moz_bug_r_a4 Reporter
	Description • 18 years ago

Please see bug 353266.

Array.prototype methods trick (bug 344495) and document.(open|write) trick (bug
346659) and XSS holes (bug 351370, bug 359137) are available on fx2.0. (bug
359137 was already fixed.)

In a feed preview page, an event handler that was registered by content script
can be called by chrome script via elem.doCommand() or elem.dispatchEvent(). 
In this case, the event handler's scripted caller is chrome script.  Thus, an
attacker can run arbitrary code with chrome privileges by using Array.prototype
methods trick or document.write trick.

--
  document.getElementById("handlersMenuList")
   .addEventListener("command", x, true);

  SubscribeHandler._feedWriter.write(window);
   or
  SubscribeHandler._feedWriter
   .QueryInterface(Components.interfaces.nsIObserver)
   .observe({}, "nsPref:changed", "browser.feeds.handler.default");

x() (if x is a function) or x.handleEvent() is called in
FeedWriter._setSelectedHandler() via handlers[0].doCommand(),
selectedAppMenuItem.doCommand() or liveBookmarksMenuItem.doCommand().

  document.getElementById("alwaysUse")
   .addEventListener("CheckboxStateChange", y, true);

  SubscribeHandler._feedWriter.write(window);
   or
  SubscribeHandler._feedWriter
   .QueryInterface(Components.interfaces.nsIObserver)
   .observe({}, "nsPref:changed", "browser.feeds.handler");

y() or y.handleEvent() is called in FeedWriter._setCheckboxCheckedState() via
aCheckbox.dispatchEvent(event).
--

* Fx1.5.0.x is not affected since it does not have feed preview feature.
* The trunk should be exploitable if an XSS hole existed.

	moz_bug_r_a4 Reporter
	Comment 1 • 18 years ago

The old testcases no longer work, since those try to use the XSS hole (bug
351370) that has been already fixed.  I'm attaching new testcases that use
another XSS hole (Bug 363597).

	moz_bug_r_a4 Reporter
	Comment 2 • 18 years ago

Is there any chance this can be fixed without relying on fixing bug 344495?

	Martijn Wargers (dead)
	Comment 3 • 17 years ago

Is this still a problem in current trunk/branch build?

	moz_bug_r_a4 Reporter
	Comment 4 • 17 years ago

Yes, at least on 1.8 branch.  It's still possible to use the feed preview page
to turn an XSS bug into an arbitrary code execution bug.

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 5 • 17 years ago

Repeating the question:
(In reply to comment #7)
> Is this still a problem in current trunk/branch build?

If this is branch only, could the bug be marked as gecko-1.8branch/ff-2.0branch?

	Daniel Veditz [:dveditz]
	Comment 6 • 17 years ago

Whether or not it's a trunk problem depends on whether there are any known universal-xss vulnerabilities on the trunk, or will be any found (or made) in the future. We've gone to a lot of trouble to make sure content can't open any chrome-privileged URIs precisely because we didn't trust that there were no such holes, but being able to open frames on arbitrary feeds means that web content _can_ still open chrome-privileged frames.

The only true solution is to make the Feed preview non-privileged. The privileged part could be a separate chrome-privileged sheet-like thing much like an oversized infobar.

	Mike Beltzner [:beltzner, not reading bugmail]
	Comment 7 • 17 years ago

Not gonna block Firefox 3 on this for now, but if you find that potential XSS vuln or figure out a fix for branch, please renom.

	Samuel Sidler (old account; do not CC)
	Comment 8 • 17 years ago

sayrer, is this something you can look at?

	Robert Sayre
	Comment 9 • 17 years ago

(In reply to comment #14)
> sayrer, is this something you can look at?
> 

Mano dealt with this stuff last time, and came up with the Fx2 solution. I am really busy with other stuff--a summary of the attributes and elements used for the attack would be much appreciated.

	Samuel Sidler (old account; do not CC)
	Comment 10 • 17 years ago

Mano, do you have time to look at this in the next week? We're about a week away from our branch freeze.

	Daniel Veditz [:dveditz]
	Comment 11 • 17 years ago

(In reply to comment #13)
> Not gonna block Firefox 3 on this for now, but if you find that potential XSS
> vuln or figure out a fix for branch, please renom.

