549257 - [@ nsExternalAppHandler::nsExternalAppHandler] caused by ImageShack Toolbar

Status: RESOLVED DUPLICATE of bug 703882

(Toolkit :: Blocklist Policy Requests, defect)

Description

[timeless]

{7378B8C2-FC38-41b8-A8C9-875D1F5B0A24} is ImageShack® Toolbar
^ seems to be present on both crashing systems
{B042753D-F57E-4e8e-A01B-7379A6D4CEFB} is BitComet Download Helper
^ only present on this crashing system
{972ce4c6-7e08-4474-a285-3208198ce6fd}
^ default theme
Black Steel is a theme

Extension 	Extension Id 	Version 	Current?
Speed Dial 	{64161300-e22b-11db-8314-0800200c9a66} 	0.9.5 	current
Adblock Plus 	{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d} 	1.1.3 	current
	{7378B8C2-FC38-41b8-A8C9-875D1F5B0A24} 	5.2.3.7 	
	{B042753D-F57E-4e8e-A01B-7379A6D4CEFB} 	1.18 	
	{972ce4c6-7e08-4474-a285-3208198ce6fd} 	3.7a2pre 	
Black Steel 	{e2c58150-9d72-11dd-ad8b-0800200c9a66} 	1.3.1 	current

Filename 	Version 	Debug Identifier 	Debug Filename
IBitCometExtension.dll 		0129FCDE419844099D589B2C7E13E6F6c 	BitCometExtension_Firefox.pdb

Signature	nsExternalAppHandler::nsExternalAppHandler(nsIMIMEInfo*, nsACString_internal const&, nsIInterfaceRequestor*, nsAString_internal const&, unsigned int, int)
UUID	0b0249bd-fce2-4e7c-bb61-bdcbf2100219
Time 	2010-02-19 07:15:51.256692
Uptime	23573
Last Crash	55338 seconds before submission
Product	Firefox
Version	3.7a2pre
Build ID	20100218045818
Branch	1.9.3
OS	Windows NT
OS Version	6.1.7600
CPU	x86
CPU Info	AuthenticAMD family 16 model 4 stepping 3
Crash Reason	EXCEPTION_ACCESS_VIOLATION
Crash Address	0x0
User Comments	WTF Mozilla? 2010 and your browser STILL crashes trying to initiate a download Every few downloads, the next one will crash the browser - I have disabled plugins, I have upgraded to 3.7a2 - **** dudes, get it sorted
Processor Notes 	
Crashing Thread
Frame 	Module 	Signature [Expand] 	Source
0 	xul.dll 	nsExternalAppHandler::nsExternalAppHandler 	uriloader/exthandler/nsExternalHelperAppService.cpp:1139
1 	xul.dll 	nsExternalHelperAppService::DoContent 	uriloader/exthandler/nsExternalHelperAppService.cpp:725
2 	xul.dll 	xul.dll@0xa1eac7 	

The crash is a null pointer dereference of a pointer that we obviously assume won't be null. i'm inclined to trust the code's assumption and blame the addon..

1093 nsExternalAppHandler::nsExternalAppHandler(nsIMIMEInfo * aMIMEInfo,
...
1139 gExtProtSvc->AddRef(); 

Most likely someone (ImageShack Toolbar) called CreateInstance with the ExtProtSvc and thus let it get destroyed.

Comment 1

[timeless]

timeless$ curl -O http://toolbar.imageshack.us/ImageShackToolbar.xpi;unzip ImageShackToolbar.xpi chrome/uploadlibrary.jar;cd chrome/; unzip uploadlibrary.jar content/factory/ComponentsFactory.js;grep mozilla.org/mime content/factory/ComponentsFactory.js
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 4027k  100 4027k    0     0   821k      0  0:00:04  0:00:04 --:--:--  899k
Archive:  ImageShackToolbar.xpi
  inflating: chrome/uploadlibrary.jar  
Archive:  uploadlibrary.jar
  inflating: content/factory/ComponentsFactory.js  
    return Components.classes["@mozilla.org/mime;1"].createInstance(Components.interfaces.nsIMIMEService);

This is bogus, it's a service as the interface name clearly states. This extension needs to be blocklisted or fixed. Thanks.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Yep.  What that addon is doing is just not cool.  I hate the fact that it doesn't just throw.  :(

Comment 3

[Jorge Villalobos [:jorgev] (he/him)]

I received a response from the developer today:

------
Hello Jorge,

Thank you for reporting this issue. We'll have a fix shortly.

Sincerely,
Mikhail | ImageShack - Support
------

I recommend giving them some time to fix the problem before considering blocklisting.

Comment 4

[Alexander Kozlov]

Hi All,

This bug happened because it's published on your site

https://developer.mozilla.org/ru/XMLHttpRequest

// Try to determine the MIME type of the file
var mimeType = "text/plain";
try {
  var mimeService = Components.classes["@mozilla.org/mime;1"].createInstance(Components.interfaces.nsIMIMEService);
  mimeType = mimeService.getTypeFromFile(file); // file is an nsIFile instance
}
catch(e) { /* eat it; just use text/plain */ }

Comment 5

[Boris Zbarsky [:bzbarsky]]

Huh.  I have no idea why that page exists or why it's wrong like that.  https://developer.mozilla.org/en/XMLHttpRequest has nothing resembling that buggy code.

Comment 6

[Boris Zbarsky [:bzbarsky]]

And I've made the minimal adjustment to the page to make it sane.