Check for negative dimensions in Image#constitute

rmagick · Oct 7, 2019 · ce95119 · ce95119
1 parent 78b30de
commit ce95119
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Showing 2 changed files with 22 additions and 4 deletions.
diff --git a/ext/RMagick/rmimage.c b/ext/RMagick/rmimage.c
@@ -4124,9 +4124,9 @@ Image_constitute(VALUE class ATTRIBUTE_UNUSED, VALUE width_arg, VALUE height_arg
     width = NUM2ULONG(width_arg);
     height = NUM2ULONG(height_arg);
 
-    if (width == 0 || height == 0)
+    if ((int)width <= 0 || (int)height <= 0)
     {
-        rb_raise(rb_eArgError, "width and height must be non-zero");
+        rb_raise(rb_eArgError, "width and height must be greater than zero");
     }
 
     map = rm_str2cstr(map_arg, &map_l);

diff --git a/spec/rmagick/image/constitute_spec.rb b/spec/rmagick/image/constitute_spec.rb
@@ -37,13 +37,31 @@
   end
 
   it 'raises an error when 0 is passed for columns' do
+    expected_message = 'width and height must be greater than zero'
+
     expect { Magick::Image.constitute(0, img.rows, 'RGBA', pixels) }
-      .to raise_error(ArgumentError, 'width and height must be non-zero')
+      .to raise_error(ArgumentError, expected_message)
+  end
+
+  it 'raises an error when a negative number is passed for columns' do
+    expected_message = 'width and height must be greater than zero'
+
+    expect { Magick::Image.constitute(-3, img.rows, 'RGBA', pixels) }
+      .to raise_error(ArgumentError, expected_message)
   end
 
   it 'raises an error when 0 is passed for rows' do
+    expected_message = 'width and height must be greater than zero'
+
     expect { Magick::Image.constitute(img.columns, 0, 'RGBA', pixels) }
-      .to raise_error(ArgumentError, 'width and height must be non-zero')
+      .to raise_error(ArgumentError, expected_message)
+  end
+
+  it 'raises an error when a negative number is passed for rows' do
+    expected_message = 'width and height must be greater than zero'
+
+    expect { Magick::Image.constitute(img.columns, -3, 'RGBA', pixels) }
+      .to raise_error(ArgumentError, expected_message)
   end
 
   it 'raises an error given the wrong number of array elements' do