We find XSS fairly regularly, it needs to get fixed.

	Mike Beltzner [:beltzner, not reading bugmail]
	Comment 13 • 17 years ago

Comment on attachment 306777 [details] [diff] [review]
patch

a1.9b4=beltzner

	Asaf Romano (gone) Assignee
	Comment 14 • 17 years ago

mozilla/browser/components/feeds/src/FeedWriter.js 1.53

	Samuel Sidler (old account; do not CC)
	Comment 15 • 17 years ago

Mano, does this same patch apply to the branch? If so, can you request approval? If not, a branch-specific one would be great.

	Asaf Romano (gone) Assignee
	Comment 16 • 17 years ago

I don't have a tree to this one on.

	moz_bug_r_a4 Reporter
	Comment 17 • 17 years ago

It seems that appendChild(), removeAttribute(), etc. are also exploitable,
since those methods fire mutation events.

	Brendan Eich [:brendan]
	Comment 18 • 17 years ago

Followup bug would be better unless the landed patch is backed out.

/be

	Asaf Romano (gone) Assignee
	Comment 19 • 17 years ago

Let's keep using this one.

	Samuel Sidler (old account; do not CC)
	Comment 20 • 17 years ago

This needs a complete trunk patch before we can take it on the branch. Punting to the next release.

	Asaf Romano (gone) Assignee
	Comment 21 • 17 years ago

Mike and I agreed to push this to early-post-beta given the scale of my upcoming rewrite.

	Asaf Romano (gone) Assignee
	Comment 22 • 17 years ago

So, after thinking about this a little more, I'm going to just rely on the fact that DOMAttrModified and other mutation events are not being dispatched for nodes which are not yet inserted into the document (and call appendChild within the sandbox).

	Asaf Romano (gone) Assignee
	Comment 23 • 17 years ago

In the js console:
var a=function() { alert('foo'); }; document.addEventListener("DOMAttrModified", a, true); var b = document.createElement("b"); b.setAttribute("f", "b"); document.documentElement.appendChild(b); b.setAttribute("m", "f");

alerts only for the second setAttribute call. Boris, Jonas,  Johnny: Can the feedwriter code rely on this? W3C's documentation is pretty vague about mutation events behavior for nodes which are not yet inserted into the document.

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 24 • 17 years ago

Mutation events do get dispatched, but in your testcase the event can't 
propagate to document, because element isn't in document.
But if you add mutation event listener to the element, the listener will be
called.

	Asaf Romano (gone) Assignee
	Comment 25 • 17 years ago

I'm fine with that, we create the elements and set the attributes on the same time. Would it be enough than to call appendChild and all  _post_ node-insertion, attribute-modifications methods  in the sandbox?

	Mike Connor [:mconnor]
	Comment 28 • 17 years ago

Comment on attachment 311175 [details] [diff] [review]
patch

>-      feedTitleLink.setAttribute("title", titleText);
>+      this._contentSandbox.feedTitleLink = feedTitleLink;
>+      this._contentSandbox.titleText = titleText;
>+      var codeStr = "feedTitleLink.setAttribute('title', titleText);";
>+      Cu.evalInSandbox(codeStr, this._contentSandbox);
>       this._safeSetURIAttribute(feedTitleLink, "href", 
>                                 parts.getPropertyAsAString("link"));

can null these after to clean up

>   _setSubscribeUsingLabel: function FW__setSubscribeUsingLabel() {
>-    var stringLabel = null;
>-
>-    switch (this._getFeedType()) {
>+    var stringLabel;
>+    var feedType = this._getFeedType();
>+    switch (feedType) {

you don't use feedType elsewhere, don't understand the change here.

>       case Ci.nsIFeed.TYPE_VIDEO:
>         stringLabel = "subscribeVideoPodcastUsing";
>         break;
> 
>       case Ci.nsIFeed.TYPE_AUDIO:
>         stringLabel = "subscribeAudioPodcastUsing";
>         break;
> 
>       default:
>         stringLabel = "subscribeFeedUsing";
>     }

you could just init stringLabel to this and it'd be a little less code overall, but that's being nitpicky.

r=me, this should be pretty safe, just needs to get tested thoroughly by QA tomorrow...

