Document that the TERM environment variable is not
subject to SendEnv and AcceptEnv. bz#2386, based loosely on a patch from
jjelen at redhat, help and ok jmc@
Provide a warning about chroot misuses (which sadly, seem
to have become quite popular because shiny). sshd cannot detect/manage/do
anything about these cases, best we can do is warn in the right spot in the
man page. ok markus
add sshd_config HostbasedAcceptedKeyTypes and
PubkeyAcceptedKeyTypes options to allow sshd to control what public key types
will be accepted. Currently defaults to all. Feedback & ok markus@
mention ssh -Q feature to list supported { MAC, cipher,
KEX, key } algorithms in more places and include the query string used to
list the relevant information; bz#2288
remember which public keys have been used for
authentication and refuse to accept previously-used keys.
This allows AuthenticationMethods=publickey,publickey to require
that users authenticate using two _different_ pubkeys.
ok markus@
Add FingerprintHash option to control algorithm used for
key fingerprints. Default changes from MD5 to SHA256 and format from hex to
base64.
Feedback and ok naddy@ markus@
/dev/random has created the same effect as /dev/arandom
(and /dev/urandom) for quite some time. Mop up the last few, by using
/dev/random where we actually want it, or not even mentioning arandom where
it is irrelevant.
[PROTOCOL auth-options.c auth-passwd.c auth-rh-rsa.c auth-rhosts.c]
[auth-rsa.c auth.c auth1.c auth2-hostbased.c auth2-kbdint.c auth2-none.c]
[auth2-passwd.c auth2-pubkey.c auth2.c canohost.c channels.c channels.h]
[clientloop.c misc.c misc.h monitor.c mux.c packet.c readconf.c]
[readconf.h servconf.c servconf.h serverloop.c session.c ssh-agent.c]
[ssh.c ssh_config.5 sshconnect.c sshconnect1.c sshconnect2.c sshd.c]
[sshd_config.5 sshlogin.c]
Add support for Unix domain socket forwarding. A remote TCP port
may be forwarded to a local Unix domain socket and vice versa or
both ends may be a Unix domain socket. This is a reimplementation
of the streamlocal patches by William Ahern from:
http://www.25thandclement.com/~william/projects/streamlocal.html
OK djm@ markus@
[servconf.c servconf.h session.c sshd.8 sshd_config.5]
Add a sshd_config PermitUserRC option to control whether ~/.ssh/rc is
executed, mirroring the no-user-rc authorized_keys option;
bz#2160; ok markus@
[Makefile.in PROTOCOL PROTOCOL.chacha20poly1305 authfile.c chacha.c]
[chacha.h cipher-chachapoly.c cipher-chachapoly.h cipher.c cipher.h]
[dh.c myproposal.h packet.c poly1305.c poly1305.h servconf.c ssh.1]
[ssh.c ssh_config.5 sshd_config.5] Add a new protocol 2 transport
cipher "chacha20-poly1305@openssh.com" that combines Daniel
Bernstein's ChaCha20 stream cipher and Poly1305 MAC to build an
authenticated encryption mode.
Inspired by and similar to Adam Langley's proposal for TLS:
http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-03
but differs in layout used for the MAC calculation and the use of a
second ChaCha20 instance to separately encrypt packet lengths.
Details are in the PROTOCOL.chacha20poly1305 file.
Feedback markus@, naddy@; manpage bits Loganden Velvindron @ AfriNIC
ok markus@ naddy@
[readconf.c servconf.c ssh_config.5 sshd_config.5]
Disallow empty Match statements and add "Match all" which matches
everything. ok djm, man page help jmc@
[auth.h kex.h kexdhs.c kexecdhs.c kexgexs.c monitor.c servconf.c]
[servconf.h session.c sshd.c sshd_config.5]
add ssh-agent(1) support to sshd(8); allows encrypted hostkeys,
or hostkeys on smartcards; most of the work by Zev Weiss; bz #1974
ok djm@
[ssh-keygen.1 ssh.1 ssh_config.5 sshd.8 sshd_config.5]
do not use Sx for sections outwith the man page - ingo informs me that
stuff like html will render with broken links;
issue reported by Eric S. Raymond, via djm
[sshd_config.5 servconf.c servconf.h packet.c serverloop.c monitor.c sshd_config
sshd.c] Add RekeyLimit to sshd with the same syntax as the client allowing
rekeying based on traffic volume or time. ok djm@, help & ok jmc@ for the man
page.
