libbinder: stability check moved to trans time

Before: stability check done when binder is read from a parcel
After: stability check done when binder is transacted on

Why this change is being made/benefits:
- vendor binders can be used as tokens in system context
- pingBinder/interfaceChain/etc.. can be done on vendor binders in a
system context, so code can generically operate on binders. This is
particularly useful for service manager and dumpstate, which previously
I was going to special-case
- policy on which binders go where is entirely reliant on SELinux
whereas before there were additional runtime restrictions

Cons to this change:
- allowed binders must be determined by context. BpBinder now checks
stability based on kLocalStability. More work would need to be done to
get this working with APEX.

Bug: 136027762
Test: binderStabilityTest
Change-Id: Iff026e81a130dbb8885ca82ec24e69a5768847eb
Merged-In: Iff026e81a130dbb8885ca82ec24e69a5768847eb

1 files changed, 0 insertions, 2 deletions

diff --git a/libs/binder/Binder.cpp b/libs/binder/Binder.cpp
index 985d8177f8..9e55c2c8c3 100644
--- a/libs/binder/Binder.cpp
+++ b/libs/binder/Binder.cpp
@@ -124,7 +124,6 @@ status_t BBinder::transact(
     uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
 {
     data.setDataPosition(0);
-    data.setTransactingBinder(this);
 
     status_t err = NO_ERROR;
     switch (code) {
@@ -139,7 +138,6 @@ status_t BBinder::transact(
     // In case this is being transacted on in the same process.
     if (reply != nullptr) {
         reply->setDataPosition(0);
-        reply->setTransactingBinder(this);
     }
 
     return err;