Adding upstream version 127.0.upstream/127.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 153 insertions, 288 deletions

diff --git a/gfx/ots/include/ots-memory-stream.h b/gfx/ots/include/ots-memory-stream.h
index cb844709c2..ec0b362fea 100644
--- a/gfx/ots/include/ots-memory-stream.h
+++ b/gfx/ots/include/ots-memory-stream.h
@@ -26,7 +26,7 @@ class MemoryStream : public OTSStream {
       return false;
     }
     std::memcpy(static_cast<char*>(ptr_) + off_, data, length);
-    off_ += length;
+    off_ += static_cast<off_t>(length);
     return true;
   }
 
@@ -82,7 +82,7 @@ class ExpandingMemoryStream : public OTSStream {
       return WriteRaw(data, length);
     }
     std::memcpy(static_cast<char*>(ptr_) + off_, data, length);
-    off_ += length;
+    off_ += static_cast<off_t>(length);
     return true;
   }
 
diff --git a/gfx/ots/moz.yaml b/gfx/ots/moz.yaml
index 50ce2b4e8f..bff78ff44b 100644
--- a/gfx/ots/moz.yaml
+++ b/gfx/ots/moz.yaml
@@ -10,8 +10,8 @@ origin:
 
   url: https://github.com/khaledhosny/ots
 
-  release: 6ba665aa307ea360283191736814863ca398398d (2023-08-16T17:30:00Z).
-  revision: 6ba665aa307ea360283191736814863ca398398d
+  release: d51fceea592507b78cf6c5fd90ba9ef6b969ffd1 (2024-03-26T11:28:30Z).
+  revision: d51fceea592507b78cf6c5fd90ba9ef6b969ffd1
 
