Messages in this thread | | | Date | Thu, 5 Nov 2015 18:48:24 +0100 | From | Klaus Ethgen <> | Subject | Re: [KERNEL] Re: [KERNEL] Re: [KERNEL] Re: [KERNEL] Re: Kernel 4.3 breaks security in systems using capabilities |
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Am Do den 5. Nov 2015 um 18:34 schrieb Serge E. Hallyn: > > Am Do den 5. Nov 2015 um 17:15 schrieb Serge E. Hallyn: > > > I think if you follow your idea to its logical conclusions, you end > > > up wanting set SECURE_ALL_BITS | SECURE_ALL_LOCKS, which will include > > > SECURE_NO_CAP_AMBIENT_RAISE, disabling ambient capabilities. > > > > That I did miss out and seems to be the solution for the problem. So > > adding cap_secure_all_bits,cap_secure_all_locks=ep to every binary that > > gets other caps should solve it? > > No that doesn't work, you have to use prctl to set those bits. If you > can get your system to be fully rootless, you can have init or initramfs > do this for you. It'll mean that root and setuid-root binaries have no > automatic privileges beside owning host (proc/sys) files.
So this is not helping much. But for me it is at least an idea to how to have abient capabilities _and_ full control for admin. It would be an un-capability but at least would allow the admin to change the behaviour.
Another one, that would be much better would be something like cap_ambient_cap capability to explicitly allow the use of ambient capabilities.
I have to say that I do not know much about prctl. Just reading the man page currently. But this seems to be about the second way of taking away rights from UID 0 instead of explicitly giving rights to selective binaries.
Regards Klaus - -- Klaus Ethgen http://www.ethgen.ch/ pub 4096R/4E20AF1C 2011-05-16 Klaus Ethgen <Klaus@Ethgen.de> Fingerprint: 85D4 CA42 952C 949B 1753 62B3 79D0 B06F 4E20 AF1C -----BEGIN PGP SIGNATURE----- Version: GnuPG v1
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