On Wed, Oct 15, 2014 at 8:05 AM, Seth Forshee <seth.forshee@xxxxxxxxxxxxx> wrote: > On Wed, Oct 15, 2014 at 07:49:39AM -0700, Andy Lutomirski wrote: >> On 10/14/2014 07:25 AM, Seth Forshee wrote: >> > Update fuse to translate uids and gids to/from the user namspace >> > of the process servicing requests on /dev/fuse. Any ids which do >> > not map into the namespace will result in errors. inodes will >> > also be marked bad when unmappable ids are received from >> > userspace. >> > >> > Due to security concerns the namespace used should be fixed, >> > otherwise a user might be able to gain elevated privileges or >> > influence processes that the user would otherwise be unable to >> > manipulate. Thus the namespace of the mounting process is used >> > for all translations, and this namespace is required to be the >> > same as the one in use when /dev/fuse was opened. >> > >> >> I'm not sure that this is necessary if my nosuid patch goes in, but I >> also don't think it makes any sense to hold this up while we find a >> perfect solution. >> >> Is there a decent way to extend this to different translation schemes in >> the future (e.g. a flag at fs setup that could be used)? > > I think it would be possible to relax the translation scheme > restrictions in the future, certainly that's easier than tightening down > a looser restriction. I still favor picking one namespace to use for > translation (surely that's how it would work with other filesystems > anyway) rather than using the current namespace during /dev/fuse I/O. I > did an implementation using the latter technique, and it's far more > complex with no benefits that I can see. Long term, I think we'll want more flexible translations for filesystems on removable media, even when both the mounter and the accessing process are in the init user namespace. But this can wait. --Andy > > Thanks, > Seth -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
