[webkit-changes] [WebKit/WebKit] bab444: CRASH in CDMInstanceSessionClearKey::requestLicense()

[Jer Noble]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: bab44461e2fb01e440683597c93800efe4bec399
      https://github.com/WebKit/WebKit/commit/bab44461e2fb01e440683597c93800efe4bec399
  Author: Jer Noble <jer.noble at apple.com>
  Date:   2025-02-25 (Tue, 25 Feb 2025)

  Changed paths:
    M Source/WebCore/platform/encryptedmedia/clearkey/CDMClearKey.cpp
    M Source/WebCore/platform/encryptedmedia/clearkey/CDMClearKey.h

  Log Message:
  -----------
  CRASH in CDMInstanceSessionClearKey::requestLicense()
rdar://145358917
https://bugs.webkit.org/show_bug.cgi?id=288498

Reviewed by Eric Carlson.

`cdmInstanceProxy()` will return a WeakPtr, and since both that class
and CDMInstanceSessionClearKey are reference-counted, their lifetimes
can become decoupled. It is therefore unsafe to dereference that `WeakPtr`
without a null-check. Separately, CDMInstanceClearKey is type specialized
and should be using dynamicDowncast rather than a statci_cast.

* Source/WebCore/platform/encryptedmedia/clearkey/CDMClearKey.cpp:
(WebCore::CDMInstanceSessionClearKey::updateLicense):
(WebCore::CDMInstanceSessionClearKey::protectedParentInstance const):
(WebCore::CDMInstanceSessionClearKey::parentInstance const): Deleted.
* Source/WebCore/platform/encryptedmedia/clearkey/CDMClearKey.h:

Canonical link: https://commits.webkit.org/291062@main



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