Browser Same Origin Policy - javascript

We have application hosted "xyz:8080/rootapp" and cometd services hosted on "xyz:9090/cometed". The JavaScript loaded from cometd server needs to access the DOM/JavaScripts loaded from (xyz:8080), the browser's same origin policy is not allowing it.
To overcome it we set 'document.domain' as "xyz" eliminating port. This solution is working well but this is becoming problem to all the iframes loaded by "xyz:8080" and I need to change each and every iframe to use domain as "xyz".
Can someone provide me hints to solve this problem without changing each and every iframe?
Do we have any http header to set domain?

You can use CORS to specify an exception to same origin, this will work in any relatively modern browser.
This page has a fairly good intro and a list of compatible browsers.
The short version is put an Access-Control-Allow-Origin header into the responses from xyz:8080 that contains either xyz:9090 or * (for unrestricted access).

Related

How to Load an external web page inside my one and hide some content (avoiding cross site problems)

I need to incorporate in my web application some content from an external dynamic web page on which I have no control.
Then I need to filter some of the content of this page or to hide it for presenting only the relevant part that is interesting for my use.
I need also that the scripts on the external page are still working on the source site of the loaded content without cross-site protection.
Is all that possible? How can I do it? Any code example, please?
I suppose that this can be made with JS on client side .
I work on back side and these themes are quite extraneous to me, please don't blame me.
No, it is not possible.
Browser same-origin policy is designed to prevent malicious websites from doing evil.
Same-origin Policy restricts JavaScript network access to prevent evil.
Same-origin Policy also restricts script API Access to prevent evil.
From the Docs:
JavaScript APIs like iframe.contentWindow, window.parent, window.open, and window.opener allow documents to directly reference each other. When two documents do not have the same origin, these references provide very limited access to Window and Location objects.
To communicate between documents from different origins, use window.postMessage.
— MDN Web Security Reference - Cross-origin script API access
One can not use <iframe> elements as a way to "avoid cross site problems". The Same Origin Policy was created to protect users from evil web pages.

http to https - Make browser request corresponding https URLs for http URLs, without needing to edit all pages and manually change all URLs to https?

I am interested in switching my entire site from http over to https.
My concern is that I have some content that uses absolute http URLs.
I will need to edit each page in order to change those URLs to relative but that might take me a while to accomplish.
What I would like to know is if there is a way to use Javascript via the Google Tag Manager in order to re-write local absolute URLs to be HTTPS and not HTTP?
If this is possible, could it be used as a permanent solution?
One solution to consider is the Content Security Policy upgrade-insecure-requests directive.
The upgrade-insecure-requests directive instructs user agents to
treat all of a site's unsecure URL's (those served over HTTP) as
though they have been replaced with secure URL's (those served over
HTTPS). This directive is intended for web sites with large numbers of
unsecure legacy URL's that need to be rewritten.
It’d amount to configuring your Web server so all pages on your site get served with this header:
Content-Security-Policy: upgrade-insecure-requests
So the effect of adding that header would be: for any page at your site served with an https URL, any time a browser sees in one of those pages an http URL for an embedded (sub)resource —whether it be a URL for a stylesheet, script, image, video, or whatever—the browser will automatically (transparently) try to fetch the resource from the corresponding https URL instead.
For more details, you can see the Upgrade Insecure Requests spec.
2018-05-11 update
The upgrade-insecure-requests directive is now supported in all major browser engines (including Edge 17+ and Safari 10.3+):
https://caniuse.com/#feat=upgradeinsecurerequests
The downside of using it now is, so far it’s only supported in Firefox (since Firefox 42) and Chrome. But it also:
has an open Safari/WebKit implementation-tracking/feature bug
is under consideration by Microsoft for implementation in Edge
P.S., I work at the W3C, where we recently (finally) enabled TLS/https access to all W3C site resources—and since the W3C has hundreds of thousands (maybe millions) of pages with http URLs for embedded subresources, the way we were able to make it happen was in part by serving the Content-Security-Policy: upgrade-insecure-requests header across the entire site.
The article Supporting HTTPS and HSTS on w3.org gives more info about the deployment details.
By the time the JavaScript is executed, the problematic resources may already be loading over even loaded.
You can simply search through your code for any instances of http:// and replace those with // or relative URLs.
If your content is more complex (say, distributed over multiple machines), you can use a mirroring script (like wget --mirror http://example.net/) to download a static version of your entire page, and search that.
Then, set up HTTPS (first for you only, then for all your testers) and check that everything works fine. Once you are sure that is the case, allow everyone to come over HTTPS. Finally, a bit later, consider redirecting HTTP to HTTPS and implementing secure cookies, HSTS and HPKP.

