Eric Biggers <ebiggers3@xxxxxxxxx> wrote: > True, but Setattr permission has already been overloaded to allow several > different types of modifications, Perhaps therein lies the problem. Setattr is too overloaded and really needs splitting along the following lines: (1) Security: ownership, access, security label, restrictions. (2) Content: alter/update, timeout. (3) Revocation and invalidation. Maybe I should create some sort of ACL for keys and map setperm onto that. I wonder if this could also intersect with user namespaces in some way so that you can make an ACL that has users from multiple namespaces - might be tricky, though. > and it makes *much* more sense than Search permission which should not allow > any modifications. And in practice I expect people care more about whether > modifications are permitted or not, than the details of the finer-grained > permissions. I disagree still. To allow users to invalidate a key you would *also* have to give them the ability to muck around with the permissions. > Sort of, but actually keyctl_set_timeout() can be called at any time, and > the timeout can be set to as little as 1 second. So I don't see how > keyctl_revoke() is that much different, fundamentally. The timeout is a property of the key content and revoked is one of the states the key can be in. > > (1) I add a flag to a key to say that it can be invalidated and a keyctl to > > change that flag. > > And who would have permission to change that flag? It seems to be the same > problem again. No. Setperm would be required to change the flag, but not to apply the invalidate operation if the flag is set. Think of Invalidate as being a mass-unlink operation effected by the garbage collector. Kernel-created DNS keys, for example, don't grant Setperm to anyone. > What would the behavior be if ->allow_invalidation() was not supplied? The obvious would be to check that you're the owner of the key. > In other words, would the purpose of this be to lock down invalidation of > dns_resolver keys, or to restrict invalidation to *only* dns_resolver keys? To restrict who could invalidate keys of a particular type. Actually, it wants to be per-key not per-key-type. Hmmm... > Granted by who, and how? And do you mean keyctl_clear(), or > keyctl_invalidate()? keyctl_clear(). Empty the keyring, not render it unusable. David -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
