matrixload: ensure sniff data is null-terminated (#4541)

kleisauke · web-flow · commit 6fb70fa48f02 · 2025-05-29T17:44:25.000+01:00
As required by `g_strlcpy()`.
diff --git a/libvips/foreign/matrixload.c b/libvips/foreign/matrixload.c
@@ -429,7 +429,8 @@ vips_foreign_load_matrix_source_is_a_source(VipsSource *source)
 
 	if ((bytes_read = vips_source_sniff_at_most(source, &data, 79)) <= 0)
 		return FALSE;
-	g_strlcpy(line, (const char *) data, 80);
+	data[bytes_read] = '\0';
+	g_strlcpy(line, (const char *) data, sizeof(line));
 
 	vips_error_freeze();
 	result = parse_matrix_header(line, &width, &height, &scale, &offset);
diff --git a/test/test-suite/test_connection.py b/test/test-suite/test_connection.py
@@ -102,6 +102,15 @@ def test_connection_matrix(self):
 
         assert (im - self.mono).abs().max() == 0
 
+    @skip_if_no("svgload_source")
+    def test_connection_svg(self):
+        svg = b'<svg xmlns="http://www.w3.org/2000/svg" width="1" height="1" />'
+        x = pyvips.Source.new_from_memory(svg)
+        im = pyvips.Image.new_from_source(x, "")
+
+        assert im.width == 1
+        assert im.height == 1
+
     def test_connection_csv(self):
         x = pyvips.Target.new_to_memory()
         self.mono.csvsave_target(x)
