It's only really hard and messy for the first guy who implements it, after that it is much easier, albeit still fairly messy. I'm not saying we need to panic, but it's more than a "non-issue".
How do you know where the key is, and how are you guaranteed to be able to read enough of it before the "shifting sands" that is timing unpredictability and general noise in the system make you read something else?
That's what really irritates me about all these side-channels that have been found ever since the first Spectre/Meltdown --- they all demonstrate something flashy like "we read a key/password/secret/something important from memory in a few minutes" while conveniently ignoring to mention the countless hours spent aligning everything just right so they could show off the one "magic trick". In a lot of the cases there's barely even any control over where it reads.
Every time something like this comes up, I feel compelled to post some bytes from somewhere random in the memory of a random process on my machine to show just how much I care; here you go:
E8 7F 00 00 00 A1 64 30 40 00 89 45 D8 8D 45 D8
C4 20 00 00-CE 20 00 00-D8 20 00 00-E2 20 00 00
F8 20 00 00-00 21 00 00-0E 21 00 00-16 21 00 00
26 21 00 00-36 21 00 00-42 21 00 00-56 21 00 00
66 21 00 00-76 21 00 00-84 21 00 00-96 21 00 00
AA 21 00 00-00 00 00 00-FF FF FF FF-B4 16 40 00
C8 16 40 00-7C 20 00 00-00 00 00 00-00 00 00 00
EC 20 00 00-00 20 00 00-00 00 00 00-00 00 00 00
I don't mean to understate the difficulty of the task, but I've also seen probably tens of repros by now that use intimate knowledge of e.g. the kernel page allocator and known post-boot state of e.g. a firmware image flashed on millions of devices to drastically cut down the search space
If a university can accomplish this task with their funding and no urgent incentive, what is the nation state actor doing with their enormous budget?
Badly enough as in they can ever do it a few times a year against a few high-value targets, or badly enough that they can do it to "only" a few tens of millions a year?
Even end-to-end encrypted communications can be bypassed if the government wants them "badly enough". But the point is that with E2E encryption, they can no longer tap into and data mine the conversions of billions in real-time to fish for crimes.
Just like when fighting malware creators, the point of security is to keep raising the standards and the difficulty for the malicious actors.
It's really not that hard. E.g. people working on browser exploits have been working on exactly this for years and years, back when just having an out-of-bounds read due to a regular browser bug was the mechanism. Turns out that programs are absolutely chock full of pointers and it doesn't take long to run across one that points to what you are looking for. Especially because programs tend to have lots of data structures that end up pointing to more and more important data structures, funneling you into the guts of the program.
Sure, reverse engineering takes work, but blindly hunting in memory with no clue it is definitely not.
Side-channel attacks are basically a persistent out-of-bounds read mechanism. That is a very bad thing (TM).
There are literally thousands of people who work on this day in and day out, and millions in bug bounty programs out there.
perhaps package servers and package management software should round up the package size to hide the identity of the package? use oblivious transfer to hide the identity of the package from the package server itself?
This makes no sense. If you have the privileges to install a rootkit, there is no need to use any speculative execution exploit.
You also, don't get to extract constantly. You only get a shot when the data is in the LFB, so the program needs to be actively reading or writing it to keep it moving back and forth from L1 and L2, at least that is the way I read the paper.