[CrOS Printing] Don't send username and filename unencrypted

This situation may come up if policy was changed after printer was
selected. We reject printing job since silently omitting username and
filename could be confusing.

Bug: 1042798
Change-Id: Iba385503d8f7e960291728d6515ca7c236220847
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2004992Reviewed-by: Sean Kau <skau@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734128}

printing/backend/cups_printer.cc

@@ -16,6 +16,7 @@
 
 namespace {
 
+const char kCUPSDeviceUri[] = "device-uri";
 const char kCUPSPrinterInfoOpt[] = "printer-info";
 const char kCUPSPrinterStateOpt[] = "printer-state";
 
@@ -123,6 +124,12 @@ std::string CupsPrinter::GetMakeAndModel() const {
   return make_and_model ? std::string(make_and_model) : std::string();
 }
 
+std::string CupsPrinter::GetUri() const {
+  const char* uri = cupsGetOption(kCUPSDeviceUri, destination_->num_options,
+                                  destination_->options);
+  return uri ? std::string(uri) : std::string();
+}
+
 bool CupsPrinter::EnsureDestInfo() const {
   if (dest_info_)
     return true;

printing/backend/cups_printer.h

@@ -77,6 +77,8 @@ class PRINTING_EXPORT CupsPrinter : public CupsOptionProvider {
 
   std::string GetMakeAndModel() const;
 
+  std::string GetUri() const;
+
   // Lazily initialize dest info as it can require a network call
   bool EnsureDestInfo() const;
 

printing/printing_context_chromeos.cc

@@ -356,6 +356,15 @@ PrintingContext::Result PrintingContextChromeos::UpdatePrinterSettings(
   SetPrintableArea(settings_.get(), media, true);
   cups_options_ = SettingsToCupsOptions(*settings_);
   send_user_info_ = settings_->send_user_info();
+  if (send_user_info_) {
+    DCHECK(printer_);
+    std::string uri_string = printer_->GetUri();
+    const base::StringPiece uri(uri_string);
+    if (!uri.starts_with("ipps:") && !uri.starts_with("https:") &&
+        !uri.starts_with("usb:") && !uri.starts_with("ippusb:")) {
+      return OnError();
+    }
+  }
   username_ = send_user_info_ ? settings_->username() : std::string();
 
   return OK;