diff --git a/libs/binder/Android.bp b/libs/binder/Android.bp
index e6071a0..e0d5378 100644
--- a/libs/binder/Android.bp
+++ b/libs/binder/Android.bp
@@ -112,6 +112,7 @@
         "Stability.cpp",
         "Status.cpp",
         "TextOutput.cpp",
+        "Utils.cpp",
         ":libbinder_aidl",
     ],
 
diff --git a/libs/binder/Binder.cpp b/libs/binder/Binder.cpp
index 6ca3b16..f2d223d 100644
--- a/libs/binder/Binder.cpp
+++ b/libs/binder/Binder.cpp
@@ -173,6 +173,10 @@
 {
     data.setDataPosition(0);
 
+    if (reply != nullptr && (flags & FLAG_CLEAR_BUF)) {
+        reply->markSensitive();
+    }
+
     status_t err = NO_ERROR;
     switch (code) {
         case PING_TRANSACTION:
diff --git a/libs/binder/IPCThreadState.cpp b/libs/binder/IPCThreadState.cpp
index 05fcc2b..a3a2f87 100644
--- a/libs/binder/IPCThreadState.cpp
+++ b/libs/binder/IPCThreadState.cpp
@@ -1244,7 +1244,9 @@
             if ((tr.flags & TF_ONE_WAY) == 0) {
                 LOG_ONEWAY("Sending reply to %d!", mCallingPid);
                 if (error < NO_ERROR) reply.setError(error);
-                sendReply(reply, 0);
+
+                constexpr uint32_t kForwardReplyFlags = TF_CLEAR_BUF;
+                sendReply(reply, (tr.flags & kForwardReplyFlags));
             } else {
                 if (error != OK || reply.dataSize() != 0) {
                     alog << "oneway function results will be dropped but finished with status "
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 27cf97c..feeb819 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -49,6 +49,7 @@
 
 #include <private/binder/binder_module.h>
 #include "Static.h"
+#include "Utils.h"
 
 #define LOG_REFS(...)
 //#define LOG_REFS(...) ALOG(LOG_DEBUG, LOG_TAG, __VA_ARGS__)
@@ -502,6 +503,11 @@
     return mHasFds;
 }
 
+void Parcel::markSensitive() const
+{
+    mDeallocZero = true;
+}
+
 void Parcel::updateWorkSourceRequestHeaderPosition() const {
     // Only update the request headers once. We only want to point
     // to the first headers read/written.
@@ -2627,6 +2633,9 @@
             LOG_ALLOC("Parcel %p: freeing with %zu capacity", this, mDataCapacity);
             gParcelGlobalAllocSize -= mDataCapacity;
             gParcelGlobalAllocCount--;
+            if (mDeallocZero) {
+                zeroMemory(mData, mDataSize);
+            }
             free(mData);
         }
         if (mObjects) free(mObjects);
@@ -2649,6 +2658,21 @@
             : continueWrite(std::max(newSize, (size_t) 128));
 }
 
+static uint8_t* reallocZeroFree(uint8_t* data, size_t oldCapacity, size_t newCapacity, bool zero) {
+    if (!zero) {
+        return (uint8_t*)realloc(data, newCapacity);
+    }
+    uint8_t* newData = (uint8_t*)malloc(newCapacity);
+    if (!newData) {
+        return nullptr;
+    }
+
+    memcpy(newData, data, std::min(oldCapacity, newCapacity));
+    zeroMemory(data, oldCapacity);
+    free(data);
+    return newData;
+}
+
 status_t Parcel::restartWrite(size_t desired)
 {
     if (desired > INT32_MAX) {
@@ -2662,7 +2686,7 @@
         return continueWrite(desired);
     }
 
-    uint8_t* data = (uint8_t*)realloc(mData, desired);
+    uint8_t* data = reallocZeroFree(mData, mDataCapacity, desired, mDeallocZero);
     if (!data && desired > mDataCapacity) {
         mError = NO_MEMORY;
         return NO_MEMORY;
@@ -2813,7 +2837,7 @@
 
