Updated openssh packages that fix one security issue, multiple bugs, andadd various enhancements are now available for Red Hat Enterprise Linux 6.The Red Hat Security Response Team has rated this update as having moderatesecurity impact. A Common Vulnerability Scoring System base score,which gives a detailed severity rating, is available from the CVE link inthe References section. OpenSSH is OpenBSD's Secure Shell protocol implementation. Thesepackages include the core files necessary for the OpenSSH client andserver.Due to the way the pam_ssh_agent_auth PAM module was built in Red HatEnterprise Linux 6, the glibc's error function was called rather than theintended error function in pam_ssh_agent_auth to report errors. As thesetwo functions expect different arguments, it was possible for an attackerto cause an application using pam_ssh_agent_auth to crash, discloseportions of its memory or, potentially, execute arbitrary code.Note that the pam_ssh_agent_auth module is not used in Red Hat EnterpriseLinux 6 by default.This update also fixes the following bugs:* All possible options for the new RequiredAuthentications directive werenot documented in the sshd_config man page. This update improves the manpage to document all the possible options. * When stopping one instance of the SSH daemon , the sshd init script stopped all sshd processes regardless of the PID ofthe processes. This update improves the init script so that it only killsprocesses with the relevant PID. As a result, the init script now worksmore reliably in a multi-instance environment. * Due to a regression, the ssh-copy-id command returned an exit status codeof zero even if there was an error in copying the key to a remote host.With this update, a patch has been applied and ssh-copy-id now returns anon-zero exit code if there is an error in copying the SSH certificate to aremote host. * When SELinux was disabled on the system, no on-disk policy was installed,a user account was used for a connection, and no "~/.ssh" configuration waspresent in that user's home directory, the SSH client terminatedunexpectedly with a segmentation fault when attempting to connect toanother system. A patch has been provided to address this issue and thecrashes no longer occur in the described scenario. * The "HOWTO" document /usr/share/doc/openssh-ldap-5.3p1/HOWTO.ldap-keysincorrectly documented the use of the AuthorizedKeysCommand directive.This update corrects the document. This update also adds the following enhancements:* When attempting to enable SSH for use with a Common Access Card ,the ssh-agent utility read all the certificates in the card even thoughonly the ID certificate was needed. Consequently, if a user entered theirPIN incorrectly, then the CAC was locked, as a match for the PIN wasattempted against all three certificates. With this update, ssh-add doesnot try the same PIN for every certificate if the PIN fails for the firstone. As a result, the CAC will not be disabled if a user enters their PINincorrectly. * This update adds a "netcat mode" to SSH. The "ssh -W host:port ..."command connects standard input and output on a client to a singleport on a server. As a result, SSH can be used to route connections viaintermediate servers. * Due to a bug, arguments for the RequiredAuthentications2 directive werenot stored in a Match block. Consequently, parsing of the config file wasnot in accordance with the man sshd_config documentation. This update fixesthe bug and users can now use the required authentication feature tospecify a list of authentication methods as expected according to the manpage. All users of openssh are advised to upgrade to these updated packages,which fix these issues and add these enhancements. After installing thisupdate, the OpenSSH server daemon will be restarted automatically.