);
}

let class_ = (stream[offset] << 8) | stream[offset+1];
this.PopulateLabel(`Class: ${class_} ${HexViewer.DNS_CLASSES[class_] ? `(${HexViewer.DNS_CLASSES[class_]})` : ""}`, 1, hexContainer, charContainer, offset, 2);
offset += 2;
const class_ = stream[index+1];
this.PopulateLabel(`Class: ${class_} ${HexViewer.DNS_CLASSES[class_] ? `(${HexViewer.DNS_CLASSES[class_]})` : ""}`, 1, hexContainer, charContainer, index, 2);
index += 2;

let ttl = (stream[offset] << 24) | (stream[offset+1] << 16) | (stream[offset+2] << 8) | stream[offset+3];
this.PopulateLabel(`TTL: ${ttl}`, 1, hexContainer, charContainer, offset, 4);
offset += 4;
const ttl = (stream[index] << 24) | (stream[index+1] << 16) | (stream[index+2] << 8) | stream[index+3];
this.PopulateLabel(`TTL: ${ttl}`, 1, hexContainer, charContainer, index, 4);
index += 4;

let len = (stream[offset] << 8) | stream[offset+1];
this.PopulateLabel(`Length: ${len}`, 1, hexContainer, charContainer, offset, 2);
offset += 2;
const len = (stream[index] << 8) | stream[index+1];
this.PopulateLabel(`Length: ${len}`, 1, hexContainer, charContainer, index, 2);
index += 2;

let data;
switch (type) {
case 1: //A
if (len === 4) {
data = `${stream[offset]}.${stream[offset+1]}.${stream[offset+2]}.${stream[offset+3]}`;
this.PopulateLabel(data, 1, hexContainer, charContainer, offset, len);
data = `${stream[index]}.${stream[index+1]}.${stream[index+2]}.${stream[index+3]}`;
this.PopulateLabel(data, 1, hexContainer, charContainer, index, len);
}
break;

Expand All @@ -618,22 +638,49 @@ class HexViewer extends Window {
data = "";
for (let j = 0; j < 16; j+=2) {
if (j > 0) data += ":";
data += stream[offset + j].toString(16).padStart(2, "0");
data += stream[offset + j + 1].toString(16).padStart(2, "0");
data += stream[index + j].toString(16).padStart(2, "0");
data += stream[index + j + 1].toString(16).padStart(2, "0");
}
this.PopulateLabel(data, 1, hexContainer, charContainer, offset, len);
this.PopulateLabel(data, 1, hexContainer, charContainer, index, len);
}
break;

case 33: //SRV
const priority = (stream[index] << 8) | stream[index + 1];
const weight = (stream[index + 2] << 8) | stream[index + 3];
const port = (stream[index + 4] << 8) | stream[index + 5];

let targetOffset = index + 6;
if ((stream[targetOffset] & 0xC0) === 0xC0) { //pointer
targetOffset += 2;
}
else {
while (targetOffset < stream.length && stream[targetOffset] !== 0 && (stream[targetOffset] & 0xC0) !== 0xC0) {
targetOffset++;
}

if (stream[targetOffset] === 0) { //null termination
targetOffset++;
}
else if ((stream[targetOffset] & 0xC0) === 0xC0) { //pointer
targetOffset += 2;
}
}

this.PopulateLabel(`Priority: ${priority}`, 1, hexContainer, charContainer, index, 2);
this.PopulateLabel(`Weight: ${weight}`, 1, hexContainer, charContainer, index + 2, 2);
this.PopulateLabel(`Port: ${port}`, 1, hexContainer, charContainer, index + 4, 2);
this.PopulateLabel("Target", 1, hexContainer, charContainer, index + 6, targetOffset - (index + 6), true);
break;

default:
this.PopulateLabel("Answer", 1, hexContainer, charContainer, offset, len);
this.PopulateLabel("Answer", 1, hexContainer, charContainer, index, len);
break;
}

