From nobody Mon Feb 9 19:06:37 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=quarantine dis=none) header.from=suse.com ARC-Seal: i=1; a=rsa-sha256; t=1627641561; cv=none; d=zohomail.com; s=zohoarc; b=e52VdjsvTkrxUFLc8DuzoUsMpgDlS2ESYS2eLEGZoux6d1VkBmGLdhr1uiJn/nHjJQpjSkNR93Jza29JYv2nscVMimy3KbDR5hk7dgwbhAdiY/OvfZBka3mcW1pU/UzAZrGVgn9HLvo/f5Gr7QjeUr4/loe6dvesa8Okt36tPzY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1627641561; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=NJFbCEIB5unsCxTI9pTYyzdTqeYA436YedIZJDFJOiE=; b=EPtzIgOIyv+dDbf5pXDdFp9j/ymmDe1C1988YYBFLzSDmthOMCGcgWxWnrBIGNhghcs5cILQI3Tmu0/tH30lPZQVcviSqPkgNfDvt2q5jFa0E8hsnzFgAPeki79aQQqFYCYRuQfXVbpVHBT94SmoXvKsRd0PZ9f241xHB//L4E4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1627641561754671.7074287231434; Fri, 30 Jul 2021 03:39:21 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.162482.297985 (Exim 4.92) (envelope-from ) id 1m9Puz-0001kP-Q5; Fri, 30 Jul 2021 10:39:05 +0000 Received: by outflank-mailman (output) from mailman id 162482.297985; Fri, 30 Jul 2021 10:39:05 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1m9Puz-0001kG-M0; Fri, 30 Jul 2021 10:39:05 +0000 Received: by outflank-mailman (input) for mailman id 162482; Fri, 30 Jul 2021 10:39:04 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1m9Puy-0001Ad-Ge for xen-devel@lists.xenproject.org; Fri, 30 Jul 2021 10:39:04 +0000 Received: from smtp-out2.suse.de (unknown [195.135.220.29]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 7e985b1b-1a0e-4c13-a8ff-559a7636a8ed; Fri, 30 Jul 2021 10:38:58 +0000 (UTC) Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 26DEE2023C; Fri, 30 Jul 2021 10:38:58 +0000 (UTC) Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id DAA311332A; Fri, 30 Jul 2021 10:38:57 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id OP02NMHWA2HPOAAAGKfGzw (envelope-from ); Fri, 30 Jul 2021 10:38:57 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 7e985b1b-1a0e-4c13-a8ff-559a7636a8ed DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1627641538; h=from:from:reply-to: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=NJFbCEIB5unsCxTI9pTYyzdTqeYA436YedIZJDFJOiE=; b=ceDdu7MD7a3kOPaxwK5kf4oBVvKBjVLEOTHq0/FpCqmy8vc/UB+LEp1hrq+roD/GfkWwwo a33oMSAtQk66z6M9rXDiTEOpZ5wXyHjvIJiu9hLh9V5hqgXW+FPu7QVsbSijXz3S3kVjcE tHQ5X5RShOX+nbFjY+JkSDbKBIdhuVs= From: Juergen Gross To: xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Konrad Rzeszutek Wilk , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Boris Ostrovsky , Stefano Stabellini , Jens Axboe , Jan Beulich Subject: [PATCH v3 2/3] xen/blkfront: don't take local copy of a request from the ring page Date: Fri, 30 Jul 2021 12:38:53 +0200 Message-Id: <20210730103854.12681-3-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210730103854.12681-1-jgross@suse.com> References: <20210730103854.12681-1-jgross@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) X-ZM-MESSAGEID: 1627641562504100001 In order to avoid a malicious backend being able to influence the local copy of a request build the request locally first and then copy it to the ring page instead of doing it the other way round as today. Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Acked-by: Roger Pau Monn=C3=A9 --- V2: - init variable to avoid potential compiler warning (Jan Beulich) --- drivers/block/xen-blkfront.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 15e840287734..b7301006fb28 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -533,7 +533,7 @@ static unsigned long blkif_ring_get_request(struct blkf= ront_ring_info *rinfo, rinfo->shadow[id].status =3D REQ_WAITING; rinfo->shadow[id].associated_id =3D NO_ASSOCIATED_ID; =20 - (*ring_req)->u.rw.id =3D id; + rinfo->shadow[id].req.u.rw.id =3D id; =20 return id; } @@ -541,11 +541,12 @@ static unsigned long blkif_ring_get_request(struct bl= kfront_ring_info *rinfo, static int blkif_queue_discard_req(struct request *req, struct blkfront_ri= ng_info *rinfo) { struct blkfront_info *info =3D rinfo->dev_info; - struct blkif_request *ring_req; + struct blkif_request *ring_req, *final_ring_req; unsigned long id; =20 /* Fill out a communications ring structure. */ - id =3D blkif_ring_get_request(rinfo, req, &ring_req); + id =3D blkif_ring_get_request(rinfo, req, &final_ring_req); + ring_req =3D &rinfo->shadow[id].req; =20 ring_req->operation =3D BLKIF_OP_DISCARD; ring_req->u.discard.nr_sectors =3D blk_rq_sectors(req); @@ -556,8 +557,8 @@ static int blkif_queue_discard_req(struct request *req,= struct blkfront_ring_inf else ring_req->u.discard.flag =3D 0; =20 - /* Keep a private copy so we can reissue requests when recovering. */ - rinfo->shadow[id].req =3D *ring_req; + /* Copy the request to the ring page. */ + *final_ring_req =3D *ring_req; =20 return 0; } @@ -690,6 +691,7 @@ static int blkif_queue_rw_req(struct request *req, stru= ct blkfront_ring_info *ri { struct blkfront_info *info =3D rinfo->dev_info; struct blkif_request *ring_req, *extra_ring_req =3D NULL; + struct blkif_request *final_ring_req, *final_extra_ring_req =3D NULL; unsigned long id, extra_id =3D NO_ASSOCIATED_ID; bool require_extra_req =3D false; int i; @@ -734,7 +736,8 @@ static int blkif_queue_rw_req(struct request *req, stru= ct blkfront_ring_info *ri } =20 /* Fill out a communications ring structure. */ - id =3D blkif_ring_get_request(rinfo, req, &ring_req); + id =3D blkif_ring_get_request(rinfo, req, &final_ring_req); + ring_req =3D &rinfo->shadow[id].req; =20 num_sg =3D blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg); num_grant =3D 0; @@ -785,7 +788,9 @@ static int blkif_queue_rw_req(struct request *req, stru= ct blkfront_ring_info *ri ring_req->u.rw.nr_segments =3D num_grant; if (unlikely(require_extra_req)) { extra_id =3D blkif_ring_get_request(rinfo, req, - &extra_ring_req); + &final_extra_ring_req); + extra_ring_req =3D &rinfo->shadow[extra_id].req; + /* * Only the first request contains the scatter-gather * list. @@ -827,10 +832,10 @@ static int blkif_queue_rw_req(struct request *req, st= ruct blkfront_ring_info *ri if (setup.segments) kunmap_atomic(setup.segments); =20 - /* Keep a private copy so we can reissue requests when recovering. */ - rinfo->shadow[id].req =3D *ring_req; + /* Copy request(s) to the ring page. */ + *final_ring_req =3D *ring_req; if (unlikely(require_extra_req)) - rinfo->shadow[extra_id].req =3D *extra_ring_req; + *final_extra_ring_req =3D *extra_ring_req; =20 if (new_persistent_gnts) gnttab_free_grant_references(setup.gref_head); --=20 2.26.2