Linus discussed this in: https://lore.kernel.org/lkml/Pine.LNX.4.58.0504090902170.1267@ppc970.osdl.org/ https://lore.kernel.org/lkml/Pine.LNX.4.58.0504090902170

Linus discussed this in: https://lore.kernel.org/lkml/Pine.LNX.4.58.0504090902170.1267@ppc970.osdl.org/ https://lore.kernel.org/lkml/Pine.LNX.4.58.0504090902170.126... The key point for me is his note that you have to more than copy the SHA1. That it will have to also be a valid zlib object with a matching header.