OpenSSH: 8.2 Release Notes

This release adds support for FIDO/U2F hardware authenticators to
OpenSSH. U2F/FIDO are open standards for inexpensive two-factor
authentication hardware that are widely used for website
authentication. In OpenSSH FIDO devices are supported by new public
key types “ecdsa-sk” and “ed25519-sk”, along with corresponding
certificate types.

FIDO/U2F OpenSSH keys consist of two parts: a “key handle” part stored
in the private key file on disk, and a per-device private key that is
unique to each FIDO/U2F token and that cannot be exported from the
token hardware. These are combined by the hardware at authentication
time to derive the real key that is used to sign authentication
challenges.

For tokens that are required to move between computers, it can be
cumbersome to have to move the private key file first. To avoid this
requirement, tokens implementing the newer FIDO2 standard support
“resident keys”, where it is possible to effectively retrieve the key
handle part of the key from the hardware.

Source: https://www.openssh.com/releasenotes.html#8.2

[RFC PATCH] mm: extend memfd with ability to create “secret” memory areas – Mike Rapoport

Extend memfd_create() system call with the ability to create memory areas
visible only in the context of the owning process and not mapped not only
to other processes but in the kernel page tables as well.

The user will create a file descriptor using the memfd_create system call.
The user than has to use ioctl() to define the desired protection mode for
the memory associated with that file descriptor and only when the mode is
set it is possible to mmap() the memory. For instance, the following
exapmple will create an uncached mapping (error handling is omitted):

Source: https://lore.kernel.org/lkml/20200130162340.GA14232@rapoport-lnx/

Keeping secrets in memfd areas [LWN.net]

The memfd subsystem wasn’t designed for address-space isolation; indeed, its initial purpose was as a sort of interprocess communication mechanism. It does, however, provide a way to create a memory region attached to a file descriptor with specific characteristics; a memfd can be “sealed”, for example, so that a recipient knows that it will not be changed. Rapoport decided that it would be a good foundation on which to build a “secret memory” feature.

Source: https://lwn.net/SubscriberLink/812325/b642e849751b9068/

in-toto: Providing farm-to-table guarantees for bits and bytes | USENIX

The software development process is quite complex and involves a number of independent actors. Developers check source code into a version control system, the code is compiled into software at a build farm, and CI/CD systems run multiple tests to ensure the software’s quality among a myriad of other operations. Finally, the software is packaged for distribution into a delivered product, to be consumed by end users. An attacker that is able to compromise any single step in the process can maliciously modify the software and harm any of the software’s users.

To address these issues, we designed in-toto, a framework that cryptographically ensures the integrity of the software supply chain. in-toto grants the end user the ability to verify the software’s supply chain from the project’s inception to its deployment. We demonstrate in-toto’s effectiveness on 30 software supply chain compromises that affected hundreds of million of users and showcase in-toto’s usage over cloud-native, hybrid-cloud and cloud-agnostic applications. in-toto is integrated into products and open source projects that are used by millions of people daily.

Source: https://www.usenix.org/conference/usenixsecurity19/presentation/torres-arias

Survivable Key Compromise in Software Update Systems

Today’s software update systems have little or no defense
against key compromise. As a result, key compromises have
put millions of software update clients at risk. Here we identify
three classes of information whose authenticity and integrity
are critical for secure software updates. Analyzing
existing software update systems with our framework, we
find their ability to communicate this information securely
in the event of a key compromise to be weak or nonexistent.
We also find that the security problems in current software
update systems are compounded by inadequate trust revocation
mechanisms. We identify core security principles that
allow software update systems to survive key compromise.
Using these ideas, we design and implement TUF, a software
update framework that increases resilience to key compromise

Source: https://www.freehaven.net/~arma/tuf-ccs2010.pdf