RHBA-2011:1177 - Bug Fix Advisory

Topic

An updated mingetty package that fixes three bugs is now available for Red Hat
Enterprise Linux 6.

Description

The mingetty program is a lightweight, minimalist getty program for use only on
virtual consoles. The mingetty program is not suitable for serial lines (the
mgetty program should be used in that case).

This update fixes the following bugs:

• Prior to this update, when mingetty was invoked with the "--chroot" option,

mingetty did not change the working directory to the new root. Furthermore,
mingetty continued even if setting constraints specified by the "--chroot",
"--chdir", and "--nice" options failed. As a result, a user was able to escape
from the changed root by using relative paths. Also, it was possible for a user
to obtain a process with a different process priority. These problems have been
resolved in this update so that the working directory is now changed to the new
root directory, all failures are now recognized, and mingetty terminates with an
error reported to the system log. (BZ#640933)

• Prior to this update, when invoking mingetty with a TTY name (a non-option

position argument) that was longer than 39 ASCII characters, a buffer overflow
occurred and the mingetty stack content could have become corrupted. This bug
has been fixed in this update so that only the first 39 bytes (34 bytes in case
of a relative path) from the TTY name are now copied. (BZ#640940)

• Prior to this update, when using a login name longer than 39 characters, such

login name was silently refused and mingetty terminated. With this update, login
names with the length up to the current runtime limit are now accepted; login
names that are above the limit are refused, an error is reported to the system
log, and mingetty terminates. (BZ#651955)

All users of mingetty should upgrade to this updated package, which fixes these
bugs.

Solution

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

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 640933 - unsafe chroot() calls in mingetty
• BZ - 640940 - Buffer overflow in open_tty()
• BZ - 651955 - If console login, username with about 100 chars are not prompted for a passwd

CVEs

(none)

References

(none)