From patchwork Mon Feb 3 10:30:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 1232678 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=EY78hb/z; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48B3yJ4pj0z9sRs for ; Mon, 3 Feb 2020 21:31:04 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727729AbgBCKa6 (ORCPT ); Mon, 3 Feb 2020 05:30:58 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:29628 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726100AbgBCKa4 (ORCPT ); Mon, 3 Feb 2020 05:30:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580725855; h=from:from: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; bh=pCLKGSqMaV4qZrcygd/MqiNrWGKg5U4tuMzI7W//FPE=; b=EY78hb/zbxzLYBZfKwqQyO15rG8Sasmcj0Gu21mG36bryA1ryJmIuUeNV4cM/iXztH0UR6 QLFfPCM10Xoy9l0Y55lUcbQYO7BMGj60SMGTCRJ+7jMdVSS6p5g3l7n3BVNYIiRpJshHco zHkSQJ3qKxkf1Cao0NVAfLyGR+W3TIE= 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-321-aDSi7BMRMNOumPCYsDuLOw-1; Mon, 03 Feb 2020 05:30:54 -0500 X-MC-Unique: aDSi7BMRMNOumPCYsDuLOw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5664613E6; Mon, 3 Feb 2020 10:30:53 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-218.rdu2.redhat.com [10.10.120.218]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9344789A99; Mon, 3 Feb 2020 10:30:52 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH net 1/4] rxrpc: Fix use-after-free in rxrpc_put_local() ver #2 From: David Howells To: netdev@vger.kernel.org Cc: dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Mon, 03 Feb 2020 10:30:51 +0000 Message-ID: <158072585191.743488.10422251782960804156.stgit@warthog.procyon.org.uk> In-Reply-To: <158072584492.743488.4616022353630142921.stgit@warthog.procyon.org.uk> References: <158072584492.743488.4616022353630142921.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Fix rxrpc_put_local() to not access local->debug_id after calling atomic_dec_return() as, unless that returned n==0, we no longer have the right to access the object. Fixes: 06d9532fa6b3 ("rxrpc: Fix read-after-free in rxrpc_queue_local()") Signed-off-by: David Howells --- net/rxrpc/local_object.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c index 36587260cabd..3aa179efcda4 100644 --- a/net/rxrpc/local_object.c +++ b/net/rxrpc/local_object.c @@ -364,11 +364,14 @@ void rxrpc_queue_local(struct rxrpc_local *local) void rxrpc_put_local(struct rxrpc_local *local) { const void *here = __builtin_return_address(0); + unsigned int debug_id; int n; if (local) { + debug_id = local->debug_id; + n = atomic_dec_return(&local->usage); - trace_rxrpc_local(local->debug_id, rxrpc_local_put, n, here); + trace_rxrpc_local(debug_id, rxrpc_local_put, n, here); if (n == 0) call_rcu(&local->rcu, rxrpc_local_rcu);