[PATCH] inetd as unprivileged user

[Jack Schmidt]

When I tried to use inetd as an unprivileged user on linux (4.9.x, x86_64, glibc or musl), I get:

inetd: can't set groups: Operation not permitted

I believe the problem is line 1486, where it compares the desired uid to 0, rather than to the current uid, to decide whether to set groups.

For example:

printf '127.0.0.1:3030 stream tcp nowait jack ./echo.sh' > inetd.conf
printf '#!/bin/sh\necho ok\nsleep 1' > echo.sh
chmod 755 echo.sh
./busybox inetd -e -f inetd.conf &
nc 127.0.0.1 3030

With the patch, it echoes "ok".

Without the patch, inetd gives an error:

inetd: can't set groups: Operation not permitted


Of course, to placate line 1486 one could use:

printf '127.0.0.1:3030 stream tcp nowait root ./echo.sh' > inetd.conf

but this results in the earlier error:

inetd: non-root must run services as himself



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