From patchwork Wed Jul 21 16:44:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Abeni X-Patchwork-Id: 12391647 X-Patchwork-Delegate: paul@paul-moore.com 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 475ECC12002 for ; Wed, 21 Jul 2021 16:45:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2823961244 for ; Wed, 21 Jul 2021 16:45:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233692AbhGUQEn (ORCPT ); Wed, 21 Jul 2021 12:04:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:60756 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233375AbhGUQEl (ORCPT ); Wed, 21 Jul 2021 12:04:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626885917; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=A774f2Th7dL8uyA+Ed6Ue0eihbrm9ddp25ruzofQLbA=; b=OdGmqLWSexS9jKNSe+g5MQcIsxi/1VMra+Q12rzbk5GMs0Xed3695/pZuN+wee9WsVigC0 M9WKUJhyTcJmFlb+VP58349LW16H+iNcTQS0jOVRy1b7B4LaNxGjUYXTY/e413DXSC4OhP 0cQRNsK//51DddWLfSHsrwqJaSMENFE= 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-216-of5nlfWPMMCHLUc7DS-L-w-1; Wed, 21 Jul 2021 12:45:16 -0400 X-MC-Unique: of5nlfWPMMCHLUc7DS-L-w-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 C7879804140; Wed, 21 Jul 2021 16:45:14 +0000 (UTC) Received: from gerbillo.redhat.com (ovpn-114-219.ams2.redhat.com [10.36.114.219]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1A677797C0; Wed, 21 Jul 2021 16:45:12 +0000 (UTC) From: Paolo Abeni To: netdev@vger.kernel.org Cc: "David S. Miller" , Jakub Kicinski , Florian Westphal , Eric Dumazet , linux-security-module@vger.kernel.org, selinux@vger.kernel.org Subject: [PATCH RFC 3/9] sk_buff: move the active_extensions into the state bitfield Date: Wed, 21 Jul 2021 18:44:35 +0200 Message-Id: <75a4e2fe7a521247984460b0687bc111239b71ef.1626882513.git.pabeni@redhat.com> In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org No functional change intended Signed-off-by: Paolo Abeni --- v1 -> v2: - add CHECK_SKB_FIELD(_state) in __copy_skb_header 2 problems: - this restrict the storage for new skb extensions to 0 or at most 1 - can't provide a build time check to ensure SKB_EXT do not exceed active_extensions I'm wondering about moving 2 random bits from the header section to the old active_extensions location (and explicitly copy them on clone) so that we can keep using 1 byte for extension and 1 byte for other state things --- include/linux/skbuff.h | 11 +++++------ net/core/skbuff.c | 1 + 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 1b811585f6fc..03be9a774c58 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -670,7 +670,6 @@ typedef unsigned char *sk_buff_data_t; * @pfmemalloc: skbuff was allocated from PFMEMALLOC reserves * @pp_recycle: mark the packet for recycling instead of freeing (implies * page_pool support on driver) - * @active_extensions: active extensions (skb_ext_id types) * @ndisc_nodetype: router type (from link layer) * @ooo_okay: allow the mapping of a socket to a queue to be changed * @l4_hash: indicate hash is a canonical 4-tuple hash over transport @@ -692,6 +691,7 @@ typedef unsigned char *sk_buff_data_t; * @_state: bitmap reporting the presence of some skb state info * @has_nfct: @_state bit for nfct info * @has_dst: @_state bit for dst pointer + * @active_extensions: @_state bits for active extensions (skb_ext_id types) * @napi_id: id of the NAPI struct this skb came from * @sender_cpu: (aka @napi_id) source CPU in XPS * @secmark: security marking @@ -796,9 +796,6 @@ struct sk_buff { head_frag:1, pfmemalloc:1, pp_recycle:1; /* page_pool recycle indicator */ -#ifdef CONFIG_SKB_EXTENSIONS - __u8 active_extensions; -#endif /* fields enclosed in headers_start/headers_end are copied * using a single memcpy() in __copy_skb_header() @@ -875,6 +872,9 @@ struct sk_buff { struct { __u8 has_nfct:1; __u8 has_dst:1; +#ifdef CONFIG_SKB_EXTENSIONS + __u8 active_extensions:5; +#endif }; }; @@ -4283,8 +4283,6 @@ static inline void skb_ext_put(struct sk_buff *skb) static inline void __skb_ext_copy(struct sk_buff *dst, const struct sk_buff *src) { - dst->active_extensions = src->active_extensions; - if (src->active_extensions) { struct skb_ext *ext = src->extensions; @@ -4296,6 +4294,7 @@ static inline void __skb_ext_copy(struct sk_buff *dst, static inline void skb_ext_copy(struct sk_buff *dst, const struct sk_buff *src) { skb_ext_put(dst); + dst->active_extensions = src->active_extensions; __skb_ext_copy(dst, src); } diff --git a/net/core/skbuff.c b/net/core/skbuff.c index e94805bd8656..2ffe18595635 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1001,6 +1001,7 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) memcpy(&new->headers_start, &old->headers_start, offsetof(struct sk_buff, headers_end) - offsetof(struct sk_buff, headers_start)); + CHECK_SKB_FIELD(_state); CHECK_SKB_FIELD(protocol); CHECK_SKB_FIELD(csum); CHECK_SKB_FIELD(hash);