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-rw-r--r--libs/binder/IPCThreadState.cpp47
-rw-r--r--libs/binder/include/binder/IPCThreadState.h31
-rw-r--r--libs/binder/tests/binderLibTest.cpp31
3 files changed, 99 insertions, 10 deletions
diff --git a/libs/binder/IPCThreadState.cpp b/libs/binder/IPCThreadState.cpp
index ef7fd44419..d2919e7f4d 100644
--- a/libs/binder/IPCThreadState.cpp
+++ b/libs/binder/IPCThreadState.cpp
@@ -366,19 +366,46 @@ status_t IPCThreadState::clearLastError()
pid_t IPCThreadState::getCallingPid() const
{
+ checkContextIsBinderForUse(__func__);
return mCallingPid;
}
const char* IPCThreadState::getCallingSid() const
{
+ checkContextIsBinderForUse(__func__);
return mCallingSid;
}
uid_t IPCThreadState::getCallingUid() const
{
+ checkContextIsBinderForUse(__func__);
return mCallingUid;
}
+const IPCThreadState::SpGuard* IPCThreadState::pushGetCallingSpGuard(const SpGuard* guard) {
+ const SpGuard* orig = mServingStackPointerGuard;
+ mServingStackPointerGuard = guard;
+ return orig;
+}
+
+void IPCThreadState::restoreGetCallingSpGuard(const SpGuard* guard) {
+ mServingStackPointerGuard = guard;
+}
+
+void IPCThreadState::checkContextIsBinderForUse(const char* use) const {
+ if (LIKELY(mServingStackPointerGuard == nullptr)) return;
+
+ if (!mServingStackPointer || mServingStackPointerGuard->address < mServingStackPointer) {
+ LOG_ALWAYS_FATAL("In context %s, %s does not make sense (binder sp: %p, guard: %p).",
+ mServingStackPointerGuard->context, use, mServingStackPointer,
+ mServingStackPointerGuard->address);
+ }
+
+ // in the case mServingStackPointer is deeper in the stack than the guard,
+ // we must be serving a binder transaction (maybe nested). This is a binder
+ // context, so we don't abort
+}
+
int64_t IPCThreadState::clearCallingIdentity()
{
// ignore mCallingSid for legacy reasons
@@ -847,15 +874,15 @@ status_t IPCThreadState::clearDeathNotification(int32_t handle, BpBinder* proxy)
}
IPCThreadState::IPCThreadState()
- : mProcess(ProcessState::self()),
- mServingStackPointer(nullptr),
- mWorkSource(kUnsetWorkSource),
- mPropagateWorkSource(false),
- mIsLooper(false),
- mStrictModePolicy(0),
- mLastTransactionBinderFlags(0),
- mCallRestriction(mProcess->mCallRestriction)
-{
+ : mProcess(ProcessState::self()),
+ mServingStackPointer(nullptr),
+ mServingStackPointerGuard(nullptr),
+ mWorkSource(kUnsetWorkSource),
+ mPropagateWorkSource(false),
+ mIsLooper(false),
+ mStrictModePolicy(0),
+ mLastTransactionBinderFlags(0),
+ mCallRestriction(mProcess->mCallRestriction) {
pthread_setspecific(gTLS, this);
clearCaller();
mIn.setDataCapacity(256);
@@ -1230,7 +1257,7 @@ status_t IPCThreadState::executeCommand(int32_t cmd)
tr.offsets_size/sizeof(binder_size_t), freeBuffer);
const void* origServingStackPointer = mServingStackPointer;
- mServingStackPointer = &origServingStackPointer; // anything on the stack
+ mServingStackPointer = __builtin_frame_address(0);
const pid_t origPid = mCallingPid;
const char* origSid = mCallingSid;
diff --git a/libs/binder/include/binder/IPCThreadState.h b/libs/binder/include/binder/IPCThreadState.h
index 23a0cb0148..ee661a5948 100644
--- a/libs/binder/include/binder/IPCThreadState.h
+++ b/libs/binder/include/binder/IPCThreadState.h
@@ -81,6 +81,36 @@ public:
*/
uid_t getCallingUid() const;
+ /**
+ * Make it an abort to rely on getCalling* for a section of
+ * execution.
