PDF: Interpret printing permission bits correctly.

pdf/pdfium/pdfium_engine.cc

 // 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.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 
 #include "base/i18n/icu_encoding_detection.h"
 #include "base/i18n/icu_string_conversions.h"
@@ skipping 574 matching lines @@
       doc_(NULL),
       form_(NULL),
       defer_page_unload_(false),
       selecting_(false),
       mouse_down_state_(PDFiumPage::NONSELECTABLE_AREA,
                         PDFiumPage::LinkTarget()),
       next_page_to_search_(-1),
       last_page_to_search_(-1),
       last_character_index_to_search_(-1),
       permissions_(0),
+      permissions_handler_revision_(-1),
       fpdf_availability_(NULL),
       next_timer_id_(0),
       last_page_mouse_down_(-1),
       first_visible_page_(-1),
       most_visible_page_(-1),
       called_do_document_action_(false),
       render_grayscale_(false),
       progressive_paint_timeout_(0),
       getting_password_(false) {
   find_factory_.Initialize(this);
@@ skipping 1711 matching lines @@
       GetCharIndex(point, &page_index, &temp, &form_type, &target);
   if (area == PDFiumPage::WEBLINK_AREA)
     url = target.url;
   return url;
 }
 
 bool PDFiumEngine::IsSelecting() {
   return selecting_;
 }
 
 bool PDFiumEngine::HasPermission(DocumentPermission permission) const {

[raymes, 2015/06/09 00:32:59]

Is it worth checking that this is not -1?

[Lei Zhang, 2015/06/09 00:39:41]

I'm interpreting -1 as unknown and treating it as "we are not respecting any
permission bits", so it fits with the < 2 comparison.

+  // PDF 1.7 spec, section 3.5.2 says: "If the revision number is 2 or greater,
+  // the operations to which user access can be controlled are as follows: ..."
+  //
+  // Thus for revision numbers less than 2, permissions are ignored and this
+  // always returns true.
+  if (permissions_handler_revision_ < 2)
+    return true;
+
+  // Handle high quality printing permission separately for security handler
+  // revision 3+.
+  if (permission == PERMISSION_PRINT_HIGH_QUALITY &&
+      permissions_handler_revision_ >= 3) {
+    return (permissions_ & kPDFPermissionPrintLowQualityMask) != 0 &&
+           (permissions_ & kPDFPermissionPrintHighQualityMask) != 0;
+  }
+
   switch (permission) {
     case PERMISSION_COPY:
       return (permissions_ & kPDFPermissionCopyMask) != 0;
     case PERMISSION_COPY_ACCESSIBLE:
       return (permissions_ & kPDFPermissionCopyAccessibleMask) != 0;
     case PERMISSION_PRINT_LOW_QUALITY:
+    case PERMISSION_PRINT_HIGH_QUALITY:

[raymes, 2015/06/09 00:32:59]

So I guess that if the revision is <3 then you only need the low quality bit in
order to print at high quality? Is that true? It might be worth making a note of
that here and also above in the revision >=3 branch

[Lei Zhang, 2015/06/09 00:39:41]

Sure.

       return (permissions_ & kPDFPermissionPrintLowQualityMask) != 0;
-    case PERMISSION_PRINT_HIGH_QUALITY:
-      return (permissions_ & kPDFPermissionPrintLowQualityMask) != 0 &&
-             (permissions_ & kPDFPermissionPrintHighQualityMask) != 0;
     default:
       return true;
   }
 }
 
 void PDFiumEngine::SelectAll() {
   SelectionChangeInvalidator selection_invalidator(this);
 
   selection_.clear();
   for (size_t i = 0; i < pages_.size(); ++i)
@@ skipping 268 matching lines @@
 
   if (!doc_) {
     client_->DocumentLoadFailed();
     return;
   }
 
   if (FPDFDoc_GetPageMode(doc_) == PAGEMODE_USEOUTLINES)
     client_->DocumentHasUnsupportedFeature("Bookmarks");
 
   permissions_ = FPDF_GetDocPermissions(doc_);
+  permissions_handler_revision_ = FPDF_GetSecurityHandlerRevision(doc_);
 
   if (!form_) {
     // Only returns 0 when data isn't available.  If form data is downloaded, or
     // if this isn't a form, returns positive values.
     if (!doc_loader_.IsDocumentComplete() &&
         !FPDFAvail_IsFormAvail(fpdf_availability_, &download_hints_)) {
       return;
     }
 
     form_ = FPDFDOC_InitFormFillEnvironment(
@@ skipping 1378 matching lines @@
     double* height) {
   FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, NULL);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf