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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b124-20020a62cf82000000b0064f6a52105csi3527948pfg.378.2023.05.31.05.49.21; Wed, 31 May 2023 05:49:34 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b="WEbs/vgq"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235944AbjEaMqf (ORCPT + 99 others); Wed, 31 May 2023 08:46:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235909AbjEaMqa (ORCPT ); Wed, 31 May 2023 08:46:30 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE7B7128 for ; Wed, 31 May 2023 05:45:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685537144; 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=704Gul1es5vKB8f3fNlqLP0xfed1dEhsuWb+SLm3klg=; b=WEbs/vgqtdc7UsAEh8O4M0ghNHBj1PiB9QnqdNiMATXe6KuZ8WDckAVxnrIYpEeGtRZpVz Dgg/KbMZeVf2+T/0e7BHrIPzac6BBLQbKaYG70TI6YRnEFVgKwlbEQiY+ZZqfCwLCr/t0y 9hwdKHHc0uU/gAIZpQIyaU3KoQxhhLU= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-625-u-3ocbAEPfKvWCDqcrmGEg-1; Wed, 31 May 2023 08:45:41 -0400 X-MC-Unique: u-3ocbAEPfKvWCDqcrmGEg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A721F3C0C897; Wed, 31 May 2023 12:45:40 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.182]) by smtp.corp.redhat.com (Postfix) with ESMTP id B74EE112132E; Wed, 31 May 2023 12:45:38 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , Chuck Lever , Boris Pismenny , John Fastabend , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v2 2/6] net: Block MSG_SENDPAGE_* from being passed to sendmsg() by userspace Date: Wed, 31 May 2023 13:45:24 +0100 Message-ID: <20230531124528.699123-3-dhowells@redhat.com> In-Reply-To: <20230531124528.699123-1-dhowells@redhat.com> References: <20230531124528.699123-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Spam-Status: No, score=-2.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1767414037981866008?= X-GMAIL-MSGID: =?utf-8?q?1767414037981866008?= It is necessary to allow MSG_SENDPAGE_* to be passed into ->sendmsg() to allow sendmsg(MSG_SPLICE_PAGES) to replace ->sendpage(). Unblocking them in the network protocol, however, allows these flags to be passed in by userspace too[1]. Fix this by marking MSG_SENDPAGE_NOPOLICY, MSG_SENDPAGE_NOTLAST and MSG_SENDPAGE_DECRYPTED as internal flags, which causes sendmsg() to object if they are passed to sendmsg() by userspace. Network protocol ->sendmsg() implementations can then allow them through. Note that it should be possible to remove MSG_SENDPAGE_NOTLAST once sendpage is removed as a whole slew of pages will be passed in in one go by splice through sendmsg, with MSG_MORE being set if it has more data waiting in the pipe. Signed-off-by: David Howells cc: Jakub Kicinski cc: Chuck Lever cc: Boris Pismenny cc: John Fastabend cc: Eric Dumazet cc: "David S. Miller" cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org Link: https://lore.kernel.org/r/20230526181338.03a99016@kernel.org/ [1] --- include/linux/socket.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/linux/socket.h b/include/linux/socket.h index bd1cc3238851..3fd3436bc09f 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -339,7 +339,9 @@ struct ucred { #endif /* Flags to be cleared on entry by sendmsg and sendmmsg syscalls */ -#define MSG_INTERNAL_SENDMSG_FLAGS (MSG_SPLICE_PAGES) +#define MSG_INTERNAL_SENDMSG_FLAGS \ + (MSG_SPLICE_PAGES | MSG_SENDPAGE_NOPOLICY | MSG_SENDPAGE_NOTLAST | \ + MSG_SENDPAGE_DECRYPTED) /* Setsockoptions(2) level. Thanks to BSD these must match IPPROTO_xxx */ #define SOL_IP 0