//console.log("offset = " + offset + " + " + len);
offset += len;
index += len;

end = offset;
end = index;

let element;
if (count < qCount + anCount) {
Expand Down
1 change: 1 addition & 0 deletions Protest/Protocols/Dns.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@ public enum RecordType : byte {
TXT = 16,
AAAA = 28,
SRV = 33,
NSEC = 47,
ANY = 255
}

Expand Down
49 changes: 32 additions & 17 deletions Protest/Protocols/Mdns.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
using Microsoft.AspNetCore.Identity.UI.Services;
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
using System;
using System.Collections.Generic;
using System.IO;
Expand Down Expand Up @@ -248,17 +249,16 @@ private static Answer[] DeconstructResponse(byte[] response, RecordType queryTyp
}

List<Answer> result = new List<Answer>();

int totalRecords = answerCount + authorityCount + additionalCount;
for (int i = 0; i < totalRecords; i++) {

Console.WriteLine($"Starting at: {index.ToString("x2")}");
for (int i = 0; i < totalRecords; i++) {

if (index + 4 >= response.Length) { break; }
if (index + 10 >= response.Length) { break; }

int nameStartIndex;
if ((response[index] & 0xFF) == 0xC0) { //pointer
nameStartIndex = response[index + 1];
if ((response[index] & 0xC0) == 0xC0) { //pointer
if (index + 1 >= response.Length) { break; }
nameStartIndex = ((response[index] & 0x3F) << 8) | response[index + 1];
index += 2;
}
else {
Expand All @@ -278,13 +278,9 @@ private static Answer[] DeconstructResponse(byte[] response, RecordType queryTyp
}
}

Answer ans = new Answer();
ans.remote = remoteEndPoint;

if (index + 10 > response.Length) {
ans.error = 254;
break;
}
Answer ans = new Answer() {
remote = remoteEndPoint
};

ans.questionString = ExtractName(response, nameStartIndex);

Expand All @@ -293,6 +289,10 @@ private static Answer[] DeconstructResponse(byte[] response, RecordType queryTyp

index += 2; //skip class

if (index + 4 > response.Length) {
ans.error = 254;
break;
}
ans.ttl = (response[index] << 24) | (response[index + 1] << 16) | (response[index + 2] << 8) | response[index + 3];
index += 4;

Expand Down Expand Up @@ -336,9 +336,19 @@ private static Answer[] DeconstructResponse(byte[] response, RecordType queryTyp
index += ans.length;
break;

case RecordType.SRV:
if (index + 6 <= response.Length) {
//ans.priority = (ushort)((response[index] << 8) | response[index + 1]);
//ans.weight = (ushort)((response[index+2] << 8) | response[index + 3]);
//ans.port = (ushort)((response[index+4] << 8) | response[index + 5]);
//index += 6;
ans.answerString = ExtractName(response, index);
}
index += ans.length;
break;

default:
ans.answerString = String.Empty; //BitConverter.ToString(response, index, ans.length);
index += ans.length;
break;
}

Expand All @@ -359,15 +369,15 @@ private static string ExtractName(byte[] response, int startIndex) {
StringBuilder name = new StringBuilder();
int index = startIndex;

while (response[index] != 0) {
if ((response[index] & 0xFF) == 0xC0) { //compressed name
while (index < response.Length && response[index] != 0) {
if ((response[index] & 0xC0) == 0xC0) { //is pointer
int pointer = ((response[index] & 0x3F) << 8) | response[index + 1];
name.Append(ExtractName(response, pointer));
break;
}
else {
int length = response[index++];
for (int i = 0; i < length; i++) {
for (int i = 0; i < length && index < response.Length; i++) {
name.Append((char)response[index++]);
}
name.Append('.');
Expand Down Expand Up @@ -476,6 +486,11 @@ private static byte[] Serialize(byte[] query, List<byte[]> data, List<Answer> an
builder.Append($"\"name\":\"{answers[i].answerString}\",");
break;

case RecordType.NSEC:
builder.Append("\"type\":\"NSEC\",");
builder.Append($"\"name\":\"{answers[i].answerString}\",");
break;

case RecordType.SRV:
builder.Append("\"type\":\"SRV\",");
builder.Append($"\"name\":\"{answers[i].answerString}\",");
Expand Down

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