[servconf.c sshd_config sshd_config.5]
Change default of MaxStartups to 10:30:100 to start doing random early
drop at 10 connections up to 100 connections. This will make it harder
to DoS as CPUs have come a long way since the original value was set
back in 2000. Prompted by nion at debian org, ok markus@
[auth.c key.c key.h ssh-keygen.1 ssh-keygen.c sshd_config.5]
[krl.c krl.h PROTOCOL.krl]
add support for Key Revocation Lists (KRLs). These are a compact way to
represent lists of revoked keys and certificates, taking as little as
a single bit of incremental cost to revoke a certificate by serial number.
KRLs are loaded via the existing RevokedKeys sshd_config option.
feedback and ok markus@
[PROTOCOL authfile.c cipher.c cipher.h kex.c kex.h monitor_wrap.c]
[myproposal.h packet.c ssh_config.5 sshd_config.5]
support AES-GCM as defined in RFC 5647 (but with simpler KEX handling)
ok and feedback djm@
[PROTOCOL authfile.c cipher.c cipher.h kex.h mac.c myproposal.h]
[packet.c ssh_config.5 sshd_config.5]
add encrypt-then-mac (EtM) modes to openssh by defining new mac algorithms
that change the packet format and compute the MAC over the encrypted
message (including the packet size) instead of the plaintext data;
these EtM modes are considered more secure and used by default.
feedback and ok djm@
[auth-options.c channels.c servconf.c servconf.h serverloop.c session.c]
[sshd_config.5]
make AllowTcpForwarding accept "local" and "remote" in addition to its
current "yes"/"no" to allow the server to specify whether just local or
remote TCP forwarding is enabled. ok markus@
[auth.h auth1.c auth2.c monitor.c servconf.c servconf.h sshd.c]
[sshd_config.5]
Support multiple required authentication via an AuthenticationMethods
option. This option lists one or more comma-separated lists of
authentication method names. Successful completion of all the methods in
any list is required for authentication to complete;
feedback and ok markus@
[auth2-pubkey.c sshd.c sshd_config.5]
Remove default of AuthorizedCommandUser. Administrators are now expected
to explicitly specify a user. feedback and ok markus@
[auth-rsa.c auth.c auth.h auth2-pubkey.c servconf.c servconf.h]
[sshd.c sshd_config sshd_config.5]
new sshd_config option AuthorizedKeysCommand to support fetching
authorized_keys from a command in addition to (or instead of) from
the filesystem. The command is run as the target server user unless
another specified via a new AuthorizedKeysCommandUser option.
patch originally by jchadima AT redhat.com, reworked by me; feedback
and ok markus@
[mac.c myproposal.h ssh_config.5 sshd_config.5]
Remove hmac-sha2-256-96 and hmac-sha2-512-96 MACs since they were removed
from draft6 of the spec and will not be in the RFC when published. Patch
from mdb at juniper net via bz#2023, ok markus.
[servconf.c servconf.h sshd_config.5]
sshd_config: extend Match to allow AcceptEnv and {Allow,Deny}{Users,Groups}
this allows 'Match LocalPort 1022' combined with 'AllowUser bauer'
ok djm@ (back in March)
- dtucker@cvs.openbsd.org 2012/05/13 01:42:32
[servconf.h servconf.c sshd.8 sshd.c auth.c sshd_config.5]
Add "Match LocalAddress" and "Match LocalPort" to sshd and adjust tests
to match. Feedback and ok djm@ markus@.
