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Re: UID mismatch across systems




I made some discoveries on a test system:

root@IDTest:/etc# date; usermod -u 204 Debian-exim
Tue Mar 28 15:01:19 PDT 2017
usermod: user Debian-exim is currently used by process 664

and this left everything, including the running process and passwd untouched.

So I don't have to worry about what happens when I usermod the id when
a process is running; usermod won't do that.  Of course I can still
edit the passwd file by hand, but by itself I assume this will leave
the uid of existing processes and files unchanged (except they will
display differently in ls or ps).

Also, after I stopped exim4 and executed the usermod command above,
only the passwd file changed.  So that's easy enough to do offline.

As documented, usermod changes the uids of files in the user home
directory and below, but leaves others untouched:
root@IDTest:/etc# find / -uid 104 -ls
find: `/proc/5056/task/5056/fd/5': No such file or directory
find: `/proc/5056/task/5056/fdinfo/5': No such file or directory
find: `/proc/5056/fd/5': No such file or directory
find: `/proc/5056/fdinfo/5': No such file or directory
131764    4 drwxr-s---   2 104      adm          4096 Mar 28 12:52
/var/log/exim4
131486    4 -rw-r-----   1 104      adm           756 Mar 28 14:56
/var/log/exim4/mainlog
 10943    0 drwxr-x---   2 104      Debian-exim       40 Mar 28 15:03 /run/exim4
root@IDTest:/etc# find / -uid 204 -ls
find: `/proc/5057/task/5057/fd/5': No such file or directory
find: `/proc/5057/task/5057/fdinfo/5': No such file or directory
find: `/proc/5057/fd/5': No such file or directory
find: `/proc/5057/fdinfo/5': No such file or directory
131766    4 drwxr-x---   5 Debian-exim Debian-exim     4096 Mar 28
12:50 /var/spool/exim4
131768    4 drwxr-x---   2 Debian-exim Debian-exim     4096 Mar 28
12:50 /var/spool/exim4/input
131769    4 drwxr-x---   2 Debian-exim Debian-exim     4096 Mar 28
12:50 /var/spool/exim4/msglog
131767    4 drwxr-x---   2 Debian-exim Debian-exim     4096 Mar 28
12:50 /var/spool/exim4/db

Ross