   license: BSD-3-Clause
   license-file: LICENSE
@@ -39,4 +39,3 @@ vendoring:
     - ots-lz4.patch
     - ots-rlbox.patch
     - ots-visibility.patch
-    - ots-1850314.patch
diff --git a/gfx/ots/ots-1850314.patch b/gfx/ots/ots-1850314.patch
deleted file mode 100644
index 88088f5064..0000000000
--- a/gfx/ots/ots-1850314.patch
+++ /dev/null
@@ -1,177 +0,0 @@
-commit 362a59be47f9e187eec43df0938def661be6c972
-Author: Jonathan Kew <jkew@mozilla.com>
-Date:   Wed Aug 30 12:55:02 2023 +0000
-
-    Bug 1850314 - Don't do glyph bounding-box fixup for "tricky" fonts, because it may disrupt glyph rendering on macOS. r=gfx-reviewers,lsalzman
-    
-    Differential Revision: https://phabricator.services.mozilla.com/D187096
-
-diff --git a/src/glyf.cc b/src/glyf.cc
-index 0ed9515ef16d6..31487957bf99b 100644
---- a/src/glyf.cc
-+++ b/src/glyf.cc
-@@ -10,6 +10,7 @@
- #include "head.h"
- #include "loca.h"
- #include "maxp.h"
-+#include "name.h"
- 
- // glyf - Glyph Data
- // http://www.microsoft.com/typography/otspec/glyf.htm
-@@ -97,7 +98,8 @@ bool OpenTypeGLYF::ParseSimpleGlyph(Buffer &glyph,
-                                     int16_t& xmin,
-                                     int16_t& ymin,
-                                     int16_t& xmax,
--                                    int16_t& ymax) {
-+                                    int16_t& ymax,
-+                                    bool is_tricky_font) {
-   // read the end-points array
-   uint16_t num_flags = 0;
-   for (int i = 0; i < num_contours; ++i) {
-@@ -219,27 +221,32 @@ bool OpenTypeGLYF::ParseSimpleGlyph(Buffer &glyph,
-   }
- 
-   if (adjusted_bbox) {
--    Warning("Glyph bbox was incorrect; adjusting (glyph %u)", gid);
--    // copy the numberOfContours field
--    this->iov.push_back(std::make_pair(glyph.buffer(), 2));
--    // output a fixed-up version of the bounding box
--    uint8_t* fixed_bbox = new uint8_t[8];
--    fixed_bboxes.push_back(fixed_bbox);
--    xmin = ots_htons(xmin);
--    std::memcpy(fixed_bbox, &xmin, 2);
--    ymin = ots_htons(ymin);
--    std::memcpy(fixed_bbox + 2, &ymin, 2);
--    xmax = ots_htons(xmax);
--    std::memcpy(fixed_bbox + 4, &xmax, 2);
--    ymax = ots_htons(ymax);
--    std::memcpy(fixed_bbox + 6, &ymax, 2);
--    this->iov.push_back(std::make_pair(fixed_bbox, 8));
--    // copy the remainder of the glyph data
--    this->iov.push_back(std::make_pair(glyph.buffer() + 10, glyph.offset() - 10));
--  } else {
--    this->iov.push_back(std::make_pair(glyph.buffer(), glyph.offset()));
-+    if (is_tricky_font) {
-+      Warning("Glyph bbox was incorrect; NOT adjusting tricky font (glyph %u)", gid);
-+    } else {
-+      Warning("Glyph bbox was incorrect; adjusting (glyph %u)", gid);
-+      // copy the numberOfContours field
-+      this->iov.push_back(std::make_pair(glyph.buffer(), 2));
-+      // output a fixed-up version of the bounding box
-+      uint8_t* fixed_bbox = new uint8_t[8];
-+      fixed_bboxes.push_back(fixed_bbox);
-+      xmin = ots_htons(xmin);
-+      std::memcpy(fixed_bbox, &xmin, 2);
-+      ymin = ots_htons(ymin);
-+      std::memcpy(fixed_bbox + 2, &ymin, 2);
-+      xmax = ots_htons(xmax);
-+      std::memcpy(fixed_bbox + 4, &xmax, 2);
-+      ymax = ots_htons(ymax);
-+      std::memcpy(fixed_bbox + 6, &ymax, 2);
-+      this->iov.push_back(std::make_pair(fixed_bbox, 8));
-+      // copy the remainder of the glyph data
-+      this->iov.push_back(std::make_pair(glyph.buffer() + 10, glyph.offset() - 10));
-+      return true;
-+    }
-   }
- 
-+  this->iov.push_back(std::make_pair(glyph.buffer(), glyph.offset()));
-+
-   return true;
- }
- 
-@@ -342,6 +349,10 @@ bool OpenTypeGLYF::Parse(const uint8_t *data, size_t length) {
-     return Error("Missing maxp or loca or head table needed by glyf table");
-   }
- 
-+  OpenTypeNAME *name = static_cast<OpenTypeNAME*>(
-+      GetFont()->GetTypedTable(OTS_TAG_NAME));
-+  bool is_tricky = name->IsTrickyFont();
-+
-   this->maxp = maxp;
- 
-   const unsigned num_glyphs = maxp->num_glyphs;
-@@ -397,7 +408,7 @@ bool OpenTypeGLYF::Parse(const uint8_t *data, size_t length) {
-       // does we will simply ignore it.
-       glyph.set_offset(0);
-     } else if (num_contours > 0) {
--      if (!ParseSimpleGlyph(glyph, i, num_contours, xmin, ymin, xmax, ymax)) {
-+      if (!ParseSimpleGlyph(glyph, i, num_contours, xmin, ymin, xmax, ymax, is_tricky)) {
-         return Error("Failed to parse glyph %d", i);
-       }
-     } else {
-diff --git a/src/glyf.h b/src/glyf.h
-index 05e846f1cb6e8..f85fdc4652fcf 100644
---- a/src/glyf.h
-+++ b/src/glyf.h
-@@ -51,7 +51,8 @@ class OpenTypeGLYF : public Table {
-                         int16_t& xmin,
-                         int16_t& ymin,
-                         int16_t& xmax,
--                        int16_t& ymax);
-+                        int16_t& ymax,
-+                        bool is_tricky_font);
-   bool ParseCompositeGlyph(
-       Buffer &glyph,
-       ComponentPointCount* component_point_count);
-diff --git a/src/name.cc b/src/name.cc
-index fc5074b0587a3..7526e1f72b9ea 100644
---- a/src/name.cc
-+++ b/src/name.cc
-@@ -366,4 +366,44 @@ bool OpenTypeNAME::IsValidNameId(uint16_t nameID, bool addIfMissing) {
-   return this->name_ids.count(nameID);
- }
- 
-+// List of font names considered "tricky" (dependent on applying original TrueType instructions) by FreeType, see
-+// https://gitlab.freedesktop.org/freetype/freetype/-/blob/2d9fce53d4ce89f36075168282fcdd7289e082f9/src/truetype/ttobjs.c#L170-241
-+static const char* tricky_font_names[] = {
-+  "cpop",
-+  "DFGirl-W6-WIN-BF",
-+  "DFGothic-EB",
-+  "DFGyoSho-Lt",
-+  "DFHei",
-+  "DFHSGothic-W5",
-+  "DFHSMincho-W3",
-+  "DFHSMincho-W7",
-+  "DFKaiSho-SB",
-+  "DFKaiShu",
-+  "DFKai-SB",
-+  "DFMing",
-+  "DLC",
-+  "HuaTianKaiTi?",
-+  "HuaTianSongTi?",
-+  "Ming(for ISO10646)",
-+  "MingLiU",
-+  "MingMedium",
-+  "PMingLiU",
-+  "MingLi43"
-+};
-+
-+bool OpenTypeNAME::IsTrickyFont() const {
-+  for (const auto& name : this->names) {
-+    const uint16_t id = name.name_id;
-+    if (id != 1) {
-+      continue;
-+    }
-+    for (const auto* p : tricky_font_names) {
-+      if (name.text.find(p) != std::string::npos) {
-+        return true;
-+      }
-+    }
-+  }
-+  return false;
-+}
-+
- }  // namespace
-diff --git a/src/name.h b/src/name.h
-index 68c7ac096d3f8..a241e77ee26bb 100644
---- a/src/name.h
-+++ b/src/name.h
-@@ -52,6 +52,7 @@ class OpenTypeNAME : public Table {
-   bool Parse(const uint8_t *data, size_t length);
-   bool Serialize(OTSStream *out);
-   bool IsValidNameId(uint16_t nameID, bool addIfMissing = false);
-+  bool IsTrickyFont() const;
- 
-  private:
-   std::vector<NameRecord> names;
diff --git a/gfx/ots/src/cff.cc b/gfx/ots/src/cff.cc
index af54a4a16c..95ff7f744b 100644
--- a/gfx/ots/src/cff.cc
+++ b/gfx/ots/src/cff.cc
@@ -41,7 +41,7 @@ enum FONT_FORMAT {
 // see Appendix. A
 const size_t kNStdString = 390;
 
