[Bug 1666203] Re: pam_tty_audit failed in pam_open_session
Toru Ikezoe
toru.ikezoe at gree.net
Tue Feb 5 09:28:57 UTC 2019
Hi Don-san.
I am able to reproduce with the following procedure.
-----------------
vagrant init ubuntu/xenial64
vagrant ssh
# at xenial64 on VM
echo 'session required pam_tty_audit.so enable=*' | sudo tee -a /etc/pam.d/common-session
-----------------
When 'vagrant ssh' from other terminal, it is fail.
I tested below environment.
-----------------
vagrant at ubuntu-xenial:~$ uname -a
Linux ubuntu-xenial 4.4.0-142-generic #168-Ubuntu SMP Wed Jan 16 21:00:45 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
vagrant at ubuntu-xenial:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial
vagrant at ubuntu-xenial:~$ dpkg -l | grep -E 'libpam|linux-image'
ii libpam-modules:amd64 1.1.8-3.2ubuntu2.1 amd64 Pluggable Authentication Modules for PAM
ii libpam-modules-bin 1.1.8-3.2ubuntu2.1 amd64 Pluggable Authentication Modules for PAM - helper binaries
ii libpam-runtime 1.1.8-3.2ubuntu2.1 all Runtime support for the PAM library
ii libpam-systemd:amd64 229-4ubuntu21.15 amd64 system and service manager - PAM module
ii libpam0g:amd64 1.1.8-3.2ubuntu2.1 amd64 Pluggable Authentication Modules library
ii linux-image-4.4.0-142-generic 4.4.0-142.168 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP
ii linux-image-virtual 4.4.0.142.148 amd64 This package will always depend on the latest minimal generic kernel image.
vagrant at ubuntu-xenial:~$
-----------------
If you cannot reproduce this issue above procedure, you try to enable/disable other pam module.
This problem is caused by an uninitialized stack variable, so it is important to manipulate the state of the stack to reproduce it.
For example, it is good to activate pam_ldap.
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https://bugs.launchpad.net/bugs/1666203
Title:
pam_tty_audit failed in pam_open_session
Status in pam package in Ubuntu:
Triaged
Status in pam package in Debian:
New
Bug description:
Dear Maintainer.
I found a bug in pam_tty_audit.
When Using the pam_tty_audit with other pam modules(ex, pam_ldap), it failed in pam_open_session.
It was triggared by use uninitialized variable in pam_tty_audit.c::pam_open_session.
* Enviroments
Ubuntu 14.04.4 LTS
linux-image-3.16.0-71-generic 3.16.0-71.92~14.04.1
libpam-ldap:amd64 184-8.5ubuntu3
libpam-modules:amd64 1.1.8-1ubuntu2.2
Ubuntu 16.04.2 TLS
linux-image-4.4.0-62-generic 4.4.0-62.83
libpam-ldap:amd64 184-8.7ubuntu1
libpam-modules:amd64 1.1.8-3.2ubuntu2
* Reproduction method
1. Install libpam-ldap.
2. Add the following to the end of /etc/pam.d/common-sessions
--------
session required pam_tty_audit.so enable=* open_only
--------
3. When logging in with ssh etc., pam_tty_audit will fail and login fails
* Solution (== 2018/04/16 Link updated ==)
apply upstream patch
https://github.com/linux-pam/linux-pam/commit/c5f829931a22c65feffee16570efdae036524bee
* Logs (on Ubuntu14.04)
-- auth.log --
May 18 14:47:03 vm sshd[2272]: Accepted publickey for test from 10.99.0.1 port 51398 ssh2: RSA 8f:39:1c:3a:f4:9d:ca:99:67:fc:e3:fd:1e:0c:5b:a8
May 18 14:47:03 vm sshd[2272]: pam_unix(sshd:session): session opened for user test by (uid=0)
May 18 14:47:03 vm sshd[2272]: pam_tty_audit(sshd:session): error setting current audit status: Invalid argument
May 18 14:47:03 vm sshd[2272]: error: PAM: pam_open_session(): Cannot make/remove an entry for the specified session
May 18 14:47:03 vm sshd[2297]: Received disconnect from 10.99.0.1: 11: disconnected by user
-- syslog --
May 18 14:47:03 vm audispd: node=vm type=USER_ACCT msg=audit(1463550423.399:58): pid=2272 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:accounting acct="test" exe="/usr/sbin/sshd" hostname=10.99.0.1 addr=10.99.0.1 terminal=ssh res=success'
May 18 14:47:03 vm audispd: node=vm type=CRED_ACQ msg=audit(1463550423.403:59): pid=2272 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:setcred acct="test" exe="/usr/sbin/sshd" hostname=10.99.0.1 addr=10.99.0.1 terminal=ssh res=success'
May 18 14:47:03 vm audispd: node=vm type=LOGIN msg=audit(1463550423.403:60): pid=2272 uid=0 old-auid=4294967295 auid=20299 old-ses=4294967295 ses=3 res=1
May 18 14:47:03 vm audispd: node=vm type=CONFIG_CHANGE msg=audit(1463550423.403:61): pid=2272 uid=0 auid=20299 ses=3 op=tty_set old-enabled=0 new-enabled=1 old-log_passwd=0 new-log_passwd=32743 res=0
May 18 14:47:03 vm audispd: node=vm type=USER_START msg=audit(1463550423.447:62): pid=2272 uid=0 auid=20299 ses=3 msg='op=PAM:session_open acct="test" exe="/usr/sbin/sshd" hostname=10.99.0.1 addr=10.99.0.1 terminal=ssh res=failed'
May 18 14:47:03 vm audispd: node=vm type=CRED_ACQ msg=audit(1463550423.447:63): pid=2297 uid=0 auid=20299 ses=3 msg='op=PAM:setcred acct="test" exe="/usr/sbin/sshd" hostname=10.99.0.1 addr=10.99.0.1 terminal=ssh res=success'
May 18 14:47:03 vm audispd: node=vm type=CRED_DISP msg=audit(1463550423.451:64): pid=2272 uid=0 auid=20299 ses=3 msg='op=PAM:setcred acct="test" exe="/usr/sbin/sshd" hostname=10.99.0.1 addr=10.99.0.1 terminal=ssh res=success'
Thanks regards.
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