5 ms·

> The problem is that the TPM holds a secret that even the user cannot access despite being the owner. Why is this a problem? > If the government is really sa

> The problem is that the TPM holds a secret that even the user cannot access despite being the owner. Why is this a problem? > If the government is really saying the equivalent of "trust us, but not the people you usually trust", I don't understand what you're talking about here. There is no additional trust necessary.

michaelmrose 5y ago
Let's say you don't want users to view foobar.com so you convince Microsoft to configure it's browser not to resolve foobar.com. No problem the users install their own browser. Now we ask Microsoft to limit software that is signed by it effectively granted permission to run some software but not others. The alternatively browser is right out. The user installs his own OS now we ask Dell to only allow it's computers to boot software that implements the same restrictions as Microsoft has agreed to. So the user gets his own computer. Now we simply ask your bank or better yet your ISP not to connect to "insecure" devices that don't follow the standards described. Now you need a substantial unlatched vulnerability to be able to resolve foobar.com At it's root to make a users own device effectively restrict what they are allowed to do you need something difficult to defeat that you control and they do not. At one point a us senator wanted this used to allow music labels to remotely destroy users computers if they believed that you were pirating music and every other restriction described has been implemented or discussed using on user devices belonging to users and most implemented.
- staticassertion 5y ago
  You can access TPMs on Linux just fine so this entire "but then what if" chain kinda makes no sense. A TPM restricts nothing on its own, it's just a hardware crypto token. I mean sure, if Microsoft decided that it wanted to do all of the things you said, and could convince all of the OEMs to help, and a bunch of services and ISPs or whatever, yes, that would suck. It's a totally fabricated hypothetical that would never play out, but sure.
  - shadilay 5y ago
    Linux is "insecure", Society^TM supports Windows only, please install Windows to continue using Bank^TM, School^TM, and irs.gov. 'Legacy' tax paying is now unsupported, please use new and improved windows.irs.gov
    - michaelmrose 5y ago
      Worse Ubuntu is "insecure" please upgrade to Microsoft Linux 2024.
      - shadilay 5y ago
        Worse, now that WSL2 exists why would you want to run Linux on baremetal anyways. EEE
  - tehbeard 5y ago
    So if it's just a hardware crypto token, how does it work with secure boot? Just the other chips on the mobo working in concert, no OS oversight?
    - staticassertion 5y ago
      It's unrelated to secure boot.
      - michaelmrose 5y ago
        It's party of an overarching set of standards called Trusted Computing.
  - josefx 5y ago
    There are quite a few computers already where Linux only runs as long as Microsoft provides a signed shim for the boot loader. There was quite a bit of a controversy because of this when secure boot came out.
Brian_K_White 5y ago
You absolutely have to trust whoever manufactured the tpm module not to have back doors. You have to trust every manufacturer of every other chip the same way also, and we have in fact found incredible breaches of that trust already many times over, and so it's too late to suggest it's a crazy thing to worry about. The only saving grace with other chips is thst they are generic and at least you usually have your choice of some range of suppliers. Will I be able to buy a laptop with an intentionally defective or fake tpm if I want, which will allow me to use modern software without trusting anyone? Probably not. Probably plenty of Chinese manufacturers would be willing to produce them, like all the HDCP defeating hdmi switches, but probably software vendors will have some way to detect and invalidate them.
- staticassertion 5y ago
  > You absolutely have to trust whoever manufactured the tpm module not to have back doors. Why? What would a backdoor in the TPM do?
  - LinuxBender 5y ago
    That would depend on future implementations. For example, should Microsoft one day decide to tie session authentication caching to TPM, then a backdoor in the TPM adds a universal chain for a state actor to log into the OS. Worried about state actors? No, but they hire contractors that I probably don't trust to keep this stuff secure. The OS could of course already have a back door, but reversing their code and finding it is higher risk than a closed access chip. I could envision a mandate to relocate the lawful intercept code from the OS to the hardware. Another implementation could be used to tie DRM to hardware and then brick any hardware that is in license violation. Actually I can think of many scenarios that have a unique identifier on the hardware could be used/abused by corporations. It should be noted that I lived through a time when corporations wanted this same setup on televisions. Each TV would have a unique chip that would give corporations control over what a person could watch, or even brick their TV. This was called the V-Chip. [0] And then of course, there was also the Clipper-Chip [1]. In terms of boiling frogs [2], TPM could be the base framework to slowly reintroduce the Clipper-Chip under a different name. i.e. used to boot-strap the pieces of code required to watch movies, buy things, browse the web, anything you can imagine. [0] - https://www.popularmechanics.com/culture/tv/a19408909/20-years-ago-v-chip/ https://www.popularmechanics.com/culture/tv/a19408909/20-yea... [1] - https://en.wikipedia.org/wiki/Clipper_chip https://en.wikipedia.org/wiki/Clipper_chip [2] - https://en.wikipedia.org/wiki/Boiling_frog https://en.wikipedia.org/wiki/Boiling_frog

