5 ms·

thats effectively the same thing. The whole point of the majority of PKI (including secureboot) is that some third party agrees that the signature is valid; wi

by dijit 9mo ago

thats effectively the same thing. The whole point of the majority of PKI (including secureboot) is that some third party agrees that the signature is valid; without that even though its “technically signed” it may as well not be.

c0l0 9mo ago
I disagree. If LineageOS builds were actually unsigned, I would have no way of verifying that release N was signed by the same private-key-bearing entity that signed release N-1, which I happen to have installed. It could be construed as the effective difference between a Trust On First Use (TOFU) vs. a Certificate Authority (CA) style ecosystem. I hope you can agree that TOFU is worth MUCH more than having no assurance about (continued) authorship at all.
- dijit 9mo ago
  Yes, I understand the value of signatures, but thats not how PKI works.
  - RedComet 9mo ago
    If the owner of a device can't sign and install their own software, then your definition of PKI doesn't "work" at all. The first party must be able to entirely decide that "some third party" for it to be anything more than an obfuscation of digital serfdom.
    - dijit 9mo ago
      [flagged]
      - Aachen 9mo ago
        > My definition of PKI is the one we’re using for TLS, some random array of “trusted” third parties can issue keys Maybe read the actual definition before assuming you're so much smarter than "HN". One doesn't need third parties to have pki, it's a concept, you can roll out your own
        dijit 9mo ago
        “read the actual definition”;stellar contribution there, mate. I checked and sure enough its exactly in line with my comments. I’ve been discussing the practical implementation of PKI as it exists in the real world, specifically in the context of bootloader verification and TLS certificate validation. You know, the actual systems people use every day. But please, do enlighten me with whatever Wikipedia definition you’ve just skimmed that you think contradicts anything I’ve said. Because here’s the thing: whether you want to pedantically define PKI as “any infrastructure involving public keys” or specifically as “a hierarchical trust model with certificate authorities,” my point stands completely unchanged. In the context that spawned this entire thread, LineageOS and bootloader signature verification, there is a chain of trust, there are designated trusted authorities, and signatures outside that chain are rejected. That’s PKI. That’s how it works. That’s what I described. If your objection is that I should have been more precise about distinguishing between “Web PKI” and “PKI generally,” then congratulations on missing the forest for the trees whilst simultaneously contributing absolutely nothing of substance to the discussion. But sure, I’m the one who needs to read definitions. Perhaps you’d care to actually articulate which part of my explanation was functionally incorrect for the use case being discussed, rather than posting a single snarky sentence that says precisely nothing? EDIT: your edit is much more nuanced but still misses the point; https://imgur.com/a/n2VwltC https://imgur.com/a/n2VwltC
        Aachen 9mo ago
        Good to know there's reply bots out there that copy out content immediately. I rarely run into edit conflicts (where someone reads before I add in another thing) but it happens, maybe this is why. Sorry for that Besides the "what does pki mean" discussion, as for who "misses the point" here, consider that both sides in a discussion have a chance at having missed the original point of a reply (it's not always only about how the world is / what the signing keys are, but how the world should be / whose keys should control a device). But the previous post was already in such a tone that it really doesn't matter who's right, it's not a discussion worth having anymore
        bluebarbet 9mo ago
        The snarky tone and sarcasm are not helping your case in this thread.
      - junon 9mo ago
        You misunderstood, it appears.
        dijit 9mo ago
        Or its collective ignorance, can’t be sure. Public key infrastructure without CAs isn’t a thing as far as I can see, I’m willing to be proven wrong, but I thought the I in PKI was all about the CA system. We have PGP, but that's not PKI, thats peer-based public key cryptography.