+ *
+ * Usage:
+ * IPCThreadState::SpGuard guard {
+ * .address = __builtin_frame_address(0),
+ * .context = "...",
+ * };
+ * const auto* orig = pushGetCallingSpGuard(&guard);
+ * {
+ * // will abort if you call getCalling*, unless you are
+ * // serving a nested binder transaction
+ * }
+ * restoreCallingSpGuard(orig);
+ */
+ struct SpGuard {
+ const void* address;
+ const char* context;
+ };
+ const SpGuard* pushGetCallingSpGuard(const SpGuard* guard);
+ void restoreGetCallingSpGuard(const SpGuard* guard);
+ /**
+ * Used internally by getCalling*. Can also be used to assert that
+ * you are in a binder context (getCalling* is valid). This is
+ * intentionally not exposed as a boolean API since code should be
+ * written to know its environment.
+ */
+ void checkContextIsBinderForUse(const char* use) const;
+
void setStrictModePolicy(int32_t policy);
int32_t getStrictModePolicy() const;
@@ -203,6 +233,7 @@ private:
Parcel mOut;
status_t mLastError;
const void* mServingStackPointer;
+ const SpGuard* mServingStackPointerGuard;
pid_t mCallingPid;
const char* mCallingSid;
uid_t mCallingUid;
diff --git a/libs/binder/tests/binderLibTest.cpp b/libs/binder/tests/binderLibTest.cpp
index 0c3fbcd2da..7679b46c4e 100644
--- a/libs/binder/tests/binderLibTest.cpp
+++ b/libs/binder/tests/binderLibTest.cpp
@@ -73,6 +73,7 @@ enum BinderLibTestTranscationCode {
BINDER_LIB_TEST_REGISTER_SERVER,
BINDER_LIB_TEST_ADD_SERVER,
BINDER_LIB_TEST_ADD_POLL_SERVER,
+ BINDER_LIB_TEST_USE_CALLING_GUARD_TRANSACTION,
BINDER_LIB_TEST_CALL_BACK,
BINDER_LIB_TEST_CALL_BACK_VERIFY_BUF,
BINDER_LIB_TEST_DELAYED_CALL_BACK,
@@ -604,6 +605,13 @@ TEST_F(BinderLibTest, CallBack)
EXPECT_THAT(callBack->getResult(), StatusEq(NO_ERROR));
}
+TEST_F(BinderLibTest, BinderCallContextGuard) {
+ sp<IBinder> binder = addServer();
+ Parcel data, reply;
+ EXPECT_THAT(binder->transact(BINDER_LIB_TEST_USE_CALLING_GUARD_TRANSACTION, data, &reply),
+ StatusEq(DEAD_OBJECT));
+}
+
TEST_F(BinderLibTest, AddServer)
{
sp<IBinder> server = addServer();
@@ -1262,6 +1270,21 @@ class BinderLibTestService : public BBinder
pthread_mutex_unlock(&m_serverWaitMutex);
return ret;
}
+ case BINDER_LIB_TEST_USE_CALLING_GUARD_TRANSACTION: {
+ IPCThreadState::SpGuard spGuard{
+ .address = __builtin_frame_address(0),
+ .context = "GuardInBinderTransaction",
+ };
+ const IPCThreadState::SpGuard *origGuard =
+ IPCThreadState::self()->pushGetCallingSpGuard(&spGuard);
+
+ // if the guard works, this should abort
+ (void)IPCThreadState::self()->getCallingPid();
+
+ IPCThreadState::self()->restoreGetCallingSpGuard(origGuard);
+ return NO_ERROR;
+ }
+
case BINDER_LIB_TEST_GETPID:
reply->writeInt32(getpid());
return NO_ERROR;
@@ -1489,6 +1512,14 @@ int run_server(int index, int readypipefd, bool usePoll)
{
binderLibTestServiceName += String16(binderserversuffix);
+ // Testing to make sure that calls that we are serving can use getCallin*
+ // even though we don't here.
+ IPCThreadState::SpGuard spGuard{
+ .address = __builtin_frame_address(0),
+ .context = "main server thread",
+ };
+ (void)IPCThreadState::self()->pushGetCallingSpGuard(&spGuard);
+
status_t ret;
sp<IServiceManager> sm = defaultServiceManager();
BinderLibTestService* testServicePtr;
generated by cgit v1.2.3-59-g8ed1b (git 2.39.0) at 2025-10-21 00:48:54 +0000