michaelmrose 5y ago

Let's say you don't want users to view foobar.com so you convince Microsoft to configure it's browser not to resolve foobar.com. No problem the users install their own browser. Now we ask Microsoft to limit software that is signed by it effectively granted permission to run some software but not others. The alternatively browser is right out. The user installs his own OS now we ask Dell to only allow it's computers to boot software that implements the same restrictions as Microsoft has agreed to. So the user gets his own computer. Now we simply ask your bank or better yet your ISP not to connect to "insecure" devices that don't follow the standards described. Now you need a substantial unlatched vulnerability to be able to resolve foobar.com At it's root to make a users own device effectively restrict what they are allowed to do you need something difficult to defeat that you control and they do not. At one point a us senator wanted this used to allow music labels to remotely destroy users computers if they believed that you were pirating music and every other restriction described has been implemented or discussed using on user devices belonging to users and most implemented.

staticassertion 5y ago
You can access TPMs on Linux just fine so this entire "but then what if" chain kinda makes no sense. A TPM restricts nothing on its own, it's just a hardware crypto token. I mean sure, if Microsoft decided that it wanted to do all of the things you said, and could convince all of the OEMs to help, and a bunch of services and ISPs or whatever, yes, that would suck. It's a totally fabricated hypothetical that would never play out, but sure.
- shadilay 5y ago
  Linux is "insecure", Society^TM supports Windows only, please install Windows to continue using Bank^TM, School^TM, and irs.gov. 'Legacy' tax paying is now unsupported, please use new and improved windows.irs.gov
  - michaelmrose 5y ago
    Worse Ubuntu is "insecure" please upgrade to Microsoft Linux 2024.
    - shadilay 5y ago
      Worse, now that WSL2 exists why would you want to run Linux on baremetal anyways. EEE
- tehbeard 5y ago
  So if it's just a hardware crypto token, how does it work with secure boot? Just the other chips on the mobo working in concert, no OS oversight?
  - staticassertion 5y ago
    It's unrelated to secure boot.
    - michaelmrose 5y ago
      It's party of an overarching set of standards called Trusted Computing.
- josefx 5y ago
  There are quite a few computers already where Linux only runs as long as Microsoft provides a signed shim for the boot loader. There was quite a bit of a controversy because of this when secure boot came out.

Brian_K_White 5y ago

You absolutely have to trust whoever manufactured the tpm module not to have back doors. You have to trust every manufacturer of every other chip the same way also, and we have in fact found incredible breaches of that trust already many times over, and so it's too late to suggest it's a crazy thing to worry about. The only saving grace with other chips is thst they are generic and at least you usually have your choice of some range of suppliers. Will I be able to buy a laptop with an intentionally defective or fake tpm if I want, which will allow me to use modern software without trusting anyone? Probably not. Probably plenty of Chinese manufacturers would be willing to produce them, like all the HDCP defeating hdmi switches, but probably software vendors will have some way to detect and invalidate them.

staticassertion 5y ago
> You absolutely have to trust whoever manufactured the tpm module not to have back doors. Why? What would a backdoor in the TPM do?
- LinuxBender 5y ago
  That would depend on future implementations. For example, should Microsoft one day decide to tie session authentication caching to TPM, then a backdoor in the TPM adds a universal chain for a state actor to log into the OS. Worried about state actors? No, but they hire contractors that I probably don't trust to keep this stuff secure. The OS could of course already have a back door, but reversing their code and finding it is higher risk than a closed access chip. I could envision a mandate to relocate the lawful intercept code from the OS to the hardware. Another implementation could be used to tie DRM to hardware and then brick any hardware that is in license violation. Actually I can think of many scenarios that have a unique identifier on the hardware could be used/abused by corporations. It should be noted that I lived through a time when corporations wanted this same setup on televisions. Each TV would have a unique chip that would give corporations control over what a person could watch, or even brick their TV. This was called the V-Chip. [0] And then of course, there was also the Clipper-Chip [1]. In terms of boiling frogs [2], TPM could be the base framework to slowly reintroduce the Clipper-Chip under a different name. i.e. used to boot-strap the pieces of code required to watch movies, buy things, browse the web, anything you can imagine. [0] - https://www.popularmechanics.com/culture/tv/a19408909/20-years-ago-v-chip/ https://www.popularmechanics.com/culture/tv/a19408909/20-yea... [1] - https://en.wikipedia.org/wiki/Clipper_chip https://en.wikipedia.org/wiki/Clipper_chip [2] - https://en.wikipedia.org/wiki/Boiling_frog https://en.wikipedia.org/wiki/Boiling_frog