Bug#427605: ITP: privbind -- Allow unprivileged apps to bind to a privileged port

[Shachar Shemesh <shachar@debian.org>]

Russell Coker wrote:
> On Wednesday 06 June 2007 20:05, Shachar Shemesh <shachar@debian.org> wrote:
>   
>>> What benefits does this offer over authbind which has been in Debian for
>>> ages?
>>>       
Before I begin answering your questions, the bug report has a link to
technical explanation of how privbind is implemented. Have you read it?

>> It uses a (I think) much more secure mode of operation. In particular:
>> - No SUID executables
>> - User who launches the daemon must be root
>>     
>
> Having a daemon instead of a SUID executable does not inherently make it more 
> secure (there has been no shortage of exploits for bugs in daemons in the 
> past).
>   
s/daemon/program that needs low port binding/

privbind does not allow regular users to bind to low ports. Privbind
allows root to run program that bind to low port as non-root.
> The usual system is that a process with UID != 0 can not bind to ports below 
> 1024.  Breaking this involves increasing the privileges of some programs.
>   
Please read the privbind man page. It does not do what you think it does.
>   
>> And, as a result:
>> - No global configuration necessary (though one will probably be added
>> later if necessary).
>>     
>
> How can there be no global configuration needed?
Please read the privbind man page. It does not do what you think it does.
>   The sysadmin needs to decide 
> which users are granted the privilege to bind to low ports and which ports 
> those users may bind to.
>   
Please read the privbind man page. It does not do what you think it does.

Shachar