[freetype2] master e1090c6: Fix access to uninitalized memory (#52613).

[Werner LEMBERG]

branch: master
commit e1090c608b72dcfc1899c33974acd056e120aa53
Author: Werner Lemberg <address@hidden>
Commit: Werner Lemberg <address@hidden>

    Fix access to uninitalized memory (#52613).
    
    Also reported as
    
      https://bugs.chromium.org/p/chromium/issues/detail?id=791317
    
    * src/base/ftbitmap.c (ft_bitmap_assure_buffer): If increasing the
    bitmap size needs a larger bitmap buffer, assure that the new memory
    areas are initialized also.
---
 ChangeLog           | 12 ++++++++++++
 src/base/ftbitmap.c | 43 +++++++++++++++++++++++++++++++++++--------
 2 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 4f4e2ee..1d59ec9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,17 @@
 2017-12-08  Werner Lemberg  <address@hidden>
 
+       Fix access to uninitalized memory (#52613).
+
+       Also reported as
+
+         https://bugs.chromium.org/p/chromium/issues/detail?id=791317
+
+       * src/base/ftbitmap.c (ft_bitmap_assure_buffer): If increasing the
+       bitmap size needs a larger bitmap buffer, assure that the new memory
+       areas are initialized also.
+
+2017-12-08  Werner Lemberg  <address@hidden>
+
        Fix `make setup dos' (#52622).
 
        * builds/detect.mk (dos_setup): Properly escape literal `>'
diff --git a/src/base/ftbitmap.c b/src/base/ftbitmap.c
index 2a2a9db..f7bd270 100644
--- a/src/base/ftbitmap.c
+++ b/src/base/ftbitmap.c
@@ -235,21 +235,48 @@
     {
       FT_UInt  len = ( width * bpp + 7 ) >> 3;
 
+      unsigned char*  in  = bitmap->buffer;
+      unsigned char*  out = buffer;
 
-      for ( i = 0; i < bitmap->rows; i++ )
-        FT_MEM_COPY( buffer + (FT_UInt)new_pitch * ( ypixels + i ),
-                     bitmap->buffer + (FT_UInt)pitch * i,
-                     len );
+      unsigned char*  limit = bitmap->buffer + pitch * bitmap->rows;
+      int             delta = new_pitch - pitch;
+
+
+      FT_MEM_ZERO( out, new_pitch * ypixels );
+      out += new_pitch * ypixels;
+
+      while ( in < limit )
+      {
+        FT_MEM_COPY( out, in, len );
+        in  += pitch;
+        out += pitch;
+
+        FT_MEM_ZERO( out, delta );
+        out += delta;
+      }
     }
     else
     {
       FT_UInt  len = ( width * bpp + 7 ) >> 3;
 
+      unsigned char*  in  = bitmap->buffer;
+      unsigned char*  out = buffer;
+
+      unsigned char*  limit = bitmap->buffer + pitch * bitmap->rows;
+      int             delta = new_pitch - pitch;
+
+
+      while ( in < limit )
+      {
+        FT_MEM_COPY( out, in, len );
+        in  += pitch;
+        out += pitch;
+
+        FT_MEM_ZERO( out, delta );
+        out += delta;
+      }
 
-      for ( i = 0; i < bitmap->rows; i++ )
-        FT_MEM_COPY( buffer + (FT_UInt)new_pitch * i,
-                     bitmap->buffer + (FT_UInt)pitch * i,
-                     len );
+      FT_MEM_ZERO( out, new_pitch * ypixels );
     }
 
     FT_FREE( bitmap->buffer );