On Fr, 2018-07-20 at 12:25 +0200, Pavel Machek wrote: > Hi! Hello, > > Let me paste the log here: > > > > 1. (This is not to compare with uswsusp but other > > tools) One advantage is: Users do not have to > > encrypt the whole swap partition as other tools. > > Well.. encrypting the partition seems like good idea anyway. Yes, but it is a policy decision the kernel should not force. STD needs to work anyway. > > 2. Ideally kernel memory should be encrypted by the > > kernel itself. We have uswsusp to support user > > space hibernation, however doing the encryption > > in kernel space has more advantages: > > 2.1 Not having to transfer plain text kernel memory to > > user space. Per Lee, Chun-Yi, uswsusp is disabled > > when the kernel is locked down: > > https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/ > > linux-fs.git/commit/?h=lockdown-20180410& > > id=8732c1663d7c0305ae01ba5a1ee4d2299b7b4612 > > due to: > > "There have some functions be locked-down because > > there have no appropriate mechanisms to check the > > integrity of writing data." > > https://patchwork.kernel.org/patch/10476751/ > > So your goal is to make hibernation compatible with kernel > lockdown? Do your patches provide sufficient security that hibernation > can be enabled with kernel lockdown? OK, maybe I am dense, but if the key comes from user space, will that be enough? > > 2.2 Not having to copy each page to user space > > one by one not in parallel, which might introduce > > significant amount of copy_to_user() and it might > > not be efficient on servers having large amount of DRAM. > > So how big speedup can be attributed by not doing copy_to_user? That would be an argument for compression in kernel space. Not encrpting would always be faster. > > 2.3 Distribution has requirement to do snapshot > > signature for verification, which can be built > > by leveraging this patch set. > > Signatures can be done by uswsusp, too, right? Not if you want to keep the chain of trust intact. User space is not signed. > > 2.4 The encryption is in the kernel, so it doesn't > > have to worry too much about bugs in user space > > utilities and similar, for example. > > Answer to bugs in userspace is _not_ to move code from userspace to kernel. Indeed. > > Joey Lee and I had a discussion on his previous work at > > https://patchwork.kernel.org/patch/10476751 > > We collaborate on this task and his snapshot signature > > feature can be based on this patch set. > > Well, his work can also work without your patchset, right? Yes. But you are objecting to encryption in kernel space at all, aren't you? Regards Oliver