[servconf.c servconf.h sshd.c sshd_config sshd_config.5]
VersionAddendum option to allow server operators to append some arbitrary
text to the SSH-... banner; ok deraadt@ "don't care" markus@
[ssh_config.5 sshd_config.5]
fix typo in IPQoS parsing: there is no "AF14" class, but there is
an "AF21" class. Spotted by giesen AT snickers.org; ok markus stevesk
[servconf.c servconf.h sshd.c sshd_config.5 sandbox-rlimit.c]
[sandbox-systrace.c sandbox.h configure.ac Makefile.in]
introduce sandboxing of the pre-auth privsep child using systrace(4).
This introduces a new "UsePrivilegeSeparation=sandbox" option for
sshd_config that applies mandatory restrictions on the syscalls the
privsep child can perform. This prevents a compromised privsep child
from being used to attack other hosts (by opening sockets and proxying)
or probing local kernel attack surface.
The sandbox is implemented using systrace(4) in unsupervised "fast-path"
mode, where a list of permitted syscalls is supplied. Any syscall not
on the list results in SIGKILL being sent to the privsep child. Note
that this requires a kernel with the new SYSTR_POLICY_KILL option.
UsePrivilegeSeparation=sandbox will become the default in the future
so please start testing it now.
feedback dtucker@; ok markus@
- djm@cvs.openbsd.org 2011/05/23 03:30:07
[auth-rsa.c auth.c auth.h auth2-pubkey.c monitor.c monitor_wrap.c pathnames.h servconf.c servconf.h sshd.8 sshd_config sshd_config.5]
allow AuthorizedKeysFile to specify multiple files, separated by spaces.
Bring back authorized_keys2 as a default search path (to avoid breaking
existing users of this file), but override this in sshd_config so it will
be no longer used on fresh installs. Maybe in 2015 we can remove it
entierly :)
feedback and ok markus@ dtucker@
[clientloop.c misc.c misc.h packet.c packet.h readconf.c readconf.h]
[servconf.c servconf.h session.c ssh.c ssh_config.5 sshd_config.5]
allow ssh and sshd to set arbitrary TOS/DSCP/QoS values instead of
hardcoding lowdelay/throughput.
bz#1733 patch from philipp AT redfish-solutions.com; ok markus@ deraadt@
[kex.c kex.h kexecdh.c kexecdhc.c kexecdhs.c readconf.c readconf.h]
[servconf.c servconf.h ssh_config.5 sshconnect2.c sshd.c sshd_config.5]
add a KexAlgorithms knob to the client and server configuration to allow
selection of which key exchange methods are used by ssh(1) and sshd(8)
and their order of preference.
ok markus@
[PROTOCOL PROTOCOL.agent PROTOCOL.certkeys auth2-jpake.c authfd.c]
[authfile.c buffer.h dns.c kex.c kex.h key.c key.h monitor.c]
[monitor_wrap.c myproposal.h packet.c packet.h pathnames.h readconf.c]
[ssh-add.1 ssh-add.c ssh-agent.1 ssh-agent.c ssh-keygen.1 ssh-keygen.c]
[ssh-keyscan.1 ssh-keyscan.c ssh-keysign.8 ssh.1 ssh.c ssh2.h]
[ssh_config.5 sshconnect.c sshconnect2.c sshd.8 sshd.c sshd_config.5]
[uuencode.c uuencode.h bufec.c kexecdh.c kexecdhc.c kexecdhs.c ssh-ecdsa.c]
Implement Elliptic Curve Cryptography modes for key exchange (ECDH) and
host/user keys (ECDSA) as specified by RFC5656. ECDH and ECDSA offer
better performance than plain DH and DSA at the same equivalent symmetric
key length, as well as much shorter keys.
Only the mandatory sections of RFC5656 are implemented, specifically the
three REQUIRED curves nistp256, nistp384 and nistp521 and only ECDH and
ECDSA. Point compression (optional in RFC5656 is NOT implemented).
Certificate host and user keys using the new ECDSA key types are supported.
