Merge pull request scipy#8817 from WarrenWeckesser/ndimage-origin-bug

BUG: ndimage: Fix validation of the origin argument in correlate and convolve.

scipy/ndimage/filters.py

@@ -49,6 +49,10 @@
            'generic_filter1d', 'generic_filter']
 
 
+def _invalid_origin(origin, lenw):
+    return (origin < -(lenw // 2)) or (origin > (lenw - 1) // 2)
+
+
 @_ni_docstrings.docfiller
 def correlate1d(input, weights, axis=-1, output=None, mode="reflect",
                 cval=0.0, origin=0):
@@ -84,9 +88,10 @@ def correlate1d(input, weights, axis=-1, output=None, mode="reflect",
     if not weights.flags.contiguous:
         weights = weights.copy()
     axis = _ni_support._check_axis(axis, input.ndim)
-    if (len(weights) // 2 + origin < 0) or (len(weights) // 2 +
-                                            origin > len(weights)):
-        raise ValueError('invalid origin')
+    if _invalid_origin(origin, len(weights)):
+        raise ValueError('Invalid origin; origin must satisfy '
+                         '-(len(weights) // 2) <= origin <= '
+                         '(len(weights)-1) // 2')
     mode = _ni_support._extend_mode_to_code(mode)
     _nd_image.correlate1d(input, weights, axis, output, mode, cval,
                           origin)
@@ -597,8 +602,11 @@ def _correlate_or_convolve(input, weights, output, mode, cval, origin,
             if not weights.shape[ii] & 1:
                 origins[ii] -= 1
     for origin, lenw in zip(origins, wshape):
-        if (lenw // 2 + origin < 0) or (lenw // 2 + origin > lenw):
-            raise ValueError('invalid origin')
+        if _invalid_origin(origin, lenw):
+            raise ValueError('Invalid origin; origin must satisfy '
+                             '-(weights.shape[k] // 2) <= origin[k] <= '
+                             '(weights.shape[k]-1) // 2')
+
     if not weights.flags.contiguous:
         weights = weights.copy()
     output = _ni_support._get_output(output, input)

scipy/ndimage/tests/test_filters.py

@@ -101,6 +101,25 @@ def test_valid_origins():
         assert_raises(ValueError, filter, data, 3, origin=2)
 
 
+def test_bad_convolve_and_correlate_origins():
+    """Regression test for gh-822."""
+    # Before gh-822 was fixed, these would generate seg. faults or
+    # other crashes on many system.
+    assert_raises(ValueError, sndi.correlate1d,
+                  [0, 1, 2, 3, 4, 5], [1, 1, 2, 0], origin=2)
+    assert_raises(ValueError, sndi.correlate,
+                  [0, 1, 2, 3, 4, 5], [0, 1, 2], origin=[2])
+    assert_raises(ValueError, sndi.correlate,
+                  np.ones((3, 5)), np.ones((2, 2)), origin=[0, 1])
+
+    assert_raises(ValueError, sndi.convolve1d,
+                  np.arange(10), np.ones(3), origin=-2)
+    assert_raises(ValueError, sndi.convolve,
+                  np.arange(10), np.ones(3), origin=[-2])
+    assert_raises(ValueError, sndi.convolve,
+                  np.ones((3, 5)), np.ones((2, 2)), origin=[0, -2])
+
+
 def test_multiple_modes():
     # Test that the filters with multiple mode cababilities for different
     # dimensions give the same result as applying a single mode.