3 ms·

I've always wondered what the point of this is. Why not just skip the signature and tell users to be careful where they get the binary? If I can't trust that th

I've always wondered what the point of this is. Why not just skip the signature and tell users to be careful where they get the binary? If I can't trust that the binary made it to me untampered, why should I believe the pubkey is any more legitimate?

thomastjeffery 3y ago
Because the website itself or the primary domain server could potentially be hacked. More likely, your DNS service (or a maliciously edited /etc/hosts) could give you a dishonest resolution, sending you to the fraudulent address. A public key does not exist in a vacuum. Ideally, it is part of a larger "web of trust", having been signed by others in that web. Unfortunately, websites like 7-zip.org do: they are socially isolated, which is where this situation of mistrust originated. Package managers (like Debian's apt or Archlinux' pacman) are at the advantage here, because the social coordination of a software repository sets the perfect circumstances for a web of trust; and the package manager itself automatically checks gpg signatures after downloading each package.
- WorldMaker 3y ago
  I think that's part of the problem, if you don't have that package manager to bootstrap your signature key ring, DNS is your next best bootstrap. It is, of course, a terrible bootstrap for trust, but it is one so many users on Windows have been relying on for such a long time. For power users on any modern Windows 10/Windows 11 there is at least WinGet now. Its manifests repo is becoming a very interesting (open) source of truth for common Windows applications. Admittedly, it in most cases doesn't seem to be checking specific code signatures in most cases either, but at least includes SHA checksums. For instance, 7zip's manifests: https://github.com/microsoft/winget-pkgs/tree/master/manifests/7/7zip/7zip https://github.com/microsoft/winget-pkgs/tree/master/manifes... It's too bad there's still not a great option for "average user that doesn't know/trust how to use a CLI", given how sadly polluted the Microsoft Store can be for many common, especially Open Source, applications. For direct instance, because winget kindly includes Microsoft Store results when searching, there is a "7zip 22" in the Microsoft Store that costs some amount of money (winget details say "PaidUnknownPrice" for the pricing information; I'm on a corporate machine right now with the actual Store access locked so can't search in the actual Store right now) and the Publisher is listed as RepackagerExpress.com. (That website currently doesn't go anywhere, giving it a spot check.) Having seen this, I may boot up my personal machine and try to report this specific Store listing for violating the Store's Open Source policies, though I'm unsure if such whackamole is all that useful. (Seems like it might be a useful winget feature request for it to provide Store Report URLs.)
  - thomastjeffery 3y ago
    Microsoft Store is precisely what I expected it to be: what likely started as an effort by some in the company to reproduce the utility of a package manager, but in the end sabotaged by the perverse incentives of capitalism. The Cathedral cannot emulate a Bazaar.
srmarm 3y ago
I think the point was the binaries would be distributed around different mirrors that might not be under the control of the author - so long as you got the key from the author the actual binary (which is a much larger filesize than the key) could have less secured mirrors.
chlorion 3y ago
This is where the TOFU model comes in, you implicitly trust the key on first use. Finding a legitimate download one time is better than having to find it every time. Bootstrapping keys is a difficult thing for sure, but TOFU is still better than nothing at all and seems to work pretty well in practice.

thomastjeffery 3y ago

Because the website itself or the primary domain server could potentially be hacked. More likely, your DNS service (or a maliciously edited /etc/hosts) could give you a dishonest resolution, sending you to the fraudulent address. A public key does not exist in a vacuum. Ideally, it is part of a larger "web of trust", having been signed by others in that web. Unfortunately, websites like 7-zip.org do: they are socially isolated, which is where this situation of mistrust originated. Package managers (like Debian's apt or Archlinux' pacman) are at the advantage here, because the social coordination of a software repository sets the perfect circumstances for a web of trust; and the package manager itself automatically checks gpg signatures after downloading each package.

WorldMaker 3y ago
I think that's part of the problem, if you don't have that package manager to bootstrap your signature key ring, DNS is your next best bootstrap. It is, of course, a terrible bootstrap for trust, but it is one so many users on Windows have been relying on for such a long time. For power users on any modern Windows 10/Windows 11 there is at least WinGet now. Its manifests repo is becoming a very interesting (open) source of truth for common Windows applications. Admittedly, it in most cases doesn't seem to be checking specific code signatures in most cases either, but at least includes SHA checksums. For instance, 7zip's manifests: https://github.com/microsoft/winget-pkgs/tree/master/manifests/7/7zip/7zip https://github.com/microsoft/winget-pkgs/tree/master/manifes... It's too bad there's still not a great option for "average user that doesn't know/trust how to use a CLI", given how sadly polluted the Microsoft Store can be for many common, especially Open Source, applications. For direct instance, because winget kindly includes Microsoft Store results when searching, there is a "7zip 22" in the Microsoft Store that costs some amount of money (winget details say "PaidUnknownPrice" for the pricing information; I'm on a corporate machine right now with the actual Store access locked so can't search in the actual Store right now) and the Publisher is listed as RepackagerExpress.com. (That website currently doesn't go anywhere, giving it a spot check.) Having seen this, I may boot up my personal machine and try to report this specific Store listing for violating the Store's Open Source policies, though I'm unsure if such whackamole is all that useful. (Seems like it might be a useful winget feature request for it to provide Store Report URLs.)
- thomastjeffery 3y ago
  Microsoft Store is precisely what I expected it to be: what likely started as an effort by some in the company to reproduce the utility of a package manager, but in the end sabotaged by the perverse incentives of capitalism. The Cathedral cannot emulate a Bazaar.

srmarm 3y ago

I think the point was the binaries would be distributed around different mirrors that might not be under the control of the author - so long as you got the key from the author the actual binary (which is a much larger filesize than the key) could have less secured mirrors.

chlorion 3y ago

This is where the TOFU model comes in, you implicitly trust the key on first use. Finding a legitimate download one time is better than having to find it every time. Bootstrapping keys is a difficult thing for sure, but TOFU is still better than nothing at all and seems to work pretty well in practice.