         // We own the data, so we can just do a realloc().
         if (desired > mDataCapacity) {
-            uint8_t* data = (uint8_t*)realloc(mData, desired);
+            uint8_t* data = reallocZeroFree(mData, mDataCapacity, desired, mDeallocZero);
             if (data) {
                 LOG_ALLOC("Parcel %p: continue from %zu to %zu capacity", this, mDataCapacity,
                         desired);
@@ -2881,6 +2905,7 @@
     mHasFds = false;
     mFdsKnown = true;
     mAllowFds = true;
+    mDeallocZero = false;
     mOwner = nullptr;
     mOpenAshmemSize = 0;
     mWorkSourceRequestHeaderPosition = 0;
diff --git a/libs/binder/Utils.cpp b/libs/binder/Utils.cpp
new file mode 100644
index 0000000..90a4502
--- /dev/null
+++ b/libs/binder/Utils.cpp
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Utils.h"
+
+#include <string.h>
+
+namespace android {
+
+void zeroMemory(uint8_t* data, size_t size) {
+    memset(data, 0, size);
+}
+
+}   // namespace android
diff --git a/libs/binder/Utils.h b/libs/binder/Utils.h
new file mode 100644
index 0000000..f94b158
--- /dev/null
+++ b/libs/binder/Utils.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cstdint>
+#include <stddef.h>
+
+namespace android {
+
+// avoid optimizations
+void zeroMemory(uint8_t* data, size_t size);
+
+}   // namespace android
diff --git a/libs/binder/include/binder/IBinder.h b/libs/binder/include/binder/IBinder.h
index eea0e89..7b37e8d 100644
--- a/libs/binder/include/binder/IBinder.h
+++ b/libs/binder/include/binder/IBinder.h
@@ -64,6 +64,10 @@
         // Corresponds to TF_ONE_WAY -- an asynchronous call.
         FLAG_ONEWAY             = 0x00000001,
 
+        // Corresponds to TF_CLEAR_BUF -- clear transaction buffers after call
+        // is made
+        FLAG_CLEAR_BUF          = 0x00000020,
+
         // Private userspace flag for transaction which is being requested from
         // a vendor context.
         FLAG_PRIVATE_VENDOR     = 0x10000000,
diff --git a/libs/binder/include/binder/Parcel.h b/libs/binder/include/binder/Parcel.h
index fbfd6c5..84bfe38 100644
--- a/libs/binder/include/binder/Parcel.h
+++ b/libs/binder/include/binder/Parcel.h
@@ -84,6 +84,13 @@
 
     bool                hasFileDescriptors() const;
 
+    // Zeros data when reallocating. Other mitigations may be added
+    // in the future.
+    //
+    // WARNING: some read methods may make additional copies of data.
+    // In order to verify this, heap dumps should be used.
+    void                markSensitive() const;
+
     // Writes the RPC header.
     status_t            writeInterfaceToken(const String16& interface);
     status_t            writeInterfaceToken(const char16_t* str, size_t len);
@@ -600,6 +607,10 @@
     mutable bool        mHasFds;
     bool                mAllowFds;
 
+    // if this parcelable is involved in a secure transaction, force the
+    // data to be overridden with zero when deallocated
+    mutable bool        mDeallocZero;
+
     release_func        mOwner;
     void*               mOwnerCookie;
 
diff --git a/libs/binder/include/private/binder/binder_module.h b/libs/binder/include/private/binder/binder_module.h
index 7be8f7b..0fe7f5b 100644
--- a/libs/binder/include/private/binder/binder_module.h
+++ b/libs/binder/include/private/binder/binder_module.h
@@ -88,7 +88,9 @@
 };
 #endif //BINDER_GET_FROZEN_INFO
 
-
+enum transaction_flags_ext {
+    TF_CLEAR_BUF = 0x20, /* clear buffer on txn complete */
+};
 
 #ifdef __cplusplus
 }   // namespace android
diff --git a/libs/binder/ndk/ibinder.cpp b/libs/binder/ndk/ibinder.cpp
index d35debc..b927f6f 100644
--- a/libs/binder/ndk/ibinder.cpp
+++ b/libs/binder/ndk/ibinder.cpp
@@ -611,7 +611,7 @@
         return STATUS_UNKNOWN_TRANSACTION;
     }
 
