Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934938AbaKNBBz (ORCPT ); Thu, 13 Nov 2014 20:01:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50892 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933409AbaKNBBx (ORCPT ); Thu, 13 Nov 2014 20:01:53 -0500 Date: Thu, 13 Nov 2014 20:01:45 -0500 From: Richard Guy Briggs To: Joe Perches Cc: linux-audit@redhat.com, linux-kernel@vger.kernel.org, sgrubb@redhat.com, eparis@parisplace.org, pmoore@redhat.com Subject: Re: [PATCH] audit: convert status version to a feature bitmap Message-ID: <20141114010145.GA5960@madcap2.tricolour.ca> References: <1415911097.4223.13.camel@perches.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1415911097.4223.13.camel@perches.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/11/13, Joe Perches wrote: > On Thu, 2014-11-13 at 15:29 -0500, 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. > > Maybe use DECLARE_BITMAP instead of u32 and test_bit/set_bit I don't think so. I'd like to code to be readable... I certainly don't need the overhead of test/set_bit. That doesn't look appropriate for anything in include/uapi/. > > diff --git 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 ) > > + > > +/* 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 > > > > /* Failure-to-log actions */ > > #define AUDIT_FAIL_SILENT 0 > > @@ -403,7 +409,10 @@ struct audit_status { > > __u32 backlog_limit; /* waiting messages limit */ > > __u32 lost; /* messages lost */ > > __u32 backlog; /* messages waiting in queue */ > > - __u32 version; /* audit api version number */ > > + union { > > + __u32 version; /* deprecated: audit api version num */ > > + __u32 feature_bitmap; /* bitmap of kernel audit features */ > > + }; > > __u32 backlog_wait_time;/* message queue wait timeout */ > > }; > > > > diff --git a/kernel/audit.c b/kernel/audit.c > > index 8ee4508..c9d0e30 100644 > > --- a/kernel/audit.c > > +++ b/kernel/audit.c > > @@ -842,7 +842,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) > > s.backlog_limit = audit_backlog_limit; > > s.lost = atomic_read(&audit_lost); > > s.backlog = skb_queue_len(&audit_skb_queue); > > - s.version = AUDIT_VERSION_LATEST; > > + s.feature_bitmap = AUDIT_FEATURE_BITMAP; > > s.backlog_wait_time = audit_backlog_wait_time; > > audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); > > break; - RGB -- Richard Guy Briggs Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat Remote, Ottawa, Canada Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545 -- 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/