Crash reading some HDF4 files - double free of pszGCPProjection

[warmerdam]

Opening and closing some HDF4 files results in heap corruption due to a double-free.

Suggested patch

warmerda@amd64[15]% svn diff hdf4imagedataset.cpp
Index: hdf4imagedataset.cpp
===================================================================
--- hdf4imagedataset.cpp        (revision 11740)
+++ hdf4imagedataset.cpp        (working copy)
@@ -1609,8 +1609,8 @@
     if ( nLatCount && nLongCount && nLatCount == nLongCount
          && pLat && pLong )
     {
-        if ( pszGCPProjection )
-            CPLFree( pszGCPProjection );
+        CPLFree( pszGCPProjection );
+        pszGCPProjection = NULL;
 
         // ASTER Level 1A
         if ( eProduct == PROD_ASTER_L1A )

[warmerdam]

Patch applied in trunk, 1.4.x branch and 1.4-esri branch.