What's new in Sudo 1.7.6p2
* Two-character CIDR-style IPv4 netmasks are now matched correctly
in the sudoers file.
* A build error with MIT Kerberos V has been resolved.
What's new in Sudo 1.7.6p1
* A non-existent includedir is now treated the same as an empty
directory and not reported as an error.
* Removed extraneous parens in LDAP filter when sudoers_search_filter
is enabled that can cause an LDAP search error.
* pkgsrc change: trying to use user-destdir.
What's new in Sudo 1.7.5?
* When using visudo in check mode, a file named "-" may be used to
check sudoers data on the standard input.
* Sudo now only fetches shadow password entries when using the
password database directly for authentication.
* Password and group entries are now cached using the same key
that was used to look them up. This fixes a problem when looking
up entries by name if the name in the retrieved entry does not
match the name used to look it up. This may happen on some systems
that do case insensitive lookups or that truncate long names.
* GCC will no longer display warnings on glibc systems that use
the warn_unused_result attribute for write(2) and other system calls.
* If a PAM account management module denies access, sudo now prints
a more useful error message and stops trying to validate the user.
* Fixed a potential hang on idle systems when the sudo-run process
exits immediately.
* Sudo now includes a copy of zlib that will be used on systems
that do not have zlib installed.
* The --with-umask-override configure flag has been added to enable
the "umask_override" sudoers Defaults option at build time.
* Sudo now unblocks all signals on startup to avoid problems caused
by the parent process changing the default signal mask.
* LDAP Sudoers entries may now specify a time period for which
the entry is valid. This requires an updated sudoers schema
that includes the sudoNotBefore and sudoNotAfter attributes.
Support for timed entries must be explicitly enabled in the
ldap.conf file. Based on changes from Andreas Mueller.
* LDAP Sudoers entries may now specify a sudoOrder attribute that
determines the order in which matching entries are applied. The
last matching entry is used, just like file-based sudoers. This
requires an updated sudoers schema that includes the sudOrder
attribute. Based on changes from Andreas Mueller.
* When run as sudoedit, or when given the -e flag, sudo now treats
command line arguments as pathnames. This means that slashes
in the sudoers file entry must explicitly match slashes in
the command line arguments. As a result, and entry such as:
user ALL = sudoedit /etc/*
will allow editing of /etc/motd but not /etc/security/default.
* NETWORK_TIMEOUT is now an alias for BIND_TIMELIMIT in ldap.conf for
compatibility with OpenLDAP configuration files.
* The LDAP API TIMEOUT parameter is now honored in ldap.conf.
* The I/O log directory may now be specified in the sudoers file.
* Sudo will no longer refuse to run if the sudoers file is writable
by root.
* Sudo now performs command line escaping for "sudo -s" and "sudo -i"
after validating the command so the sudoers entries do not need
to include the backslashes.
* Logging and email sending are now done in the locale specified
by the "sudoers_locale" setting ("C" by default). Email send by
sudo now includes MIME headers when "sudoers_locale" is not "C".
* The configure script has a new option, --disable-env-reset, to
allow one to change the default for the sudoers Default setting
"env_reset" at compile time.
* When logging "sudo -l command", sudo will now prepend "list "
to the command in the log line to distinguish between an
actual command invocation in the logs.
* Double-quoted group and user names may now include escaped double
quotes as part of the name. Previously this was a parse error.
* Sudo once again restores the state of the signal handlers it
modifies before executing the command. This allows sudo to be
used with the nohup command.
* Resuming a suspended shell now works properly when I/O logging
is not enabled (the I/O logging case was already correct).
What's new in Sudo 1.7.4p6?
* A bug has been fixed in the I/O logging support that could cause
visual artifacts in full-screen programs such as text editors.
What's new in Sudo 1.7.4p5?
* A bug has been fixed that would allow a command to be run without the
user entering a password when sudo's -g flag is used without the -u flag.
* If user has no supplementary groups, sudo will now fall back on checking
the group file explicitly, which restores historic sudo behavior.
* A crash has been fixed when sudo's -g flag is used without the -u flag
and the sudoers file contains an entry with no runas user or group listed.
* A bug has been fixed in the I/O logging support that could cause
visual artifacts in full-screen programs such as text editors,.
* A crash has been fixed when the Solaris project support is enabled
and sudo's -g flag is used without the -u flag.
