apparmor profile denied for saslauthd: /run/saslauthd/mux

[Mattias Åsander]

[Impact]

When using openldap with sasl authentication, the slapd process will communicate with the saslauthd daemon via a socket in {,/var}/run/saslauthd/mux. Unfortunately, this will fail in every Ubuntu release from trusty onwards, because slapd's apparmor profile doesn't contain the necessary directive to allow it to read/write from/to the socket specified above.

The fix is simple: just add the necessary directive to allow slapd to read/write from/to the saslauthd socket.

[Test Case]

One can reproduce the problem by doing:

$ lxc launch ubuntu-daily:groovy openldap-bugbug1557157-groovy
$ lxc shell openldap-bugbug1557157-groovy
# apt install slapd sasl2-bin ldap-utils apparmor-utils

(As the domain name, use "example.com").

# sed -i -e 's/^START=.*/START=yes/' /etc/default/saslauthd
# cat > /etc/ldap/sasl2/slapd.conf << __EOF__
mech_list: PLAIN
pwcheck_method: saslauthd
__EOF__
# adduser openldap sasl
# aa-enforce /etc/apparmor.d/usr.sbin.slapd
# systemctl restart slapd.service
# systemctl restart saslauthd.service
# passwd root

(You can choose any password here. You will need to type it when running the next command.)

# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN

The command will fail with something like:

ldap_sasl_interactive_bind_s: Other (e.g., implementation specific) error (80)
        additional info: SASL(-1): generic failure: Password verification failed

[Regression Potential]

This is an extremely simple and well contained fix, so I don't envision any possible regressions after applying it. It is important noticing that, since the problem affects older Ubuntu releases, the openldap package will have to be rebuilt against possible newer versions of libraries and other depencencies, which, albeit unlikely, may cause issues.

[Original Description]

When using slapd with saslauthd the processes communicate via the {,/var}/run/saslauthd/mux socket (this is the default location for the saslauthd server from the sasl2-bin package in the /etc/default/saslauthd config), but the apparmor profile for usr.sbin.slapd does not allow access to this socket/file.

Syslog message:
apparmor="DENIED" operation="connect" profile="/usr/sbin/slapd" name="/run/saslauthd/mux" pid=1880
4 comm="slapd" requested_mask="r" denied_mask="r" fsuid=108 ouid=0

Please add the following line to /etc/apparmor.d/usr.sbin.slapd:
/{,var/}run/saslauthd/mux rw,

Ubuntu version: Ubuntu 14.04.4 LTS
slapd version: 2.4.31-1+nmu2ubu

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Marian Rainer-Harbach (marianrh)]

Still occurs in 20.04.

[Bryce Harrington (bryce)]

Can you explain the configuration process for saslauthd with slapd? Or a copy of your config file would do.

[Marian Rainer-Harbach (marianrh)]

My configs are:

/etc/default/saslauthd:
#
# Settings for saslauthd daemon
# Please read /usr/share/doc/sasl2-bin/README.Debian for details.
#

# Should saslauthd run automatically on startup? (default: no)
START=yes

# Description of this saslauthd instance. Recommended.
# (suggestion: SASL Authentication Daemon)
DESC="SASL Authentication Daemon"

# Short name of this saslauthd instance. Strongly recommended.
# (suggestion: saslauthd)
NAME="saslauthd"

# Which authentication mechanisms should saslauthd use? (default: pam)
#
# Available options in this Debian package:
# getpwent -- use the getpwent() library function
# kerberos5 -- use Kerberos 5
# pam -- use PAM
# rimap -- use a remote IMAP server
# shadow -- use the local shadow password file
# sasldb -- use the local sasldb database file
# ldap -- use LDAP (configuration is in /etc/saslauthd.conf)
#
# Only one option may be used at a time. See the saslauthd man page
# for more information.
#
# Example: MECHANISMS="pam"
MECHANISMS="kerberos5"

# Additional options for this mechanism. (default: none)
# See the saslauthd man page for information about mech-specific options.
MECH_OPTIONS=""

# How many saslauthd processes should we run? (default: 5)
# A value of 0 will fork a new process for each connection.
THREADS=5

