tree e2ab8d26a932a437711a2eb1fae30a6cbc9530c4
parent 6cdbec3e6711cd621019b396b1c96891f8cf0596
author aestes@apple.com <aestes@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1570656559 +0000
committer aestes@apple.com <aestes@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1570656559 +0000

[Cocoa] IPC::decode should gracefully handle a nil allowed class
https://bugs.webkit.org/show_bug.cgi?id=202753

Reviewed by Geoffrey Garen.

If IPC::decode is called with a nil allowed class, an NSInvalidArgumentException will be
thrown when trying to create an NSArray literal with a nil value. Depending on who calls
IPC::decode, this exception might or might not be caught, leading to dropped messages or
crashes.

One case of this happening is tracked by rdar://problem/55839467. In this case, the nil
allowed class was due to a build misconfiguration, and the exception caused the UI process
to not respond to a synchronous IPC message, hanging the WebContent process.

rdar://problem/55839467 was resolved by fixing the build misconfiguration, but this patch
improves IPC::decode so that a nil allowed class results in a message decoding failure
rather than a maybe-caught NSException.

* Shared/Cocoa/ArgumentCodersCocoa.h:
(IPC::decode):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@250934 268f45cc-cd09-0410-ab3c-d52691b4dbfc