tree ec05da3f7245e212bb803d190c9b5073240cc335
parent aaf236971732a8f462fcc215e314ea491afe1c40
author Todd Kjos <tkjos@google.com> 1638298312 -0800
committer Treehugger Robot <treehugger-gerrit@google.com> 1669679180 +0000

UPSTREAM: binder: defer copies of pre-patched txn data

BINDER_TYPE_PTR objects point to memory areas in the
source process to be copied into the target buffer
as part of a transaction. This implements a scatter-
gather model where non-contiguous memory in a source
process is "gathered" into a contiguous region in
the target buffer.

The data can include pointers that must be fixed up
to correctly point to the copied data. To avoid making
source process pointers visible to the target process,
this patch defers the copy until the fixups are known
and then copies and fixeups are done together.

There is a special case of BINDER_TYPE_FDA which applies
the fixup later in the target process context. In this
case the user data is skipped (so no untranslated fds
become visible to the target).

Reviewed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-5-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bug: 137131904
Bug: 257685302
(cherry picked from commit 09184ae9b5756cc469db6fd1d1cfdcffbf627c2d)
[cmllamas: fix trivial merge conflict]
Change-Id: I6de75b192d1e3b2cc73c8d91077d97b608e8c5a9
Signed-off-by: Carlos Llamas <cmllamas@google.com>