	Mike Connor [:mconnor]
	Comment 29 • 17 years ago

Comment on attachment 311175 [details] [diff] [review]
patch

a1.9b5 on this patch, as its fixing an sg:critical bug and has potential regression impact in the wild.

Please make sure that the existing litmus tests cover the functionality we're touching here, and send mail to qa@mozilla.org asking that they be run ASAP on all platforms.  If there are missing tests, please tell QA what the tests should cover.

	Shawn Wilsher :sdwilsh
	Comment 30 • 17 years ago

It seems to me that this wouldn't be too hard to automate testing on? (not that I'm volunteering - my plate is plenty full)

The testcases seem to basically be already written (some modification so they don't use an alert box maybe, but that shouldn't be too hard either...)

	Asaf Romano (gone) Assignee
	Comment 31 • 17 years ago

No, you cannot test this, we generally fix XSS holes :p

	Shawn Wilsher :sdwilsh
	Comment 32 • 17 years ago

right but, if we can exploit said vulnerability in a test, the test should fail, right?

	Asaf Romano (gone) Assignee
	Comment 33 • 17 years ago

But we cannot. As far as i can tell, none of the tests attached here can be used to test this bug on current trunk.

	Boris Zbarsky [:bzbarsky]
	Comment 34 • 17 years ago

XSS-like conditions can be created by code with UniversalXPConnect privileges, no?

	Asaf Romano (gone) Assignee
	Comment 35 • 17 years ago

I couldn't find a way (even with privileges enabled) to call about:feed's SubscribeHandler.init on trunk without using the console / urlbar as described in testcase 6. 

	Asaf Romano (gone) Assignee
	Comment 36 • 17 years ago

I'll write some tests later as we figure out how to do so...

	Asaf Romano (gone) Assignee
	Comment 37 • 17 years ago

mozilla/browser/components/feeds/src/FeedWriter.js 1.54

Mail sent to qa@m.c.

	Boris Zbarsky [:bzbarsky]
	Comment 38 • 17 years ago

> without using the console / urlbar as described in testcase 6. 

So if you inject code into the Firefox window that calls eval(content.code), it doesn't work?

	Asaf Romano (gone) Assignee
	Comment 39 • 17 years ago

Firefox window as in browser.xul? I guess that might work, though it requires the chrome-testing framework....

	Boris Zbarsky [:bzbarsky]
	Comment 40 • 17 years ago

Why?  You can do that from inside a mochitest if you really want to...

Doing it from chrome mochitests might work as long as you can get the feed preview page loaded first.

	Samuel Sidler (old account; do not CC)
	Comment 41 • 16 years ago

Is there any work being done here for an updated branch patch, presumably one that also includes a fix for bug 430658?

	Samuel Sidler (old account; do not CC)
	Comment 42 • 16 years ago

Still don't have a branch patch and given the size of the trunk patch we don't want to take it at the last minute. Moving to 1.8.1.16, but we need to get a patch soon so we can land it early in the cycle.

	Samuel Sidler (old account; do not CC)
	Comment 43 • 16 years ago

Mano, we could really use a branch patch here...

	Mike Connor [:mconnor]
	Comment 45 • 16 years ago

Comment on attachment 334770 [details] [diff] [review]
combined branch patch

This feels like pain.

	Daniel Veditz [:dveditz]
	Comment 46 • 16 years ago

qanote: testcase 7 can't be used to verify because the stepping-stone bug was fixed in FF2.0.0.15. Either we need a 2.0.0.16-working testcase that uses another yet-unfixed XSS bug, or this patch needs to be verified by applying the patch to a 2.0.0.14 source tree.

	Daniel Veditz [:dveditz]
	Comment 47 • 16 years ago

Comment on attachment 334770 [details] [diff] [review]
combined branch patch

It'd be good to get a second review given the size of the patch and the limited testing time we've got left for this release. Johnny: you reviewed an earlier iteration, you up for it?

	Samuel Sidler (old account; do not CC)
	Comment 48 • 16 years ago

Comment on attachment 334770 [details] [diff] [review]
combined branch patch

Approved for 1.8.1.17. Please land ASAP on the branch. a=ss

	Asaf Romano (gone) Assignee
	Comment 49 • 16 years ago

Checking in src/FeedWriter.js;
/cvsroot/mozilla/browser/components/feeds/src/FeedWriter.js,v  <--  FeedWriter.js
new revision: 1.2.2.33; previous revision: 1.2.2.32
done

	moz_bug_r_a4 Reporter
	Comment 50 • 16 years ago

The fx2 patch caused a syntax error on Windows.

