Hi all, On Thu, Jul 26, 2018 at 04:14:04PM +0800, joeyli wrote: > On Thu, Jul 26, 2018 at 09:30:46AM +0200, Oliver Neukum wrote: > > On Di, 2018-07-24 at 00:23 +0800, Yu Chen wrote: > > > > > > Good point, we once tried to generate key in kernel, but people > > > suggest to generate key in userspace and provide it to the > > > kernel, which is what ecryptfs do currently, so it seems this > > > should also be safe for encryption in kernel. > > > https://www.spinics.net/lists/linux-crypto/msg33145.html > > > Thus Chun-Yi's signature can use EFI key and both the key from > > > user space. > > > > Hi, > > > > ecryptfs can trust user space. It is supposed to keep data > > safe while the system is inoperative. The whole point of Secure > > Boot is a cryptographic system of trust that does not include > > user space. > > > > I seriously doubt we want to use trusted computing here. So the > > key needs to be generated in kernel space and stored in a safe > > manner. As we have a saolution doing that, can we come to ausable > > synthesis? > > > > Regards > > Oliver > > Crurently there have two solutions, they are trusted key and EFI key. > Both of them are generated in kernel and are not visible in user space. > > The trusted key is generated by kernel then sealed by the TPM's > SRK. So the trusted key can be stored in anywhere then be enrolled > to kernel when we need it. EVM already uses it. > > The EFI key is Jiri Kosina's idea. It is stored in boot services > variable, which means that it can only be access by signed EFI binary > (e.g. signed EFI boot stub) when secure boot be enabled. SLE applied > this solution a couple of years. > > I am working on put the EFI key to key retention service. Then > EFI key can be a master key of encrypted key. EVM can also use > it: > https://github.com/joeyli/linux-s4sign/commit/bae39460393ada4c0226dd07cd5e3afcef86b71f > https://github.com/joeyli/linux-s4sign/commit/f552f97cc3cca5acd84f424b7f946ffb5fe8e9ec > > That's why I want to use key retention service in hibernation > encryption/authentication. Which means that we can use key > API to access trusted key and EFI key. > Here is a proof of concept for using the key retention service to encrypt/sign snapshot image. It's using EFI key now, I will add encrypted key support in the key handler later: https://github.com/joeyli/linux-s4sign/commit/6311e97038974bc5de8121769fb4d34470009566 My next step is that cleaning up the my EFI key type patches and submit it to EFI/keys subsystem ASAP. Then I will clean up my hibernation encryption/authentication solution for reviewing. Thanks Joey Lee
