On Fri, Sep 03, 2021 at 08:33:25AM -0400, Greg Wooledge wrote: > On Fri, Sep 03, 2021 at 08:23:07AM -0400, Roberto C. Sánchez wrote: > > On Fri, Sep 03, 2021 at 08:03:23AM -0400, Greg Wooledge wrote: > > > Out of curiosity, I checked my system to see if there were any system > > > users with home directories under /home. The only one I found is "ntp". > > > How old is your system? I just checked a machine that I initially as a > > Woody (3.0) system in 2001 and there is no ntp user directory under > > /home. > > Well, you probably didn't install the ntp pacakge. ;-) > > I *think* this system was installed as stretch, so I downloaded a stretch > package of ntp: > > unicorn:~/tmp/x$ dpkg-deb -R ../ntp_4.2.8p10+dfsg-3+deb9u2_amd64.deb . > unicorn:~/tmp/x$ grep adduser DEBIAN/postinst > adduser --system --quiet --ingroup ntp --no-create-home ntp > > I'm not 100% sure, but I think that creates a user with a home directory > under /home, even though it doesn't actually create that directory. > > I also just fired up a fresh wheezy chroot and the ntp postinst > > has this: > > > > adduser --system --quiet --ingroup ntp --no-create-home ntp > > > > Did you perhaps modify your ntp config at a time when you might have > > been limited on space under /var? > > ... uh, I don't think so? > > Let's test this sucker and find out: > > unicorn:~/tmp/x$ sudo adduser --system --quiet --ingroup ntp --no-create-home > zzntp > unicorn:~/tmp/x$ grep zzntp /etc/passwd > zzntp:x:115:112::/home/zzntp:/usr/sbin/nologin > > As I guessed. That's what it did.
Quite right. That explains the motivation a few years ago to begin explicitly specifying the home directory as /nonexistent for system users not meant to have an actual home directory. So, the existence of /home/ntp on the OP's system, or any system installed from a Debian release prior to the last 4-ish years, could be attributed to some process or series of actions that decides, "hey, this ntp user's home directory is missing, I should create it". Whether those actions be manual or the result of some script or service, that seems the most likely way for that directory to appear on a system. Regards, -Roberto -- Roberto C. Sánchez