Messages in this thread | | | Date | Thu, 6 Oct 2005 10:25:46 -0400 (EDT) | From | James Morris <> | Subject | Re: [Keyrings] [PATCH] Keys: Add LSM hooks for key management |
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On Thu, 6 Oct 2005, David Howells wrote:
> James Morris <jmorris@namei.org> wrote: > > > I think this looks ok from an SELinux point of view if keys are treated as > > opaque objects, i.e. like files. > > I'll make some changes based on the suggestions I've received. Those who > request the return of keyfs can go boil their heads.
You know, I was thinking, ext3 could be much more compact if it was just a set of custom syscalls and had no VFS representation.
What about a per process /proc/pid/keys, which contains keyrings and keys, which can be opened, closed, use xattrs for any special access control etc. ?
> > We could do something like create a new object class (kernkey or > > something) and implement SELinux permissions for the class such as read, > > write, search, link, setattr and getattr. Your KEY_VIEW perm could be > > translated to SELinux getattr. > > Should I expand the permissions mask to include a setattr?
Possibly for setperm and chown.
> > I'm not sure if we need user-level labeling of keys via the set & get > > security ops, although LSPP may require some form of get_security. If we > > don't need to manually set security attributes but still view them, they > > could be displayed via /proc/keys rather than implementing a separate > > multiplexed syscall. > > Would it be worth me adding a key type op by which a security module can ask > the type its opinion (or by which key_alloc() can ask the type to give the > security module an earful)?
Well, SELinux is the only significant LSM in the tree and I don't think it needs to set the labels. So, no.
> > keyctl_chown_key() > > keyctl_setperm_key() > > Okay. > > > keyctl_set_reqkey_keyring() > > Should this really be securified? It merely controls the default destination > for a key created by request_key(), and is limited to the keyrings the process > is subscribed to in any case.
Ok, if needed, it can be added later.
> > All users of key_permission() need to propagate the error code from the > > LSM back to the user. > > Really? Why?
Because the LSM has final say on the error code returned to the caller. If the LSM runs out of memory, for example, it's silly to return -EACCES.
> Note that the fact that key_permission() fails for a key is sometimes ignored, > such as when I'm doing a search and one potentially matching key fails, but a > subsequent matching key passes.
Ok, that sounds like an internal issue to be resolved, ensuring that if you are returning to the caller, the LSM's error code is returned.
- James -- James Morris <jmorris@namei.org> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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