NaCl: enable meta-based validation for shared libraries.

chrome/browser/nacl_host/nacl_process_host.cc

Index: chrome/browser/nacl_host/nacl_process_host.cc
diff --git a/chrome/browser/nacl_host/nacl_process_host.cc b/chrome/browser/nacl_host/nacl_process_host.cc
index 50d9616bf65694bc9b7557d231c8fd7526fe813b..5bed3a5bc093d456e01459d4ca6c5dccec92494e 100644
--- a/chrome/browser/nacl_host/nacl_process_host.cc
+++ b/chrome/browser/nacl_host/nacl_process_host.cc
@@ -623,6 +623,8 @@ bool NaClProcessHost::OnMessageReceived(const IPC::Message& msg) {
                         OnQueryKnownToValidate)
     IPC_MESSAGE_HANDLER(NaClProcessMsg_SetKnownToValidate,
                         OnSetKnownToValidate)
+    IPC_MESSAGE_HANDLER_DELAY_REPLY(NaClProcessMsg_ResolveFileNonce,
+                                    OnResolveFileNonce)
 #if defined(OS_WIN)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(NaClProcessMsg_AttachDebugExceptionHandler,
                                     OnAttachDebugExceptionHandler)
@@ -761,7 +763,6 @@ bool NaClProcessHost::StartNaClExecution() {
   if (params.uses_irt) {
     base::PlatformFile irt_file = nacl_browser->IrtFile();
     CHECK_NE(irt_file, base::kInvalidPlatformFileValue);
-
     // Send over the IRT file handle.  We don't close our own copy!
     if (!ShareHandleToSelLdr(data.handle, irt_file, false, &params.handles))
       return false;
@@ -930,6 +931,63 @@ void NaClProcessHost::OnSetKnownToValidate(const std::string& signature) {
   NaClBrowser::GetInstance()->SetKnownToValidate(signature, off_the_record_);
 }
 
+void NaClProcessHost::FileResolved(
+    base::PlatformFile* file,
+    const base::FilePath& file_path,
+    IPC::Message* reply_msg) {
+
+  if (*file != base::kInvalidPlatformFileValue) {
+    IPC::PlatformFileForTransit handle = IPC::GetFileHandleForProcess(
+        *file,
+        process_->GetData().handle,
+        true /* close_source */);
+    NaClProcessMsg_ResolveFileNonce::WriteReplyParams(
+        reply_msg,
+        handle,
+        file_path);
+  } else {
+    NaClProcessMsg_ResolveFileNonce::WriteReplyParams(
+        reply_msg,
+        IPC::InvalidPlatformFileForTransit(),
+        base::FilePath(FILE_PATH_LITERAL("")));
+  }
+  Send(reply_msg);
+}
+
+void NaClProcessHost::OnResolveFileNonce(uint64 nonce,
+                                         IPC::Message* reply_msg) {
+  // Was the file registered?
+  base::FilePath file_path;
+  if (!NaClBrowser::GetInstance()->GetFilePath(nonce, &file_path)){

[bennet.yee, 2013/05/16 01:52:48]

this should never happen in normal operation -- and is a good signal that the
renderer and/or the NaCl module was compromised.  perhaps logging something? 
kill either the renderer or the NaCl module, or both?  justin: any advice?

[Nick Bray (chromium), 2013/05/16 16:38:17]

This could happen someone launches 10+ NaCl modules at once.  The file path
cache has a limited size, and it will evict the oldest entry.  Queries for
evicted entries will fail gracefully.  Added a comment.

+     NaClProcessMsg_ResolveFileNonce::WriteReplyParams(
+         reply_msg,
+         IPC::InvalidPlatformFileForTransit(),
+         base::FilePath(FILE_PATH_LITERAL("")));
+     Send(reply_msg);
+     return;
+  }
+
+  // Scratch space to share between the callbacks.
+  base::PlatformFile* data = new base::PlatformFile();
+
+  // Open the file.
+  if (!content::BrowserThread::PostBlockingPoolTaskAndReply(
+      FROM_HERE,
+      base::Bind(nacl::OpenNaClExecutableImpl,
+                 file_path, data),
+      base::Bind(&NaClProcessHost::FileResolved,
+                 weak_factory_.GetWeakPtr(),
+                 base::Owned(data),
+                 file_path,
+                 reply_msg))) {
+     NaClProcessMsg_ResolveFileNonce::WriteReplyParams(
+         reply_msg,
+         IPC::InvalidPlatformFileForTransit(),
+         base::FilePath(FILE_PATH_LITERAL("")));
+     Send(reply_msg);
+  }
+}
+
 #if defined(OS_WIN)
 void NaClProcessHost::OnAttachDebugExceptionHandler(const std::string& info,
                                                     IPC::Message* reply_msg) {