-typedef std::pair<uint32_t, DICT_OPERAND_TYPE> Operand;
+typedef std::pair<int32_t, DICT_OPERAND_TYPE> Operand;
 
 bool ReadOffset(ots::Buffer &table, uint8_t off_size, uint32_t *offset) {
   if (off_size > 4) {
@@ -172,7 +172,7 @@ bool CheckOffset(const Operand& operand, size_t table_length) {
   if (operand.second != DICT_OPERAND_INTEGER) {
     return OTS_FAILURE();
   }
-  if (operand.first >= table_length) {
+  if (operand.first >= static_cast<int32_t>(table_length) || operand.first < 0) {
     return OTS_FAILURE();
   }
   return true;
@@ -182,7 +182,7 @@ bool CheckSid(const Operand& operand, size_t sid_max) {
   if (operand.second != DICT_OPERAND_INTEGER) {
     return OTS_FAILURE();
   }
-  if (operand.first > sid_max) {
+  if (operand.first > static_cast<int32_t>(sid_max) || operand.first < 0) {
     return OTS_FAILURE();
   }
   return true;
@@ -202,15 +202,13 @@ bool ParseDictDataBcd(ots::Buffer &table, std::vector<Operand> &operands) {
       if ((nibble & 0xf) == 0xf) {
         // TODO(yusukes): would be better to store actual double value,
         // rather than the dummy integer.
-        operands.push_back(std::make_pair(static_cast<uint32_t>(0),
-                                           DICT_OPERAND_REAL));
+        operands.push_back(std::make_pair(0, DICT_OPERAND_REAL));
         return true;
       }
       return OTS_FAILURE();
     }
     if ((nibble & 0x0f) == 0x0f) {
-      operands.push_back(std::make_pair(static_cast<uint32_t>(0),
-                                         DICT_OPERAND_REAL));
+      operands.push_back(std::make_pair(0, DICT_OPERAND_REAL));
       return true;
     }
 
@@ -256,7 +254,7 @@ bool ParseDictDataEscapedOperator(ots::Buffer &table,
   if ((op <= 14) ||
       (op >= 17 && op <= 23) ||
       (op >= 30 && op <= 38)) {
-    operands.push_back(std::make_pair((12U << 8) + op, DICT_OPERATOR));
+    operands.push_back(std::make_pair((12 << 8) + op, DICT_OPERATOR));
     return true;
   }
 
