Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934580AbaKMWML (ORCPT ); Thu, 13 Nov 2014 17:12:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38514 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933765AbaKMWMJ (ORCPT ); Thu, 13 Nov 2014 17:12:09 -0500 From: Paul Moore To: Richard Guy Briggs Cc: linux-audit@redhat.com, linux-kernel@vger.kernel.org, sgrubb@redhat.com, eparis@parisplace.org Subject: Re: [PATCH] audit: convert status version to a feature bitmap Date: Thu, 13 Nov 2014 17:12:06 -0500 Message-ID: <1745832.tbkjBzSGxr@sifl> Organization: Red Hat User-Agent: KMail/4.14.2 (Linux/3.16.7-gentoo; KDE/4.14.2; x86_64; ; ) In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, November 13, 2014 03:29:10 PM Richard Guy Briggs wrote: > The version field defined in the audit status structure was found to have > limitations in terms of its expressibility of features supported. This is > distict from the get/set features call to be able to command those features > that are present. > > Converting this field from a version number to a feature bitmap will allow > distributions to selectively backport and support certain features and will > allow upstream to be able to deprecate features in the future. It will > allow userspace clients to first query the kernel for which features are > actually present and supported. Currently, EINVAL is returned rather than > EOPNOTSUP, which isn't helpful in determining if there was an error in the > command, or if it simply isn't supported yet. Past features are not > represented by this bitmap, but their use may be converted to EOPNOTSUP if > needed in the future. > > Since "version" is too generic to convert with a #define, use a union in the > struct status, introducing the member "feature_bitmap" unionized with > "version". > > Convert existing AUDIT_VERSION_* macros over to AUDIT_FEATURE_BITMAP* > counterparts, leaving the former for backwards compatibility. > > Signed-off-by: Richard Guy Briggs > --- > include/uapi/linux/audit.h | 17 +++++++++++++---- > kernel/audit.c | 2 +- > 2 files changed, 14 insertions(+), 5 deletions(-) Looks good for the most part, just a naming nit pick and a question about the deprecated AUDIT_VERSION_* defines; see below ... > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > index 4d100c8..74aa584 100644 > --- a/include/uapi/linux/audit.h > +++ b/include/uapi/linux/audit.h > @@ -322,9 +322,15 @@ enum { > #define AUDIT_STATUS_BACKLOG_LIMIT 0x0010 > #define AUDIT_STATUS_BACKLOG_WAIT_TIME 0x0020 > > -#define AUDIT_VERSION_BACKLOG_LIMIT 1 > -#define AUDIT_VERSION_BACKLOG_WAIT_TIME 2 > -#define AUDIT_VERSION_LATEST AUDIT_VERSION_BACKLOG_WAIT_TIME > +#define AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT 0x00000001 > +#define AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME 0x00000002 > +#define AUDIT_FEATURE_BITMAP ( AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT | \ > + AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME ) How about AUDIT_FEATURE_BIMAP_ALL instead of just AUDIT_FEATURE_BITMAP? > +/* deprecated: AUDIT_VERSION_* */ > +#define AUDIT_VERSION_LATEST AUDIT_FEATURE_BITMAP > +#define AUDIT_VERSION_BACKLOG_LIMIT AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT > +#define AUDIT_VERSION_BACKLOG_WAIT_TIME > ... AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME So what terrible things happen to userspace if AUDIT_VERSION_BACKLOG_WAIT_TIME becomes 0x03 instead of 0x02? -- paul moore security and virtualization @ redhat -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/