--- lcdf-typetools/lcdf-typetools-src/libefont/t1rw.cc
+++ lcdf-typetools/lcdf-typetools-src/libefont/t1rw.cc	2018-02-22 22:32:26.288398000 +0000
@@ -117,7 +117,7 @@ inline int
 Type1Reader::eexec(int c)
 {
     unsigned char answer = (unsigned char)(c ^ (_r >> 8));
-    _r = (((unsigned char)c + _r) * t1C1 + t1C2) & 0xFFFF;
+    _r = (((unsigned char)c + _r) * (uint32_t) t1C1 + t1C2) & 0xFFFF;
     return answer;
 }
 
@@ -439,7 +439,7 @@ inline unsigned char
 Type1Writer::eexec(int p)
 {
     unsigned char c = ((unsigned char)p ^ (_r >> 8)) & 0xFF;
-    _r = ((c + _r) * t1C1 + t1C2) & 0xFFFF;
+    _r = ((c + _r) * (uint32_t) t1C1 + t1C2) & 0xFFFF;
     return c;
 }