Re: [PATCH 6/7] SELinux: The copy-up operation must have read permission on the lower file

[David Howells]

David Howells <dhowells@xxxxxxxxxx> wrote:

> > This means that it expects to trigger those capability checks as part of
> > its subsequent actions.  Raising those capabilities temporarily in its
> > credentials will pass the capability module checks but won't address the
> > corresponding SELinux checks (both capability and file-based), so you'll
> > end up triggering an entire set of checks against the current process'
> > credentials.  This same pattern is repeated elsewhere in overlayfs.
> 
> Hmmm...  Yes.  I need to check whether the lower file can be read *before*
> overriding the creds.

Actually, I think ovl_permission() does sufficient checks on the lower inode
by calling __inode_permission() upon it.

David
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