Quoting Stephen Smalley (sds@xxxxxxxxxxxxx): > On Tue, 2009-03-17 at 12:39 -0500, Serge E. Hallyn wrote: > > Quoting Stephen Smalley (sds@xxxxxxxxxxxxx): > > > > So do you think it makes sense to have CAP_MAC_ADMIN and CAP_FOWNER > > > > in CAP_FS_MASK? In other words are you objecting to CAP_SYS_ADMIN > > > > because of all of its other implications, or because you disagree > > > > that labels for security modules should be treated as mere fs data > > > > here? > > > > > > For CAP_FOWNER, yes (and it is already there). CAP_MAC_ADMIN is less > > > > Sorry, I meant CAP_SETFCAP. Should it be added? > > Sure - it is only used for filesystem operations. Ok, so then: > > > > ideal as it isn't clearly tied to filesystem accesses, and likewise for > > > CAP_MAC_OVERRIDE (but that one is included in CAP_FS_MASK already). > > > > So it is. I didn't realize that. > > > > > Ideally the capability space would be partitioned into capabilities that > > > affect filesystem accesses and the rest so that setfsuid() would yield > > > the expected behavior of only affecting filesystem access. > > > CAP_SYS_ADMIN is even less suitable due to its pervasive use outside of > > > the filesystem. So that's the first concern. > > > > > > The second one is that we don't want CAP_SYS_ADMIN (or CAP_MAC_ADMIN) to > > > be required when setting SELinux labels. Only the SELinux permission > > > checks should govern setting those labels (aside from the usual DAC > > > ownership || CAP_FOWNER check). > > > > So if a non-selinux kernel is booted, then you think only the usual > > DAC checks should be required to set selinux labels? > > I'm talking about the dumb NFS server case (non-SELinux NFS server > providing label and data storage to SELinux clients, MAC enforcement > handled client-side). But we aren't there yet, so I don't think we have > to worry about it right now. But in cap_inode_setxattr, any security.* xattrs are controlled by CAP_SYS_ADMIN. So do you think that this should be changed to a CAP_XATTR_SECURITY capability which can be added to CAP_FS_MASK? Or do you think it's ok that fsuid=0 does not allow you to set security.selinux (or security.SMACK64, etc) xattrs when selinux is not compiled in? (You may have already answered this with your EOPNOTSUPP comment, but I want to make sure I understand right) > > Does anyone know what the trusted xattrs are used for? > > Not beyond what attr(5) says about them. Well, if attr(5) says CAP_SYS_ADMIN being needed is the very thing that defines these xattrs, then changing that seems a bigger deal. That really does seem akin to changing kernel-user API. thanks, -serge -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@xxxxxxxxxxxxx with the words "unsubscribe selinux" without quotes as the message.
