Some background around the e1kFallbackAddToFrame bug

[schomatis]

This bug was first reported a year ago in

https://github.com/fundacion-sadosky/vbox_cve_2017_10235

after the patch was released by Oracle in

https://www.virtualbox.org/changeset/67974/vbox

but it seems the bug has been reintroduced since then when the checks around u16MaxPktLen were moved to another function (that can be bypassed) in

https://www.virtualbox.org/changeset/68727/vbox

Personally, I do not agree with this type of disclosure but I do have to note that the obscure way Oracle handled the security advisory in the CPU of July 2017 gave very little visibility to the bug and with our own security advisory release having very little impact it made it very easy for the bug to creep up again since it hasn't been acknowledged that the e1kFallbackAddToFrame function is very insecure.

/cc @jheguia