@@ -277,8 +275,9 @@ bool ParseDictDataNumber(ots::Buffer &table, uint8_t b0,
           !table.ReadU8(&b2)) {
         return OTS_FAILURE();
       }
+      //the two-byte value needs to be casted to int16_t in order to get the right sign
       operands.push_back(std::make_pair(
-          static_cast<uint32_t>((b1 << 8) + b2), DICT_OPERAND_INTEGER));
+          static_cast<int16_t>((b1 << 8) + b2), DICT_OPERAND_INTEGER));
       return true;
 
     case 29:  // longint
@@ -289,7 +288,7 @@ bool ParseDictDataNumber(ots::Buffer &table, uint8_t b0,
         return OTS_FAILURE();
       }
       operands.push_back(std::make_pair(
-          static_cast<uint32_t>((b1 << 24) + (b2 << 16) + (b3 << 8) + b4),
+          (b1 << 24) + (b2 << 16) + (b3 << 8) + b4,
           DICT_OPERAND_INTEGER));
       return true;
 
@@ -300,7 +299,7 @@ bool ParseDictDataNumber(ots::Buffer &table, uint8_t b0,
       break;
   }
 
-  uint32_t result;
+  int32_t result;
   if (b0 >=32 && b0 <=246) {
     result = b0 - 139;
   } else if (b0 >=247 && b0 <= 250) {
@@ -332,7 +331,7 @@ bool ParseDictDataReadNext(ots::Buffer &table,
       return ParseDictDataEscapedOperator(table, operands);
     }
     operands.push_back(std::make_pair(
-        static_cast<uint32_t>(op), DICT_OPERATOR));
+        static_cast<int32_t>(op), DICT_OPERATOR));
     return true;
   } else if (op <= 27 || op == 31 || op == 255) {
     // reserved area.
@@ -367,13 +366,13 @@ bool ParseDictDataReadOperands(ots::Buffer& dict,
   return true;
 }
 
-bool ValidCFF2DictOp(uint32_t op, DICT_DATA_TYPE type) {
+bool ValidCFF2DictOp(int32_t op, DICT_DATA_TYPE type) {
   if (type == DICT_DATA_TOPLEVEL) {
     switch (op) {
-      case (12U << 8) + 7:  // FontMatrix
+      case (12 << 8) + 7:  // FontMatrix
       case 17:              // CharStrings
-      case (12U << 8) + 36: // FDArray
-      case (12U << 8) + 37: // FDSelect
+      case (12 << 8) + 36: // FDArray
+      case (12 << 8) + 37: // FDSelect
       case 24:              // vstore
         return true;
       default:
@@ -384,8 +383,8 @@ bool ValidCFF2DictOp(uint32_t op, DICT_DATA_TYPE type) {
       return true;
   } else if (type == DICT_DATA_PRIVATE) {
     switch (op) {
-      case (12U << 8) + 14: // ForceBold
-      case (12U << 8) + 19: // initialRandomSeed
+      case (12 << 8) + 14: // ForceBold
+      case (12 << 8) + 19: // initialRandomSeed
       case 20:              // defaultWidthX
       case 21:              // nominalWidthX
         return false;
@@ -426,7 +425,7 @@ bool ParsePrivateDictData(
     }
 
     // got operator
-    const uint32_t op = operands.back().first;
+    const int32_t op = operands.back().first;
     operands.pop_back();
 
     if (cff2 && !ValidCFF2DictOp(op, DICT_DATA_PRIVATE)) {
@@ -446,8 +445,8 @@ bool ParsePrivateDictData(
         break;
 
