From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: Re: [PATCH] capabilities: Ambient capability set V1 Date: Tue, 24 Feb 2015 11:28:48 -0600 (CST) Message-ID: References: <20150223161625.GD25477@ubuntumail> <20150223164623.GB32181@mail.hallyn.com> <20150223181553.GE25477@ubuntumail> <20150224051928.GA14755@mail.hallyn.com> <20150224154715.GA20682@mail.hallyn.com> <20150224164429.GB29685@ubuntumail> Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <20150224164429.GB29685@ubuntumail> Sender: linux-kernel-owner@vger.kernel.org To: Serge Hallyn Cc: "Serge E. Hallyn" , Serge Hallyn , Andy Lutomirski , Aaron Jones , Ted Ts'o , linux-security-module@vger.kernel.org, akpm@linuxfoundation.org, "Andrew G. Morgan" , Mimi Zohar , Austin S Hemmelgarn , Markku Savela , Jarkko Sakkinen , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Michael Kerrisk , Jonathan Corbet List-Id: linux-api@vger.kernel.org On Tue, 24 Feb 2015, Serge Hallyn wrote: > Unless I'm misunderstanding what you are saying, apps do have surprises. > They drop capabilities, execute a file, and the result has capabilities > which the app couldn't have expected. At least if the bits have to be > in fI to become part of pP', the app has a clue. Well yes but the surprises do not occur in the cap bits they are manipulating or inspecting via prctl. > To be clear, I'm suggesting that the rules at exec become: > > pI' = pI Ok that is new and on its own may solve the issue? > pA' = pA (pA is ambient) Thats what this patch does > pP' = (X & fP) | (pI & (fI | pA)) Hmmm... fP is empty for the file not having caps. so pP' = pI & pA > pE' = pP' & fE fE? So the inherited caps are not effective? fE would be empty for a file not having caps thus the ambient caps would not be available in the child.