Messages in this thread | | | Subject | Re: [RFC] module: signature infrastructure | From | Mimi Zohar <> | Date | Tue, 04 Sep 2012 09:40:48 -0400 |
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On Tue, 2012-09-04 at 15:21 +0300, Kasatkin, Dmitry wrote: > On Tue, Sep 4, 2012 at 3:07 PM, Kasatkin, Dmitry > <dmitry.kasatkin@intel.com> wrote: > > Hi, > > > > Please read bellow... > > > > On Tue, Sep 4, 2012 at 8:55 AM, Rusty Russell <rusty@rustcorp.com.au> wrote: > >> OK, I took a look at the module.c parts of David and Dmitry's patchsets, > >> and didn't really like either, but I stole parts of David's to make > >> this. > >> > >> So, here's the module.c part of module signing. I hope you two got time > >> to discuss the signature format details?
The integrity subsystem currently defines 3 extended attribute formats in security/integrity.h.
enum evm_ima_xattr_type { IMA_XATTR_DIGEST = 0x01, EVM_XATTR_HMAC, EVM_IMA_XATTR_DIGSIG, };
integrity_digsig_verify() is called to appraise EVM signatures stored as EVM_IMA_XATTR_DIGSIG. In Dmitry's patches, this same call is used to appraise modules. If you decide to define a new format, it should be included here as well.
> Mimi suggested a scheme where > >> the private key would never be saved on disk (even temporarily), but I > >> didn't see patches. Frankly it's something we can do later; let's aim > >> at getting the format right for the next merge window.
Right, the key is a build issue, which doesn't affect the format.
> > In our patches key is stored on the disc in encrypted format...
An updated version of Dmitry's patches are in the 'modsig' branch of git://git.kernel.org/pub/scm/linux/kernel/git/kasatkin/linux-digsig. For now, although commit 59f1d53 "modsig: build rules and scripts to generate keys and sign modules" writes the ephemeral key to disk, it is encrypted.
thanks,
Mimi
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