* Sudo no longer exits with an error when support for auditing is
compiled in but auditing is not enabled.
* Fixed a bug introduced in sudo 1.7.3 where the ticket file was not
being honored when the "targetpw" sudoers Defaults option was enabled.
* The LOG_INPUT and LOG_OUTPUT tags in sudoers are now parsed correctly.
* A crash has been fixed in "sudo -l" when sudo is built with auditing
support and the user is not allowed to run any commands on the host.
* Install README.LDAP when "ldap" is enabled in PKG_OPTIONS.
* Fix build problem when "kerberos" is enabled in PKG_OPTIONS.
Bump PKGREVISION since default PLIST has changed.
relevant bugs) version:
Major changes between version 1.7.4p3 and 1.7.4p4:
* A potential security issue has been fixed with respect to the
handling of sudo's -g command line option when -u is also
specified. The flaw may allow an attacker to run commands as a
user that is not authorized by the sudoers file.
* A bug has been fixed where "sudo -l" output was incomplete if
multiple sudoers sources were defined in nsswitch.conf and there
was an error querying one of the sources.
* The log_input, log_output, and use_pty sudoers options now work
correctly on AIX. Previously, sudo would hang if they were
enabled.
* Fixed "make install" when sudo is built in a directory other
than the directory that holds the sources.
* The runas_default sudoers setting now works properly in a
per-command Defaults line.
* Suspending and resuming the bash shell when PAM is in use now
works properly. The SIGCONT signal was not being propagated to
the child process.
Major changes between version 1.7.4p2 and 1.7.4p3:
* A bug has been fixed where duplicate HOME environment variables
could be set when the env_reset setting was disabled and the
always_set_home setting was enabled in sudoers.
* The value of sysconfdir is now substituted into the path to the
sudoers.d directory in the installed sudoers file.
* Fixed compilation problems on Irix and other platforms.
* If multiple PAM "auth" actions are specified and the user enters
^C at the password prompt, sudo will now abort any subsequent
"auth" actions. Previously it was necessary to enter ^C once for
each "auth" action.
Major changes between version 1.7.4p1 and 1.7.4p2:
* Fixed a bug where sudo could spin in a cpu loop waiting for the
child process.
* Packaging fixes for sudo.pp to better handle patchlevels.
Major changes between version 1.7.4 and 1.7.4p1:
* Fix a bug introduced in sudo 1.7.3 that prevented the -k and -K
options from functioning when the tty_tickets sudoers option was
enabled.
* Sudo no longer prints a warning when the -k or -K options are
specified and the ticket file does not exist.
* Changes to the configure script to enable cross-compilation of
Sudo.
Major changes between version 1.7.3 and 1.7.4:
* Sudoedit will now preserve the file extension in the name of the
temporary file being edited. The extension is used by some
editors (such as emacs) to choose the editing mode.
* Time stamp files have moved from /var/run/sudo to either
/var/db/sudo, /var/lib/sudo or /var/adm/sudo. The directories
are checked for existence in that order. This prevents users
from receiving the sudo lecture every time the system reboots.
Time stamp files older than the boot time are ignored on systems
where it is possible to determine this.
* Ancillary documentation (README files, LICENSE, etc) is now
installed in a sudo documentation directory.
* Sudo now recognizes "tls_cacert" as an alias for "tls_cacertfile"
in ldap.conf.
* Defaults settings that are tied to a user, host or command may
now include the negation operator. For example:
Defaults:!millert lecture
will match any user but millert.
* The default PATH environment variable, used when no PATH variable
exists, now includes /usr/sbin and /sbin.
* Sudo now uses polypkg for cross-platform packing.
* On Linux, sudo will now restore the nproc resource limit before
executing a command, unless the limit appears to have been
modified by pam_limits. This avoids a problem with bash scripts
that open more than 32 descriptors on SuSE Linux, where
sysconf(_SC_CHILD_MAX) will return -1 when RLIMIT_NPROC is set
to RLIMIT_UNLIMITED (-1).
* Visudo will now treat an unrecognized Defaults entry as a parse
error (sudo will warn but still run).
* The HOME and MAIL environment variables are now reset based on
the target user's password database entry when the env_reset
sudoers option is enabled (which is the case in the default
configuration). Users wishing to preserve the original values
should use a sudoers entry like:
Defaults env_keep += HOME
to preserve the old value of HOME and
Defaults env_keep += MAIL
to preserve the old value of MAIL.
