As discussed with smaug (see also [0]) we should potentially *not* query the triggeringPrincipal from mOSHE when creating a new session entry [1]. This needs more investigation. [0] https://bugzilla.mozilla.org/show_bug.cgi?id=1341754#c14 [1] https://dxr.mozilla.org/mozilla-central/source/docshell/base/nsDocShell.cpp#10416

Thomas, to get some more background info, you could read Comments 14 (15,16,17,...) from Bug 1341754. The essential question is, should we query the triggeringPrincipal and PrincipalToInherit from mOSHE [1] in case there is an mOSHE or not. Potentially we could remove that if-else branch and always use the else branch, but we need to do some audit. To fix the bug, ideally we run a bunch of tests (in particular loading about: pages) and investigate the principalToInherit and TriggeringPrincipal in the different scenarios. Once we have a list of that, we can move on with the code fix. [1] https://dxr.mozilla.org/mozilla-central/source/docshell/base/nsDocShell.cpp#10623-10634

Thanks for the info. Assign to myself so I can take a look later