Note that this code has not been tested for interoperability and may be
subject to change.
feedback and ok markus@
[servconf.c sshd_config.5]
expose some more sshd_config options inside Match blocks:
AuthorizedKeysFile AuthorizedPrincipalsFile
HostbasedUsesNameFromPacketOnly PermitTunnel
bz#1764; feedback from imorgan AT nas.nasa.gov; ok dtucker@
[auth-options.c auth-options.h auth.c auth.h auth2-pubkey.c]
[key.c servconf.c servconf.h sshd.8 sshd_config.5]
add some optional indirection to matching of principal names listed
in certificates. Currently, a certificate must include the a user's name
to be accepted for authentication. This change adds the ability to
specify a list of certificate principal names that are acceptable.
When authenticating using a CA trusted through ~/.ssh/authorized_keys,
this adds a new principals="name1[,name2,...]" key option.
For CAs listed through sshd_config's TrustedCAKeys option, a new config
option "AuthorizedPrincipalsFile" specifies a per-user file containing
the list of acceptable names.
If either option is absent, the current behaviour of requiring the
username to appear in principals continues to apply.
These options are useful for role accounts, disjoint account namespaces
and "user@realm"-style naming policies in certificates.
feedback and ok markus@
[auth-rh-rsa.c auth-rsa.c auth.c auth.h auth2-hostbased.c auth2-pubkey.c]
[authfile.c authfile.h hostfile.c hostfile.h servconf.c servconf.h]
[ssh-keygen.c ssh.1 sshconnect.c sshd_config.5]
Add a TrustedUserCAKeys option to sshd_config to specify CA keys that
are trusted to authenticate users (in addition than doing it per-user
in authorized_keys).
Add a RevokedKeys option to sshd_config and a @revoked marker to
known_hosts to allow keys to me revoked and banned for user or host
authentication.
feedback and ok markus@
- djm@cvs.openbsd.org 2010/02/26 20:29:54
[PROTOCOL PROTOCOL.agent PROTOCOL.certkeys addrmatch.c auth-options.c]
[auth-options.h auth.h auth2-pubkey.c authfd.c dns.c dns.h hostfile.c]
[hostfile.h kex.h kexdhs.c kexgexs.c key.c key.h match.h monitor.c]
[myproposal.h servconf.c servconf.h ssh-add.c ssh-agent.c ssh-dss.c]
[ssh-keygen.1 ssh-keygen.c ssh-rsa.c ssh.1 ssh.c ssh2.h sshconnect.c]
[sshconnect2.c sshd.8 sshd.c sshd_config.5]
Add support for certificate key types for users and hosts.
OpenSSH certificate key types are not X.509 certificates, but a much
simpler format that encodes a public key, identity information and
some validity constraints and signs it with a CA key. CA keys are
regular SSH keys. This certificate style avoids the attack surface
of X.509 certificates and is very easy to deploy.
Certified host keys allow automatic acceptance of new host keys
when a CA certificate is marked as sh/known_hosts.
see VERIFYING HOST KEYS in ssh(1) for details.
Certified user keys allow authentication of users when the signing
CA key is marked as trusted in authorized_keys. See "AUTHORIZED_KEYS
FILE FORMAT" in sshd(8) for details.
Certificates are minted using ssh-keygen(1), documentation is in
the "CERTIFICATES" section of that manpage.
Documentation on the format of certificates is in the file
PROTOCOL.certkeys
feedback and ok markus@
[channels.c ssh.1 servconf.c sshd_config.5 sshd.c channels.h servconf.h
ssh-keyscan.1 ssh-keyscan.c readconf.c sshconnect.c misc.c ssh.c
readconf.h scp.1 sftp.1 ssh_config.5 misc.h]
Remove RoutingDomain from ssh since it's now not needed. It can be
replaced with "route exec" or "nc -V" as a proxycommand. "route exec"
also ensures that trafic such as DNS lookups stays withing the specified
routingdomain. For example (from reyk):
# route -T 2 exec /usr/sbin/sshd
or inherited from the parent process
$ route -T 2 exec sh
$ ssh 10.1.2.3
ok deraadt@ markus@ stevesk@ reyk@
[sshd_config.5 readconf.c ssh_config.5 scp.1 servconf.c sftp.1 ssh.1]
Rename RDomain config option to RoutingDomain to be more clear and
consistent with other options.
