linux: Crash browser on too-big messages to zygote.

content/common/zygote_commands_linux.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_COMMON_ZYGOTE_COMMANDS_LINUX_H_
 #define CONTENT_COMMON_ZYGOTE_COMMANDS_LINUX_H_
 
 namespace content {
 
 // Contents of the initial message sent from the zygote to the browser when it
 // is ready to go.
 static const char kZygoteHelloMessage[] = "ZYGOTE_OK";
 
+// Maximum allowable length for messages sent to the zygote.
+const size_t kZygoteMaxMessageLength = 2048;
+
 // File descriptors initialized by the Zygote Host
 const int kZygoteSocketPairFd = 3;
 const int kZygoteRendererSocketFd = 5;
 // This file descriptor is special. It is passed to the Zygote and a setuid
 // helper will be called to locate the process of the Zygote on the system.
 // This mechanism is used when multiple PID namespaces exist because of the
 // setuid sandbox.
 // It is very important that this file descriptor does not exist in multiple
 // processes.
 // This number must be kept in sync in sandbox/linux/suid/sandbox.c
@@ skipping 11 matching lines @@
   // Check what happend to a child process.
   kZygoteCommandGetTerminationStatus = 2,
 
   // Read a bitmask of kSandboxLinux*
   kZygoteCommandGetSandboxStatus = 3
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_ZYGOTE_COMMANDS_LINUX_H_