       // array
-      case (12U << 8) + 12:  // StemSnapH (delta)
-      case (12U << 8) + 13:  // StemSnapV (delta)
+      case (12 << 8) + 12:  // StemSnapH (delta)
+      case (12 << 8) + 13:  // StemSnapV (delta)
         if (operands.empty()) {
           return OTS_FAILURE();
         }
@@ -458,12 +457,12 @@ bool ParsePrivateDictData(
       case 11:  // StdVW
       case 20:  // defaultWidthX
       case 21:  // nominalWidthX
-      case (12U << 8) + 9:   // BlueScale
-      case (12U << 8) + 10:  // BlueShift
-      case (12U << 8) + 11:  // BlueFuzz
-      case (12U << 8) + 17:  // LanguageGroup
-      case (12U << 8) + 18:  // ExpansionFactor
-      case (12U << 8) + 19:  // initialRandomSeed
+      case (12 << 8) + 9:   // BlueScale
+      case (12 << 8) + 10:  // BlueShift
+      case (12 << 8) + 11:  // BlueFuzz
+      case (12 << 8) + 17:  // LanguageGroup
+      case (12 << 8) + 18:  // ExpansionFactor
+      case (12 << 8) + 19:  // initialRandomSeed
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
@@ -477,7 +476,14 @@ bool ParsePrivateDictData(
         if (operands.back().second != DICT_OPERAND_INTEGER) {
           return OTS_FAILURE();
         }
-        if (operands.back().first >= 1024 * 1024 * 1024) {
+        // In theory a negative operand could occur here, if the Local Subrs
+        // were stored before the Private dict, but this does not seem to be
+        // well supported by implementations, and mishandling of a negative
+        // offset (e.g. by using unsigned offset arithmetic) might become a
+        // vector for exploitation.  AFAIK no major font creation tool will
+        // generate such an offset, so to be on the safe side, we don't allow
+        // it here.
+        if (operands.back().first >= 1024 * 1024 * 1024 || operands.back().first < 0) {
           return OTS_FAILURE();
         }
         if (operands.back().first + offset >= table.length()) {
@@ -505,14 +511,14 @@ bool ParsePrivateDictData(
       }
 
       // boolean
-      case (12U << 8) + 14:  // ForceBold
+      case (12 << 8) + 14:  // ForceBold
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
         if (operands.back().second != DICT_OPERAND_INTEGER) {
           return OTS_FAILURE();
         }
-        if (operands.back().first >= 2) {
+        if (operands.back().first >= 2 || operands.back().first < 0) {
           return OTS_FAILURE();
         }
         break;
@@ -532,7 +538,7 @@ bool ParsePrivateDictData(
         }
         vsindex = operands.back().first;
         if (vsindex < 0 ||
-            vsindex >= (int32_t)out_cff->region_index_count.size()) {
+            vsindex >= static_cast<int32_t>(out_cff->region_index_count.size())) {
           return OTS_FAILURE();
         }
         out_cff->vsindex_per_font.back() = vsindex;
@@ -546,11 +552,15 @@ bool ParsePrivateDictData(
         if (operands.size() < 1) {
           return OTS_FAILURE();
         }
-        if (vsindex >= (int32_t)out_cff->region_index_count.size()) {
+        if (vsindex >= static_cast<int32_t>(out_cff->region_index_count.size())) {
           return OTS_FAILURE();
         }
         uint16_t k = out_cff->region_index_count.at(vsindex);
-        uint16_t n = operands.back().first;
+          
+        if (operands.back().first > static_cast<uint16_t>(0xffff) || operands.back().first < 0){
+          return OTS_FAILURE();
+        }
+        uint16_t n = static_cast<uint16_t>(operands.back().first);
         if (operands.size() < n * (k + 1) + 1) {
           return OTS_FAILURE();
         }
@@ -644,7 +654,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
       if (operands.back().second != DICT_OPERATOR) continue;
 
       // got operator
-      const uint32_t op = operands.back().first;
+      const int32_t op = operands.back().first;
       operands.pop_back();
 
       if (op == 18 && type == DICT_DATA_FDARRAY) {
@@ -686,7 +696,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
     if (operands.back().second != DICT_OPERATOR) continue;
 
     // got operator
-    const uint32_t op = operands.back().first;
+    const int32_t op = operands.back().first;
     operands.pop_back();
 
     if (cff2 && !ValidCFF2DictOp(op, type)) {
@@ -700,10 +710,10 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
       case 2:   // Copyright
       case 3:   // FullName
       case 4:   // FamilyName
-      case (12U << 8) + 0:   // Copyright
-      case (12U << 8) + 21:  // PostScript
-      case (12U << 8) + 22:  // BaseFontName
-      case (12U << 8) + 38:  // FontName
+      case (12 << 8) + 0:   // Copyright
+      case (12 << 8) + 21:  // PostScript
+      case (12 << 8) + 22:  // BaseFontName
+      case (12 << 8) + 38:  // FontName
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
@@ -715,8 +725,8 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
       // array
       case 5:   // FontBBox
       case 14:  // XUID
-      case (12U << 8) + 7:   // FontMatrix
-      case (12U << 8) + 23:  // BaseFontBlend (delta)
+      case (12 << 8) + 7:   // FontMatrix
+      case (12 << 8) + 23:  // BaseFontBlend (delta)
         if (operands.empty()) {
           return OTS_FAILURE();
         }
@@ -724,21 +734,21 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
 
