From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AC58C43331 for ; Fri, 3 Apr 2020 21:29:54 +0000 (UTC) Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EA4BA20737 for ; Fri, 3 Apr 2020 21:29:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="L4pDGaXT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA4BA20737 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-audit-bounces@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585949392; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=Ua7n2527W3h3zC4V+o5qhlULM2Fh1v9vd5TzmhjU/j8=; b=L4pDGaXTyy6YroZvmia0mWmlx2JoHLHNa3uj3ZWd4fAMrz8hk4hHluv7XKd83IImAd4cvR 7w6N74z9+pqZrckst0MnzWFTkFfyDXrM1csN50Zah5DakokO9XyMB21vQ+4U+tJDWWeunE LMdXmoFD9FOxL53I7xPsO4KvvXC4hs8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-102-iM6NfBwTPDafQyR0dnR_SA-1; Fri, 03 Apr 2020 17:29:50 -0400 X-MC-Unique: iM6NfBwTPDafQyR0dnR_SA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 36901800D50; Fri, 3 Apr 2020 21:29:41 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BF9AD9A251; Fri, 3 Apr 2020 21:29:40 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id C3B814E461; Fri, 3 Apr 2020 21:29:39 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 033LLsFP018232 for ; Fri, 3 Apr 2020 17:21:54 -0400 Received: by smtp.corp.redhat.com (Postfix) id A301926DF8; Fri, 3 Apr 2020 21:21:54 +0000 (UTC) Received: from madcap2.tricolour.ca (unknown [10.3.128.9]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 363DD26DF1; Fri, 3 Apr 2020 21:21:41 +0000 (UTC) Date: Fri, 3 Apr 2020 17:21:38 -0400 From: Richard Guy Briggs To: Amol Grover Subject: Re: [PATCH 3/3 RESEND] auditsc: Do not use RCU primitive to read from cred pointer Message-ID: <20200403212138.kr72jr57ppzsv6rm@madcap2.tricolour.ca> References: <20200402055640.6677-1-frextrite@gmail.com> <20200402055640.6677-3-frextrite@gmail.com> <20200403075613.GA2788@workstation-portable> MIME-Version: 1.0 In-Reply-To: <20200403075613.GA2788@workstation-portable> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-loop: linux-audit@redhat.com X-Mailman-Approved-At: Fri, 03 Apr 2020 17:29:38 -0400 Cc: Juri Lelli , Peter Zijlstra , Ben Segall , Joel Fernandes , Vincent Guittot , James Morris , Madhuparna Bhowmik , Ingo Molnar , Mel Gorman , linux-kernel-mentees@lists.linuxfoundation.org, "Paul E . McKenney" , Jann Horn , Steven Rostedt , Shakeel Butt , Thomas Gleixner , Dietmar Eggemann , David Howells , linux-kernel@vger.kernel.org, linux-audit@redhat.com, "Eric W . Biederman" , Andrew Morton X-BeenThere: linux-audit@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Linux Audit Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-audit-bounces@redhat.com Errors-To: linux-audit-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline On 2020-04-03 13:26, Amol Grover wrote: > On Thu, Apr 02, 2020 at 08:56:36AM -0400, Paul Moore wrote: > > On Thu, Apr 2, 2020 at 1:57 AM Amol Grover wrote: > > > task_struct::cred is only used task-synchronously and does > > > not require any RCU locks, hence, rcu_dereference_check is > > > not required to read from it. > > > > > > Suggested-by: Jann Horn > > > Co-developed-by: Joel Fernandes (Google) > > > Signed-off-by: Joel Fernandes (Google) > > > Signed-off-by: Amol Grover > > > --- > > > kernel/auditsc.c | 15 +++++---------- > > > 1 file changed, 5 insertions(+), 10 deletions(-) > > > > This is the exact same patch I ACK'd back in February, yes? > > > > https://lore.kernel.org/linux-audit/CAHC9VhQCbg1V290bYEZM+izDPRpr=XYXakohnDaMphkBBFgUaA@mail.gmail.com > > > > Hi Paul, > > That's correct. I've resend the series out of the fear that the first 2 > patches might've gotten lost as it's been almost a month since I last > sent them. Could you please ack this again, and if you don't mind could > you please go through the other 2 patches and ack them aswell? Via who's tree are you expecting this will make it upstream? > Thanks > Amol > > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > > index 4effe01ebbe2..d3510513cdd1 100644 > > > --- a/kernel/auditsc.c > > > +++ b/kernel/auditsc.c > > > @@ -430,24 +430,19 @@ static int audit_field_compare(struct task_struct *tsk, > > > /* Determine if any context name data matches a rule's watch data */ > > > /* Compare a task_struct with an audit_rule. Return 1 on match, 0 > > > * otherwise. > > > - * > > > - * If task_creation is true, this is an explicit indication that we are > > > - * filtering a task rule at task creation time. This and tsk == current are > > > - * the only situations where tsk->cred may be accessed without an rcu read lock. > > > */ > > > static int audit_filter_rules(struct task_struct *tsk, > > > struct audit_krule *rule, > > > struct audit_context *ctx, > > > struct audit_names *name, > > > - enum audit_state *state, > > > - bool task_creation) > > > + enum audit_state *state) > > > { > > > const struct cred *cred; > > > int i, need_sid = 1; > > > u32 sid; > > > unsigned int sessionid; > > > > > > - cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation); > > > + cred = tsk->cred; > > > > > > for (i = 0; i < rule->field_count; i++) { > > > struct audit_field *f = &rule->fields[i]; > > > @@ -745,7 +740,7 @@ static enum audit_state audit_filter_task(struct task_struct *tsk, char **key) > > > rcu_read_lock(); > > > list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TASK], list) { > > > if (audit_filter_rules(tsk, &e->rule, NULL, NULL, > > > - &state, true)) { > > > + &state)) { > > > if (state == AUDIT_RECORD_CONTEXT) > > > *key = kstrdup(e->rule.filterkey, GFP_ATOMIC); > > > rcu_read_unlock(); > > > @@ -791,7 +786,7 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk, > > > list_for_each_entry_rcu(e, list, list) { > > > if (audit_in_mask(&e->rule, ctx->major) && > > > audit_filter_rules(tsk, &e->rule, ctx, NULL, > > > - &state, false)) { > > > + &state)) { > > > rcu_read_unlock(); > > > ctx->current_state = state; > > > return state; > > > @@ -815,7 +810,7 @@ static int audit_filter_inode_name(struct task_struct *tsk, > > > > > > list_for_each_entry_rcu(e, list, list) { > > > if (audit_in_mask(&e->rule, ctx->major) && > > > - audit_filter_rules(tsk, &e->rule, ctx, n, &state, false)) { > > > + audit_filter_rules(tsk, &e->rule, ctx, n, &state)) { > > > ctx->current_state = state; > > > return 1; > > > } > > > -- > > > 2.24.1 > > > > paul moore - RGB -- Richard Guy Briggs Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635 -- Linux-audit mailing list Linux-audit@redhat.com https://www.redhat.com/mailman/listinfo/linux-audit