Avoid smallint overflow in PNG crc

deshipu · deshipu · commit d12ac5ba4fee · 2022-07-26T22:02:34.000+02:00
diff --git a/stage.py b/stage.py
@@ -346,7 +346,7 @@ def read_header(self):
             (
                 size, chunk, self.width, self.height, self.depth, self.mode,
                 self.compression, self.filters, self.interlaced, crc
-            ) = struct.unpack(">I4sIIBBBBBI", f.read(25))
+            ) = struct.unpack(">I4sIIBBBBB4s", f.read(25))
             assert size == 13  # header length
             assert chunk == b'IHDR'
             if self.depth != 4 or self.mode != 3 or self.interlaced != 0:

Original file line number	Diff line number	Diff line change
`@@ -346,7 +346,7 @@ def read_header(self):`
`346`	`346`	`(`
`347`	`347`	`size, chunk, self.width, self.height, self.depth, self.mode,`
`348`	`348`	`self.compression, self.filters, self.interlaced, crc`
`349`		`- ) = struct.unpack(">I4sIIBBBBBI", f.read(25))`
	`349`	`+ ) = struct.unpack(">I4sIIBBBBB4s", f.read(25))`
`350`	`350`	`assert size == 13 # header length`
`351`	`351`	`assert chunk == b'IHDR'`
`352`	`352`	`if self.depth != 4 or self.mode != 3 or self.interlaced != 0:`