[clue-tech] sshd authorization strategies

[Dan Harris]

Dan Harris wrote:
> Angelo Bertolli wrote:
>> Dan Harris wrote:
>>> However, I'm not clear how this gets around my initial problem..  I 
>>> don't want all accounts to have ssh access, only some, but I don't 
>>> want to have to add each user to sshd_config and restart the service 
>>> every time ( plus the 256 limit is looming ).
>>
>> Well, I think something like /bin/false as a shell won't allow ssh 
>> file tranfers.  And I'm pretty sure even rbash doesn't (which is why I 
>> ended up having to use rssh).  So the default shell for a new user on 
>> your system can be something like /bin/false that disallows access.  
>> (At least that's how I used to have users without any shell access.)
>>
>> Then you can give scp users rssh.
>>
>> Then you can give full shell users a non-restricted shell, but maybe 
>> rssh is good enough for them anyway.
>>
>> The man page says:
>>
>> The allow/deny directives are processed in the following order: 
>> DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups.
>>
>> So right now do you have something like DenyUsers * ?
>>
>> Maybe you can change that to DenyUsers root, and then AllowUsers 
>> root at backup
>>
> 
> Sounds like a plan!  I'll give it a shot.  Thanks for your help.
> 
> -Dan

Well, I tried those settings and it won't let any user other than 
root at backup-server log in.  The log says "not allowed because not listed in 
AllowUsers".  Apparently, if you have anything in AllowUsers, that's all you get.

-Dan