Closed Bug 1828264 Opened 2 years ago Closed 1 year ago

Assertion from creating a OffscreenCanvas on a media track graph thread

Categories

(Core :: DOM: Core & HTML, defect)

Product:
Core
Component:
DOM: Core & HTML
Version:
Firefox 112
Type:
defect

Tracking

()

Status:
VERIFIED FIXED
Milestone:
116 Branch
Tracking Flags:
Tracking Status
firefox-esr102 --- wontfix
firefox112 --- wontfix
firefox113 --- wontfix
firefox114 --- wontfix
firefox115 --- wontfix
firefox116 --- verified
firefox117 --- verified

People

(Reporter: d4ni31, Assigned: peterv)

References

Details

(Keywords: crash, csectype-dos, reporter-external)

Attachments

(5 files)

poc.html
1.12 KB, text/html
Details
stack.txt
7.23 KB, text/plain
Details
Bug 1828264 - Assertion from creating a OffscreenCanvas on a media track graph thread. r?farre!
48 bytes, text/x-phabricator-request
Details | Review
Bug 1828264 - Testcase. r?farre!
48 bytes, text/x-phabricator-request
Details | Review
Diff of generated binding code
7.60 KB, patch
Details | Diff | Splinter Review
Attached file poc.html —

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36

Steps to reproduce:

Title

  • Memory Corruption in CanvasRenderingContext2D

Summary

  • A Memory Corruption exists in the CanvasRenderingContext2D
  • The browser process crashes when triggering this bug.

Test environment

Product : Mozilla Firefox 112.0
OS : Windows 11 x64

Trace

void OffscreenCanvasRenderingContext2D::AddShutdownObserver() {
  WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
  if (!workerPrivate) {
    // We may be using OffscreenCanvas on the main thread.
    CanvasRenderingContext2D::AddShutdownObserver();		// [1]
    return;
  }

  mOffscreenShutdownObserver =
      MakeAndAddRef<OffscreenCanvasShutdownObserver>(this);
  mWorkerRef = WeakWorkerRef::Create(
      workerPrivate,
      [observer = mOffscreenShutdownObserver] { observer->OnShutdown(); });
}

void CanvasRenderingContext2D::AddShutdownObserver() {
  MOZ_ASSERT(!mShutdownObserver);
  MOZ_ASSERT(NS_IsMainThread());

  mShutdownObserver = new CanvasShutdownObserver(this);
  nsContentUtils::RegisterShutdownObserver(mShutdownObserver);		// [2]
}

/* static */
void nsContentUtils::RegisterShutdownObserver(nsIObserver* aObserver) {
  nsCOMPtr<nsIObserverService> observerService =
      mozilla::services::GetObserverService();		// [3]
  if (observerService) {
    observerService->AddObserver(aObserver, NS_XPCOM_SHUTDOWN_OBSERVER_ID,
                                 false);
  }
}

namespace mozilla {
namespace services {
already_AddRefed<nsIObserverService> GetObserverService()
{
  if (MOZ_UNLIKELY(gXPCOMShuttingDown)) {
    return nullptr;
  }
  if (!gObserverService) {
    nsCOMPtr<nsIObserverService> os = do_GetService("@mozilla.org/observer-service;1");
    os.swap(gObserverService);
  }
  return do_AddRef(gObserverService);		// [4]
}
}
}

template <class T>
inline already_AddRefed<T> do_AddRef(T* aObj) {
  RefPtr<T> ref(aObj);					// [5]
  return ref.forget();
}

AddressSanitizer

[Child 58153, Main Thread] WARNING: NS_ENSURE_TRUE(nsContentUtils::IsJavascriptMIMEType(type)) failed: file /builds/worker/checkouts/gecko/dom/script/ScriptLoader.cpp:908
Assertion failure: NS_IsMainThread(), at /builds/worker/checkouts/gecko/dom/canvas/CanvasRenderingContext2D.cpp:1169
#01: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a96bf67]
#02: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a94e788]
#03: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a9d0313]
#04: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1ab20a13]
#05: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1ab20c0f]
#06: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a9d0e8c]
#07: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1ab1f744]
#08: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x17920db3]
#09: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a69e7da]
#10: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26897beb]
#11: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26896602]
#12: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26874e16]
#13: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x268571db]
#14: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26896633]
#15: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x2689a1b2]
#16: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26acf279]
#17: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x19cfdde4]
#18: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b799588]
#19: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b7969ea]
#20: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b73432b]
#21: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b73686e]
#22: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b713a3e]
#23: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b71117c]
#24: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b7190b1]
#25: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b72300d]
#26: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b699c6a]
#27: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b74bf1c]
#28: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1f360281]
#29: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1f35edcb]
#30: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x11872452]
#31: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x118670d1]
#32: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c6ed958]
#33: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c6ee5e1]
#34: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c2a92d9]
#35: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c2ac3c6]
#36: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c4094c0]
#37: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x11872452]
#38: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x11885d4a]
#39: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1398ff61]
#40: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x137385a4]
#41: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x13738207]
#42: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x118648d5]
#43: ???[/home/dohyun/Desktop/debug_firefox/libnspr4.so +0x9e388]
#44: ???[/lib/x86_64-linux-gnu/libpthread.so.0 +0x8609]
#45: clone[/lib/x86_64-linux-gnu/libc.so.6 +0x11f133]
#46: ??? (???:???)

Program /home/dohyun/Desktop/debug_firefox/firefox (pid = 58153) received signal 11.
Stack:
#01: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x29d9aeae]
#02: ???[/lib/x86_64-linux-gnu/libpthread.so.0 +0x14420]
#03: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a96bf9c]
[Parent 57791, IPDL Background] WARNING: Call to Send() failed: file /builds/worker/checkouts/gecko/ipc/glue/NodeChannel.cpp:217
#04: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a94e788]
#05: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a9d0313]
#06: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1ab20a13]
#07: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1ab20c0f]
#08: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a9d0e8c]
[Parent 57791, Main Thread] WARNING: Dropping message as channel has been closed: file /builds/worker/checkouts/gecko/ipc/glue/NodeChannel.cpp:209
#09: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1ab1f744]
#10: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x17920db3]
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
#11: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1a69e7da]
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
#12: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26897beb]
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
#13: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26896602]
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
#14: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26874e16]
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
#15: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x268571db]
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
#16: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26896633]
[Parent 57791, IPC I/O Parent] WARNING: [1.1]: Ignoring message 'EVENT_MESSAGE' to unknown peer 254CB52223948247.70FD630D961C290C: file /builds/worker/checkouts/gecko/ipc/glue/NodeController.cpp:344
#17: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x2689a1b2]
#18: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x26acf279]
#19: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x19cfdde4]
#20: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b799588]
#21: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b7969ea]
#22: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b73432b]
#23: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b73686e]
#24: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b713a3e]
#25: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b71117c]
#26: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b7190b1]
#27: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b72300d]
#28: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b699c6a]
#29: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1b74bf1c]
#30: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1f360281]
#31: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1f35edcb]
#32: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x11872452]
#33: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x118670d1]
#34: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c6ed958]
#35: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c6ee5e1]
#36: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c2a92d9]
#37: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c2ac3c6]
#38: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1c4094c0]
#39: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x11872452]
#40: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x11885d4a]
#41: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x1398ff61]
#42: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x137385a4]
#43: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x13738207]
#44: ???[/home/dohyun/Desktop/debug_firefox/libxul.so +0x118648d5]
#45: ???[/home/dohyun/Desktop/debug_firefox/libnspr4.so +0x9e388]
#46: ???[/lib/x86_64-linux-gnu/libpthread.so.0 +0x8609]
#47: clone[/lib/x86_64-linux-gnu/libc.so.6 +0x11f133]
#48: ??? (???:???)
Sleeping for 300 seconds.
Type 'gdb /home/dohyun/Desktop/debug_firefox/firefox 58153' to attach your debugger to this thread.
[Parent 57791, Main Thread] WARNING: IPC Connection Error: [Parent][PContentParent] RunMessage(msgname=PExtensions::Msg_DocumentChange) Channel error: cannot send/recv: file /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1927
[Parent 57791, Main Thread] WARNING: IPC Connection Error: [Parent][PContentParent] RunMessage(msgname=PBrowser::Msg_OnProgressChange) Channel error: cannot send/recv: file /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1927
[Parent 57791, Main Thread] WARNING: IPC Connection Error: [Parent][PContentParent] RunMessage(msgname=PContent::Msg_ScriptError) Channel error: cannot send/recv: file /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1927
[Parent 57791, Main Thread] WARNING: IPC Connection Error: [Parent][PContentParent] RunMessage(msgname=PContent::Msg_StoreAndBroadcastBlobURLRegistration) Channel error: cannot send/recv: file /builds/worker/checkouts/gecko/ipc/glue/MessageChannel.cpp:1927

Proof-of-Concept

  • Please check the attached file!

Reproduce

  • open a poc.html in Firefox
  • Wait a few seconds.

Actual results:

.

Expected results:

.

Summary modify

  • A Memory Corruption exists in the CanvasRenderingContext2D
  • The Renderer process crashes when triggering this bug.

It looks like the stack you are giving is for a thread safety assertion, not memory corruption. It is possible that a thread safety issue could lead to other issues, of course.

If you could symbolicate this stack then it would be easier to triage the issue.

