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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 7795BC352AA for ; Tue, 1 Oct 2019 10:54:37 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4BC912133F for ; Tue, 1 Oct 2019 10:54:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4BC912133F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40328 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iFFng-0006fm-9K for qemu-devel@archiver.kernel.org; Tue, 01 Oct 2019 06:54:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51951) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iFFkT-0003bG-NP for qemu-devel@nongnu.org; Tue, 01 Oct 2019 06:51:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iFFkO-0007RS-5b for qemu-devel@nongnu.org; Tue, 01 Oct 2019 06:51:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47096) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iFFkM-0007OI-5w for qemu-devel@nongnu.org; Tue, 01 Oct 2019 06:51:11 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 20E3E10CC201; Tue, 1 Oct 2019 10:51:07 +0000 (UTC) Received: from thuth.com (ovpn-116-70.ams2.redhat.com [10.36.116.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3C56D26199; Tue, 1 Oct 2019 10:51:06 +0000 (UTC) From: Thomas Huth To: Peter Maydell Subject: [PULL 4/5] hw/core/loader: Fix possible crash in rom_copy() Date: Tue, 1 Oct 2019 12:50:56 +0200 Message-Id: <20191001105057.3949-5-thuth@redhat.com> In-Reply-To: <20191001105057.3949-1-thuth@redhat.com> References: <20191001105057.3949-1-thuth@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.65]); Tue, 01 Oct 2019 10:51:07 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Both, "rom->addr" and "addr" are derived from the binary image that can be loaded with the "-kernel" paramer. The code in rom_copy() then calculates: d = dest + (rom->addr - addr); and uses "d" as destination in a memcpy() some lines later. Now with bad kernel images, it is possible that rom->addr is smaller than addr, thus "rom->addr - addr" gets negative and the memcpy() then tries to copy contents from the image to a bad memory location. This could maybe be used to inject code from a kernel image into the QEMU binary, so we better fix it with an additional sanity check here. Cc: qemu-stable@nongnu.org Reported-by: Guangming Liu Buglink: https://bugs.launchpad.net/qemu/+bug/1844635 Message-Id: <20190925130331.27825-1-thuth@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Thomas Huth --- hw/core/loader.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/core/loader.c b/hw/core/loader.c index 0d60219364..5099f27dc8 100644 --- a/hw/core/loader.c +++ b/hw/core/loader.c @@ -1281,7 +1281,7 @@ int rom_copy(uint8_t *dest, hwaddr addr, size_t size) if (rom->addr + rom->romsize < addr) { continue; } - if (rom->addr > end) { + if (rom->addr > end || rom->addr < addr) { break; } -- 2.18.1