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
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index a2333ae..c75f036 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -35,6 +35,7 @@
#include <binder/IPCThreadState.h>
#include <binder/Parcel.h>
#include <binder/ProcessState.h>
+#include <binder/Stability.h>
#include <binder/Status.h>
#include <binder/TextOutput.h>
@@ -167,11 +168,10 @@
status_t Parcel::finishFlattenBinder(
const sp<IBinder>& /*binder*/, const flat_binder_object& flat)
{
- // internal::Stability::tryMarkCompilationUnit(binder.get());
-
status_t status = writeObject(flat, false);
if (status != OK) return status;
+ // internal::Stability::tryMarkCompilationUnit(binder.get());
// Cannot change wire protocol w/o SM update
// return writeInt32(internal::Stability::get(binder.get()));
return OK;
@@ -185,10 +185,6 @@
// status_t status = readInt32(&stability);
// if (status != OK) return status;
- // if (binder != nullptr && !internal::Stability::check(stability, mRequiredStability)) {
- // return BAD_TYPE;
- // }
-
// status = internal::Stability::set(binder.get(), stability, true /*log*/);
// if (status != OK) return status;
@@ -356,10 +352,6 @@
return NO_ERROR;
}
-void Parcel::setTransactingBinder(const sp<IBinder>& binder) const {
- mRequiredStability = internal::Stability::get(binder.get());
-}
-
status_t Parcel::setData(const uint8_t* buffer, size_t len)
{
if (len > INT32_MAX) {
@@ -2615,10 +2607,9 @@
mObjectsCapacity = 0;
mNextObjectHint = 0;
mObjectsSorted = false;
- mAllowFds = true;
mHasFds = false;
mFdsKnown = true;
- mRequiredStability = internal::Stability::UNDECLARED;
+ mAllowFds = true;
mOwner = nullptr;
mOpenAshmemSize = 0;