netCDF multidim: fix use-after-free on string variables in ReadOneEle…

…ment()
OSGeo · Aug 13, 2024 · 817153c · 817153c
1 parent b15aca7
commit 817153c
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/autotest/gdrivers/netcdf_multidim.py b/autotest/gdrivers/netcdf_multidim.py
@@ -1250,6 +1250,15 @@ def dims_from_non_netcdf(rg):
         assert var
         assert var.Read() == ["", "0123456789"]
 
+        var = rg.CreateMDArray(
+            "my_var_string_array_zero_dim", [], gdal.ExtendedDataType.CreateString()
+        )
+        assert var
+        assert var.Write(["foo"]) == gdal.CE_None
+        var = rg.OpenMDArray("my_var_string_array_zero_dim")
+        assert var
+        assert var.Read() == ["foo"]
+
     f()
 
     def f2():

diff --git a/frmts/netcdf/netcdfmultidim.cpp b/frmts/netcdf/netcdfmultidim.cpp
@@ -3403,9 +3403,9 @@ bool netCDFVariable::ReadOneElement(const GDALExtendedDataType &src_datatype,
         NCDF_ERR(ret);
         if (ret != NC_NOERR)
             return false;
-        nc_free_string(1, &pszStr);
         GDALExtendedDataType::CopyValue(&pszStr, src_datatype, pDstBuffer,
                                         bufferDataType);
+        nc_free_string(1, &pszStr);
         return true;
     }