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authorColin Watson <cjwatson@debian.org>2008-07-22 19:45:18 +0000
committerColin Watson <cjwatson@debian.org>2008-07-22 19:45:18 +0000
commit137d76ba65883aa8143af1fcad83b57e7badef0c (patch)
treef426e804bb5248ceafedfab7bb78ae6e6752942c /ssh.0
parentdac7d049dad31f5f84d421d4eb628a7e13f977d7 (diff)
parentef94e5613d37bcbf880f21ee6094e4b1c7683a4c (diff)
* New upstream release (closes: #474301). Important changes not previously
backported to 4.7p1: - 4.9/4.9p1 (http://www.openssh.com/txt/release-4.9): + Added chroot(2) support for sshd(8), controlled by a new option "ChrootDirectory" (closes: #139047, LP: #24777). + Linked sftp-server(8) into sshd(8). The internal sftp server is used when the command "internal-sftp" is specified in a Subsystem or ForceCommand declaration. When used with ChrootDirectory, the internal sftp server requires no special configuration of files inside the chroot environment. + Added a protocol extension method "posix-rename@openssh.com" for sftp-server(8) to perform POSIX atomic rename() operations; sftp(1) prefers this if available (closes: #308561). + Removed the fixed limit of 100 file handles in sftp-server(8). + ssh(8) will now skip generation of SSH protocol 1 ephemeral server keys when in inetd mode and protocol 2 connections are negotiated. This speeds up protocol 2 connections to inetd-mode servers that also allow Protocol 1. + Accept the PermitRootLogin directive in a sshd_config(5) Match block. Allows for, e.g. permitting root only from the local network. + Reworked sftp(1) argument splitting and escaping to be more internally consistent (i.e. between sftp commands) and more consistent with sh(1). Please note that this will change the interpretation of some quoted strings, especially those with embedded backslash escape sequences. + Support "Banner=none" in sshd_config(5) to disable sending of a pre-login banner (e.g. in a Match block). + ssh(1) ProxyCommands are now executed with $SHELL rather than /bin/sh. + ssh(1)'s ConnectTimeout option is now applied to both the TCP connection and the SSH banner exchange (previously it just covered the TCP connection). This allows callers of ssh(1) to better detect and deal with stuck servers that accept a TCP connection but don't progress the protocol, and also makes ConnectTimeout useful for connections via a ProxyCommand. + scp(1) incorrectly reported "stalled" on slow copies (closes: #140828). + scp(1) date underflow for timestamps before epoch. + ssh(1) used the obsolete SIG DNS RRtype for host keys in DNS, instead of the current standard RRSIG. + Correctly drain ACKs when a sftp(1) upload write fails midway, avoids a fatal() exit from what should be a recoverable condition. + Fixed ssh-keygen(1) selective host key hashing (i.e. "ssh-keygen -HF hostname") to not include any IP address in the data to be hashed. + Make ssh(1) skip listening on the IPv6 wildcard address when a binding address of 0.0.0.0 is used against an old SSH server that does not support the RFC4254 syntax for wildcard bind addresses. + Enable IPV6_V6ONLY socket option on sshd(8) listen socket, as is already done for X11/TCP forwarding sockets (closes: #439661). + Fix FD leak that could hang a ssh(1) connection multiplexing master. + Make ssh(1) -q option documentation consistent with reality. + Fixed sshd(8) PAM support not calling pam_session_close(), or failing to call it with root privileges (closes: #372680). + Fix activation of OpenSSL engine support when requested in configure (LP: #119295). - 5.1/5.1p1 (http://www.openssh.com/txt/release-5.1): + Introduce experimental SSH Fingerprint ASCII Visualisation to ssh(1) and ssh-keygen(1). Visual fingerprint display is controlled by a new ssh_config(5) option "VisualHostKey". The intent is to render SSH host keys in a visual form that is amenable to easy recall and rejection of changed host keys. + sshd_config(5) now supports CIDR address/masklen matching in "Match address" blocks, with a fallback to classic wildcard matching. + sshd(8) now supports CIDR matching in ~/.ssh/authorized_keys from="..." restrictions, also with a fallback to classic wildcard matching. + Added an extended test mode (-T) to sshd(8) to request that it write its effective configuration to stdout and exit. Extended test mode also supports the specification of connection parameters (username, source address and hostname) to test the application of sshd_config(5) Match rules. + ssh(1) now prints the number of bytes transferred and the overall connection