* The tty_tickets option is now on by default.
* Fixed a problem in the restoration of the AIX authdb registry
setting.
* If PAM is in use, wait until the process has finished before
closing the PAM session.
* Fixed "sudo -i -u user" where user has no shell listed in the
password database.
* When logging I/O, sudo now handles pty read/write returning ENXIO,
as seen on FreeBSD when the login session has been killed.
* Sudo now performs I/O logging in the C locale. This avoids
locale-related issues when parsing floating point numbers in the
timing file.
* Added support for Ubuntu-style admin flag dot files.
Major changes between version 1.7.2p8 and 1.7.3:
* Support for logging a command's input and output as well as the
ability to replay sessions. For more information, see the
documentation for the log_input and log_output Defaults options
in the sudoers manual. Also see the sudoreplay manual for
information on replaying I/O log sessions.
* The use_pty sudoers option can be used to force a command to be
run in a pseudo-pty, even when I/O logging is not enabled.
* On some systems, sudo can now detect when a user has logged out
and back in again when tty-based time stamps are in use.
Supported systems include Solaris systems with the devices file
system, Mac OS X, and Linux systems with the devpts filesystem
(pseudo-ttys only).
* On AIX systems, the registry setting in /etc/security/user is
now taken into account when looking up users and groups.
Sudo now applies the correct the user and group ids when running
a command as a user whose account details come from a different
source (e.g. LDAP or DCE vs. local files).
* Support for multiple sudoers_base and uri entries in ldap.conf.
When multiple entries are listed, sudo will try each one in the
order in which they are specified.
* Sudo's SELinux support should now function correctly when running
commands as a non-root user and when one of stdin, stdout or stderr
is not a terminal.
* Sudo will now use the Linux audit system with configure with the
--with-linux-audit flag.
* Sudo now uses mbr_check_membership() on systems that support it
to determine group membership. Currently, only Darwin (Mac OS X)
supports this.
* When the tty_tickets sudoers option is enabled but there is no
terminal device, sudo will no longer use or create a tty-based
ticket file. Previously, sudo would use a tty name of "unknown".
As a consequence, if a user has no terminal device, sudo will now
always prompt for a password.
* The passwd_timeout and timestamp_timeout options may now be
specified as floating point numbers for more granular timeout
values.
* Negating the fqdn option in sudoers now works correctly when sudo
is configured with the --with-fqdn option. In previous versions
of sudo the fqdn was set before sudoers was parsed.
Major changes between sudo 1.7.2p7 and 1.7.2p8:
* Fixed a crash on AIX when LDAP support is in use.
* Fixed problems with the QAS non-Unix group support
For more detail: http://www.sudo.ws/sudo/alerts/secure_path.html
Summary:
Sudo "secure path" feature works by replacing the PATH environment
variable with a value specified in the sudoers file, or at
compile time if the --with-secure-path configure option is used.
The flaw is that sudo only replaces the first instance of PATH
in the environment. If the program being run through sudo uses
the last instance of PATH in the environment, an attacker may
be able to avoid the "secure path" restrictions.
Sudo versions affected:
Sudo 1.3.1 through 1.6.9p22 and Sudo 1.7.0 through 1.7.2p6.
Sudo versions 1.7.2p6 and 1.6.9p22 are now available. These releases
fix a privilege escalation bug in the sudoedit functionality.
Summary:
A flaw exists in sudo's -e option (aka sudoedit) in sudo versions
1.6.8 through 1.7.2p5 that may give a user with permission to
run sudoedit the ability to run arbitrary commands. This bug
is related to, but distinct from, CVE 2010-0426.
Sudo versions affected:
1.6.8 through 1.7.2p5 inclusive.
Major changes between version 1.7.2p3 and 1.7.2p4:
* Fix a bug that could allow users with permission to run sudoedit
to run arbitrary commands.
Major changes between version 1.7.2p2 and 1.7.2p3:
* Fix printing of entries with multiple host entries on a single line.
* Fix use after free when sending error messages via email.
* Use setrlimit64(), if available, instead of setrlimit() when
setting AIX resource limits since rlim_t is 32bits.
* Fix size arg when realloc()ing include stack.
* Avoid a duplicate fclose() of the sudoers file.
Major changes between sudo 1.7.2p1 and 1.7.2p2:
* Fixed a a bug where the negation operator in a Cmnd_List
was not being honored.
