OpenSSH has dropped libwrap support in OpenSSH 6.7p in 2014
(f2719b7c in github.com/openssh/openssh-portable) and we
maintain the patch ourselves since 2016 (a0ee8cc636).
Over the years, the libwrap support has deteriotated and probably
that was reason for removal upstream. Original idea of libwrap was
to drop illegitimate connection as soon as possible, but over the
years the code was pushed further down and down and ended in the
forked client connection handler.
The negative effects of late dropping is increasing attack surface
for hosts that are to be dropped anyway. Apart from hypothetical
future vulnerabilities in connection handling, today a malicious
host listed in /etc/hosts.allow still can trigger sshd to enter
connection throttling mode, which is enabled by default (see
MaxStartups in sshd_config(5)), effectively casting DoS attack.
Note that on OpenBSD this attack isn't possible, since they enable
MaxStartups together with UseBlacklist.
A only negative effect from early drop, that I can imagine, is that
now main listener parses file in /etc, and if our root filesystems
goes bad, it would get stuck. But unlikely you'd be able to login
in that case anyway.
Implementation details:
- For brevity we reuse the same struct request_info. This isn't
a documented feature of libwrap, but code review, viewing data
in a debugger and real life testing shows that if we clear
RQ_CLIENT_NAME and RQ_CLIENT_ADDR every time, it works as intended.
- We set SO_LINGER on the socket to force immediate connection reset.
- We log message exactly as libwrap's refuse() would do.
Differential revision: https://reviews.freebsd.org/D33044
From OpenSSH 8.8p1's release notes:
---
Potentially-incompatible changes
================================
This release disables RSA signatures using the SHA-1 hash algorithm
by default. This change has been made as the SHA-1 hash algorithm is
cryptographically broken, and it is possible to create chosen-prefix
hash collisions for <USD$50K [1]
For most users, this change should be invisible and there is
no need to replace ssh-rsa keys. OpenSSH has supported RFC8332
RSA/SHA-256/512 signatures since release 7.2 and existing ssh-rsa keys
will automatically use the stronger algorithm where possible.
Incompatibility is more likely when connecting to older SSH
implementations that have not been upgraded or have not closely tracked
improvements in the SSH protocol. For these cases, it may be necessary
to selectively re-enable RSA/SHA1 to allow connection and/or user
authentication via the HostkeyAlgorithms and PubkeyAcceptedAlgorithms
options. For example, the following stanza in ~/.ssh/config will enable
RSA/SHA1 for host and user authentication for a single destination host:
Host old-host
HostkeyAlgorithms +ssh-rsa
PubkeyAcceptedAlgorithms +ssh-rsa
We recommend enabling RSA/SHA1 only as a stopgap measure until legacy
implementations can be upgraded or reconfigured with another key type
(such as ECDSA or Ed25519).
[1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and
Application to the PGP Web of Trust" Leurent, G and Peyrin, T
(2020) https://eprint.iacr.org/2020/014.pdf
---
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
OpenSSH v8.8p1 was motivated primarily by a security update and
deprecation of RSA/SHA1 signatures. It also has a few minor bug fixes.
The security update was already applied to FreeBSD as an independent
change, and the RSA/SHA1 deprecation is excluded from this commit but
will immediately follow.
MFC after: 1 month
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
These files were intended to track version and perhaps maintainership
information for contrib software. However, they were never used beyond
bzip2, netcat, and OpenSSH, and generally haven't been kept up to date
recently (my OpenSSH 8.7p1 update notwithstanding). Just remove them to
avoid having confusing or outdated information.
Suggested by: des
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
OpenSSL assumes the same value for AT_HWCAP=16 (Linux)
So it ends up calling elf_auxv_info() with AT_CANARY which
returns ENOENT, and all acceleration features are disabled.
With this, my ARM64 test machine runs the benchmark
`openssl speed -evp aes-256-gcm` nearly 20x faster
going from 100 MB/sec to 2000 MB/sec
It also improves sha256 from 300 MB/sec to 1800 MB/sec
This fix has been accepted but not yet merged upstream:
https://github.com/openssl/openssl/pull/17082
PR: 259937
Reviewed by: manu, imp
MFC after: immediate
Relnotes: yes
Fixes: 88e852c0b5 ("OpenSSL: Merge OpenSSL 1.1.1j")
Sponsored by: Ampere Computing LLC
Sponsored by: Klara Inc.
Differential Revision: https://reviews.freebsd.org/D33060
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
We want to set ENABLE_SK_INTERNAL only when building with USB support.
We'll leave it off in config.h and enble it via our bespoke build's
Makefile.inc.
Sponsored by: The FreeBSD Foundation
Two local changes were committed upstream and are present in OpenSSH
8.7p1. Remove references from FREEBSD-upgrade now that we have updated
to that version.
