From d3761d8274036f03107712dd0d27a3ce7ae1a1f0 Mon Sep 17 00:00:00 2001
From: Sergey Prigogin <sprigogin@google.com>
Date: Fri, 18 Feb 2022 21:46:21 -0800
Subject: Crash the agent when receiving an invalid TextEventMessage

Test: later
Bug: N/A
Change-Id: I9840bb3802bfd5cf4891bc8d2017bf6c6ce6b080
---
 .../app/src/main/cpp/base128_input_stream.cc                   | 10 ++++++----
 .../app/src/main/cpp/base128_input_stream.h                    |  2 +-
 .../screen-sharing-agent/app/src/main/cpp/control_messages.cc  |  7 +++++--
 3 files changed, 12 insertions(+), 7 deletions(-)

(limited to 'emulator')

diff --git a/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.cc b/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.cc
index d5f63ee494f..6d36e693a82 100644
--- a/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.cc
+++ b/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.cc
@@ -18,6 +18,8 @@
 
 #include <unistd.h>
 
+#include <memory>
+
 namespace screensharing {
 
 using namespace std;
@@ -112,7 +114,7 @@ bool Base128InputStream::ReadBool() {
   return c != 0;
 }
 
-u16string Base128InputStream::ReadString16() {
+unique_ptr<u16string> Base128InputStream::ReadString16() {
   int len = ReadInt32();
   if (len < 0) {
     throw StreamFormatException::InvalidFormat();
@@ -122,12 +124,12 @@ u16string Base128InputStream::ReadString16() {
   }
   --len;
   if (len == 0) {
-    return u16string();
+    return make_unique<u16string>();
   }
-  auto result = u16string(static_cast<unsigned int>(len), '\0');
+  auto result = make_unique<u16string>(static_cast<unsigned int>(len), '\0');
   try {
     for (int i = 0; i < len; i++) {
-      result[i] = ReadUInt16();
+      (*result)[i] = ReadUInt16();
     }
   } catch (EndOfFile& e) {
     throw StreamFormatException::PrematureEndOfStream();
diff --git a/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.h b/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.h
index 82627f4c75b..ad57c7eb163 100644
--- a/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.h
+++ b/emulator/screen-sharing-agent/app/src/main/cpp/base128_input_stream.h
@@ -44,7 +44,7 @@ public:
   int64_t ReadInt64();
   uint64_t ReadUInt64() { return static_cast<uint64_t>(ReadInt64()); }
   bool ReadBool();
-  std::u16string ReadString16();
+  std::unique_ptr<std::u16string> ReadString16();
 
   class StreamFormatException : public IoException {
   public:
diff --git a/emulator/screen-sharing-agent/app/src/main/cpp/control_messages.cc b/emulator/screen-sharing-agent/app/src/main/cpp/control_messages.cc
index 5c908140eb1..210f524cc15 100644
--- a/emulator/screen-sharing-agent/app/src/main/cpp/control_messages.cc
+++ b/emulator/screen-sharing-agent/app/src/main/cpp/control_messages.cc
@@ -71,8 +71,11 @@ KeyEventMessage* KeyEventMessage::deserialize(Base128InputStream& stream) {
 }
 
 TextInputMessage* TextInputMessage::deserialize(Base128InputStream& stream) {
-  u16string text = stream.ReadString16();
-  return new TextInputMessage(text);
+  unique_ptr<u16string> text = stream.ReadString16();
+  if (text == nullptr || text->empty()) {
+    Log::Fatal("Received a TextInputMessage without text");
+  }
+  return new TextInputMessage(*text);
 }
 
 SetDeviceOrientationMessage* SetDeviceOrientationMessage::deserialize(Base128InputStream& stream) {
-- 
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