[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] severe security issue on dom0/xend/xm/non-root users
Tommi Virtanen wrote: Kurt Garloff wrote:The frontend (that would acquire the privileged socket) would need to be setuid root for this and then could enforce whatever policies, much more flexible than the Unix group membership model if you want.Oh, the group-restricted UNIX domain socket wins there, too. Your model: - setuid client that only lets certain users open ports <1024 My model: - setgid client that only lets certain users connect to the protected socket OR - just add the certain users to the group, and let them access the protected socket. The UNIX domain socket way is both more flexible and _more secure_ -- it only needs setgid where the port<1024 thing needs setuid. Agree 100%. There are no advantages to the port<1024 method over using Unix domain sockets. Kurt Garloff wrote: You're very flexible in your setuid root client. 1. You may restrict the set of users that is able to call the client,e.g. it might be root:trusted 4750. This would impose the same restrictions as your group protection mechanism. 2. The first thing the client does it to acquire the privileged port and then drop capabilities immediately afterwards. Securityflaws in the client will thus at most grant the exploiter a privileged socket. (This has nothing to do with xen, just a general rule for setuid root apps.) 3. The client can impose whatever restrictions it likes, e.g. checking SSL certificates, asking for passwords, checking a configuration file, whatever. You can 1 and 3 just as easily with the Unix domain socket method. Although you could also do 2, there's no need (2 is not a flexibility advantage, it's just something you have to do to make the port<1024 method secure). -- David Hopwood <david.nospam.hopwood@xxxxxxxxxxxxxxxx> ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |