Postgres in Sandstorm: initdb: could not look up effective user ID 1209: user does not exist

[Nolan Darilek]

Thoughts on how to deal with this? Postgres' initdb process seens to
want to look up the current user ID on startup and fails. Maybe there's
some aspect of the initialization process that I could circumvent to
avoid this, but I don't know enough about Postgres to know what that
might be.


If Sandstorm is going to randomize UIDs/GIDs, I feel like it should at
least stub /etc/passwd, /etc/group, or whatever syscalls access this
information, because I've hit this issue before. This may be a good move
from a security perspective, but I used to have Postgres working because
I could assume that apps were run under 1000, and with that not being a
valid assumption anymore, I don't even know how to get past this.


Assume that using another datastore is not an option here. It's Postgres
or bust.


Thanks.

[Kenton Varda]

Hmm, as an app-only fix, what if you made /etc/passwd be a symlink to /tmp/passwd which you auto-generate based on the current UID during app startup?

Hacky but seemingly not that difficult?

-Kenton

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[Ian Denhardt]

How does it respond to /etc/passwd being symlink to something in /var
(which you initialize on startup)?

I'm thinking:

echo "postgres:x:$(id -u):$(id -g):PostgreSQL user:/var/lib/postgres:/bin/sh" >> /var/etc/passwd

Or such.

Quoting Nolan Darilek (2017-03-17 16:05:02)

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[Ian Denhardt]

Quoting Kenton Varda (2017-03-18 19:09:06)

> Hmm, as an app-only fix, what if you made /etc/passwd be a symlink to
> /tmp/passwd which you auto-generate based on the current UID during app
> startup?
> Hacky but seemingly not that difficult?
> -Kenton

Bah, beat me to it.

[manas.sa...@gmail.com]

Anyone got any solution.......for this issue
in docker file, i have added during the startup

RUN ln -s /etc/passwd /tmp/passwd

and then run
echo "postgres:x:$(id -u):$(id -g):PostgreSQL user:/var/lib/postgres:/bin/sh" >> /tmp/passwd

but still have an issue .....can anyone guide me in more briefly how to overcome this issue?