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
/usr/include/gssapi.h claims that it is deprecated, and gssapi/gssapi.h
should be used instead. So, test HAVE_GSSAPI_GSSAPI_H first falling
back to HAVE_GSSAPI_H.
This will be submitted upstream.
Fixes: 6eac665c81 ("openssh: diff reduction against...")
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31810
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
Tools like Phabricator use the @generated tag to identify files that
may be excluded from review by default.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Since config.h was last regenerated FreeBSD has added (a stub) libdl,
and has removed sys/dir.h. Regenerate config.h to avoid spurious
additional changes when OpenSSH is next updated.
There should be no issue if this change is MFC'd, but I don't plan to do
so. Although configure checks for libdl HAVE_LIBDL isn't even used, and
sys/dir.h was non-functional before being removed. The state of these
two config.h settings should make no difference in the built OpenSSH.
Sponsored by: The FreeBSD Foundation
We define LIBWRAP at build time in secure/usr.sbin/sshd/Makefile if
WITH_TCPWRAPPERS is in effect, so it should not be set in config.h.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
freebsd-configure.sh runs configure twice, --with-kerberos5 and
--without-kerberos5, in order to build a config.h that defaults to
kerberos5 disabled, and a small config file that represents the
differences.
Rename config.h.orig to config.h.kerberos5 to clarify the intent of this
script.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Login class-based restrictions were introduced in 5b400a39b8. The
code was adapted for sshd's Capsicum sandbox and received many changes
over time, including at least fc3c19a9fc, bd393de91c, and
e8c56fba29.
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
FreeBSD's kernel TLS supports Chacha20 for both TLS 1.2 and TLS 1.3.
NB: This commit has not yet been merged upstream as it is deemed a new
feature and did not make the feature freeze cutoff for OpenSSL 3.0.
Reviewed by: jkim
MFC after: 5 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31443
Most of this upstream commit touched tests not included in the
vendor import. The one change merged in is to remove a constant
only present in an internal header to appease the older tests.
Reviewed by: jkim
Obtained from: OpenSSL (e1fdd5262e4a45ce3aaa631768e877ee7b6da21b)
MFC after: 5 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31442
KTLS support has been changed to be off by default, and configuration is
via a single "option" rather two "modes". Documentation is updated
accordingly.
Reviewed by: jkim
Obtained from: OpenSSL (6878f4300213cfd7d4f01e26a8b97f70344da100)
MFC after: 5 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31441
It has always been the case that KTLS is not compiled by default. However
if it is compiled then it was automatically used unless specifically
configured not to. This is problematic because it avoids any crypto
implementations from providers. A user who configures all crypto to use
the FIPS provider may unexpectedly find that TLS related crypto is actually
being performed outside of the FIPS boundary.
Instead we change KTLS so that it is disabled by default.
We also swap to using a single "option" (i.e. SSL_OP_ENABLE_KTLS) rather
than two separate "modes", (i.e. SSL_MODE_NO_KTLS_RX and
SSL_MODE_NO_KTLS_TX).
Reviewed by: jkim
Obtained from: OpenSSL (a3a54179b6754fbed6d88e434baac710a83aaf80)
MFC after: 5 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31440
Linux kernel is going to support ChaCha20-Poly1305 in TLS offload.
Add support for this cipher.
Reviewed by: jkim
Obtained from: OpenSSL (3aa7212e0a4fd1533c8a28b8587dd8b022f3a66f)
MFC after: 5 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31439
BIO_get_ktls_send() and BIO_get_ktls_recv() are documented as
returning either 0 or 1. However, they were actually returning the
internal value of the associated BIO flag for the true case instead of
1.
Also trim redundant ternary operators.
Reviewed by: jkim
Obtained from: OpenSSL (f16e52b67c9261bdc7e1284a50502a802921ac6d)
MFC after: 5 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31438
Replace it with a tutorial hosted on kerberos.org and the classic
"dialogue" from Bill Bryant. The change has been reported and
merged upstream (https://github.com/heimdal/heimdal/commit/7f3445f1b7).
MFC after: 3 days
PR: 251854
Reported by: ktullavik@gmail.com
Submitted by: bjk (upstream github)
Reviewed by: bcr
Add a handler for EBUSY sendfile error in addition to
EAGAIN. With EBUSY returned the data still can be partially
sent and user code has to be notified about it, otherwise it
may try to send data multiple times.
PR: 251969
Reviewed by: jkim
Obtained from: OpenSSL (dfcfd17f2818cf520ce6381aed9ec3d2fc12170d)
MFC after: 1 week
Sponsored by: Netflix (merging to FreeBSD)
Differential Revision: https://reviews.freebsd.org/D28714
This was introduced in 8998619212, and left behind when the hpn-ssh
patches were removed in 60c59fad88. Although Being able to log
SO_RCVBUF in debug mode might have some small value on its own, it's
not worth carrying an extra diff against upstream.
Reviewed by: kevans
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D28610