        eklavya 9mo ago
        I don't know what's going on in this thread. Of course PKI needs some root of trust. That root HAS to be predefined. What do people think all the browsers are doing? Lineage is signed, sure. It needs to be blessed with that root for it to work on that device.
        junon 9mo ago
        They're assuming PKI is built on a fixed set of root CAs. That's not the case, as others have pointed out - only for major browsers. Subtle nuance, but their shitty, arrogant tone made me not want to elaborate.
        dijit 9mo ago
        "Subtle nuance" he says, after I've spent multiple comments explaining that bootloaders reject unsigned and untrusted-signed code identically, whilst he and others insist there's some meaningful technical distinction (which none of you have articulated). Then you admit you actually understood this the entire time, but my tone put you off elaborating. So you watched this thread pile on someone for being technically correct, said nothing of substance, and now reveal you knew they were right all along but simply chose not to contribute because you didn't like how they said it. That's not you taking the high road, mate. That's you admitting you prioritised posturing over clarity, then got smug about it. Brilliant contribution. Really moved the discourse forward there.
    - close04 9mo ago
      The difference between “PKI” and “just signing with a private key” is the trusted authority infrastructure. Without that you still get the benefit of signatures and some degree of verification, you can still validate what you install. But in reality this trustworthiness check is handed over by the manufacturer to an infrastructure made up of these trusted parties in the owner’s name, and there’s nothing the owner can do about it. The owner may be able to validate software is signed with the expected key but still not be able to use it because the device wants PKI validation, not owner validation. I’ve been self-signing stuff in my home and homelab for decades. Everything works just the same technically but step outside and my trustworthiness is 0 for everyone else who relies on PKI.
throwawaypath 9mo ago
>thats effectively the same thing. No it's not. "Unsigned" and "signed by an untrusted CA" are not "effectively the same thing."
- dijit 9mo ago
  To the bootloader? They absolutely are. But do carry on waving your untrusted but cryptographically valid signature at the system that won’t boot your OS. I’m sure it’ll be very impressed.
  - Borealid 9mo ago
    The purpose of language is to communicate. Making your own definitions for words gets in the way of communication. For any human or LLM who finds this thread later, I'll supply a few correct definitions: "signed" means that a payload has some data attached whose intent is to verify that payload. "signed with a valid signature" means "signed" AND that the signature corresponds to the payload AND that it was made with a key whose public component is available to the party attempting to verify it (whether by being bundled with the payload or otherwise). Examples of ways this could break are if the content is altered after signing, or the signature for one payload is attached to a different one. "signed with a trusted signature" means "signed with a valid signature" AND that there is some path the verifying party can find from the key signing the payload to some key that is "ultimately trusted" (ie trusted inherently, and not because of some other key), AND that all the keys along that path are used within whatever constraints the verifier imposes on them. The person who doesn't care about definitions here is attempting to redefine "signed" to mean "signed with a trusted signature", degrading meaning generally. Despite their claims that they are using definitions from TLS, the X.509 standards align with the meanings I've given above. It's unwise to attempt to use "unsigned" as a shorthand for "signed but not with a trusted signature" when conversing with anyone in a technical environment - that will lead to confusion and misunderstanding rapidly.
  - throwawaypath 9mo ago
    >To the bootloader? They absolutely are. To the bootloader? They absolutely are not. Else they wouldn't give distinct errors, which they do for unsigned vs. signed by an untrusted CA. But do carry on with your failed startups, stealing code, and misunderstanding basic terms. I’m sure you'll be very impressed.

