Merge "libbinder: Parcel: validate read data before write" into tm-dev am: fde1dbb

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/30026349

Change-Id: I50a1109ea468e66ccc657014a22f83914b2f16e5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

Author: Steven Moreland

libs/binder/Parcel.cpp

@@ -888,6 +888,10 @@ void* Parcel::writeInplace(size_t len)
         //printf("Writing %ld bytes, padded to %ld\n", len, padded);
         uint8_t* const data = mData+mDataPos;
 
+        if (status_t status = validateReadData(mDataPos + padded); status != OK) {
+            return nullptr; // drops status
+        }
+
         // Need to pad at end?
         if (padded != len) {
 #if BYTE_ORDER == BIG_ENDIAN
@@ -1405,6 +1409,10 @@ status_t Parcel::writeObject(const flat_binder_object& val, bool nullMetaData)
     const bool enoughObjects = mObjectsSize < mObjectsCapacity;
     if (enoughData && enoughObjects) {
 restart_write:
+        if (status_t status = validateReadData(mDataPos + sizeof(val)); status != OK) {
+            return status;
+        }
+
         *reinterpret_cast<flat_binder_object*>(mData+mDataPos) = val;
 
         // remember if it's a file descriptor
@@ -1621,6 +1629,10 @@ status_t Parcel::writeAligned(T val) {
 
     if ((mDataPos+sizeof(val)) <= mDataCapacity) {
 restart_write:
+        if (status_t status = validateReadData(mDataPos + sizeof(val)); status != OK) {
+            return status;
+        }
+
         memcpy(mData + mDataPos, &val, sizeof(val));
         return finishWrite(sizeof(val));
     }