[freetype2] master b5e003f 1/2: [cff] Commit vstore data and regions on allocation.

[Werner Lemberg]

branch: master
commit b5e003f1f2866940a9c5bb1632f79ed76161f839
Author: Ben Wagner <bungeman@chromium.org>
Commit: Alexei Podtelezhnikov <apodtele@gmail.com>

    [cff] Commit vstore data and regions on allocation.
    
    The vstore->regionCount and vstore->dataCount were read directly
    from the data. However, vstore->varRegionList and vstore->varData
    would still contain uninitialized entries with uninitialized
    pointers in the event of an error, leading to issues when attempting
    to clean up.
    
    Reportd as
      https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=40104
    
    * src/cff/cffload.c (cff_vstore_load): Read the region and data counts
    into locals and update the vstore counts immediately after each entry
    becomes free-able.
---
 src/cff/cffload.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/cff/cffload.c b/src/cff/cffload.c
index 3e7c971..8016059 100644
--- a/src/cff/cffload.c
+++ b/src/cff/cffload.c
@@ -1138,6 +1138,8 @@
     {
       FT_UInt   vsOffset;
       FT_UInt   format;
+      FT_UInt   dataCount;
+      FT_UInt   regionCount;
       FT_ULong  regionListOffset;
 
 
@@ -1161,15 +1163,15 @@
 
       /* read top level fields */
       if ( FT_READ_ULONG( regionListOffset )   ||
-           FT_READ_USHORT( vstore->dataCount ) )
+           FT_READ_USHORT( dataCount ) )
         goto Exit;
 
       /* make temporary copy of item variation data offsets; */
       /* we'll parse region list first, then come back       */
-      if ( FT_QNEW_ARRAY( dataOffsetArray, vstore->dataCount ) )
+      if ( FT_QNEW_ARRAY( dataOffsetArray, dataCount ) )
         goto Exit;
 
-      for ( i = 0; i < vstore->dataCount; i++ )
+      for ( i = 0; i < dataCount; i++ )
       {
         if ( FT_READ_ULONG( dataOffsetArray[i] ) )
           goto Exit;
@@ -1178,13 +1180,14 @@
       /* parse regionList and axisLists */
       if ( FT_STREAM_SEEK( vsOffset + regionListOffset ) ||
            FT_READ_USHORT( vstore->axisCount )           ||
-           FT_READ_USHORT( vstore->regionCount )         )
+           FT_READ_USHORT( regionCount )                 )
         goto Exit;
 
-      if ( FT_QNEW_ARRAY( vstore->varRegionList, vstore->regionCount ) )
+      vstore->regionCount = 0;
+      if ( FT_QNEW_ARRAY( vstore->varRegionList, regionCount ) )
         goto Exit;
 
-      for ( i = 0; i < vstore->regionCount; i++ )
+      for ( i = 0; i < regionCount; i++ )
       {
         CFF_VarRegion*  region = &vstore->varRegionList[i];
 
@@ -1192,6 +1195,9 @@
         if ( FT_QNEW_ARRAY( region->axisList, vstore->axisCount ) )
           goto Exit;
 
+        /* keep track of how many axisList to deallocate on error */
+        vstore->regionCount++;
+
         for ( j = 0; j < vstore->axisCount; j++ )
         {
           CFF_AxisCoords*  axis = &region->axisList[j];
@@ -1211,10 +1217,11 @@
       }
 
       /* use dataOffsetArray now to parse varData items */
-      if ( FT_QNEW_ARRAY( vstore->varData, vstore->dataCount ) )
+      vstore->dataCount = 0;
+      if ( FT_QNEW_ARRAY( vstore->varData, dataCount ) )
         goto Exit;
 
-      for ( i = 0; i < vstore->dataCount; i++ )
+      for ( i = 0; i < dataCount; i++ )
       {
         CFF_VarData*  data = &vstore->varData[i];
 
@@ -1236,6 +1243,9 @@
         if ( FT_QNEW_ARRAY( data->regionIndices, data->regionIdxCount ) )
           goto Exit;
 
+        /* keep track of how many regionIndices to deallocate on error */
+        vstore->dataCount++;
+
         for ( j = 0; j < data->regionIdxCount; j++ )
         {
           if ( FT_READ_USHORT( data->regionIndices[j] ) )