Contributed by weerd on from the hush-hush dept.
Damien Miller (djm@) posted to announce@ with the announcement of OpenSSH 5.4. Some highlights of this release are the disabling of protocol 1 by default, certificate authentication, a new 'netcat mode', many changes on the sftp front (both client and server) and a collection of assorted bugfixes. The new release can already be found on a large number of mirrors and of course on www.openssh.com.
Please read on for the full release announcement:
OpenSSH 5.4 has just been released. It will be available from the mirrors listed at http://www.openssh.com/ shortly. OpenSSH is a 100% complete SSH protocol version 1.3, 1.5 and 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html This is a major feature and bugfix release. Changes since OpenSSH 5.3 ========================= Features: * After a transition period of about 10 years, this release disables SSH protocol 1 by default. Clients and servers that need to use the legacy protocol must explicitly enable it in ssh_config / sshd_config or on the command-line. * Remove the libsectok/OpenSC-based smartcard code and add support for PKCS#11 tokens. This support is automatically enabled on all platforms that support dlopen(3) and was inspired by patches written by Alon Bar-Lev. Details in the ssh(1) and ssh-add(1) manpages. * Add support for certificate authentication of users and hosts using a new, minimal OpenSSH certificate format (not X.509). Certificates contain a public key, identity information and some validity constraints and are signed with a standard SSH public key using ssh-keygen(1). CA keys may be marked as trusted in authorized_keys or via a TrustedUserCAKeys option in sshd_config(5) (for user authentication), or in known_hosts (for host authentication). Documentation for certificate support may be found in ssh-keygen(1), sshd(8) and ssh(1) and a description of the protocol extensions in PROTOCOL.certkeys. * Added a 'netcat mode' to ssh(1): "ssh -W host:port ..." This connects stdio on the client to a single port forward on the server. This allows, for example, using ssh as a ProxyCommand to route connections via intermediate servers. bz#1618 * Add the ability to revoke keys in sshd(8) and ssh(1). User keys may be revoked using a new sshd_config(5) option "RevokedKeys". Host keys are revoked through known_hosts (details in the sshd(8) man page). Revoked keys cannot be used for user or host authentication and will trigger a warning if used. * Rewrite the ssh(1) multiplexing support to support non-blocking operation of the mux master, improve the resilience of the master to malformed messages sent to it by the slave and add support for requesting port- forwardings via the multiplex protocol. The new stdio-to-local forward mode ("ssh -W host:port ...") is also supported. The revised multiplexing protocol is documented in the file PROTOCOL.mux in the source distribution. * Add a 'read-only' mode to sftp-server(8) that disables open in write mode and all other fs-modifying protocol methods. bz#430 * Allow setting an explicit umask on the sftp-server(8) commandline to override whatever default the user has. bz#1229 * Many improvements to the sftp(1) client, many of which were implemented by Carlos Silva through the Google Summer of Code program: - Support the "-h" (human-readable units) flag for ls - Implement tab-completion of commands, local and remote filenames - Support most of scp(1)'s commandline arguments in sftp(1), as a first step towards making sftp(1) a drop-in replacement for scp(1). Note that the rarely-used "-P sftp_server_path" option has been moved to "-D sftp_server_path" to make way for "-P port" to match scp(1). - Add recursive transfer support for get/put and on the commandline * New RSA keys will be generated with a public exponent of RSA_F4 == (2**16)+1 == 65537 instead of the previous value 35. * Passphrase-protected SSH protocol 2 private keys are now protected with AES-128 instead of 3DES. This applied to newly-generated keys as well as keys that are reencrypted (e.g. by changing their passphrase). Bugfixes: * Hold authentication debug messages until after successful authentication. Fixes a minor information leak of environment variables specified in authorized_keys if an attacker happens to know the public key in use. * When using ChrootDirectory, make sure we test for the existence of the user's shell inside the chroot and not outside (bz#1679) * Cache user and group name lookups in sftp-server using user_from_[ug]id(3) to improve performance on hosts where these operations are slow (e.g. NIS or LDAP). bz#1495 * Fix problem that prevented passphrase reading from being interrupted in some circumstances; bz#1590 * Ignore and log any Protocol 1 keys where the claimed size is not equal to the actual size. * Make HostBased authentication work with a ProxyCommand. bz#1569 * Avoid run-time failures when specifying hostkeys via a relative path by prepending the current working directory in these cases. bz#1290 * Do not prompt for a passphrase if we fail to open a keyfile, and log the reason why the open failed to debug. bz#1693 * Document that the PubkeyAuthentication directive is allowed in a sshd_config(5) Match block. bz#1577 * When converting keys, truncate key comments at 72 chars as per RFC4716. bz#1630 * Do not allow logins if /etc/nologin exists but is not readable by the user logging in. * Output a debug log if sshd(8) can't open an existing authorized_keys. bz#1694 * Quell tc[gs]etattr warnings when forcing a tty (ssh -tt), since we usually don't actually have a tty to read/set; bz#1686 * Prevent sftp from crashing when given a "-" without a command. Also, allow whitespace to follow a "-". bz#1691 * After sshd receives a SIGHUP, ignore subsequent HUPs while sshd re-execs itself. Prevents two HUPs in quick succession from resulting in sshd dying. bz#1692 * Clarify in sshd_config(5) that StrictModes does not apply to ChrootDirectory. Permissions and ownership are always checked when chrooting. bz#1532 * Set close-on-exec on various descriptors so they don't get leaked to child processes. bz#1643 * Fix very rare race condition in x11/agent channel allocation: don't read after the end of the select read/write fdset and make sure a reused FD is not touched before the pre-handlers are called. * Fix incorrect exit status when multiplexing and channel ID 0 is recycled. bz#1570 * Fail with an error when an attempt is made to connect to a server with ForceCommand=internal-sftp with a shell session (i.e. not a subsystem session). Avoids stuck client when attempting to ssh to such a service. bz#1606: * Warn but do not fail if stat()ing the subsystem binary fails. This helps with chrootdirectory+forcecommand=sftp-server and restricted shells. bz #1599 * Change "Connecting to host..." message to "Connected to host." and delay it until after the sftp protocol connection has been established. Avoids confusing sequence of messages when the underlying ssh connection experiences problems. bz#1588 * Use the HostKeyAlias rather than the hostname specified on the commandline when prompting for passwords. bz#1039 * Correct off-by-one in percent_expand(): we would fatal() when trying to expand EXPAND_MAX_KEYS, allowing only EXPAND_MAX_KEYS-1 to actually work. Note that nothing in OpenSSH actually uses close to this limit at present. bz#1607 * Fix passing of empty options from scp(1) and sftp(1) to the underlying ssh(1). Also add support for the stop option "--". * Fix an incorrect magic number and typo in PROTOCOL; bz#1688 * Don't escape backslashes when displaying the SSH2 banner. bz#1533 * Don't unnecessarily dup() the in and out fds for sftp-server. bz#1566 * Force use of the correct hash function for random-art signature display
Thanks to all the OpenSSH developers for this new release. Now is the time for you to go and upgrade your ssh installations to 5.4!
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