From nobody Thu Apr 25 12:31:43 2024 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=none dis=none) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; t=1637353843; cv=none; d=zohomail.com; s=zohoarc; b=V/caQSJA2kNAfYp2HoJclRIOFhGKrU5hDftYONBIeXz3/zFq6JYIc9pOngXyTmzu4Z5EZ5Te3thoWHjyDYWaTdQtD/G+jsTzlyifG1FRE0/GznHghZcemylSLdD97UCpyYJ8gpG/n+m69FlFReLRNpJ6a/AniDlv6GO0tdIULKM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1637353843; h=Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=TparO/48TZ88nybqrPiuUfTrltKxKbsDiU3Zv52mhrs=; b=OVx1+yaZxZINOYTOuAOS25BH62Nq1Qpx6dIy483hS1zdd12JU4cAx1oW5x2lHOFo6+JoQseYUIf1PC9otmH0JMIA7z0XEsQtOTbUOWP5V8Us6/75mEju0mdjoFUAeRAn6BP1TcB4Iaa+iOYbOT8UIttbjTSPg2uuIkxw7CQUcng= 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=none dis=none) Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1637353843266287.91184623956144; Fri, 19 Nov 2021 12:30:43 -0800 (PST) Received: from list by lists.xenproject.org with outflank-mailman.228260.394926 (Exim 4.92) (envelope-from ) id 1moAWN-0004Gb-PR; Fri, 19 Nov 2021 20:30:07 +0000 Received: by outflank-mailman (output) from mailman id 228260.394926; Fri, 19 Nov 2021 20:30:07 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1moAWN-0004GU-Lt; Fri, 19 Nov 2021 20:30:07 +0000 Received: by outflank-mailman (input) for mailman id 228260; Fri, 19 Nov 2021 20:30:05 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1moAWL-00044k-LK for xen-devel@lists.xenproject.org; Fri, 19 Nov 2021 20:30:05 +0000 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 76098ce3-4977-11ec-a9d2-d9f7a1cc8784; Fri, 19 Nov 2021 21:29:59 +0100 (CET) Received: by mail.kernel.org (Postfix) with ESMTPSA id 5D08761108; Fri, 19 Nov 2021 20:29:56 +0000 (UTC) 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: 76098ce3-4977-11ec-a9d2-d9f7a1cc8784 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637353796; bh=ToeTFTsoG8RQjmG78bJhuXqP6zSZHWT6qNk31D0MUoU=; h=From:To:Cc:Subject:Date:From; b=HY0Wc0K3QU2jjN81tsHd7ofj+cn8CV/0zrvORkAufQty7mgSC5HNLx5jH2utPuyqK h1AgZo9MEqDHOPlWQ4Fk0NHudI/ZO67jSVP+0ZeIFY+fvBCdSYLjWyRy/3B4J9/DkO XEldKjW38qyT8TNQiscbakt71vNHJxNaH4jXrGOtkyPEmStyMR0rWKSAUgLM4QwtyN LdaKPCNa4n2T77M0QvxBUu9/5/gk0tS2+tvGwNEQKWIQ7Y2XWFX59lkdTzkO2qJ8vL YbZzsrmxYctOuMNtFhv7qmdcxG/UIR7+AwJQMTL+7ixA1Lb1hDlG+lhL309Lm5rjfA ak/Iv7GH6QuSw== From: Stefano Stabellini To: jgross@suse.com Cc: boris.ostrovsky@oracle.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, sstabellini@kernel.org, jbeulich@suse.com, Stefano Stabellini , stable@vger.kernel.org Subject: [PATCH v2] xen: detect uninitialized xenbus in xenbus_init Date: Fri, 19 Nov 2021 12:29:51 -0800 Message-Id: <20211119202951.403525-1-sstabellini@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @kernel.org) X-ZM-MESSAGEID: 1637353844384100001 Content-Type: text/plain; charset="utf-8" From: Stefano Stabellini If the xenstore page hasn't been allocated properly, reading the value of the related hvm_param (HVM_PARAM_STORE_PFN) won't actually return error. Instead, it will succeed and return zero. Instead of attempting to xen_remap a bad guest physical address, detect this condition and return early. Note that although a guest physical address of zero for HVM_PARAM_STORE_PFN is theoretically possible, it is not a good choice and zero has never been validly used in that capacity. Also recognize the invalid value of INVALID_PFN which is ULLONG_MAX. For 32-bit Linux, any pfn above ULONG_MAX would get truncated. Pfns above ULONG_MAX should never be passed by the Xen tools to HVM guests anyway, so check for this condition and return early. Cc: stable@vger.kernel.org Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky --- Changes in v2: - add check for ULLONG_MAX (unitialized) - add check for ULONG_MAX #if BITS_PER_LONG =3D=3D 32 (actual error) - add pr_err error message drivers/xen/xenbus/xenbus_probe.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_= probe.c index 94405bb3829e..c7472ff27a93 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -951,6 +951,20 @@ static int __init xenbus_init(void) err =3D hvm_get_parameter(HVM_PARAM_STORE_PFN, &v); if (err) goto out_error; + /* Uninitialized. */ + if (v =3D=3D 0 || v =3D=3D ULLONG_MAX) { + err =3D -ENOENT; + goto out_error; + } + /* Avoid truncation on 32-bit. */ +#if BITS_PER_LONG =3D=3D 32 + if (v > ULONG_MAX) { + pr_err("%s: cannot handle HVM_PARAM_STORE_PFN=3D%llx > ULONG_MAX\n", + __func__, v); + err =3D -EINVAL; + goto out_error; + } +#endif xen_store_gfn =3D (unsigned long)v; xen_store_interface =3D xen_remap(xen_store_gfn << XEN_PAGE_SHIFT, --=20 2.25.1