       // number
       case 13:  // UniqueID
-      case (12U << 8) + 2:   // ItalicAngle
-      case (12U << 8) + 3:   // UnderlinePosition
-      case (12U << 8) + 4:   // UnderlineThickness
-      case (12U << 8) + 5:   // PaintType
-      case (12U << 8) + 8:   // StrokeWidth
-      case (12U << 8) + 20:  // SyntheticBase
+      case (12 << 8) + 2:   // ItalicAngle
+      case (12 << 8) + 3:   // UnderlinePosition
+      case (12 << 8) + 4:   // UnderlineThickness
+      case (12 << 8) + 5:   // PaintType
+      case (12 << 8) + 8:   // StrokeWidth
+      case (12 << 8) + 20:  // SyntheticBase
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
         break;
-      case (12U << 8) + 31:  // CIDFontVersion
-      case (12U << 8) + 32:  // CIDFontRevision
-      case (12U << 8) + 33:  // CIDFontType
-      case (12U << 8) + 34:  // CIDCount
-      case (12U << 8) + 35:  // UIDBase
+      case (12 << 8) + 31:  // CIDFontVersion
+      case (12 << 8) + 32:  // CIDFontRevision
+      case (12 << 8) + 33:  // CIDFontType
+      case (12 << 8) + 34:  // CIDCount
+      case (12 << 8) + 35:  // UIDBase
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
@@ -746,7 +756,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
           return OTS_FAILURE();
         }
         break;
-      case (12U << 8) + 6:   // CharstringType
+      case (12 << 8) + 6:   // CharstringType
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
@@ -761,14 +771,14 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
         break;
 
       // boolean
-      case (12U << 8) + 1:   // isFixedPitch
+      case (12 << 8) + 1:   // isFixedPitch
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
         if (operands.back().second != DICT_OPERAND_INTEGER) {
           return OTS_FAILURE();
         }
-        if (operands.back().first >= 2) {
+        if (operands.back().first >= 2 || operands.back().first < 0) {
           return OTS_FAILURE();
         }
         break;
@@ -778,7 +788,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
-        if (operands.back().first <= 2) {
+        if (operands.back().first <= 2 && operands.back().first >= 0) {
           // predefined charset, ISOAdobe, Expert or ExpertSubset, is used.
           break;
         }
@@ -795,7 +805,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
         if (operands.size() != 1) {
           return OTS_FAILURE();
         }
-        if (operands.back().first <= 1) {
+        if (operands.back().first <= 1 && operands.back().first >= 0) {
           break;  // predefined encoding, "Standard" or "Expert", is used.
         }
         if (!CheckOffset(operands.back(), table.length())) {
@@ -856,7 +866,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
         break;
       }
 
-      case (12U << 8) + 36: {  // FDArray
+      case (12 << 8) + 36: {  // FDArray
         if (type != DICT_DATA_TOPLEVEL) {
           return OTS_FAILURE();
         }
@@ -885,7 +895,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
         break;
       }
 
-      case (12U << 8) + 37: {  // FDSelect
+      case (12 << 8) + 37: {  // FDSelect
         if (type != DICT_DATA_TOPLEVEL) {
           return OTS_FAILURE();
         }
@@ -1043,19 +1053,19 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
         if (operands.back().second != DICT_OPERAND_INTEGER) {
           return OTS_FAILURE();
         }
-        const uint32_t private_offset = operands.back().first;
+        const int32_t private_offset = operands.back().first;
         operands.pop_back();
         if (operands.back().second != DICT_OPERAND_INTEGER) {
           return OTS_FAILURE();
         }
-        const uint32_t private_length = operands.back().first;
-        if (private_offset > table.length()) {
+        const int32_t private_length = operands.back().first;
+        if (private_offset > static_cast<int32_t>(table.length())) {
           return OTS_FAILURE();
         }
-        if (private_length >= table.length()) {
+        if (private_length >= static_cast<int32_t>(table.length()) || private_length < 0) {
           return OTS_FAILURE();
         }
-        if (private_length + private_offset > table.length()) {
+        if (private_length + private_offset > static_cast<int32_t>(table.length()) || private_length + private_offset < 0) {
           return OTS_FAILURE();
         }
         // parse "15. Private DICT data"
@@ -1067,7 +1077,7 @@ bool ParseDictData(ots::Buffer& table, ots::Buffer& dict,
       }
 