# Other options (default: -c -m /var/run/saslauthd)
# Note: You MUST specify the -m option or saslauthd won't run!
#
# WARNING: DO NOT SPECIFY THE -d OPTION.
# The -d option will cause saslauthd to run in the foreground instead of as
# a daemon. This will PREVENT YOUR SYSTEM FROM BOOTING PROPERLY. If you wish
# to run saslauthd in debug mode, please run it by hand to be safe.
#
# See /usr/share/doc/sasl2-bin/README.Debian for Debian-specific information.
# See the saslauthd man page and the output of 'saslauthd -h' for general
# information about these options.
#
# Example for chroot Postfix users: "-c -m /var/spool/postfix/var/run/saslauthd"
# Example for non-chroot Postfix users: "-c -m /var/run/saslauthd"
#
# To know if your Postfix is running chroot, check /etc/postfix/master.cf.
# If it has the line "smtp inet n - y - - smtpd" or "smtp inet n - - - - smtpd"
# then your Postfix is running in a chroot.
# If it has the line "smtp inet n - n - - smtpd" then your Postfix is NOT
# running in a chroot.
OPTIONS="-c -m /var/run/saslauthd"

/etc/ldap/sasl2/slapd.conf:
mech_list: plain
pwcheck_method: saslauthd

As the reporter of this bug stated, AppArmor denies slapd access to the saslauthd socket /run/saslauthd/mux.

[Launchpad Janitor (janitor)]

This bug was fixed in the package openldap - 2.4.50+dfsg-1ubuntu2

---------------
openldap (2.4.50+dfsg-1ubuntu2) groovy; urgency=medium

  * d/apparmor-profile: Update apparmor profile to grant access to
    the saslauthd socket, so that SASL authentication works. (LP: #1557157)

 -- Sergio Durigan Junior <email address hidden> Fri, 12 Jun 2020 18:20:42 -0400

[Brian Murray (brian-murray)]

Hello Mattias, or anyone else affected,

Accepted openldap into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/openldap/2.4.49+dfsg-2ubuntu1.3 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Brian Murray (brian-murray)]

Hello Mattias, or anyone else affected,

Accepted openldap into eoan-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/openldap/2.4.48+dfsg-1ubuntu1.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-eoan to verification-done-eoan. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-eoan. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Brian Murray (brian-murray)]

Hello Mattias, or anyone else affected,

Accepted openldap into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/openldap/2.4.45+dfsg-1ubuntu1.6 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Brian Murray (brian-murray)]

Hello Mattias, or anyone else affected,

Accepted openldap into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/openldap/2.4.42+dfsg-2ubuntu3.9 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted openldap (2.4.48+dfsg-1ubuntu1.2) for eoan have finished running.
The following regressions have been reported in tests triggered by the package:

asterisk/1:16.2.1~dfsg-2build2 (armhf)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/eoan/update_excuses.html#openldap

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted openldap (2.4.49+dfsg-2ubuntu1.3) for focal have finished running.
The following regressions have been reported in tests triggered by the package:

apache2/2.4.41-4ubuntu3 (armhf)
cyrus-imapd/3.0.13-5 (armhf)
kopanocore/8.7.0-7ubuntu1 (armhf)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/focal/update_excuses.html#openldap

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Andreas Hasenack (ahasenack)]

bionic verification

First reproducing the problem:
  Version table:
 *** 2.4.45+dfsg-1ubuntu1.5 500
        500 http://br.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://br.archive.ubuntu.com/ubuntu bionic-security/main amd64 Packages
        100 /var/lib/dpkg/status

Command fails:
root@bionic-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
ldap_sasl_interactive_bind_s: Other (e.g., implementation specific) error (80)
 additional info: SASL(-1): generic failure: Password verification failed

And dmesg shows the apparmor denial:
[17283.881912] audit: type=1400 audit(1594228773.536:453): apparmor="DENIED" operation="connect" namespace="root//lxd-bionic-openldap-saslauthd-1557157_<var-snap-lxd-common-lxd>" profile="/usr/sbin/slapd" name="/run/saslauthd/mux" pid=153401 comm="slapd" requested_mask="wr" denied_mask="wr" fsuid=1000111 ouid=1000000

With the updated package from proposed:
  Version table:
 *** 2.4.45+dfsg-1ubuntu1.6 500
        500 http://br.archive.ubuntu.com/ubuntu bionic-proposed/main amd64 Packages
        100 /var/lib/dpkg/status

The ldapsearch command works, and there is no apparmor error in dmesg:
root@bionic-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
SASL username: root
SASL SSF: 0
dn: dc=example,dc=com
objectClass: top
objectClass: dcObject
objectClass: organization
o: example
dc: example

Bionic verification succeeded.