* Sudo no longer produces a parse error when #includedir references
a directory that contains no valid filenames.
* The sudo.man.pl and sudoers.man.pl files are now included in
the distribution for people who wish to regenerate the man pages.
* Fixed the emulation of krb5_get_init_creds_opt_alloc() for MIT kerberos.
* When authenticating via PAM, set PAM_RUSER and PAM_RHOST early so
they can be used during authentication.
Changes in 1.7.2p1 since 1.7.2:
===============================
* Fixed the expansion of the %h escape in #include file names introduced in
sudo 1.7.1.
Changes in 1.7.2 since 1.7.1:
=============================
* A new #includedir directive is available in sudoers. This can be used to
implement an /etc/sudo.d directory. Files in an includedir are not edited
by visudo unless they contain a syntax error.
* The -g option did not work properly when only setting the group (and not
the user). Also, in -l mode the wrong user was displayed for sudoers
entries where only the group was allowed to be set.
* Fixed a problem with the alias checking in visudo which could prevent
visudo from exiting.
* Sudo will now correctly parse the shell-style /etc/environment file format
used by pam_env on Linux.
* When doing password and group database lookups, sudo will only cache an
entry by name or by id, depending on how the entry was looked up.
Previously, sudo would cache by both name and id from a single lookup, but
this breaks sites that have multiple password or group database names that
map to the same uid or gid.
* User and group names in sudoers may now be enclosed in double quotes to
avoid having to escape special characters.
* BSM audit fixes when changing to a non-root uid.
* Experimental non-Unix group support. Currently only works with Quest
Authorization Services and allows Active Directory groups fixes for
Minix-3.
* For Netscape/Mozilla-derived LDAP SDKs the certificate and key paths may
be specified as a directory or a file. However, version 5.0 of the SDK
only appears to support using a directory (despite documentation to the
contrary). If SSL client initialization fails and the certificate or key
paths look like they could be default file name, strip off the last path
element and try again.
* A setenv() compatibility fix for Linux systems, where a NULL value is
treated the same as an empty string and the variable name is checked
against the NULL pointer.
pkgsrc change: add LICENSE.
What's new in Sudo 1.7.1?
* A new Defaults option "pwfeedback" will cause sudo to provide visual
feedback when the user is entering a password.
* A new Defaults option "fast_glob" will cause sudo to use the fnmatch()
function for file name globbing instead of glob(). When this option
is enabled, sudo will not check the file system when expanding wildcards.
This is faster but a side effect is that relative paths with wildcard
will no longer work.
* New BSM audit support for systems that support it such as FreeBSD
and Mac OS X.
* The file name specified with the #include directive may now include
a %h escape which is expanded to the short form of hostname.
* The -k flag may now be specified along with a command, causing the
user's timestamp file to be ignored.
* New support for Tivoli-based LDAP START_TLS, present in AIX.
* New support for /etc/netsvc.conf on AIX.
* The unused alias checks in visudo now handle the case of an alias
referring to another alias.
* pkgsrc change: relax restriction to kerberos package.
What's new in Sudo 1.7.0?
* Rewritten parser that converts sudoers into a set of data structures.
This eliminates a number of ordering issues and makes it possible to
apply sudoers Defaults entries before searching for the command.
It also adds support for per-command Defaults specifications.
* Sudoers now supports a #include facility to allow the inclusion of other
sudoers-format files.
* Sudo's -l (list) flag has been enhanced:
o applicable Defaults options are now listed
o a command argument can be specified for testing whether a user
may run a specific command.
o a new -U flag can be used in conjunction with "sudo -l" to allow
root (or a user with "sudo ALL") list another user's privileges.
* A new -g flag has been added to allow the user to specify a
primary group to run the command as. The sudoers syntax has been
extended to include a group section in the Runas specification.
* A uid may now be used anywhere a username is valid.
* The "secure_path" run-time Defaults option has been restored.
* Password and group data is now cached for fast lookups.
* The file descriptor at which sudo starts closing all open files is now
configurable via sudoers and, optionally, the command line.
* Visudo will now warn about aliases that are defined but not used.
* The -i and -s command line flags now take an optional command
to be run via the shell. Previously, the argument was passed
to the shell as a script to run.
* Improved LDAP support. SASL authentication may now be used in
conjunction when connecting to an LDAP server. The krb5_ccname
parameter in ldap.conf may be used to enable Kerberos.
