Description of FIDO/U2F support (from OpenSSH 8.2 release notes,
https://www.openssh.com/txt/release-8.2):
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.
ssh-keygen(1) may be used to generate a FIDO token-backed key, after
which they may be used much like any other key type supported by
OpenSSH, so long as the hardware token is attached when the keys are
used. FIDO tokens also generally require the user explicitly
authorise operations by touching or tapping them.
Generating a FIDO key requires the token be attached, and will
usually require the user tap the token to confirm the operation:
$ ssh-keygen -t ecdsa-sk -f ~/.ssh/id_ecdsa_sk
Generating public/private ecdsa-sk key pair.
You may need to touch your security key to authorize key generation.
Enter file in which to save the key (/home/djm/.ssh/id_ecdsa_sk):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/djm/.ssh/id_ecdsa_sk
Your public key has been saved in /home/djm/.ssh/id_ecdsa_sk.pub
This will yield a public and private key-pair. The private key file
should be useless to an attacker who does not have access to the
physical token. After generation, this key may be used like any
other supported key in OpenSSH and may be listed in authorized_keys,
added to ssh-agent(1), etc. The only additional stipulation is that
the FIDO token that the key belongs to must be attached when the key
is used.
To enable FIDO/U2F support, this change regenerates ssh_namespace.h,
adds ssh-sk-helper, and sets ENABLE_SK_INTERNAL (unless building
WITHOUT_USB).
devd integration is not included in this change, and is under
investigation for the base system. In the interim the security/u2f-devd
port can be installed to provide appropriate devd rules.
Reviewed by: delphij, kevans
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D32509
Some notable changes, from upstream's release notes:
- sshd(8): Remove support for obsolete "host/port" syntax.
- ssh(1): When prompting whether to record a new host key, accept the key
fingerprint as a synonym for "yes".
- ssh-keygen(1): when acting as a CA and signing certificates with an RSA
key, default to using the rsa-sha2-512 signature algorithm.
- ssh(1), sshd(8), ssh-keygen(1): this release removes the "ssh-rsa"
(RSA/SHA1) algorithm from those accepted for certificate signatures.
- ssh-sk-helper(8): this is a new binary. It is used by the FIDO/U2F
support to provide address-space isolation for token middleware
libraries (including the internal one).
- ssh(1): this release enables UpdateHostkeys by default subject to some
conservative preconditions.
- scp(1): this release changes the behaviour of remote to remote copies
(e.g. "scp host-a:/path host-b:") to transfer through the local host
by default.
- scp(1): experimental support for transfers using the SFTP protocol as
a replacement for the venerable SCP/RCP protocol that it has
traditionally used.
Additional integration work is needed to support FIDO/U2F in the base
system.
Deprecation Notice
------------------
OpenSSH will disable the ssh-rsa signature scheme by default in the
next release.
Reviewed by: imp
MFC after: 1 month
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29985
For some reason poly64 was omitted when this file was last generated
(perhaps it was inlined by the Clang version then in use).
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Login class-based restrictions were introduced in 5b400a39b8ad. The
code was adapted for sshd's Capsicum sandbox and received many changes
over time, including at least fc3c19a9fcee, bd393de91cc3, and
e8c56fba2926.
During an attempt to upstream the work a much simpler approach was
suggested. Adopt it now in the in-tree OpenSSH to reduce conflicts with
future updates.
Submitted by: Yuchiro Naito (against OpenSSH-portable on GitHub)
Obtained from: https://github.com/openssh/openssh-portable/pull/262
Reviewed by: allanjude, kevans
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D31760
This completely removes client-side support for the SSH 1 protocol,
which was already disabled in 12 but is still enabled in 11. For that
reason, we will not be able to merge 7.6p1 or newer back to 11.
I have worked hard to reduce diffs against the vendor branch. One
notable change in that respect is that we no longer prefer DSA over
RSA - the reasons for doing so went away years ago. This may cause
some surprises, as ssh will warn about unknown host keys even for
hosts whose keys haven't changed.
MFC after: 6 weeks