NOTE: if you currently use RDomain in the ssh client or server config,
or ssh/sshd -o, you must update to use RoutingDomain.
ok markus@ djm@
[ssh.c sftp.c scp.c]
When passing user-controlled options with arguments to other programs,
pass the option and option argument as separate argv entries and
not smashed into one (e.g., as -l foo and not -lfoo). Also, always
pass a "--" argument to stop option parsing, so that a positional
argument that starts with a '-' isn't treated as an option. This
fixes some error cases as well as the handling of hostnames and
filenames that start with a '-'.
Based on a diff by halex@
ok halex@ djm@ deraadt@
[ssh_config.5 sshd.c misc.h ssh-keyscan.1 readconf.h sshconnect.c
channels.c channels.h servconf.h servconf.c ssh.1 ssh-keyscan.c scp.1
sftp.1 sshd_config.5 readconf.c ssh.c misc.c]
Allow to set the rdomain in ssh/sftp/scp/sshd and ssh-keyscan.
ok markus@
- markus@cvs.openbsd.org 2009/10/08 14:03:41
[sshd_config readconf.c ssh_config.5 servconf.c sshd_config.5]
disable protocol 1 by default (after a transition period of about 10 years)
ok deraadt
[auth.h auth2.c monitor.c monitor.h monitor_wrap.c monitor_wrap.h]
[readconf.c readconf.h servconf.c servconf.h ssh2.h ssh_config.5]
[sshconnect2.c sshd_config.5 jpake.c jpake.h schnorr.c auth2-jpake.c]
[Makefile.in]
Add support for an experimental zero-knowledge password authentication
method using the J-PAKE protocol described in F. Hao, P. Ryan,
"Password Authenticated Key Exchange by Juggling", 16th Workshop on
Security Protocols, Cambridge, April 2008.
This method allows password-based authentication without exposing
the password to the server. Instead, the client and server exchange
cryptographic proofs to demonstrate of knowledge of the password while
revealing nothing useful to an attacker or compromised endpoint.
This is experimental, work-in-progress code and is presently
compiled-time disabled (turn on -DJPAKE in Makefile.inc).
"just commit it. It isn't too intrusive." deraadt@
[sshd_config sshd_config.5 sshd.8 servconf.c]
increase default size of ssh protocol 1 ephemeral key from 768 to 1024
bits; prodded by & ok dtucker@ ok deraadt@
- djm@cvs.openbsd.org 2008/06/10 03:57:27
[servconf.c match.h sshd_config.5]
support CIDR address matching in sshd_config "Match address" blocks, with
full support for negation and fall-back to classic wildcard matching.
For example:
Match address 192.0.2.0/24,3ffe:ffff::/32,!10.*
PasswordAuthentication yes
addrmatch.c code mostly lifted from flowd's addr.c
feedback and ok dtucker@
[monitor.c monitor_wrap.c session.h servconf.c servconf.h session.c]
[sshd_config sshd_config.5]
Make the maximum number of sessions run-time controllable via
a sshd_config MaxSessions knob. This is useful for disabling
login/shell/subsystem access while leaving port-forwarding working
(MaxSessions 0), disabling connection multiplexing (MaxSessions 1) or
simply increasing the number of allows multiplexed sessions.
Because some bozos are sure to configure MaxSessions in excess of the
number of available file descriptors in sshd (which, at peak, might be
as many as 9*MaxSessions), audit sshd to ensure that it doesn't leak fds
on error paths, and make it fail gracefully on out-of-fd conditions -
sending channel errors instead of than exiting with fatal().
bz#1090; MaxSessions config bits and manpage from junyer AT gmail.com
ok markus@
[servconf.c servconf.h session.c sshd_config.5]
Enable the AllowAgentForwarding option in sshd_config (global and match
context), to specify if agents should be permitted on the server.
