From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 2C5F1C2BB55 for ; Thu, 16 Apr 2020 14:11:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F25BF206D6 for ; Thu, 16 Apr 2020 14:11:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587046302; bh=YT2uPu+CvbKPtXH7NT0G3Z7bnBFybUw4cBTirjFdyIA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=W3JjDb6uHRaY5DNFGPV+waHmxsdjpPI42cZyJu/mZnD+Tn3MNNFeCAcXVuNlLKSjK wprHcOiy/fTzfmO03/Pe5F2qqWNvIzrz2cRHJGAFNBoPY1JQkueQcbdfmHvISBgzWz ukxUJYeuPYD4Gisvpy+KBAZAJBM2cUn5yJuRQMhM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393716AbgDPOLk (ORCPT ); Thu, 16 Apr 2020 10:11:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:33614 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2898685AbgDPNrd (ORCPT ); Thu, 16 Apr 2020 09:47:33 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7AA45208E4; Thu, 16 Apr 2020 13:47:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044852; bh=YT2uPu+CvbKPtXH7NT0G3Z7bnBFybUw4cBTirjFdyIA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0GkmhrybmWNBXjbeB+uVkEpcSZsoqllQYl4BIzaeCewp55/g4L8CiwNn67227o7ER nc96ua3Nivd6QdngvEoc8TGZV1AM3UxEgma63bQXVdcsXrDzgbzMB/TVlvn8n8NuiL gLlkZCuRrEpGQJmi+RtiCFBXRnAXLIJnjX7SGgMk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Janosch Frank , David Hildenbrand , Claudio Imbrenda , Christian Borntraeger Subject: [PATCH 5.4 126/232] KVM: s390: vsie: Fix region 1 ASCE sanity shadow address checks Date: Thu, 16 Apr 2020 15:23:40 +0200 Message-Id: <20200416131330.817189531@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200416131316.640996080@linuxfoundation.org> References: <20200416131316.640996080@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Hildenbrand commit a1d032a49522cb5368e5dfb945a85899b4c74f65 upstream. In case we have a region 1 the following calculation (31 + ((gmap->asce & _ASCE_TYPE_MASK) >> 2)*11) results in 64. As shifts beyond the size are undefined the compiler is free to use instructions like sllg. sllg will only use 6 bits of the shift value (here 64) resulting in no shift at all. That means that ALL addresses will be rejected. The can result in endless loops, e.g. when prefix cannot get mapped. Fixes: 4be130a08420 ("s390/mm: add shadow gmap support") Tested-by: Janosch Frank Reported-by: Janosch Frank Cc: # v4.8+ Signed-off-by: David Hildenbrand Link: https://lore.kernel.org/r/20200403153050.20569-2-david@redhat.com Reviewed-by: Claudio Imbrenda Reviewed-by: Christian Borntraeger [borntraeger@de.ibm.com: fix patch description, remove WARN_ON_ONCE] Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman --- arch/s390/mm/gmap.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -787,14 +787,18 @@ static void gmap_call_notifier(struct gm static inline unsigned long *gmap_table_walk(struct gmap *gmap, unsigned long gaddr, int level) { + const int asce_type = gmap->asce & _ASCE_TYPE_MASK; unsigned long *table; if ((gmap->asce & _ASCE_TYPE_MASK) + 4 < (level * 4)) return NULL; if (gmap_is_shadow(gmap) && gmap->removed) return NULL; - if (gaddr & (-1UL << (31 + ((gmap->asce & _ASCE_TYPE_MASK) >> 2)*11))) + + if (asce_type != _ASCE_TYPE_REGION1 && + gaddr & (-1UL << (31 + (asce_type >> 2) * 11))) return NULL; + table = gmap->table; switch (gmap->asce & _ASCE_TYPE_MASK) { case _ASCE_TYPE_REGION1: