Date: Sun, 28 Feb 2021 01:23:01 +0300 From: Yuri Pankov <yuripv@yuripv.dev> To: Gareth de Vaux <bsd@lordcow.org>, freebsd-questions@freebsd.org Subject: Re: user account disappeared Message-ID: <a45744ec-75c9-4ef6-0202-4a2c0633248d@yuripv.dev> In-Reply-To: <YDqquH5y8wM4F7uO@lordcow.org> References: <YDqquH5y8wM4F7uO@lordcow.org>
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Gareth de Vaux wrote: > Hi all, one of my users in a jail has mysteriously half disappeared. I've renamed the user to 'lostuser', the password hash, and the process it's running to protect privacy below: > > I suddenly can't log in over ssh: > > sshd[22485]: Invalid user lostuser from XYZ > > # su - lostuser > su: unknown login: lostuser > > # ls -ld /home/lostuser > drwx------ 8 1012 users 18 Jan 23 11:19 /home/lostuser > > $HOME still exists but only showing the userid. > > # egrep "1012|lostuser" /etc/passwd > lostuser:*:1012:1000:User &:/home/lostuser:/usr/local/bin/bash > > # egrep "1012|lostuser" /etc/master.passwd > lostuser:$6$9xxxxx/:1012:1000::0:0:User &:/home/lostuser:/usr/local/bin/bash > > Entries are still in /etc/*passwd ? > > # ls -l /etc/*passwd /etc/group > -rw-r--r-- 1 root wheel 605 Nov 6 16:52 /etc/group > -rw------- 1 root wheel 4092 Jan 23 12:22 /etc/master.passwd > -rw-r--r-- 1 root wheel 2621 Jan 23 12:22 /etc/passwd You should remember that authentication generally does NOT use textual /etc/passwd and /etc/master.passwd directly and rather relies on /etc/spwd.db database (see pwd_mkdb(8)) -- what is the timestamp on it? If it's out of sync, recreate the database using: /usr/sbin/pwd_mkdb -p /etc/master.passwd If that helps, *why* it is out of sync is the real question. > This process is still running, which is a network server which is still functioning: > > # ps aux | grep lostuser > 1012 56261 0.0 0.1 44952 21288 7 S+J 3Dec20 9:52.21 /usr/local/bin/python3.6 /home/lostuser/xyz > > also obviously showing the userid and not the username. > > > # grep lostuser /var/log/auth.log > ... > Dec 31 10:56:34 ns1 sshd[43798]: Accepted publickey for lostuser from xyz > Dec 31 10:56:57 ns1 sshd[44133]: Disconnected from user lostuser > Jan 10 09:37:05 ns1 sshd[9679]: Accepted publickey for lostuser from xyz > Jan 10 09:37:09 ns1 sshd[10241]: Disconnected from user lostuser > Jan 23 11:19:11 ns1 sshd[45905]: Accepted publickey for lostuser from xyz > Jan 23 11:19:14 ns1 sshd[46228]: Disconnected from user lostuser > Feb 27 18:06:49 ns1 sshd[93323]: Invalid user lostuser from xyz > Feb 27 18:06:49 ns1 sshd[93323]: Connection closed by invalid user lostuser xyz > > 23 Jan 2021 was the last successful login, and later that day /etc/*passwd was touched due to me changing the > password of a different user, confirmed as the only change from diff'ing against backups. > > Last buildworld upgrade on 3 Nov 2020 (host and jail): > > $ uname -a > FreeBSD ns1.lordcow.org 11.4-STABLE FreeBSD 11.4-STABLE #0 r367290: Tue Nov 3 12:11:29 SAST 2020 root@lordcow.org:/usr/obj/usr/src/sys/GENERIC amd64 > > The last ports upgrade was 13 Feb 2021, before that I'm not sure. > > The last entry in /var/log/userlog was 23 Jul 2020, and: > > # ls -l /var/log/userlog > -rw------- 1 root wheel 4202 Jul 23 2020 /var/log/userlog > > > ie. timeline: > > 23 Jul 2020 Last userlog change > 3 Nov 2020 buildkernel/buildworld and reboot > 3 Dec 2020 lostuser network server process spawned and still functioning > 23 Jan 2021 Last successful login to lostuser > 23 Jan 2021 Unrelated user's password intentionally changed with passwd > 13 Feb 2021 ports upgrade > 27 Feb 2021 Discover user doesn't exist anymore but still has entries in /etc/*passwd and a process running > > Any ideas?
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