commit f183fdd024bfa87e929219ac537b7090eabae9b1
author Steven Moreland <smoreland@google.com> Tue Oct 27 00:12:12 2020 +0000
committer Steven Moreland <smoreland@google.com> Mon Nov 09 21:05:06 2020 +0000
tree 4ec6148be9104ef1e4e6b7be15d15599db2ab64b
parent b40b64d0f8740dfa06da50b56ed48bf496dee4f8

libbinder: support TF_CLEAR_BUF

This flag instructs the kernel to clear transactions from send/reply
buffers for certain transactions which may contain sensitive data, as a
security precaution.

Bug: 171501998
Test: binderLibTest (only checks there is no error)
Change-Id: I69d732e5cc2b15472dc52d47c66716bc1b3be6ae

libs/binder/IPCThreadState.cpp

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 "