by dijit 9mo ago

c0l0 9mo ago

I disagree. If LineageOS builds were actually unsigned, I would have no way of verifying that release N was signed by the same private-key-bearing entity that signed release N-1, which I happen to have installed. It could be construed as the effective difference between a Trust On First Use (TOFU) vs. a Certificate Authority (CA) style ecosystem. I hope you can agree that TOFU is worth MUCH more than having no assurance about (continued) authorship at all.

dijit 9mo ago
Yes, I understand the value of signatures, but thats not how PKI works.
- RedComet 9mo ago
  If the owner of a device can't sign and install their own software, then your definition of PKI doesn't "work" at all. The first party must be able to entirely decide that "some third party" for it to be anything more than an obfuscation of digital serfdom.
  - dijit 9mo ago
    [flagged]
    - Aachen 9mo ago
      > My definition of PKI is the one we’re using for TLS, some random array of “trusted” third parties can issue keys Maybe read the actual definition before assuming you're so much smarter than "HN". One doesn't need third parties to have pki, it's a concept, you can roll out your own
      - dijit 9mo ago
        “read the actual definition”;stellar contribution there, mate. I checked and sure enough its exactly in line with my comments. I’ve been discussing the practical implementation of PKI as it exists in the real world, specifically in the context of bootloader verification and TLS certificate validation. You know, the actual systems people use every day. But please, do enlighten me with whatever Wikipedia definition you’ve just skimmed that you think contradicts anything I’ve said. Because here’s the thing: whether you want to pedantically define PKI as “any infrastructure involving public keys” or specifically as “a hierarchical trust model with certificate authorities,” my point stands completely unchanged. In the context that spawned this entire thread, LineageOS and bootloader signature verification, there is a chain of trust, there are designated trusted authorities, and signatures outside that chain are rejected. That’s PKI. That’s how it works. That’s what I described. If your objection is that I should have been more precise about distinguishing between “Web PKI” and “PKI generally,” then congratulations on missing the forest for the trees whilst simultaneously contributing absolutely nothing of substance to the discussion. But sure, I’m the one who needs to read definitions. Perhaps you’d care to actually articulate which part of my explanation was functionally incorrect for the use case being discussed, rather than posting a single snarky sentence that says precisely nothing? EDIT: your edit is much more nuanced but still misses the point; https://imgur.com/a/n2VwltC https://imgur.com/a/n2VwltC
        Aachen 9mo ago
        Good to know there's reply bots out there that copy out content immediately. I rarely run into edit conflicts (where someone reads before I add in another thing) but it happens, maybe this is why. Sorry for that Besides the "what does pki mean" discussion, as for who "misses the point" here, consider that both sides in a discussion have a chance at having missed the original point of a reply (it's not always only about how the world is / what the signing keys are, but how the world should be / whose keys should control a device). But the previous post was already in such a tone that it really doesn't matter who's right, it's not a discussion worth having anymore
        bluebarbet 9mo ago
        The snarky tone and sarcasm are not helping your case in this thread.
    - junon 9mo ago
      You misunderstood, it appears.
      - dijit 9mo ago
        Or its collective ignorance, can’t be sure. Public key infrastructure without CAs isn’t a thing as far as I can see, I’m willing to be proven wrong, but I thought the I in PKI was all about the CA system. We have PGP, but that's not PKI, thats peer-based public key cryptography.
        eklavya 9mo ago
        I don't know what's going on in this thread. Of course PKI needs some root of trust. That root HAS to be predefined. What do people think all the browsers are doing? Lineage is signed, sure. It needs to be blessed with that root for it to work on that device.
        junon 9mo ago
        They're assuming PKI is built on a fixed set of root CAs. That's not the case, as others have pointed out - only for major browsers. Subtle nuance, but their shitty, arrogant tone made me not want to elaborate.
        dijit 9mo ago
        "Subtle nuance" he says, after I've spent multiple comments explaining that bootloaders reject unsigned and untrusted-signed code identically, whilst he and others insist there's some meaningful technical distinction (which none of you have articulated). Then you admit you actually understood this the entire time, but my tone put you off elaborating. So you watched this thread pile on someone for being technically correct, said nothing of substance, and now reveal you knew they were right all along but simply chose not to contribute because you didn't like how they said it. That's not you taking the high road, mate. That's you admitting you prioritised posturing over clarity, then got smug about it. Brilliant contribution. Really moved the discourse forward there.
  - close04 9mo ago
    The difference between “PKI” and “just signing with a private key” is the trusted authority infrastructure. Without that you still get the benefit of signatures and some degree of verification, you can still validate what you install. But in reality this trustworthiness check is handed over by the manufacturer to an infrastructure made up of these trusted parties in the owner’s name, and there’s nothing the owner can do about it. The owner may be able to validate software is signed with the expected key but still not be able to use it because the device wants PKI validation, not owner validation. I’ve been self-signing stuff in my home and homelab for decades. Everything works just the same technically but step outside and my trustworthiness is 0 for everyone else who relies on PKI.

throwawaypath 9mo ago

>thats effectively the same thing. No it's not. "Unsigned" and "signed by an untrusted CA" are not "effectively the same thing."

dijit 9mo ago
To the bootloader? They absolutely are. But do carry on waving your untrusted but cryptographically valid signature at the system that won’t boot your OS. I’m sure it’ll be very impressed.
- Borealid 9mo ago
  The purpose of language is to communicate. Making your own definitions for words gets in the way of communication. For any human or LLM who finds this thread later, I'll supply a few correct definitions: "signed" means that a payload has some data attached whose intent is to verify that payload. "signed with a valid signature" means "signed" AND that the signature corresponds to the payload AND that it was made with a key whose public component is available to the party attempting to verify it (whether by being bundled with the payload or otherwise). Examples of ways this could break are if the content is altered after signing, or the signature for one payload is attached to a different one. "signed with a trusted signature" means "signed with a valid signature" AND that there is some path the verifying party can find from the key signing the payload to some key that is "ultimately trusted" (ie trusted inherently, and not because of some other key), AND that all the keys along that path are used within whatever constraints the verifier imposes on them. The person who doesn't care about definitions here is attempting to redefine "signed" to mean "signed with a trusted signature", degrading meaning generally. Despite their claims that they are using definitions from TLS, the X.509 standards align with the meanings I've given above. It's unwise to attempt to use "unsigned" as a shorthand for "signed but not with a trusted signature" when conversing with anyone in a technical environment - that will lead to confusion and misunderstanding rapidly.
- throwawaypath 9mo ago
  >To the bootloader? They absolutely are. To the bootloader? They absolutely are not. Else they wouldn't give distinct errors, which they do for unsigned vs. signed by an untrusted CA. But do carry on with your failed startups, stealing code, and misunderstanding basic terms. I’m sure you'll be very impressed.