1460997 - Out-of-process interceptor using incorrect protection flags for trampoline memory

Status: RESOLVED FIXED

(Core :: General, enhancement, P1)

Description

[(No longer employed by Mozilla) Aaron Klotz]

The out-of-process interceptor's trampolines create a section of shared memory. The local view only needs to be r/w because we only modify the trampolines, we don't execute them.

On Windows 7, VirtualProtect sometimes fails when we request r/w/x. We don't actually need our local view to be executable. When we request r/w, everything works.

I have a hypothesis as to why the failure only happened "sometimes," but it's clear from my testing that this fix is effective.

Comment 1

[(No longer employed by Mozilla) Aaron Klotz]

Attachment: Use r/w instead of r/w/x for local writing to out-of-process trampolines

Comment 2

[(No longer employed by Mozilla) Aaron Klotz]

https://hg.mozilla.org/integration/mozilla-inbound/rev/3b78d37d61ae46ae3fc35305b27655b80fa06155
Bug 1460997: Out-of-process interceptors should use r/w instead of r/w/x when changing protection attributes prior to writing a trampoline; r=handyman

Comment 3

[Eliza Balazs [:ebalazs_]]

https://hg.mozilla.org/mozilla-central/rev/3b78d37d61ae