As the man page states:
``Note that disabling Agent forwarding does not improve security
unless users are also denied shell access, as they can always install
their own forwarders.''
ok djm@, ok and a mild frown markus@
- djm@cvs.openbsd.org 2008/04/04 05:14:38
[sshd_config.5]
ChrootDirectory is supported in Match blocks (in fact, it is most useful
there). Spotted by Minstrel AT minstrel.org.uk
[servconf.c servconf.h session.c sftp-server.c sftp.h sshd_config]
[sshd_config.5]
add sshd_config ChrootDirectory option to chroot(2) users to a directory
and tweak internal sftp server to work with it (no special files in
chroot required). ok markus@
[sshd_config.5 servconf.c]
Allow PermitRootLogin in a Match block. Allows for, eg, permitting root
only from the local network. ok markus@, man page bit ok jmc@
[kex.h mac.c mac.h monitor_wrap.c myproposal.h packet.c ssh.1]
[ssh_config.5 sshd.8 sshd_config.5]
Add a new MAC algorithm for data integrity, UMAC-64 (not default yet,
must specify umac-64@openssh.com). Provides about 20% end-to-end speedup
compared to hmac-md5. Represents a different approach to message
authentication to that of HMAC that may be beneficial if HMAC based on
one of its underlying hash algorithms is found to be vulnerable to a
new attack. http://www.ietf.org/rfc/rfc4418.txt
in conjunction with and OK djm@
[scp.1 ssh_config.5 sftp-server.8 ssh-agent.1 sshd_config.5 sftp.1
ssh-keygen.1 ssh-keyscan.1 ssh-add.1 sshd.8 ssh.1 ssh-keysign.8]
convert to new .Dd format;
(We will need to teach mdoc2man.awk to understand this too.)
[auth2.c sshd_config.5 servconf.c]
Remove ChallengeResponseAuthentication support inside a Match
block as its interaction with KbdInteractive makes it difficult to
support. Also, relocate the CR/kbdint option special-case code into
servconf. "please commit" djm@, ok markus@ for the relocation.
[monitor_wrap.c servconf.c servconf.h monitor.c sshd_config.5]
Teach Match how handle config directives that are used before
authentication. This allows configurations such as permitting password
authentication from the local net only while requiring pubkey from
offsite. ok djm@, man page bits ok jmc@
[channels.c channels.h servconf.c servconf.h sshd_config.5]
Make PermitOpen take a list of permitted ports and act more like most
other keywords (ie the first match is the effective setting). This
also makes it easier to override a previously set PermitOpen. ok djm@
[servconf.c servconf.h session.c sshd.8 sshd_config sshd_config.5]
Add ForceCommand keyword to sshd_config, equivalent to the "command="
key option, man page entry and example in sshd_config.
Feedback & ok djm@, man page corrections & ok jmc@
[channels.c channels.h servconf.c sshd_config.5]
Add PermitOpen directive to sshd_config which is equivalent to the
"permitopen" key option. Allows server admin to allow TCP port
forwarding only two specific host/port pairs. Useful when combined
with Match.
If permitopen is used in both sshd_config and a key option, both
must allow a given connection before it will be permitted.
Note that users can still use external forwarders such as netcat,
so to be those must be controlled too for the limits to be effective.
Feedback & ok djm@, man page corrections & ok jmc@.
[sshd.c servconf.h servconf.c sshd_config.5 auth.c]
Add support for conditional directives to sshd_config via a "Match"
keyword, which works similarly to the "Host" directive in ssh_config.
Lines after a Match line override the default set in the main section
if the condition on the Match line is true, eg
AllowTcpForwarding yes
Match User anoncvs
AllowTcpForwarding no
will allow port forwarding by all users except "anoncvs".
Currently only a very small subset of directives are supported.
ok djm@
[misc.c ssh_config.5 sshd_config.5]
Allow config directives to contain whitespace by surrounding them by double
quotes. mindrot #482, man page help from jmc@, ok djm@
dtucker@openbsd.org
jmc@openbsd.org
djm@openbsd.org
deraadt@openbsd.org
sobrado@openbsd.org
Damien Miller
Darren Tucker