-    constexpr binder_flags_t kAllFlags = FLAG_PRIVATE_VENDOR | FLAG_ONEWAY;
+    constexpr binder_flags_t kAllFlags = FLAG_PRIVATE_VENDOR | FLAG_ONEWAY | FLAG_CLEAR_BUF;
     if ((flags & ~kAllFlags) != 0) {
         LOG(ERROR) << __func__ << ": Unrecognized flags sent: " << flags;
         return STATUS_BAD_VALUE;
diff --git a/libs/binder/ndk/include_ndk/android/binder_ibinder.h b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
index 33763d5..ce3d1db 100644
--- a/libs/binder/ndk/include_ndk/android/binder_ibinder.h
+++ b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
@@ -43,7 +43,6 @@
 
 #if __ANDROID_API__ >= 29
 
-// Also see TF_* in kernel's binder.h
 typedef uint32_t binder_flags_t;
 enum {
     /**
diff --git a/libs/binder/ndk/include_platform/android/binder_ibinder_platform.h b/libs/binder/ndk/include_platform/android/binder_ibinder_platform.h
index a99d555..e315c79 100644
--- a/libs/binder/ndk/include_platform/android/binder_ibinder_platform.h
+++ b/libs/binder/ndk/include_platform/android/binder_ibinder_platform.h
@@ -20,6 +20,17 @@
 
 __BEGIN_DECLS
 
+// platform values for binder_flags_t
+enum {
+    /**
+     * The transaction and reply will be cleared by the kernel in read-only
+     * binder buffers storing transactions.
+     *
+     * Introduced in API level 31.
+     */
+    FLAG_CLEAR_BUF = 0x20,
+};
+
 /**
  * Makes calls to AIBinder_getCallingSid work if the kernel supports it. This
  * must be called on a local binder server before it is sent out to any othe
diff --git a/libs/binder/ndk/include_platform/android/binder_parcel_platform.h b/libs/binder/ndk/include_platform/android/binder_parcel_platform.h
index 114a781..d54c1a1 100644
--- a/libs/binder/ndk/include_platform/android/binder_parcel_platform.h
+++ b/libs/binder/ndk/include_platform/android/binder_parcel_platform.h
@@ -33,4 +33,15 @@
  */
 bool AParcel_getAllowFds(const AParcel*);
 
+/**
+ * Data written to the parcel will be zero'd before being deleted or realloced.
+ *
+ * The main use of this is marking a parcel that will be used in a transaction
+ * with FLAG_CLEAR_BUF. When FLAG_CLEAR_BUF is used, the reply parcel will
+ * automatically be marked as sensitive when it is created.
+ *
+ * \param parcel The parcel to clear associated data from.
+ */
+void AParcel_markSensitive(const AParcel* parcel);
+
 __END_DECLS
diff --git a/libs/binder/ndk/libbinder_ndk.map.txt b/libs/binder/ndk/libbinder_ndk.map.txt
index 947cc98..6962f86 100644
--- a/libs/binder/ndk/libbinder_ndk.map.txt
+++ b/libs/binder/ndk/libbinder_ndk.map.txt
@@ -121,15 +121,16 @@
     AServiceManager_registerLazyService; # llndk
     AServiceManager_waitForService; # apex llndk
 
-    AParcel_reset;
-    AParcel_getDataSize;
     AParcel_appendFrom;
     AParcel_create;
+    AParcel_getDataSize;
+    AParcel_reset;
 };
 
 LIBBINDER_NDK_PLATFORM {
   global:
     AParcel_getAllowFds;
+    AParcel_markSensitive;
     extern "C++" {
         AIBinder_fromPlatformBinder*;
         AIBinder_toPlatformBinder*;
diff --git a/libs/binder/ndk/parcel.cpp b/libs/binder/ndk/parcel.cpp
index 2f95318..3e3eda1 100644
--- a/libs/binder/ndk/parcel.cpp
+++ b/libs/binder/ndk/parcel.cpp
@@ -226,6 +226,10 @@
     return parcel->get()->dataPosition();
 }
 