Xpath of element on another website/cross domain

I want to get the XPATH of an element on a website (my own domain), which I got it using JavaScript code as mentioned in this answer.
Now what I want to click on button which will open a url (cross domain) window and when user click on an element on that window it's XPATH is captured.
I tried doing the same using iframe with no luck.
Now my question is there a way to get the XPATH of an element of another website/ Cross domain?
Sorry this is not possible without cooperation from the other (x-domain) site. Browsers are designed not to allow access to the DOM of x-domain documents (iframe included) for security reasons.
If you had cooperation from the other site, they could load your javascript file and then use postmessage to pass the xpath to the original page.
Other options would be to create a bookmarklet users could use on the other page, or a browser extension (Chrome and FF are pretty easy to develop for)... depends on your use case.
From your comments, I've gathered that you want to capture information from another website that doesn't have Access-Control-Allow-Origin headers that include your domain (e.g. the other site does not have CORS enabled). This is not possible to do cross-domain and client-side due to the Same-Origin Policy implemented in most modern browsers. The Same-Origin Policy prevents any resources on your site from interacting with resources on any other site (unless the other site explicitly shares them with your site using the Access-Control-Allow-Origin HTTP header).
If you want to get information about another site from your site, there is no way around using server-side code. A simple solution would be to implement a server-side proxy that re-serves off-site pages from your own origin, so the Same-Origin Policy will not be violated.
You may get the data using jQuery's load function, and append it to your page.
From there, the DOM nodes from your external page should be accessible for your processing.
$('#where-you-want').load('//example.com body', function() {
console.log($('#where-you-want'))
// process the DOM node under `#where-you-want` here with XPath.
})
You can see this in action here: http://jsfiddle.net/xsvkdugo/
P.S.: this assumes you are working with a CORS-enabled site.

Get innerHTML of iframe loaded in chrome background page

I'm loading a webpage inside iframe of a background page in chrome extension. I need to fetch the content (i.e. DOM) of iframe. I'm getting protocol error. how to overcome this situation, any workaround.
"Unsafe JavaScript attempt to access frame with URL https://swym.3ds.com/ from frame with URL chrome-extension://ohhaffjbbhlfbbpcdcajbkeippadmipk/back.html. The frame requesting access has a protocol of 'chrome-extension', the frame being accessed has a protocol of 'https'. Protocols must match."
I'm trying to implement a desktop notification for the above site, hiding the process from user eye.
I tried using XMLHTTPRequest and Jquery GET, unfortunately my site loading is unstandard, it doesn't work as intended.
Any suggestion on this topic will be very helpful.
It seems you're facing Cross-origin resource sharing issues. Do a quick check for resources loaded with protocols, convert http://www.example.com resources to //www.example.com Also refer MDN CORS Article
Javascript cannot access content on another domain as it poses security risks. If you have control over the domains, you may use postMessage to overcome this. Take a look at this link

Frames with JavaScript

How can I manipulate using JavaScript (JQuery) a site, not in my server, that I loaded in a frame?
I'm afraid you can't. The Same Origin Policy prevents it.
The same origin policy prevents a document or script loaded from one origin from getting or setting properties of a document from another origin. This policy dates all the way back to Netscape Navigator 2.0.
the only conceivable workaround is to fetch the page through a proxy on your own web server, and do the JavaScript operations on that. This, though, will destroy any relative links on the page, and is therefore usually not a workable approach without a lot of work (fixing relative links, etc.)

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