BUG: protect against access an attribute of a NULL pointer

Have PyArray_GetCastSafety return -1 if from is NULL

1 files changed, 7 insertions, 2 deletions

diff --git a/numpy/core/src/multiarray/convert_datatype.c b/numpy/core/src/multiarray/convert_datatype.c
index d197a4bea..716e5dd3d 100644
--- a/numpy/core/src/multiarray/convert_datatype.c
+++ b/numpy/core/src/multiarray/convert_datatype.c
@@ -417,6 +417,9 @@ PyArray_GetCastSafety(
     if (to != NULL) {
         to_dtype = NPY_DTYPE(to);
     }
+    if (from == NULL) {
+        return -1;
+    }
     PyObject *meth = PyArray_GetCastingImpl(NPY_DTYPE(from), to_dtype);
     if (meth == NULL) {
         return -1;
@@ -3293,8 +3296,10 @@ void_to_void_resolve_descriptors(
                 casting = NPY_NO_CASTING | _NPY_CAST_IS_VIEW;
             }
         }
-        NPY_CASTING field_casting = PyArray_GetCastSafety(
-                given_descrs[0]->subarray->base, given_descrs[1]->subarray->base, NULL);
+
+        PyArray_Descr *from_base = (from_sub == NULL) ? NULL : from_sub->base;
+        PyArray_Descr *to_base = (to_sub == NULL) ? NULL : to_sub->base;
+        NPY_CASTING field_casting = PyArray_GetCastSafety(from_base, to_base, NULL);
         if (field_casting < 0) {
             return -1;
         }