The test case involves both audio worklets and offscreen canvas.

Group: firefox-core-security → gfx-core-security
Component: Untriaged → Graphics: Canvas2D
Product: Firefox → Core
Attached file stack.txt —

This is the stack I get locally when loading the attachment.

I think we'll hit a release assert in nsObserverService::AddObserver() (via EnsureValidCall()) so I'm not sure how much of a security issue this is. Calling GetObserverService() could technically race if the observer service is starting up or shutting down but I think in practice it should always be running by this point. It still seems potentially bad if we're creating an offscreen canvas from an unexpected thread.

Status: UNCONFIRMED → NEW
Ever confirmed: true
Summary: Memory Corruption in CanvasRenderingContext2D → Assertion from creating a OffscreenCanvas on a media track graph thread

Memory Corruption in CanvasRenderingContext2D

There doesn't seem to be any memory corruption. A release assertion will kill the browser, but in a non-exploitable way (to prevent potential future problems caused by thread-unsafe code).

Release firefox crashes the child process and looks like bp-ef12d643-42c4-4630-ac51-6ce8a0230419

Group: gfx-core-security
Keywords: crash, csectype-dos

The severity field is not set for this bug.
:lsalzman, could you have a look please?

For more information, please visit BugBot documentation.

Flags: needinfo?(lsalzman)

OffscreenCanvas was designed to be used from the main thread, or a worker thread. These is an audio worklet, slightly different context and it appears we don't get a full blown worker context for shutdown events. I will look into how to best handle this.

Assignee: nobody → aosmond
Flags: needinfo?(lsalzman) → needinfo?(aosmond)

Emilio, should OffscreenCanvas exposed on worklet threads? I see we are following the specification (Worker instead of DedicatedWorker).

Flags: needinfo?(emilio)

I don't think so... Worklet doesn't implement Worker afaict? So Exposed=Worker shouldn't expose stuff to audio worklets. I think this might be a bindings bug?

Flags: needinfo?(peterv)
Flags: needinfo?(emilio)
Flags: needinfo?(echen)

Comment 9 is correct, Worklet has nothing to do with Worker, this shouldn't be exposed.

I don't think this is a bindings bug as such, it's a bug in our structured handling code (https://searchfox.org/mozilla-central/source/dom/base/StructuredCloneHolder.cpp#1200-1217). We're missing step 3.4.2 from https://html.spec.whatwg.org/multipage/structured-data.html#structureddeserializewithtransfer. I thought we had an existing bug for that, but I can't find it right now.

Assignee: aosmond → peterv
Status: NEW → ASSIGNED
Flags: needinfo?(peterv)
Flags: needinfo?(echen)
Flags: needinfo?(aosmond)
Component: Graphics: Canvas2D → DOM: Core & HTML
Attachment #9333897 - Attachment description: WIP: Bug 1828264 - Assertion from creating a OffscreenCanvas on a media track graph thread. r?farre! → Bug 1828264 - Assertion from creating a OffscreenCanvas on a media track graph thread. r?farre!

Depends on D178173

Pushed by pvanderbeken@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/18efba6ba1de Assertion from creating a OffscreenCanvas on a media track graph thread. r=farre https://hg.mozilla.org/integration/autoland/rev/6f8b0b36ee84 Testcase. r=farre
Flags: sec-bounty?
Pushed by pvanderbeken@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/81e8bc2a7253 Assertion from creating a OffscreenCanvas on a media track graph thread. r=farre https://hg.mozilla.org/integration/autoland/rev/8c256ebacc5a Testcase. r=farre
Pushed by pvanderbeken@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/47f66db5a370 Assertion from creating a OffscreenCanvas on a media track graph thread. r=farre https://hg.mozilla.org/integration/autoland/rev/599e77c29bb6 Testcase. r=farre

https://hg.mozilla.org/mozilla-central/rev/47f66db5a370
https://hg.mozilla.org/mozilla-central/rev/599e77c29bb6

Status: ASSIGNED → RESOLVED
Closed: 1 year ago
status-firefox116: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → 116 Branch

Since nightly and release are affected, beta will likely be affected too.
For more information, please visit BugBot documentation.

status-firefox115: --- → affected
Regressions: 1837370
Flags: sec-bounty? → sec-bounty-

I was able to reproduce the issue on Win10x64 using FF build 114.0a1(20230415205259)(tab crashed when open poc.html from description).
Verified as fixed on Win10x64/Ubuntu 20.04 using FF build 116.0(20230724170120) and 117.0a1. (tab did not crashed anymore).

Status: RESOLVED → VERIFIED
status-firefox116: fixed → verified
status-firefox117: --- → verified
Flags: qe-verify+
Flags: needinfo?(peterv)
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