4 ms·
There's absolutely no technical reason that a signed bootloader would have to only boot signed kernels. With UEFI Secure Boot, the only signed component is the
by daeken 15y ago
There's absolutely no technical reason that a signed bootloader would have to only boot signed kernels. With UEFI Secure Boot, the only signed component is the bootloader -- there's absolutely no way in which this can affect the kernel. Now, it's possible that there could be procedural mandates around this, e.g. an authority that signs your bootloader and won't do so without mandating that the kernel and all drivers be signed as well, but does this exist, or will it exist?
- mjg59 15y agoIt'd be easy to generate a signed bootloader that runs unsigned kernels. It'd also be easy to then use that bootloader to boot malware to attack Windows. For secure boot to be in any way useful it would then be necessary to blacklist that signed bootloader. Signed kernels that load unsigned drivers have the same problem.
- daeken 15y agoI'm not arguing that Secure Boot is useful or good in any way, I'm simply saying that from a technical perspective, signed bootloader does not mean signed kernel.
- mjg59 15y agoFrom a technical perspective, you're absolutely right. From a real world perspective, it requires a signed kernel and signed drivers.
- lukeschlather 15y agoHardware encryption should mitigate that issue, just so unsigned kernels aren't allowed access to the keys (which would prevent you from running hardware encryption with an unsigned kernel, but that's sensible.)
- mjg59 15y agoThe keys aren't an issue. The issue is whether you can run untrusted ring 0 code before running another OS, because if you can then you can subvert the trust model.
- tlb 15y agoA computer that boots code that loads un-signed modules isn't secure at all. I suspect that will be the outcome of UEFI: no effective increase in security, and hassles installing new operating systems. Frankly, I have no interest in my computer being secure in this way (running only code signed by companies). UEFI might have a place in kiosks or shared computers in public libraries, but not for a computer I own and physically control.
- silon3 15y agoUnless I can choose not to trust Microsoft, I don't trust Microsoft. A way to add/remove signing keys is necessary (think NSAKEY).
- tlb 15y agoAdding a key may involve typing in hundreds of hex digits to a BIOS screen, with typical BIOS user interface. That will be a barrier to switching to Linux.
- keeperofdakeys 15y agoThe authority exists, the manufactures. The whole purpose of secure boot is to stop untrusted code running. If something the manufactures sign can run third party code, then it can be used to run untrusted code. This means they will either never make such a key, or revoke it when they do sign it. This simply means, with its current design, linux is incompatible with secure boot.