* Support for /etc/nsswitch.conf. LDAP users may now use nsswitch.conf
to specify the sudoers order. E.g.:
sudoers: ldap files
to check LDAP, then /etc/sudoers. The default is "files", even
when LDAP support is compiled in. This differs from sudo 1.6
where LDAP was always consulted first.
* Support for /etc/environment on AIX and Linux. If sudo is run
with the -i flag, the contents of /etc/environment are used to
populate the new environment that is passed to the command being
run.
* If no terminal is available or if the new -A flag is specified,
sudo will use a helper program to read the password if one is
configured. Typically, this is a graphical password prompter
such as ssh-askpass.
* A new Defaults option, "mailfrom" that sets the value of the
"From:" field in the warning/error mail. If unspecified, the
login name of the invoking user is used.
* A new Defaults option, "env_file" that refers to a file containing
environment variables to be set in the command being run.
* A new flag, -n, may be used to indicate that sudo should not
prompt the user for a password and, instead, exit with an error
if authentication is required.
* If sudo needs to prompt for a password and it is unable to disable
echo (and no askpass program is defined), it will refuse to run
unless the "visiblepw" Defaults option has been specified.
* Prior to version 1.7.0, hitting enter/return at the Password: prompt
would exit sudo. In sudo 1.7.0 and beyond, this is treated as
an empty password. To exit sudo, the user must press ^C or ^D
at the prompt.
* visudo will now check the sudoers file owner and mode in -c (check)
mode when the -s (strict) flag is specified.
660) The -i flag should imply resetting the environment, as it did in
sudo version prior to 1.6.9. Also, the -i and -E flags are
mutually exclusive.
661) Fixed the configure test for dirfd() under Linux.
662) Fixed test for whether -lintl is required to link.
663) Changed how sudo handles the child process when sending mail.
This fixes a problem on Linux with the mail_always option.
664) Fixed a problem with line continuation characters inside of
quoted strings.
Major changes since Sudo 1.6.9p15:
o There was missing whitespace before the ldap libraries in the Makefile
for some configurations.
o LDAPS_PORT may not be defined on older Solaris LDAP SDKs.
o If the LDAP server could not be contacted and the user was not present
in sudoers, a syntax error in sudoers was incorrectly reported.
and ${REAL_ROOT_GROUP} instead. The pkginstall framework checks for
the name of the user and group, not the uid and gid, when comparing
permissions. This fixes the following spurious warning from appearing:
The following files are used by sudo-1.6.9p15 and have
the wrong ownership and/or permissions:
/usr/pkg/etc/sudoers (m=0440, o=0, g=0)
653) Fixed installation of sudo_noexec.so on AIX.
654) Updated libtool to version 1.5.26.
655) Fixed printing of default SELinux role and type in -V mode.
656) The HOME environment variable is once again preserved by default,
as per the documentation.
pkgsrc changes:
- Explict to depends security/heimdal package when kerberos option is
specified. PR pkg/37999 should be fixed.
Change:
646) Sudo will now set the nproc resource limit to unlimited on Linux
systems to work around Linux's setuid() resource limit semantics.
On PAM systems the resource limits will be reset by pam_limits.so
before the command is executed.
647) SELinux support that can be used to implement role based access
control (RBAC). A role and (optional) type may be specified
in sudoers or on the command line. These are then used in the
security context that the command is run as.
648) Fixed a Kerberos 5 compilation problem with MIT Kerberos.
Sudo 1.6.9p13 released.
649) Fixed an invalid assumption in the PAM conversation function
introduced in version 1.6.9p9. The conversation function may
be called for non-password reading purposes as well.
650) Fixed freeing an uninitialized pointer in -l mode, introduced in
version 1.6.9p13.
651) Check /etc/sudoers after LDAP even if the user was found in LDAP.
This allows Defaults options in /etc/sudoers to take effect.
652) Add missing checks for enforcing mode in SELinux RBAC mode.
Sudo 1.6.9p14 released.
Changes from 1.6.9p11:
641) Added a configure check for the ber_set_option() function.
642) Fixed a compilation problem with the HP-UX K&R C compiler.
643) Revamped the Kerberos 5 ticket verification code.
644) Added support for the checkpeer ldap.conf variable for
netscape-based LDAP SDKs.
645) Fixed a problem where an incomplete password could be echoed
to the screen if there was a read timeout.