       // ROS
-      case (12U << 8) + 30:
+      case (12 << 8) + 30:
         if (font_format != FORMAT_UNKNOWN) {
           return OTS_FAILURE();
         }
diff --git a/gfx/ots/src/colr.cc b/gfx/ots/src/colr.cc
index 8931c77c32..a09d3ab3a4 100644
--- a/gfx/ots/src/colr.cc
+++ b/gfx/ots/src/colr.cc
@@ -193,7 +193,15 @@ bool ParsePaintColrLayers(const ots::Font* font,
                           colrState& state)
 {
   if (setContains(state.visited, data)) {
+#ifdef OTS_COLR_CYCLE_CHECK
+    // A cycle would imply an infinite loop during painting, unless the renderer
+    // detects and breaks it. To be safe, reject the table.
     return OTS_FAILURE_MSG("Cycle detected in PaintColrLayers");
+#else
+    // Just issue a warning and return (as we've already checked this subgraph).
+    OTS_WARNING("Cycle detected in COLRv1 glyph paint graph (PaintColrLayers)\n");
+    return true;
+#endif
   }
   state.visited.insert(data);
 
@@ -393,7 +401,12 @@ bool ParsePaintColrGlyph(const ots::Font* font,
                          colrState& state)
 {
   if (setContains(state.visited, data)) {
+#ifdef OTS_COLR_CYCLE_CHECK
     return OTS_FAILURE_MSG("Cycle detected in PaintColrGlyph");
+#else
+    OTS_WARNING("Cycle detected in COLRv1 glyph paint graph (PaintColrGlyph)\n");
+    return true;
+#endif
   }
   state.visited.insert(data);
 
diff --git a/gfx/ots/src/glyf.cc b/gfx/ots/src/glyf.cc
index 31487957bf..12c0537f64 100644
--- a/gfx/ots/src/glyf.cc
+++ b/gfx/ots/src/glyf.cc
@@ -95,10 +95,10 @@ bool OpenTypeGLYF::ParseFlagsForSimpleGlyph(Buffer &glyph,
 bool OpenTypeGLYF::ParseSimpleGlyph(Buffer &glyph,
                                     unsigned gid,
                                     int16_t num_contours,
-                                    int16_t& xmin,
-                                    int16_t& ymin,
-                                    int16_t& xmax,
-                                    int16_t& ymax,
+                                    int16_t xmin,
+                                    int16_t ymin,
+                                    int16_t xmax,
+                                    int16_t ymax,
                                     bool is_tricky_font) {
   // read the end-points array
   uint16_t num_flags = 0;
diff --git a/gfx/ots/src/glyf.h b/gfx/ots/src/glyf.h
index f85fdc4652..c0d5871edf 100644
--- a/gfx/ots/src/glyf.h
+++ b/gfx/ots/src/glyf.h
@@ -48,10 +48,10 @@ class OpenTypeGLYF : public Table {
   bool ParseSimpleGlyph(Buffer &glyph,
                         unsigned gid,
                         int16_t num_contours,
-                        int16_t& xmin,
-                        int16_t& ymin,
-                        int16_t& xmax,
-                        int16_t& ymax,
+                        int16_t xmin,
+                        int16_t ymin,
+                        int16_t xmax,
+                        int16_t ymax,
                         bool is_tricky_font);
   bool ParseCompositeGlyph(
       Buffer &glyph,
diff --git a/gfx/ots/src/maxp.cc b/gfx/ots/src/maxp.cc
index 232e4a9889..90f53b0e39 100644
--- a/gfx/ots/src/maxp.cc
+++ b/gfx/ots/src/maxp.cc
@@ -29,39 +29,49 @@ bool OpenTypeMAXP::Parse(const uint8_t *data, size_t length) {
     return Error("numGlyphs is 0");
   }
 
