Download OpenSSH 4.9

The Openbsd Project has a new version of Openssh in the form of 4.9 announced. The new version can be downloaded for Unix and Linux distributions by clicking on this link. Openssh is an implementation of the ssh protocol, which allows encrypted connections between (usually) *nix machines and provides a more secure alternative to telnet and rlogin. Version 4.9 of Openssh ships with a number of new features and bug fixes. What they are exactly, can be read below:

Security:

• Disable execution of ~/.ssh/rc for sessions where a command has been forced by the sshd_config ForceCommand directive. Users who had write access to this file could use it to execute abritrary commands. This behavior was documented, but was an unsafe default and an extra hassle for administrators.

New features:

• Added chroot(2) support for sshd(8), controlled by a new option “ChrootDirectory”. Please refer to sshd_config(5) for details, and please use this feature carefully. (bz#177 bz#1352)
• 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. Please refer to sshd_config(5) for more information.
• Added a “no-user-rc” option for authorized_keys to disable execution of ~/.ssh/rc
• Added a protocol extension method “posix-rename@openssh.com” for sftp-server(8) to perform POSIX atomic rename() operations. (bz#1400)
• Removed the fixed limit of 100 file handles in sftp-server(8). The server will now dynamically allocate handles up to the number of available file descriptors. (bz#1397)
• 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 (bz#440)
• Accept the PermitRootLogin directive in a sshd_config(5) Match block. Allows for, eg permitting root only from the local network.
• Reworked sftp(1) argument splitting and escaping to be more internally consistent (ie 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. (bz#778)
• Support “Banner=none” in sshd_config(5) to disable sending of a pre-login banner (eg 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.
• Many new regression tests, including interop tests against PuTTY’s plink.
• Support BSM auditing on Mac OS X

The following bugs have been fixed in this release:

• scp(1) incorrectly reported “stalled” on slow copies. (bz#799)
• scp(1) date underflow for timestamps before epoch. (bz#828)
• scp(1) and sftp(1) progressmeter type fixes. (bz#842)
• SSH2_MSG_UNIMPLEMENTED packets did not correctly reset the client keepalive logic, causing disconnections on servers that did not explicitly implement “keepalive@openssh.com”. (bz#1307)
• ssh(1) used the obsolete SIG DNS RRtype for host keys in DNS, instead of the current standard RRSIG. (bz#1317)
• Extract magic buffer size constants in scp(1) to #defines. (bz#1333)
• Correctly drain ACKs when a sftp(1) upload write fails midway, avoids a fatal() exit from what should be a recoverable condition. (bz#1354)
• Avoid pointer arithmetic and strict aliasing warnings. (bz#1355)
• Fixed packet size advertisements. Previously TCP and agent forwarding incorrectly advertised the channel window size as the packet size, causing fatal errors under some conditions. (bz#1360)
• Document KbdInteractiveAuthentication in sshd_config(5). (bz#1367)
• Fixed sftp(1) file handle leak on download when the local file could not be opened. (bz#1375)
• Fixed ssh-keygen(1) selective host key hashing (ie “ssh-keygen -HF hostname”) to not include any IP address in the data to be hashed. (bz#1376)
• Fix clobbering of struct passwd from multiple getpwid calls, resulting in fatal errors inside tilde_expand_filename. (bz#1377)
• Fix parsing of port-forwarding specifications to correctly detect errors in either specified port number. (bz#1378)
• Fix memory leak in ssh(1) ~ escape commandline handling. (bz#1379)
• 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. (bz#1381)
• Remove extra backslashes in the RB_PROTOTYPE macro definition. (bz#1385)
• Support ssh(1) RekeyLimits up to the maximum allowed by the protocol: 2**32-1. (bz#1390)
• Enable IPV6_V6ONLY socket option on sshd(8) listen socket, as is already done for X11/TCP forwarding sockets. (bz#1392)
• Fix FD leak that could hang a ssh(1) connection multiplexing master. (bz#1398)
• Improve error messages when hostname resolution fails due to a system error. (bz#1417)
• Make ssh(1) -q option documentation consistent with reality. (bz#1427 bz#1429)

Portable OpenSSH bugs fixed:

• Fixed sshd(8) PAM support not calling pam_session_close(), or failing to call it with root privileges. (bz#926)
• Made sshd(8) use configuration-specified SyslogFacility for hosts_access(3) messages for denied connections. (bz#1042)
• Implement getgrouplist(3) for AIX, enabling NSS LDAP to work on this platform. (bz#1081)
• Fix compilation errors on AIX due to misdefinition of LLONG_MAX. (bz#1347)
• Force use of local glob(3) implementation on Mac OS X and FreeBSD, as the platform versions lack features or have unexpected behaviour. (bz#1407)
• Reduce stdout/stderr noise from ssh-copy-id. (bz#1431)
• Fix activation of OpenSSL engine support when requested in configure. (bz#1437)

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