Here is an extra "}".
http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/browser/components/feeds/src/FeedWriter.js&rev=1.2.2.33&mark=788#782


Error: missing catch or finally after try
Source File: file:///C:/test/fx-2.0.0.17pre-2008-08-26-03/firefox/components/FeedWriter.js
Line: 736, Column: 6
Source Code:
      else {

Error: BrowserFeedWriter is not defined
Source File: chrome://browser/content/feeds/subscribe.js
Line: 45

	Mike Shaver (:shaver -- probably not reading bugmail closely)
	Comment 51 • 16 years ago

Preeeetty sure we need the syntax error fixed before we can ship 2.0.0.17, so unmarking it as branch-fixed until that's addressed.

How did this code ever work in testing the #ifdef XP_WIN block?  We really, *really* can't be checking untested code into the stable branches, so I'm very much hoping that something else happened. :(

	Asaf Romano (gone) Assignee
	Comment 52 • 16 years ago

Bad merge :-/

	:Gavin Sharp [email: gavin@gavinsharp.com]
	Comment 53 • 16 years ago

With that fixed I get:
Error: uncaught exception: [Exception... "'[JavaScript Error: "result has no properties" {file: "file:///I:/mozb/mozilla/ff-opt/dist/bin/components/FeedWriter.js" line: 381}]' when calling method: [nsIFeedWriter::write]"  nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)"  location: "JS frame :: chrome://browser/content/feeds/subscribe.js :: SH_init :: line 46"  data: yes]

with all of the testcases, along with:
Security Error: Content at about:feeds may not load or link to chrome://global/content/mozilla.xhtml.

I assume this is the expected failure (I get the same on trunk).

	:Gavin Sharp [email: gavin@gavinsharp.com]
	Comment 54 • 16 years ago

mozilla/browser/components/feeds/src/FeedWriter.js 	1.2.2.34 

	juan becerra [:juanb]
	Comment 55 • 16 years ago

Verified on Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.17) Gecko/2008082909 Firefox/2.0.0.17 using test cases here. This is the output in the error console while running test case 8, in comment #57:

Error: result has no properties
Source File: file:///C:/Program%20Files/Mozilla%20Firefox/components/FeedWriter.js
Line: 354

Error: uncaught exception: [Exception... "'[JavaScript Error: "result has no properties" {file: "file:///C:/Program%20Files/Mozilla%20Firefox/components/FeedWriter.js" line: 354}]' when calling method: [nsIFeedWriter::write]"  nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)"  location: "JS frame :: chrome://browser/content/feeds/subscribe.js :: SH_init :: line 46"  data: yes]

Error: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMLocation.href]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"  location: "native frame :: <unknown filename> :: <TOP_LEVEL> :: line 0"  data: no]

	Alexander Sack
	Comment 56 • 16 years ago

doesnt apply on 1.8.0 from what i can see. If i am mistaking flip wanted1.8.0.x or blocking1.8.0.15 to ? again. Thanks!

	juan becerra [:juanb]
	Comment 57 • 16 years ago

In 20015 test case #8 opens up an alert window, and in 20017 it doesn't.

	:Gavin Sharp [email: gavin@gavinsharp.com]
	Comment 58 • 16 years ago

moz_bug, could you file a new bug on the omissions? Tracking multiple patches in one bug just leads to confusion.

	Martijn Wargers (dead)
	Comment 59 • 16 years ago

And it seems to me that should block the fx2.0.0.17 release, right?

	Mike Beltzner [:beltzner, not reading bugmail]
	Comment 60 • 16 years ago

(In reply to comment #70)
> moz_bug, could you file a new bug on the omissions? Tracking multiple patches
> in one bug just leads to confusion.

I have been convinced that's the right thing to do, instead of continually expanding the scope of this single bug. We'll leave this part of the issue as fixed & verified, and stamp out the others in future releases.

(In reply to comment #71)
> And it seems to me that should block the fx2.0.0.17 release, right?

No, we've waited before, and can continue to do so again.

	Asaf Romano (gone) Assignee
	Comment 61 • 16 years ago

CC me on it please if you wanst me to fix it.