commit a88402105b781a519f07d420a5dfb326262f85bc
author Lei Zhang <thestig@chromium.org> Fri Jan 26 03:02:03 2024 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Jan 26 03:02:03 2024 +0000
tree 129c84695098992eac21f25a7d1ff12512c864b3
parent e06220af320e6984f91eab9f0b4d3c3310cb2cb5

Check for errors first in LoadSimpleFont() and LoadCompositeFont()

Check the input font and handle invalid cases first. Mark some variables
as const along the way.

Change-Id: If43ba8f5d9d55a9133d128e6107e1431c2d973aa
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/115830
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Thomas Sepez <tsepez@google.com>

fpdfsdk/fpdf_edittext.cpp

diff --git a/fpdfsdk/fpdf_edittext.cpp b/fpdfsdk/fpdf_edittext.cpp
index aa1e18b..5a3238d 100644
--- a/fpdfsdk/fpdf_edittext.cpp
+++ b/fpdfsdk/fpdf_edittext.cpp
@@ -303,13 +303,6 @@
                                     std::unique_ptr<CFX_Font> font,
                                     pdfium::span<const uint8_t> font_data,
                                     int font_type) {
-  auto font_dict = doc->NewIndirect<CPDF_Dictionary>();
-  font_dict->SetNewFor<CPDF_Name>("Type", "Font");
-  font_dict->SetNewFor<CPDF_Name>(
-      "Subtype", font_type == FPDF_FONT_TYPE1 ? "Type1" : "TrueType");
-  ByteString name = BaseFontNameForType(font.get(), font_type);
-  font_dict->SetNewFor<CPDF_Name>("BaseFont", name);
-
   // If it doesn't have a single char, just fail.
   RetainPtr<CFX_Face> face = font->GetFace();
   if (face->GetGlyphCount() <= 0) {
@@ -324,6 +317,13 @@
     return nullptr;
   }
 
+  auto font_dict = doc->NewIndirect<CPDF_Dictionary>();
+  font_dict->SetNewFor<CPDF_Name>("Type", "Font");
+  font_dict->SetNewFor<CPDF_Name>(
+      "Subtype", font_type == FPDF_FONT_TYPE1 ? "Type1" : "TrueType");
+  const ByteString name = BaseFontNameForType(font.get(), font_type);
+  font_dict->SetNewFor<CPDF_Name>("BaseFont", name);
+
   font_dict->SetNewFor<CPDF_Number>(
       "FirstChar", static_cast<int>(char_codes_and_indices[0].char_code));
   auto widths_array = doc->NewIndirect<CPDF_Array>();
@@ -353,13 +353,25 @@
                                        std::unique_ptr<CFX_Font> font,
                                        pdfium::span<const uint8_t> font_data,
                                        int font_type) {
+  // If it doesn't have a single char, just fail.
+  RetainPtr<CFX_Face> face = font->GetFace();
+  if (face->GetGlyphCount() <= 0) {
+    return nullptr;
+  }
+
+  auto char_codes_and_indices =
+      face->GetCharCodesAndIndices(pdfium::kMaximumSupplementaryCodePoint);
+  if (char_codes_and_indices.empty()) {
+    return nullptr;
+  }
+
   auto font_dict = doc->NewIndirect<CPDF_Dictionary>();
   font_dict->SetNewFor<CPDF_Name>("Type", "Font");
   font_dict->SetNewFor<CPDF_Name>("Subtype", "Type0");
   // TODO(npm): Get the correct encoding, if it's not identity.
   ByteString encoding = "Identity-H";
   font_dict->SetNewFor<CPDF_Name>("Encoding", encoding);
-  ByteString name = BaseFontNameForType(font.get(), font_type);
+  const ByteString name = BaseFontNameForType(font.get(), font_type);
   font_dict->SetNewFor<CPDF_Name>(
       "BaseFont", font_type == FPDF_FONT_TYPE1 ? name + "-" + encoding : name);
 
@@ -384,18 +396,6 @@
   cid_font_dict->SetNewFor<CPDF_Reference>("FontDescriptor", doc,
                                            font_descriptor_dict->GetObjNum());
 
-  // If it doesn't have a single char, just fail.
-  RetainPtr<CFX_Face> face = font->GetFace();
-  if (face->GetGlyphCount() <= 0) {
-    return nullptr;
-  }
-
-  auto char_codes_and_indices =
-      face->GetCharCodesAndIndices(pdfium::kMaximumSupplementaryCodePoint);
-  if (char_codes_and_indices.empty()) {
-    return nullptr;
-  }
-
   std::multimap<uint32_t, uint32_t> to_unicode;
   std::map<uint32_t, uint32_t> widths;
   for (const auto& item : char_codes_and_indices) {