Updated stunnel packages fix signal vulnerability

Updated stunnel packages are now available for Red Hat Linux 7.1, 7.2, 7.3,
and 8.0. These updates correct a potential vulnerability in stunnel's
signal handling.

Stunnel is a wrapper for network connections. It can be used to tunnel an
unencrypted network connection over a secure connection (encrypted using
SSL or TLS) or to provide a secure means of connecting to services that do
not natively support encryption.

When configured to listen for incoming connections (instead of being
invoked by xinetd), stunnel can be configured to either start a thread or a
child process to handle each new connection. If Stunnel is configured to
start a new child process to handle each connection, it will receive a
SIGCHLD signal when that child exits.

Stunnel versions prior to 4.04 would perform tasks in the SIGCHLD signal
handler which, if interrupted by another SIGCHLD signal, could be unsafe.
This could lead to a denial of service.

All users are urged to upgrade to these errata packages, which modify
stunnel's signal handler so that it is not vulnerable to this issue.

NOTE: After upgrading, any instances of stunnel configured to run in daemon
mode should be restarted, and any active network connections that are
currently being serviced by stunnel should be terminated and reestablished.

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

To update all RPMs for your particular architecture, run:

rpm -Fvh [filenames]

where [filenames] is a list of the RPMs you wish to upgrade. Only those
RPMs which are currently installed will be updated. Those RPMs which are
not installed but included in the list will not be updated. Note that you
can also use wildcards (*.rpm) if your current directory *only* contains the
desired RPMs.

Please note that this update is also available via Red Hat Network. Many
people find this an easier way to apply updates. To use Red Hat Network,
launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate
RPMs being upgraded on your system.

82325 - stunnel security errata required

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-1563
http://marc.theaimsgroup.com/?l=stunnel-users&m=103600188215117

DoS, handler, reentrancy, signal, stunnel