Trouble Writing Firefox Add on (Registering Observers, Javascript) - http

Question

I am writing an add-on for firefox but I seem to have a few issues with the channel. I am trying to write a program that receives a websites certificate information and saves it in a specific format. It does not pick up the information I need.
Heres my code:(Sorry for putting a lot there, but its all essential.)
const {Cc,Ci,Cu} = require("chrome");
let console = (Cu.import("resource://gre/modules/devtools/Console.jsm", {})).console;
console.log("Importing console.\n");
// Cu.import("resource://gre/modules/XPCOMUtils.jsm");
this._loadHandler = function(e) {myExtension.onPageLoad(e); };
var utils = require('sdk/window/utils');
var gBrowser = utils.getMostRecentBrowserWindow().getBrowser();
gBrowser.addEventListener("load", this._loadHandler, true);
// We register an observer on page load, through page load event listener. Is this round-about?
// Can we register it directly?
var myExtension = {
onPageLoad: function(aEvent) {
var doc = aEvent.originalTarget; // doc is document that triggered "onload" event
var i = 0;
console.log("Page has been loaded.\n");
this.registerObserver("http-on-examine-response");
this.initialized = true;
},
onPageUnload: function(aEvent) {
console.log("Page has been unloaded.\n");
this.unregisterObserver("http-on-examine-response");
},
registerObserver: function(topic) {
var observerService = Cc["#mozilla.org/observer-service;1"]
.getService(Ci.nsIObserverService);
observerService.addObserver(this, topic, false);
console.log("Observer Registered.\n");
},
unregisterObserver: function(topic) {
var observerService = Cc["#mozilla.org/observer-service;1"]
.getService(Ci.nsIObserverService);
observerService.removeObserver(this, topic);
console.log("Observer Unregistered.\n");
},
//Observation Function
observe: function(channel, topic, data) {
console.log("Running Observe....\n");
this.examine_cert(channel);
},
examine_cert: function(channel) {
channel.QueryInterface(Ci.nsIHttpChannel);
//Assigns the channel of the http resource in the host port
var host = channel.URI.hostPort;
//Checks for security info
var si = channel.securityInfo;
if (!si){
console.log("No securityInfo for "+ host +" , returning\n");
return;
}
//Gets Certificates status
si.QueryInterface(Ci.nsISSLStatusProvider);
var st = si.SSLStatus;
if (!st){
console.log(st + "\n");
console.log("No SSLStatus for "+ host +" , returning\n");
return;
}
st.QueryInterface(Ci.nsISSLStatus);
var cert = st.serverCert;
if (!cert){
console.log("No serverCert for "+ host +" , returning\n");
return;
}
// by now we must have a non-empty cert, print it and the status
console.log( "status: " + st + "\n");
console.log( "cert : " + cert.commonName + "\n");
//certobj.ciphername = st.cipherName; // apparently, parsed out of cert when SSLStatus is made
//certobj.keyLength = st.keyLength;
//certobj.secretKeyLength = st.secretKeyLength;
},
// Recursively descend into the object, looking for displayName matching re;
// also, validate objects as we go.
findASN1Object: function (struc, re) {
if (!struc){
console.log("\nCertificate does not have a valid structure.\n");
return;
}
// Shortcut: object with displayName matching re found, return it immediately
if (re.test(struc.displayName)) return struc;
var s = Ci;
try {
s = struc.QueryInterface(Ci.nsIASN1Sequence);
}
catch (e) {
console.log("\nCertificate failed nsIASN1Sequence conversion\n");
}
if ( !s || ! s.isValidContainer) {
console.log("\nCertificate does not have a valid container.\n");
return;
}
// check all the objects recursively
for (var i=0; i<s.ASN1Objects.length; i++) {
struc = s.ASN1Objects.queryElementAt(i, Ci.nsIASN1Object);
var res = this.findASN1Object(struc, re);
if (res) return res;
}
},
//------ Object containment:
// nsIHttpChannel > securityInfo (nsISSLStatusProvider) > SSLStatus (nsISSLStatus) > serverCert (nsIX509Cert)
fillCertObj: function(obj, cert) {
obj.cert = cert;
console.log("\nCert:" + cert + "\n");
obj.notBefore = cert.validity.notBefore;
obj.notAfter = cert.validity.notAfter;
if (cert.issuer) {
obj.issuerMd5Fingerprint = cert.issuer.md5Fingerprint;
obj.issuerSha1Fingerprint = cert.issuer.sha1Fingerprint;
}
else {
//console.log("no issuer: "+ [cert.commonName, cert.issuer, cert.sha1Fingerprint]); \
console.log("\nThe Certificate doesn't have an Issuer.\n");
}
var keys = ["commonName", "organization", "organizationalUnit", "serialNumber","emailAddress",
"issuerCommonName", "issuerOrganization", "issuerOrganizationUnit","md5Fingerprint", "sha1Fingerprint" ];
for (var i in keys){
obj[keys[i]] = cert[keys[i]];