+void AParcel_markSensitive(const AParcel* parcel) {
+    return parcel->get()->markSensitive();
+}
+
 binder_status_t AParcel_writeStrongBinder(AParcel* parcel, AIBinder* binder) {
     sp<IBinder> writeBinder = binder != nullptr ? binder->getBinder() : nullptr;
     return parcel->get()->writeStrongBinder(writeBinder);
diff --git a/libs/binder/rust/src/binder.rs b/libs/binder/rust/src/binder.rs
index 6d0a369..037ee95 100644
--- a/libs/binder/rust/src/binder.rs
+++ b/libs/binder/rust/src/binder.rs
@@ -33,8 +33,7 @@
 
 /// Additional operation flags.
 ///
-/// Can be either 0 for a normal RPC, or [`IBinder::FLAG_ONEWAY`] for a
-/// one-way RPC.
+/// `IBinder::FLAG_*` values.
 pub type TransactionFlags = u32;
 
 /// Super-trait for Binder interfaces.
@@ -91,6 +90,8 @@
 
     /// Corresponds to TF_ONE_WAY -- an asynchronous call.
     const FLAG_ONEWAY: TransactionFlags = sys::FLAG_ONEWAY;
+    /// Corresponds to TF_CLEAR_BUF -- clear transaction buffers after call is made.
+    const FLAG_CLEAR_BUF: TransactionFlags = sys::FLAG_CLEAR_BUF;
 
     /// Is this object still alive?
     fn is_binder_alive(&self) -> bool;
diff --git a/libs/binder/rust/src/parcel.rs b/libs/binder/rust/src/parcel.rs
index 2c1e5a4..6c34824 100644
--- a/libs/binder/rust/src/parcel.rs
+++ b/libs/binder/rust/src/parcel.rs
@@ -100,6 +100,14 @@
 
 // Data serialization methods
 impl Parcel {
+    /// Data written to parcelable is zero'd before being deleted or reallocated.
+    pub fn mark_sensitive(&mut self) {
+        unsafe {
+            // Safety: guaranteed to have a parcel object, and this method never fails
+            sys::AParcel_markSensitive(self.as_native())
+        }
+    }
+
     /// Write a type that implements [`Serialize`] to the `Parcel`.
     pub fn write<S: Serialize + ?Sized>(&mut self, parcelable: &S) -> Result<()> {
         parcelable.serialize(self)
diff --git a/libs/binder/rust/sys/BinderBindings.hpp b/libs/binder/rust/sys/BinderBindings.hpp
index 3f20a4f..ef142b5 100644
--- a/libs/binder/rust/sys/BinderBindings.hpp
+++ b/libs/binder/rust/sys/BinderBindings.hpp
@@ -18,6 +18,7 @@
 #include <android/binder_ibinder_platform.h>
 #include <android/binder_manager.h>
 #include <android/binder_parcel.h>
+#include <android/binder_parcel_platform.h>
 #include <android/binder_process.h>
 #include <android/binder_shell.h>
 #include <android/binder_status.h>
@@ -78,6 +79,7 @@
 
 enum {
     FLAG_ONEWAY = FLAG_ONEWAY,
+    FLAG_CLEAR_BUF = FLAG_CLEAR_BUF,
 };
 
 } // namespace consts
diff --git a/libs/binder/tests/binderLibTest.cpp b/libs/binder/tests/binderLibTest.cpp
index 98f0868..ad4729d 100644
--- a/libs/binder/tests/binderLibTest.cpp
+++ b/libs/binder/tests/binderLibTest.cpp
@@ -402,6 +402,14 @@
     EXPECT_EQ(NO_ERROR, ret);
 }
 
+TEST_F(BinderLibTest, NopTransactionClear) {
+    status_t ret;
+    Parcel data, reply;
+    // make sure it accepts the transaction flag
+    ret = m_server->transact(BINDER_LIB_TEST_NOP_TRANSACTION, data, &reply, TF_CLEAR_BUF);
+    EXPECT_EQ(NO_ERROR, ret);
+}
+
 TEST_F(BinderLibTest, Freeze) {
     status_t ret;
     Parcel data, reply, replypid;