Check for user being a system user is incorrect

[unix-guy]

The code here checks /etc/login.defs to see if the user's UID is less than UID_MIN.

However, login.defs also has settings to defined min/max SYSTEM UID range:

# System accounts
SYS_UID_MIN               201
SYS_UID_MAX               999

In our use case, this causes problems because the admin ID is created very early in provisioning BEFORE we can set our standard values for UID_MIN / UID_MAX... and after we do, then the admin ID falls outside the range and is marked as a system user.

The check would be better to also validate against SYS_UID_MAX.

        uid_min = None
        try:
            uid_min = int(ext_utils.get_line_starting_with("UID_MIN", "/etc/login.defs").split()[1])
        except (ValueError, KeyError, AttributeError, EnvironmentError):
            pass
        if uid_min is None:
            uid_min = 100
        if user_entry is not None and user_entry[2] < uid_min:
            logger.error(
                "CreateAccount: " + user + " is a system user. Will not set password.")
            return "Failed to set password for system user: " + user + " (0x06)."

https://github.com/Azure/azure-linux-extensions/blob/b4d783a87157675f81505aa94af5bb2935a1307d/Utils/distroutils.py#L175

[ikiris04]

Same issue here, from man page for login.defs

   UID_MAX (number), UID_MIN (number)

Range of user IDs used for the creation of regular users by useradd or newusers.

       The default value for UID_MIN (resp.  UID_MAX) is 1000 (resp. 60000).

The UID_MIN and UID_MAX really just affect useradd command (which is the reason why we use it since other extensions execute useradd) and are not necessarily representative of system accounts