linux-integrity.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Greg KH <gregkh@linuxfoundation.org>
To: Roberto Sassu <roberto.sassu@huawei.com>
Cc: "zohar@linux.ibm.com" <zohar@linux.ibm.com>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH 03/12] digest_lists: Basic definitions
Date: Mon, 28 Jun 2021 11:32:18 +0200	[thread overview]
Message-ID: <YNmXIk7orQavkEME@kroah.com> (raw)
In-Reply-To: <4acc7e8f15834b83b310b9e2ff9ba3d2@huawei.com>

On Mon, Jun 28, 2021 at 09:27:05AM +0000, Roberto Sassu wrote:
> > From: Greg KH [mailto:gregkh@linuxfoundation.org]
> > Sent: Monday, June 28, 2021 10:46 AM
> > On Mon, Jun 28, 2021 at 08:30:32AM +0000, Roberto Sassu wrote:
> > > > > +struct compact_list_hdr {
> > > > > +	__u8 version;
> > > >
> > > > You should never need a version, that way lies madness.
> > >
> > > We wanted to have a way to switch to a new format, if necessary.
> > 
> > Then just add a new ioctl if you need that in the future, no need to try
> > to cram it into this one.
> 
> Given that digest lists are generated elsewhere, it would be still
> unclear when the ioctl() would be issued. Maybe the kernel needs
> to parse both v1 and v2 digest lists (I expect that v1 cannot be easily
> converted to v2, if they are signed).
> 
>  It would be also unpractical if digest lists are loaded at kernel
> initialization time (I didn't send the patch yet).

Then that is up to your api design, I do not know.  But note that
"version" fields almost always never work, so be careful about assuming
that this will solve any future issues.

> > > > > +	__le16 type;
> > > > > +	__le16 modifiers;
> > > > > +	__le16 algo;
> > > > > +	__le32 count;
> > > > > +	__le32 datalen;
> > > >
> > > > Why are user/kernel apis specified in little endian format?  Why would
> > > > that matter?  Shouldn't they just be "native" endian?
> > >
> > > I thought this would make it clear that the kernel always expects the
> > > digest lists to be in little endian.
> > 
> > Why would a big endian system expect the data from userspace to be in
> > little endian?  Shouldn't this always just be "native" endian given that
> > this is not something that is being sent to hardware?
> 
> The digest list might come from a system with different endianness.

Ok, I have no idea what digests really are used for then.  So stick with
little endian and be sure to properly convert within the kernel as
needed.

thanks,

greg k-h

  reply	other threads:[~2021-06-28  9:32 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-25 16:56 [RFC][PATCH 00/12] Huawei Digest Lists Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 01/12] ima: Add digest, algo, measured parameters to ima_measure_critical_data() Roberto Sassu
2021-06-25 18:26   ` Mimi Zohar
2021-06-25 16:56 ` [RFC][PATCH 02/12] digest_lists: Overview Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 03/12] digest_lists: Basic definitions Roberto Sassu
2021-06-27 10:53   ` Greg KH
2021-06-27 15:23     ` Matthew Wilcox
2021-06-27 15:35       ` Greg KH
2021-06-28  8:30     ` Roberto Sassu
2021-06-28  8:46       ` Greg KH
2021-06-28  9:27         ` Roberto Sassu
2021-06-28  9:32           ` Greg KH [this message]
2021-06-28  9:51             ` Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 04/12] digest_lists: Objects Roberto Sassu
2021-06-27 10:56   ` Greg KH
2021-06-28  8:14     ` Roberto Sassu
2021-06-28  8:47       ` Greg KH
2021-06-25 16:56 ` [RFC][PATCH 05/12] digest_lists: Methods Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 06/12] digest_lists: Parser Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 07/12] digest_lists: Interfaces - digest_list_add, digest_list_del Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 08/12] digest_lists: Interfaces - digest_lists_loaded Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 09/12] digest_lists: Interfaces - digest_label Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 10/12] digest_lists: Interfaces - digest_query Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 11/12] digest_lists: Interfaces - digests_count Roberto Sassu
2021-06-25 16:56 ` [RFC][PATCH 12/12] digest_lists: Tests Roberto Sassu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YNmXIk7orQavkEME@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=roberto.sassu@huawei.com \
    --cc=zohar@linux.ibm.com \
    --subject='Re: [RFC][PATCH 03/12] digest_lists: Basic definitions' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).