[Andreas Hasenack (ahasenack)]

Eoan verification

First, reproducing the bug:

  Version table:
 *** 2.4.48+dfsg-1ubuntu1.1 500
        500 http://br.archive.ubuntu.com/ubuntu eoan-updates/main amd64 Packages
        500 http://br.archive.ubuntu.com/ubuntu eoan-security/main amd64 Packages
        100 /var/lib/dpkg/status

ldapsearch fails:
root@eoan-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
ldap_sasl_interactive_bind_s: Other (e.g., implementation specific) error (80)
 additional info: SASL(-1): generic failure: Password verification failed

And dmesg shows the apparmor DENIED message:
[17713.076558] audit: type=1400 audit(1594229202.756:559): apparmor="DENIED" operation="connect" namespace="root//lxd-eoan-openldap-saslauthd-1557157_<var-snap-lxd-common-lxd>" profile="/usr/sbin/slapd" name="/run/saslauthd/mux" pid=162867 comm="slapd" requested_mask="wr" denied_mask="wr" fsuid=1000111 ouid=1000000

With the package from proposed:
  Version table:
 *** 2.4.48+dfsg-1ubuntu1.2 500
        500 http://br.archive.ubuntu.com/ubuntu eoan-proposed/main amd64 Packages
        100 /var/lib/dpkg/status

ldapsearch works:
root@eoan-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
SASL username: root
SASL SSF: 0
dn: dc=example,dc=com
objectClass: top
objectClass: dcObject
objectClass: organization
o: example
dc: example

And there is no DENIED message in dmesg.

eoan verification succeeded.

[Andreas Hasenack (ahasenack)]

Focal verification

First, reproducing the problem:

  Version table:
 *** 2.4.49+dfsg-2ubuntu1.2 500
        500 http://br.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        500 http://br.archive.ubuntu.com/ubuntu focal-security/main amd64 Packages
        100 /var/lib/dpkg/status

ldapsearch fails:
root@focal-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
ldap_sasl_interactive_bind_s: Other (e.g., implementation specific) error (80)
 additional info: SASL(-1): generic failure: Password verification failed

and dmesg complains:
[18037.506232] audit: type=1400 audit(1594229527.198:647): apparmor="DENIED" operation="connect" namespace="root//lxd-focal-openldap-saslauthd-1557157_<var-snap-lxd-common-lxd>" profile="/usr/sbin/slapd" name="/run/saslauthd/mux" pid=171680 comm="slapd" requested_mask="wr" denied_mask="wr" fsuid=1000112 ouid=1000000

With the proposed packages:
 *** 2.4.49+dfsg-2ubuntu1.3 500
        500 http://br.archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
        100 /var/lib/dpkg/status

ldapsearch works:
root@focal-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
SASL username: root
SASL SSF: 0
dn: dc=example,dc=com
objectClass: top
objectClass: dcObject
objectClass: organization
o: example
dc: example

And there is no apparmor DENIED message in dmesg.

Focal verification succeeded.

[Andreas Hasenack (ahasenack)]

Xenial verification

Reproducing the error:
root@xenial-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
ldap_sasl_interactive_bind_s: Other (e.g., implementation specific) error (80)
 additional info: SASL(-1): generic failure: Password verification failed

And dmesg:
[qua jul 8 11:50:42 2020] audit: type=1400 audit(1594219843.513:405): apparmor="DENIED" operation="connect" namespace="root//lxd-xenial-openldap-saslauthd-1557157_<var-snap-lxd-common-lxd>" profile="/usr/sbin/slapd" name="/run/saslauthd/mux" pid=83468 comm="slapd" requested_mask="wr" denied_mask="wr" fsuid=1000112 ouid=1000000

