Messages in this thread | | | Date | Thu, 5 Feb 2015 01:20:42 +0100 | From | "Serge E. Hallyn" <> | Subject | Re: [capabilities] Allow normal inheritance for a configurable set of capabilities |
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Quoting Casey Schaufler (casey@schaufler-ca.com): > On 2/2/2015 10:08 AM, Serge Hallyn wrote: > > Quoting Casey Schaufler (casey@schaufler-ca.com): > >> I'm game to participate in such an effort. The POSIX scheme > >> is workable, but given that it's 20 years old and hasn't > >> developed real traction it's hard to call it successful. > > Over the years we've several times discussed possible reasons for this > > and how to help. I personally think it's two things: 1. lack of > > toolchain and fs support. The fact that we cannot to this day enable > > ping using capabilities by default because of cpio, tar and non-xattr > > filesystems is disheartening. 2. It's hard for users and applications > > to know what caps they need. yes the API is a bear to use, but we can > > hide that behind fancier libraries. But using capabilities requires too > > much in-depth knowledge of precisely what caps you might need for > > whatever operations library may now do when you asked for something. > > The fix for that is to a change to the audit system. If the audit system > reported the capabilities relevant to the decision you'd have what you > need. If you failed because you didn't have CAP_CHMOD or you succeeded > because you had CAP_SYS_ADMIN it should show up in the audit record. > Other systems have used this approach. > > You could, of course, create a separate capability result log, and I > believe that Nokia had done something along those lines. I think that > adding it to the audit trail is a more rational approach.
I wonder how much that would end up affecting performance, assuming it left an audit message at every ns_capable() failure. Even if it was only done under a certain sysctl, it could certainly be useful.
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