Catch struct.error from truncated EXIF when reading JPEG DPI

Tests/test_file_jpeg.py

@@ -767,6 +767,13 @@ def test_dpi_exif_string(self):
             # This should return the default
             assert im.info.get("dpi") == (72, 72)
 
+    def test_dpi_exif_truncated(self):
+        # Arrange
+        with Image.open("Tests/images/truncated_exif_dpi.jpg") as im:
+            # Act / Assert
+            # This should return the default
+            assert im.info.get("dpi") == (72, 72)
+
     def test_no_dpi_in_exif(self):
         # Arrange
         # This is photoshop-200dpi.jpg with resolution removed from EXIF:

src/PIL/JpegImagePlugin.py

@@ -170,11 +170,19 @@ def APP(self, marker):
                 # 1 dpcm = 2.54 dpi
                 dpi *= 2.54
             self.info["dpi"] = dpi, dpi
-        except (TypeError, KeyError, SyntaxError, ValueError, ZeroDivisionError):
-            # SyntaxError for invalid/unreadable EXIF
+        except (
+            struct.error,
+            KeyError,
+            SyntaxError,
+            TypeError,
+            ValueError,
+            ZeroDivisionError,
+        ):
+            # struct.error for truncated EXIF
             # KeyError for dpi not included
-            # ZeroDivisionError for invalid dpi rational value
+            # SyntaxError for invalid/unreadable EXIF
             # ValueError or TypeError for dpi being an invalid float
+            # ZeroDivisionError for invalid dpi rational value
             self.info["dpi"] = 72, 72