}
obj.subjectAltName = [];
var san = this.findASN1Object(cert.ASN1Structure, /^Certificate Subject Alt Name$/);
if (san) {
//this.log("SAN:", [san.displayName, san.displayValue]);
var m, re = /DNS Name: ((?:\*\.)?[a-z0-9.-]+)/g;
// *.smth1.smth2.smth3....smthn where smth has only a-z,0-9,or - or
// smth1.smth2.smth3....smthn where smth has only a-z,0-9,or -
// push domain names contained in displayValue onto the list subjectAltName
while (m = re.exec(san.displayValue))
obj.subjectAltName.push(m[1]);
}
console.log("Filled Certificate.\n");
},
init_cert: function(){
var certobj = this.newCertObj();
//certobj.host = host;
//certobj.ciphername = st.cipherName;
//certobj.keyLength = st.keyLength;
//certobj.secretKeyLength = st.secretKeyLength;
//this.fillCertObj(certobj.now, cert);
console.log(certobj);
},
newCertObj: function() {
console.log("Creating Empty Certificate.\n");
return {
flags: 0,
host: "",
warn: {},
now: {
commonName: "",
organization: "",
organizationalUnit: "",
serialNumber: "",
emailAddress: "",
notBefore: "",
notAfter: "",
issuerCommonName: "",
issuerOrganization: "",
issuerOrganizationUnit: "",
md5Fingerprint: "",
sha1Fingerprint: "",
issuerMd5Fingerprint: "",
issuerSha1Fingerprint: "",
cert: null,
},
old: {
commonName: "",
organization: "",
organizationalUnit: "",
serialNumber: "",
emailAddress: "",
notBefore: "",
notAfter: "",
issuerCommonName: "",
issuerOrganization: "",
issuerOrganizationUnit: "",
md5Fingerprint: "",
sha1Fingerprint: "",
issuerMd5Fingerprint: "",
issuerSha1Fingerprint: "",
cert: null,
},
};
},
}

Answer 1

It's not wise to register and unregister observer on page load because it will be catching http requests from everywhere. So register it on startup of addon and unregister it on shutdown/unload of addon.
And you should check the loadContext to see for what window/tab/frame/ajax/background is making the request. See here for more on loadContext: https://stackoverflow.com/a/25223307/1828637
But anyways this should work the way you have it meaning reg on page load and unreg on page unload:
const {
Cc, Ci, Cu
} = require("chrome");
let console = (Cu.import("resource://gre/modules/devtools/Console.jsm", {})).console;
console.log("Importing console.\n");
// Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");
this._loadHandler = function(e) {
myExtension.onPageLoad(e);
};
var utils = require('sdk/window/utils');
var gBrowser = utils.getMostRecentBrowserWindow().getBrowser();
gBrowser.addEventListener("load", this._loadHandler, true);
// We register an observer on page load, through page load event listener. Is this round-about?
// Can we register it directly?
var myExtension = {
observers: {
'http-on-examine-response': {
observe: function(aSubject, aTopic, aData) {
console.log("Running Observe....\n");
myExtension.examine_cert(aSubject);
},
reg: function() {
Services.obs.addObserver(myExtension.observers['http-on-examine-response'], 'http-on-examine-response', false);
},
unreg: function() {
Services.obs.removeObserver(myExtension.observers['http-on-examine-response'], 'http-on-examine-response');
}
}
},
onPageLoad: function(aEvent) {
var doc = aEvent.originalTarget; // doc is document that triggered "onload" event
var i = 0;
console.log("Page has been loaded.\n");
myExtension.observers['http-on-examine-response'].reg();
this.initialized = true;
},
onPageUnload: function(aEvent) {
console.log("Page has been unloaded.\n");
myExtension.observers['http-on-examine-response'].unreg();
},
examine_cert: function(channel) {
channel.QueryInterface(Ci.nsIHttpChannel);
//Assigns the channel of the http resource in the host port
var host = channel.URI.hostPort;
//Checks for security info
var si = channel.securityInfo;
if (!si) {
console.log("No securityInfo for " + host + " , returning\n");
return;
}
//Gets Certificates status
si.QueryInterface(Ci.nsISSLStatusProvider);
var st = si.SSLStatus;
if (!st) {
console.log(st + "\n");
console.log("No SSLStatus for " + host + " , returning\n");
return;
}
st.QueryInterface(Ci.nsISSLStatus);
var cert = st.serverCert;
if (!cert) {
console.log("No serverCert for " + host + " , returning\n");
return;
}
// by now we must have a non-empty cert, print it and the status
console.log("status: " + st + "\n");
console.log("cert : " + cert.commonName + "\n");
//certobj.ciphername = st.cipherName; // apparently, parsed out of cert when SSLStatus is made
//certobj.keyLength = st.keyLength;
//certobj.secretKeyLength = st.secretKeyLength;
},
// Recursively descend into the object, looking for displayName matching re;
// also, validate objects as we go.
