Quoting Stephen Smalley (sds@xxxxxxxxxxxxx): > On Tue, 2009-03-17 at 13:23 -0500, Serge E. Hallyn wrote: > > 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? > > I think that would be preferable to CAP_SYS_ADMIN, yes. > > > 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? > > Just to be clear, at present fsuid is irrelevant to setting the > security.* xattrs since it doesn't affect the CAP_SYS_ADMIN capability > at all, so it all depends on the initial capability state prior to using > setfsuid(), typically the full capability set. Right. > > (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. > > Perhaps, although it isn't clear that this API is in use by anyone or in > use in a way that would actually distinguish based on individual > capability. > > But if you were to add CAP_SYS_ADMIN to CAP_FS_MASK in order to ensure > that setfsuid() does in fact affect all filesystem accesses, how much > meaningful difference remains between fsuid==0 and euid==0? It > obviously takes you far afield of only affecting filesystem accesses. Ok, thanks for time. It's all pretty clear to me now: CAP_MKNOD and CAP_LINUX_IMMUTABLE need to be added to the CAP_FS_MASK because, in 2.0 timeframe, fsuid==0 gave you those privileges. xattrs didn't exist back then, so the setting of security.* and trusted.* xattrs doesn't need to be enabled by fsuid==0. So really CAP_SETFCAP also doesn't need to be added to CAP_FS_MASK either. I'll send out a patch later today for 2.6, unless Igor wants to do it (since he's the one who found this originally). 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.