With the updated packages, ldapsearch works:
root@xenial-openldap-saslauthd-1557157:~# apt-cache policy slapd
slapd:
  Installed: 2.4.42+dfsg-2ubuntu3.9
  Candidate: 2.4.42+dfsg-2ubuntu3.9
  Version table:
 *** 2.4.42+dfsg-2ubuntu3.9 500
        500 http://br.archive.ubuntu.com/ubuntu xenial-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
...

root@xenial-openldap-saslauthd-1557157:~# ldapsearch -H ldapi:/// -LLL -b 'dc=example,dc=com' -s base -U root -Y PLAIN
SASL/PLAIN authentication started
Please enter your password:
SASL username: root
SASL SSF: 0
dn: dc=example,dc=com
objectClass: top
objectClass: dcObject
objectClass: organization
o: example
dc: example

And no dmesg apparmor error.

Xenial verification succeeded.

[Andreas Hasenack (ahasenack)]

The asterisk DEP8 armhf test was retried and is now green.

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted openldap (2.4.49+dfsg-2ubuntu1.3) for focal have finished running.
The following regressions have been reported in tests triggered by the package:

cyrus-imapd/3.0.13-5 (armhf)
apache2/2.4.41-4ubuntu3 (armhf)
kopanocore/8.7.0-7ubuntu1 (armhf)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/focal/update_excuses.html#openldap

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Andreas Hasenack (ahasenack)]

Kopanocore armhf is the only persistent red, but this test/package is known to be flaky on armhf.

[Launchpad Janitor (janitor)]

This bug was fixed in the package openldap - 2.4.49+dfsg-2ubuntu1.3

---------------
openldap (2.4.49+dfsg-2ubuntu1.3) focal; urgency=medium

  * d/apparmor-profile: Update apparmor profile to grant access to
    the saslauthd socket, so that SASL authentication works. (LP: #1557157)

 -- Sergio Durigan Junior <email address hidden> Fri, 12 Jun 2020 18:18:58 -0400

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for openldap has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package openldap - 2.4.48+dfsg-1ubuntu1.2

---------------
openldap (2.4.48+dfsg-1ubuntu1.2) eoan; urgency=medium

  [ Andreas Hasenack ]
  * d/p/ITS-9171-Insert-callback-in-the-right-place.patch: Import upstream
    patch to fix slapd crashing in certain configurations when a client
    attempts a login to a locked account. (LP: #1866303)

  [ Sergio Durigan Junior ]
  * d/apparmor-profile: Update apparmor profile to grant access to
    the saslauthd socket, so that SASL authentication works. (LP: #1557157)

 -- Andreas Hasenack <email address hidden> Wed, 01 Jul 2020 16:43:06 -0300

[Launchpad Janitor (janitor)]

This bug was fixed in the package openldap - 2.4.45+dfsg-1ubuntu1.6

---------------
openldap (2.4.45+dfsg-1ubuntu1.6) bionic; urgency=medium

  [ Andreas Hasenack ]
  * d/p/ITS-9171-Insert-callback-in-the-right-place.patch: Import upstream
    patch to fix slapd crashing in certain configurations when a client
    attempts a login to a locked account. (LP: #1866303)

  [ Sergio Durigan Junior ]
  * d/apparmor-profile: Update apparmor profile to grant access to
    the saslauthd socket, so that SASL authentication works. (LP: #1557157)

 -- Andreas Hasenack <email address hidden> Wed, 01 Jul 2020 16:38:55 -0300

[Launchpad Janitor (janitor)]

This bug was fixed in the package openldap - 2.4.42+dfsg-2ubuntu3.9

---------------
openldap (2.4.42+dfsg-2ubuntu3.9) xenial; urgency=medium

  [ Andreas Hasenack ]
  * d/p/ITS-9171-Insert-callback-in-the-right-place.patch: Import upstream
    patch to fix slapd crashing in certain configurations when a client
    attempts a login to a locked account. (LP: #1866303)

  [ Sergio Durigan Junior]
  * d/apparmor-profile: Update apparmor profile to grant access to
    the saslauthd socket, so that SASL authentication works. (LP: #1557157)

 -- Andreas Hasenack <email address hidden> Wed, 01 Jul 2020 16:33:08 -0300