findASN1Object: function(struc, re) {
if (!struc) {
console.log("\nCertificate does not have a valid structure.\n");
return;
}
// Shortcut: object with displayName matching re found, return it immediately
if (re.test(struc.displayName)) return struc;
var s = Ci;
try {
s = struc.QueryInterface(Ci.nsIASN1Sequence);
} catch (e) {
console.log("\nCertificate failed nsIASN1Sequence conversion\n");
}
if (!s || !s.isValidContainer) {
console.log("\nCertificate does not have a valid container.\n");
return;
}
// check all the objects recursively
for (var i = 0; i < s.ASN1Objects.length; i++) {
struc = s.ASN1Objects.queryElementAt(i, Ci.nsIASN1Object);
var res = this.findASN1Object(struc, re);
if (res) return res;
}
},
//------ Object containment:
// nsIHttpChannel > securityInfo (nsISSLStatusProvider) > SSLStatus (nsISSLStatus) > serverCert (nsIX509Cert)
fillCertObj: function(obj, cert) {
obj.cert = cert;
console.log("\nCert:" + cert + "\n");
obj.notBefore = cert.validity.notBefore;
obj.notAfter = cert.validity.notAfter;
if (cert.issuer) {
obj.issuerMd5Fingerprint = cert.issuer.md5Fingerprint;
obj.issuerSha1Fingerprint = cert.issuer.sha1Fingerprint;
} else {
//console.log("no issuer: "+ [cert.commonName, cert.issuer, cert.sha1Fingerprint]); \
console.log("\nThe Certificate doesn't have an Issuer.\n");
}
var keys = ["commonName", "organization", "organizationalUnit", "serialNumber", "emailAddress",
"issuerCommonName", "issuerOrganization", "issuerOrganizationUnit", "md5Fingerprint", "sha1Fingerprint"
];
for (var i in keys) {
obj[keys[i]] = cert[keys[i]];
}
obj.subjectAltName = [];
var san = this.findASN1Object(cert.ASN1Structure, /^Certificate Subject Alt Name$/);
if (san) {
//this.log("SAN:", [san.displayName, san.displayValue]);
var m, re = /DNS Name: ((?:\*\.)?[a-z0-9.-]+)/g;
// *.smth1.smth2.smth3....smthn where smth has only a-z,0-9,or - or
// smth1.smth2.smth3....smthn where smth has only a-z,0-9,or -
// push domain names contained in displayValue onto the list subjectAltName
while (m = re.exec(san.displayValue))
obj.subjectAltName.push(m[1]);
}
console.log("Filled Certificate.\n");
},
init_cert: function() {
var certobj = this.newCertObj();
//certobj.host = host;
//certobj.ciphername = st.cipherName;
//certobj.keyLength = st.keyLength;
//certobj.secretKeyLength = st.secretKeyLength;
//this.fillCertObj(certobj.now, cert);
console.log(certobj);
},
newCertObj: function() {
console.log("Creating Empty Certificate.\n");
return {
flags: 0,
host: "",
warn: {},
now: {
commonName: "",
organization: "",
organizationalUnit: "",
serialNumber: "",
emailAddress: "",
notBefore: "",
notAfter: "",
issuerCommonName: "",
issuerOrganization: "",
issuerOrganizationUnit: "",
md5Fingerprint: "",
sha1Fingerprint: "",
issuerMd5Fingerprint: "",
issuerSha1Fingerprint: "",
cert: null,
},
old: {
commonName: "",
organization: "",
organizationalUnit: "",
serialNumber: "",
emailAddress: "",
notBefore: "",
notAfter: "",
issuerCommonName: "",
issuerOrganization: "",
issuerOrganizationUnit: "",
md5Fingerprint: "",
sha1Fingerprint: "",
issuerMd5Fingerprint: "",
issuerSha1Fingerprint: "",
cert: null,
},
};
},
}
lastly why are you wrapping in the pseudo-class myExtension? When doing addon-sdk or bootstrap addons you don't have to do that anymore. It makes things easier so you don't have to track what scope you are in.