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[23.128.96.18]) by mx.google.com with ESMTP id s8si3056835edr.527.2021.07.08.06.15.25; Thu, 08 Jul 2021 06:15:56 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@suse.com header.s=susede1 header.b=JbRdunVs; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=NONE dis=NONE) header.from=suse.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231849AbhGHNRJ (ORCPT + 99 others); Thu, 8 Jul 2021 09:17:09 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:49840 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231519AbhGHNRI (ORCPT ); Thu, 8 Jul 2021 09:17:08 -0400 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-out1.suse.de (Postfix) with ESMTPS id 91BB022360; Thu, 8 Jul 2021 13:14:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1625750065; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=kjDxg716BeRs2qtkJRO5dJhtTxFQMs1Qz7BRV05AbBo=; b=JbRdunVsKhyiVVBCo8yMgJQKvZpa5rMbzks6AVmCpSyppVRrYJBCrq2uPHRVMi9+QXBsdF DIsyBIzkB6codFI98AJt3j6MOUMCRKVb7cGf7TDfT0EcgGFtJx0/J+97cnxQpbYyyFMGnt yDwCVoelae67WiglcvOVtpIZpldRzdE= 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 4A36F1338E; Thu, 8 Jul 2021 13:14:25 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id 7uMMEDH65mAYagAAGKfGzw (envelope-from ); Thu, 08 Jul 2021 13:14:25 +0000 Subject: Re: [PATCH v2 3/3] xen/blkfront: don't trust the backend response data blindly To: Jan Beulich Cc: Boris Ostrovsky , Stefano Stabellini , Konrad Rzeszutek Wilk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Jens Axboe , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org References: <20210708124345.10173-1-jgross@suse.com> <20210708124345.10173-4-jgross@suse.com> From: Juergen Gross Message-ID: <49aa4ddb-ca58-e0df-0675-daa72866d3db@suse.com> Date: Thu, 8 Jul 2021 15:14:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="GZlw9XRimbRflKEqbIeJ6AKoGzpNRdN8y" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --GZlw9XRimbRflKEqbIeJ6AKoGzpNRdN8y Content-Type: multipart/mixed; boundary="vTD9BTL08Q22LyNlkVoVSug6qRFaht5uE"; protected-headers="v1" From: Juergen Gross To: Jan Beulich Cc: Boris Ostrovsky , Stefano Stabellini , Konrad Rzeszutek Wilk , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Jens Axboe , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Message-ID: <49aa4ddb-ca58-e0df-0675-daa72866d3db@suse.com> Subject: Re: [PATCH v2 3/3] xen/blkfront: don't trust the backend response data blindly References: <20210708124345.10173-1-jgross@suse.com> <20210708124345.10173-4-jgross@suse.com> In-Reply-To: --vTD9BTL08Q22LyNlkVoVSug6qRFaht5uE Content-Type: multipart/mixed; boundary="------------A72E68CB9B686B2D3C20F643" Content-Language: en-US This is a multi-part message in MIME format. --------------A72E68CB9B686B2D3C20F643 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 08.07.21 15:11, Jan Beulich wrote: > On 08.07.2021 14:43, Juergen Gross wrote: >> Today blkfront will trust the backend to send only sane response data.= >> In order to avoid privilege escalations or crashes in case of maliciou= s >> backends verify the data to be within expected limits. Especially make= >> sure that the response always references an outstanding request. >> >> Introduce a new state of the ring BLKIF_STATE_ERROR which will be >> switched to in case an inconsistency is being detected. Recovering fro= m >> this state is possible only via removing and adding the virtual device= >> again (e.g. via a suspend/resume cycle). >> >> Signed-off-by: Juergen Gross >=20 > Reviewed-by: Jan Beulich > albeit ... >=20 >> @@ -1602,7 +1628,8 @@ static irqreturn_t blkif_interrupt(int irq, void= *dev_id) >> case BLKIF_OP_DISCARD: >> if (unlikely(bret.status =3D=3D BLKIF_RSP_EOPNOTSUPP)) { >> struct request_queue *rq =3D info->rq; >> - printk(KERN_WARNING "blkfront: %s: %s op failed\n", >> + >> + pr_warn_ratelimited("blkfront: %s: %s op failed\n", >> info->gd->disk_name, op_name(bret.operation)); >> blkif_req(req)->error =3D BLK_STS_NOTSUPP; >> info->feature_discard =3D 0; >> @@ -1614,13 +1641,13 @@ static irqreturn_t blkif_interrupt(int irq, vo= id *dev_id) >> case BLKIF_OP_FLUSH_DISKCACHE: >> case BLKIF_OP_WRITE_BARRIER: >> if (unlikely(bret.status =3D=3D BLKIF_RSP_EOPNOTSUPP)) { >> - printk(KERN_WARNING "blkfront: %s: %s op failed\n", >> + pr_warn_ratelimited("blkfront: %s: %s op failed\n", >> info->gd->disk_name, op_name(bret.operation)); >> blkif_req(req)->error =3D BLK_STS_NOTSUPP; >> } >> if (unlikely(bret.status =3D=3D BLKIF_RSP_ERROR && >> rinfo->shadow[id].req.u.rw.nr_segments =3D=3D 0)) { >> - printk(KERN_WARNING "blkfront: %s: empty %s op failed\n", >> + pr_warn_ratelimited("blkfront: %s: empty %s op failed\n", >> info->gd->disk_name, op_name(bret.operation)); >> blkif_req(req)->error =3D BLK_STS_NOTSUPP; >> } >> @@ -1635,8 +1662,8 @@ static irqreturn_t blkif_interrupt(int irq, void= *dev_id) >> case BLKIF_OP_READ: >> case BLKIF_OP_WRITE: >> if (unlikely(bret.status !=3D BLKIF_RSP_OKAY)) >> - dev_dbg(&info->xbdev->dev, "Bad return from blkdev data " >> - "request: %x\n", bret.status); >> + dev_dbg_ratelimited(&info->xbdev->dev, >> + "Bad return from blkdev data request: %x\n", bret.status); >> =20 >> break; >> default: >=20 > ... all of these look kind of unrelated to the topic of the patch, > and the conversion also isn't mentioned as on-purpose in the > description. Hmm, yes, I'll add a sentence to the commit message. 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