Check fread() return values in CFX_FolderFontInfo::GetFontData().

core/src/fxge/ge/fx_ge_fontmap.cpp

Index: core/src/fxge/ge/fx_ge_fontmap.cpp
diff --git a/core/src/fxge/ge/fx_ge_fontmap.cpp b/core/src/fxge/ge/fx_ge_fontmap.cpp
index af0a9efdaadc71e0c0cfa3127adcc9eaec471cf9..4f627ac96b471be15b635638927181540b770d20 100644
--- a/core/src/fxge/ge/fx_ge_fontmap.cpp
+++ b/core/src/fxge/ge/fx_ge_fontmap.cpp
@@ -1510,8 +1510,10 @@ FX_DWORD CFX_FolderFontInfo::GetFontData(void* hFont,
     }
   }
   if (datasize && size >= datasize && pFile) {

[Nico, 2015/11/02 19:55:43]

From how I understood the code, this check was supposed to make sure this would
never happen (no idea if it did so successfully)…

[Lei Zhang, 2015/11/02 19:59:09]

Just because the buffer is big enough, and |pFile| is not NULL, that does not
mean fread() is guaranteed to succeed. e.g. the OS can have a bad day and say
"no data for you!"

-    FXSYS_fseek(pFile, offset, FXSYS_SEEK_SET);
-    FXSYS_fread(buffer, datasize, 1, pFile);
+    if (FXSYS_fseek(pFile, offset, FXSYS_SEEK_SET) < 0 ||
+        FXSYS_fread(buffer, datasize, 1, pFile) != 1) {
+      datasize = 0;
+    }
   }
   if (pFile) {
     FXSYS_fclose(pFile);