[freetype2] master 8667042: [cff] Integer overflow.

[Werner LEMBERG]

branch: master
commit 8667042997cb9095d3c925417b29f5a3163ab352
Author: Werner Lemberg <address@hidden>
Commit: Werner Lemberg <address@hidden>

    [cff] Integer overflow.
    
    Reported as
    
      https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2089
    
    * src/cff/cffload.c (cff_blend_doBlend): User OVERFLOW_ADD_INT32.
---
 ChangeLog         | 10 ++++++++++
 src/cff/cffload.c |  9 ++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7f68614..6442e87 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2017-06-05  Werner Lemberg  <address@hidden>
+
+       [cff] Integer overflow.
+
+       Reported as
+
+         https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2089
+
+       * src/cff/cffload.c (cff_blend_doBlend): User OVERFLOW_ADD_INT32.
+
 2017-06-04  Werner Lemberg  <address@hidden>
 
        [cff, truetype] Integer overflows.
diff --git a/src/cff/cffload.c b/src/cff/cffload.c
index 3beaeb1..2ee4387 100644
--- a/src/cff/cffload.c
+++ b/src/cff/cffload.c
@@ -1352,9 +1352,12 @@
       sum = cff_parse_num( parser, &parser->stack[i + base] ) * 65536;
 
       for ( j = 1; j < blend->lenBV; j++ )
-        sum += FT_MulFix( *weight++,
-                          cff_parse_num( parser,
-                                         &parser->stack[delta++] ) * 65536 );
+        sum = OVERFLOW_ADD_INT32(
+                sum,
+                FT_MulFix(
+                  *weight++,
+                  cff_parse_num( parser,
+                                 &parser->stack[delta++] ) * 65536 ) );
 
       /* point parser stack to new value on blend_stack */
       parser->stack[i + base] = subFont->blend_top;