From: Thiago Jung Bauermann Subject: Re: [PATCH 5/6] MODSIGN: Export module signature definitions. Date: Thu, 20 Apr 2017 18:07:15 -0300 Message-ID: <1544111.Uq9hhXcF4r@morokweng> References: <1492691712.3081.85.camel@linux.vnet.ibm.com> <1492546666-16615-6-git-send-email-bauerman@linux.vnet.ibm.com> <21102.1492699057@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: Mimi Zohar , linux-security-module@vger.kernel.org, linux-ima-devel@lists.sourceforge.net, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Dmitry Kasatkin , Herbert Xu , "David S. Miller" , Claudio Carvalho To: David Howells Return-path: In-Reply-To: <21102.1492699057@warthog.procyon.org.uk> Sender: owner-linux-security-module@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Am Donnerstag, 20. April 2017, 15:37:37 BRT schrieb David Howells: > Mimi Zohar wrote: > > On Tue, 2017-04-18 at 17:17 -0300, Thiago Jung Bauermann wrote: > > > IMA will use the module_signature format for append signatures, so > > > export > > > the relevant definitions and factor out the code which verifies that the > > > appended signature trailer is valid. > > > > > > Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it > > > and be able to use validate_module_signature without having to depend on > > > CONFIG_MODULE_SIG. > > > > Basically we want to generalize the concept of an appended signature. > > Referring to it as a "module signature format" seems a bit confusing. > > > > David, would you have a problem with changing the appended string from > > "~Module signature appended~\n" to something more generic? > > Conceptually, no. Is it possible that doing so could break someone's module > that they load on multiple versions of the kernel? Say a module that only > exports things and doesn't use anything from the core or any other module. I think that changing the appended string has limited value because very few people actually see them. It's just a marker. We could s/module_signature/ appended_signature/ in the code but keep the actual string unchanged. What do you think? Alternatively, we could change the string but accept both the old and the new string for backwards compatibility. -- Thiago Jung Bauermann IBM Linux Technology Center