throughput for SSH protocol 2 sessions when in verbose mode (previously these statistics were displayed for protocol 1 connections only). + sftp-server(8) now supports extension methods statvfs@openssh.com and fstatvfs@openssh.com that implement statvfs(2)-like operations. + sftp(1) now has a "df" command to the sftp client that uses the statvfs@openssh.com to produce a df(1)-like display of filesystem space and inode utilisation (requires statvfs@openssh.com support on the server). + Added a MaxSessions option to sshd_config(5) to allow control of the number of multiplexed sessions supported over a single TCP connection. This allows increasing the number of allowed sessions above the previous default of 10, disabling connection multiplexing (MaxSessions=1) or disallowing login/shell/subsystem sessions entirely (MaxSessions=0). + Added a no-more-sessions@openssh.com global request extension that is sent from ssh(1) to sshd(8) when the client knows that it will never request another session (i.e. when session multiplexing is disabled). This allows a server to disallow further session requests and terminate the session in cases where the client has been hijacked. + ssh-keygen(1) now supports the use of the -l option in combination with -F to search for a host in ~/.ssh/known_hosts and display its fingerprint. + ssh-keyscan(1) now defaults to "rsa" (protocol 2) keys, instead of "rsa1". + Added an AllowAgentForwarding option to sshd_config(8) to control whether authentication agent forwarding is permitted. Note that this is a loose control, as a client may install their own unofficial forwarder. + ssh(1) and sshd(8): avoid unnecessary malloc/copy/free when receiving network data, resulting in a ~10% speedup. + ssh(1) and sshd(8) will now try additional addresses when connecting to a port forward destination whose DNS name resolves to more than one address. The previous behaviour was to try the only first address and give up if that failed. + ssh(1) and sshd(8) now support signalling that channels are half-closed for writing, through a channel protocol extension notification "eow@openssh.com". This allows propagation of closed file descriptors, so that commands such as "ssh -2 localhost od /bin/ls | true" do not send unnecessary data over the wire. + sshd(8): increased the default size of ssh protocol 1 ephemeral keys from 768 to 1024 bits. + When ssh(1) has been requested to fork after authentication ("ssh -f") with ExitOnForwardFailure enabled, delay the fork until after replies for any -R forwards have been seen. Allows for robust detection of -R forward failure when using -f. + "Match group" blocks in sshd_config(5) now support negation of groups. E.g. "Match group staff,!guests". + sftp(1) and sftp-server(8) now allow chmod-like operations to set set[ug]id/sticky bits. + The MaxAuthTries option is now permitted in sshd_config(5) match blocks. + Multiplexed ssh(1) sessions now support a subset of the ~ escapes that are available to a primary connection. + ssh(1) connection multiplexing will now fall back to creating a new connection in most error cases (closes: #352830). + Make ssh(1) deal more gracefully with channel requests that fail. Previously it would optimistically assume that requests would always succeed, which could cause hangs if they did not (e.g. when the server runs out of file descriptors). + ssh(1) now reports multiplexing errors via the multiplex slave's stderr where possible (subject to LogLevel in the mux master). + Prevent sshd(8) from erroneously applying public key restrictions leaned from ~/.ssh/authorized_keys to other authentication methods when public key authentication subsequently fails (LP: #161047). + Fixed an UMAC alignment problem that manifested on Itanium platforms.
Diffstat (limited to 'ssh.0')
-rw-r--r--ssh.048
1 files changed, 40 insertions, 8 deletions
diff --git a/ssh.0 b/ssh.0
index 8ec0bb397..21e5ac9a3 100644
--- a/ssh.0
+++ b/ssh.0
@@ -130,6 +130,11 @@ DESCRIPTION
130 The recommended way to start X11 programs at a remote site is 130 The recommended way to start X11 programs at a remote site is
131 with something like ssh -f host xterm. 131 with something like ssh -f host xterm.
132 132
133 If the ExitOnForwardFailure configuration option is set to
134 ``yes'', then a client started with -f will wait for all remote
135 port forwards to be successfully established before placing it-
136 self in the background.
137
133 -g Allows remote hosts to connect to local forwarded ports. 138 -g Allows remote hosts to connect to local forwarded ports.