-  if (version >> 16 == 1) {
-    this->version_1 = true;
-    if (!table.ReadU16(&this->max_points) ||
-        !table.ReadU16(&this->max_contours) ||
-        !table.ReadU16(&this->max_c_points) ||
-        !table.ReadU16(&this->max_c_contours) ||
-        !table.ReadU16(&this->max_zones) ||
-        !table.ReadU16(&this->max_t_points) ||
-        !table.ReadU16(&this->max_storage) ||
-        !table.ReadU16(&this->max_fdefs) ||
-        !table.ReadU16(&this->max_idefs) ||
-        !table.ReadU16(&this->max_stack) ||
-        !table.ReadU16(&this->max_size_glyf_instructions) ||
-        !table.ReadU16(&this->max_c_components) ||
-        !table.ReadU16(&this->max_c_depth)) {
-      return Error("Failed to read version 1 table data");
-    }
-
-    if (this->max_zones == 0) {
-      // workaround for ipa*.ttf Japanese fonts.
-      Warning("Bad maxZones: %u", this->max_zones);
-      this->max_zones = 1;
-    } else if (this->max_zones == 3) {
-      // workaround for Ecolier-*.ttf fonts.
-      Warning("Bad maxZones: %u", this->max_zones);
-      this->max_zones = 2;
-    }
-
-    if ((this->max_zones != 1) && (this->max_zones != 2)) {
-      return Error("Bad maxZones: %u", this->max_zones);
-    }
-  } else {
-    this->version_1 = false;
+  this->version_1 = false;
+
+  // Per https://learn.microsoft.com/en-gb/typography/opentype/spec/maxp,
+  // the only two 'maxp' version numbers are 0.5 (for CFF/CFF2) and 1.0
+  // (for TrueType).
+  // If it's version 0.5, there is nothing more to read.
+  if (version == 0x00005000) {
+    return true;
+  }
+
+  if (version != 0x00010000) {
+    Warning("Unexpected version 0x%08x; attempting to read as version 1.0",
+            version);
+  }
+
+  // Otherwise, try to read the version 1.0 fields:
+  if (!table.ReadU16(&this->max_points) ||
+      !table.ReadU16(&this->max_contours) ||
+      !table.ReadU16(&this->max_c_points) ||
+      !table.ReadU16(&this->max_c_contours) ||
+      !table.ReadU16(&this->max_zones) ||
+      !table.ReadU16(&this->max_t_points) ||
+      !table.ReadU16(&this->max_storage) ||
+      !table.ReadU16(&this->max_fdefs) ||
+      !table.ReadU16(&this->max_idefs) ||
+      !table.ReadU16(&this->max_stack) ||
+      !table.ReadU16(&this->max_size_glyf_instructions) ||
+      !table.ReadU16(&this->max_c_components) ||
+      !table.ReadU16(&this->max_c_depth)) {
+    Warning("Failed to read version 1.0 fields, downgrading to version 0.5");
+    return true;
+  }
+
+  this->version_1 = true;
+
+  if (this->max_zones < 1) {
+    // workaround for ipa*.ttf Japanese fonts.
+    Warning("Bad maxZones: %u", this->max_zones);
+    this->max_zones = 1;
+  } else if (this->max_zones > 2) {
+    // workaround for Ecolier-*.ttf fonts and bad fonts in some PDFs
+    Warning("Bad maxZones: %u", this->max_zones);
+    this->max_zones = 2;
   }
 
   return true;
diff --git a/gfx/ots/src/ots.cc b/gfx/ots/src/ots.cc
index 73b1d235cf..1ee4498363 100644
--- a/gfx/ots/src/ots.cc
+++ b/gfx/ots/src/ots.cc
@@ -728,12 +728,18 @@ bool ProcessGeneric(ots::FontFile *header,
   ots::Table *loca = font->GetTable(OTS_TAG_LOCA);
   ots::Table *cff  = font->GetTable(OTS_TAG_CFF);
   ots::Table *cff2 = font->GetTable(OTS_TAG_CFF2);
+  ots::OpenTypeMAXP *maxp = static_cast<ots::OpenTypeMAXP*>(
+    font->GetTypedTable(OTS_TAG_MAXP));
 
   if (glyf && loca) {
     if (font->version != 0x000010000) {
       OTS_WARNING_MSG_HDR("wrong sfntVersion for glyph data");
       font->version = 0x000010000;
     }
+    if (!maxp->version_1) {
+      return OTS_FAILURE_MSG_TAG("wrong maxp version for glyph data",
+                                 OTS_TAG_MAXP);
+    }
     if (cff)
        cff->Drop("font contains both CFF and glyf/loca tables");
     if (cff2)
@@ -747,6 +753,10 @@ bool ProcessGeneric(ots::FontFile *header,
        glyf->Drop("font contains both CFF and glyf tables");
     if (loca)
        loca->Drop("font contains both CFF and loca tables");
+    if (maxp->version_1) {
+      OTS_WARNING_MSG_HDR("fixing incorrect maxp version for CFF font");
+      maxp->version_1 = false;
+    }
   } else if (font->GetTable(OTS_TAG('C','B','D','T')) &&
              font->GetTable(OTS_TAG('C','B','L','C'))) {
       // We don't sanitize bitmap tables, but don’t reject bitmap-only fonts if