637) Fixed a compilation problem on SCO related to how they
store the high resolution timestamps in struct stat.
638) Avoid checking the passwd file group multiple times
in the LDAP query when the user's passwd group is also
listed in the supplemental group vector.
639) The URI specifier can now be used in ldap.conf even when
the LDAP SDK doesn't support ldap_initialize().
640) New %p prompt escape that expands to the user whose password
is being prompted, as specified by the rootpw, targetpw and
runaspw sudoers flags. Based on a diff from Patrick Schoenfeld.
Major changes since Sudo 1.6.9p9:
o Moved LDAP options into a table for simplified parsing/setting.
o Fixed a problem with how some LDAP options were being applied.
o Added support for connecting directly to LDAP servers via SSL/TLS
for servers that don't support the start_tls extension.
Major changes since Sudo 1.6.9p8:
o The ALL command in sudoers now implies SETENV permissions.
o The command search is now performed using the target user's
auxiliary group vector, not just the target's primary group.
o When determining if the PAM prompt is the default "Password: ",
compare the localized version if possible.
o New passprompt_override option in sudoers to cause sudo's prompt
to be used in all cases. Also set when the -p flag is used.
Major changes since Sudo 1.6.9p7:
o Fixed a bug where a sudoers entry with no runas user specified
was treated differently from a line with the default runas user
explicitly specified.
pkgsrc change: added DESTDIR support.
Major changes since Sudo 1.6.9p6:
o Reverted back to to using TCSAFLUSH instead of TCSADRAIN when
turning off echo during password reading.
o Fixed a configure bug that was preventing the addition of -lutil for
login.conf support on FreeBSD and NetBSD.
o Added a configure check for struct in6_addr since some systems
define AF_INET6 but have no real IPv6 support.
Major changes since Sudo 1.6.9p5:
o Worked around bugs in the session support of some PAM implementations.
The full tty path is now passed to PAM as well.
o Sudo now only prints the password prompt if the process is in the
foreground.
o inttypes.h is now included when appropriate if it is present.
o Simplified alias allocation in the parser.
617) Fixed a bug in the IP address matching introduced by the IPV6 merge.
618) For "visudo -f file" we now use the permissions of the original file
and not the hard-coded sudoers owner/group/mode. This makes
it possible to use visudo with a revision control system.
619) Fixed sudoedit when used on a non-existent file.
620) Regenerated configure using autoconf 2.6.1 and libtool 1.5.24.
621) Groups and netgroups are now valid in an LDAP sudoRunas statement.
pkgsrc change:
Make these options mutual exclusive: kerberos pam skey.
(Really, combinations of kerberos and pam, pam and skey are conflicts.)
CHANGES:
609) Worked around a bug ins some PAM implementations that caused a crash
when no tty was present.
610) Fixed a crash on some platforms in the error logging function.
611) Documentation improvements.
Sudo 1.6.9p1 released.
612) Fixed updating of the saved environment when the environ pointer
gets changed out from underneath us.
Sudo 1.6.9p2 released.
613) Fixed a bug related to supplemental group matching introduced
in 1.6.9.
Sudo 1.6.9p3 released.
614) Added IPv6 support from YOSHIFUJI Hideaki.
615) Fixed sudo_noexec installation path.
616) Fixed a K&R compilation error.
Sudo 1.6.9p4 released.
and visudo manpages in man/man1, and the sudoers manpage in man/man5.
Remove the platform-specific PLISTs that only differed in the location
of the man pages.
Bump the PKGREVISION to 5.
(in fact, it's not clear that there is a good way to do so). The resulting
configuration works fine *except* if it encounters a host that has 3DES
but no DES service keys in its keytab.
Fix this by explicitly passing 0 ("default enctype") to Kerberos.
install script. The latter are special install-sh script options that
check whether the invoking user is the root user or not, which is
completely unnecessary.
cleanse environment of variables that alter behavior of Kerberos library
so the user can't override the default keytab location, and do *not*
ignore missing keytab errors. Prevents root compromise via spoofed KDC
on systems with Kerberos libraries but no host key in keytab, no keytab,
or keytab overidden via environment.
Don't insist that the keytab key be DES -- some Kerberos sites are 3DES/AES
only.
Somewhat less invasive than the fix Todd incorporated into the 1.6.9 branch
of sudo (presently beta) but equivalent (though not as clean).