134 139
135 -I smartcard_device 140 -I smartcard_device
@@ -274,13 +279,14 @@ DESCRIPTION
274 User 279 User
275 UserKnownHostsFile 280 UserKnownHostsFile
276 VerifyHostKeyDNS 281 VerifyHostKeyDNS
282 VisualHostKey
277 XAuthLocation 283 XAuthLocation
278 284
279 -p port 285 -p port
280 Port to connect to on the remote host. This can be specified on 286 Port to connect to on the remote host. This can be specified on
281 a per-host basis in the configuration file. 287 a per-host basis in the configuration file.
282 288
283 -q Quiet mode. Causes all warning and diagnostic messages to be 289 -q Quiet mode. Causes most warning and diagnostic messages to be
284 suppressed. 290 suppressed.
285 291
286 -R [bind_address:]port:host:hostport 292 -R [bind_address:]port:host:hostport
@@ -571,12 +577,27 @@ VERIFYING HOST KEYS
571 577
572 $ ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key 578 $ ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key
573 579
574 If the fingerprint is already known, it can be matched and verified, and 580 If the fingerprint is already known, it can be matched and the key can be
575 the key can be accepted. If the fingerprint is unknown, an alternative 581 accepted or rejected. Because of the difficulty of comparing host keys
576 method of verification is available: SSH fingerprints verified by DNS. 582 just by looking at hex strings, there is also support to compare host
577 An additional resource record (RR), SSHFP, is added to a zonefile and the 583 keys visually, using random art. By setting the VisualHostKey option to
578 connecting client is able to match the fingerprint with that of the key 584 ``yes'', a small ASCII graphic gets displayed on every login to a server,
579 presented. 585 no matter if the session itself is interactive or not. By learning the
586 pattern a known server produces, a user can easily find out that the host
587 key has changed when a completely different pattern is displayed. Be-
588 cause these patterns are not unambiguous however, a pattern that looks
589 similar to the pattern remembered only gives a good probability that the
590 host key is the same, not guaranteed proof.
591
592 To get a listing of the fingerprints along with their random art for all
593 known hosts, the following command line can be used:
594
595 $ ssh-keygen -lv -f ~/.ssh/known_hosts
596
597 If the fingerprint is unknown, an alternative method of verification is
598 available: SSH fingerprints verified by DNS. An additional resource
599 record (RR), SSHFP, is added to a zonefile and the connecting client is
600 able to match the fingerprint with that of the key presented.
580 601
581 In this example, we are connecting a client to a server, 602 In this example, we are connecting a client to a server,
582 ``host.example.com''. The SSHFP resource records should first be added 603 ``host.example.com''. The SSHFP resource records should first be added
@@ -714,6 +735,13 @@ FILES
714 host-based authentication without permitting login with 735 host-based authentication without permitting login with
715 rlogin/rsh. 736 rlogin/rsh.
716 737
738 ~/.ssh/
739 This directory is the default location for all user-specific con-
740 figuration and authentication information. There is no general
741 requirement to keep the entire contents of this directory secret,
742 but the recommended permissions are read/write/execute for the
743 user, and not accessible by others.
744
717 ~/.ssh/authorized_keys 745 ~/.ssh/authorized_keys
718 Lists the public keys (RSA/DSA) that can be used for logging in 746 Lists the public keys (RSA/DSA) that can be used for logging in
719 as this user. The format of this file is described in the 747 as this user. The format of this file is described in the
@@ -825,6 +853,10 @@ SEE ALSO
825 853
826 The Secure Shell (SSH) Public Key File Format, RFC 4716, 2006. 854 The Secure Shell (SSH) Public Key File Format, RFC 4716, 2006.
827 855
856 A. Perrig and D. Song, Hash Visualization: a New Technique to improve
857 Real-World Security, 1999, International Workshop on Cryptographic
858 Techniques and E-Commerce (CrypTEC '99).
859
828AUTHORS 860AUTHORS
829 OpenSSH is a derivative of the original and free ssh 1.2.12 release by 861 OpenSSH is a derivative of the original and free ssh 1.2.12 release by
830 Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo 862 Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo
@@ -832,4 +864,4 @@ AUTHORS
832 created OpenSSH. Markus Friedl contributed the support for SSH protocol 864 created OpenSSH. Markus Friedl contributed the support for SSH protocol
833 versions 1.5 and 2.0. 865 versions 1.5 and 2.0.
834 866
835OpenBSD 4.2 June 12, 2007 13 867OpenBSD 4.4 July 2, 2008 14