1 files changed, 43 insertions, 33 deletions

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;