openssh, pam_ssh_agent_auth security update

CentOS Errata and Security Advisory CESA-2014:1552

OpenSSH is OpenBSD’s SSH (Secure Shell) protocol implementation.
These packages include the core files necessary for both the OpenSSH client
and server.

It was discovered that OpenSSH clients did not correctly verify DNS SSHFP
records. A malicious server could use this flaw to force a connecting
client to skip the DNS SSHFP record check and require the user to perform
manual host verification of the DNS SSHFP record. (CVE-2014-2653)

It was found that OpenSSH did not properly handle certain AcceptEnv
parameter values with wildcard characters. A remote attacker could use this
flaw to bypass intended environment variable restrictions. (CVE-2014-2532)

This update also fixes the following bugs:

• Based on the SP800-131A information security standard, the generation of
  a digital signature using the Digital Signature Algorithm (DSA) with the
  key size of 1024 bits and RSA with the key size of less than 2048 bits is
  disallowed after the year 2013. After this update, ssh-keygen no longer
  generates keys with less than 2048 bits in FIPS mode. However, the sshd
  service accepts keys of size 1024 bits as well as larger keys for
  compatibility reasons. (BZ#993580)

• Previously, the openssh utility incorrectly set the oom_adj value to -17
  for all of its children processes. This behavior was incorrect because the
  children processes were supposed to have this value set to 0. This update
  applies a patch to fix this bug and oom_adj is now properly set to 0 for
  all children processes as expected. (BZ#1010429)

• Previously, if the sshd service failed to verify the checksum of an
  installed FIPS module using the fipscheck library, the information about
  this failure was only provided at the standard error output of sshd. As a
  consequence, the user could not notice this message and be uninformed when
  a system had not been properly configured for FIPS mode. To fix this bug,
  this behavior has been changed and sshd now sends such messages via the
  syslog service. (BZ#1020803)

• When keys provided by the pkcs11 library were removed from the ssh agent
  using the “ssh-add -e” command, the user was prompted to enter a PIN.
  With this update, a patch has been applied to allow the user to remove the
  keys provided by pkcs11 without the PIN. (BZ#1042519)

In addition, this update adds the following enhancements:

• With this update, ControlPersist has been added to OpenSSH. The option in
  conjunction with the ControlMaster configuration directive specifies that
  the master connection remains open in the background after the initial
  client connection has been closed. (BZ#953088)

• When the sshd daemon is configured to force the internal SFTP session,
  and the user attempts to use a connection other than SFTP, the appropriate
  message is logged to the /var/log/secure file. (BZ#997377)

• Support for Elliptic Curve Cryptography modes for key exchange (ECDH) and
  host user keys (ECDSA) as specified by RFC5656 has been added to the
  openssh packages. However, they are not enabled by default and the user has
  to enable them manually. For more information on how to configure ECDSA and
  ECDH with OpenSSH, see: https://access.redhat.com/solutions/711953
  (BZ#1028335)

All openssh users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add these
enhancements.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-cr-announce/2014-October/027588.html

Affected packages:
openssh
openssh-askpass
openssh-clients
openssh-ldap
openssh-server
pam_ssh_agent_auth

Upstream details at:
https://access.redhat.com/errata/RHSA-2014:1552