From patchwork Fri Jun 5 11:27:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 11589491 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9FD9E90 for ; Fri, 5 Jun 2020 11:28:15 +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 768FD2053B for ; Fri, 5 Jun 2020 11:28:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UlM8lffs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 768FD2053B 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:59554 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jhAWE-0003xE-Nv for patchwork-qemu-devel@patchwork.kernel.org; Fri, 05 Jun 2020 07:28:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52608) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jhAVf-0002YM-JX for qemu-devel@nongnu.org; Fri, 05 Jun 2020 07:27:39 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:25940 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jhAVe-00031Z-D6 for qemu-devel@nongnu.org; Fri, 05 Jun 2020 07:27:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591356457; h=from:from:reply-to:subject:subject: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=QWTx3Iur+g/wLWbDzYDLshZvaZWBO0zM7EOG0uIUw90=; b=UlM8lffs+57/nu7fZLFl0iObEr2rreXJRy6K9jpYg7TdOBKmmcsJivfuoH763gZrxxjOSB v9lb6nl/gFNzjh7Oi1UXQnNDSnlLF7e5+AElAjHgNoNICTcrGQ1JI4UwKXaBTRtvBaCQ3b ii++xJH+Ifp+F5JWdAmT4aMlvZS9NTk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-101-sSjkiy1TPpy4WkZiG_9TPw-1; Fri, 05 Jun 2020 07:27:35 -0400 X-MC-Unique: sSjkiy1TPpy4WkZiG_9TPw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3E05B18A8223; Fri, 5 Jun 2020 11:27:34 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-113-50.ams2.redhat.com [10.36.113.50]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0CAE760BE2; Fri, 5 Jun 2020 11:27:31 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id ED4721750A; Fri, 5 Jun 2020 13:27:24 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Subject: [PULL 1/2] ati-vga: check mm_index before recursive call (CVE-2020-13800) Date: Fri, 5 Jun 2020 13:27:23 +0200 Message-Id: <20200605112724.18622-2-kraxel@redhat.com> In-Reply-To: <20200605112724.18622-1-kraxel@redhat.com> References: <20200605112724.18622-1-kraxel@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/05 03:40:54 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: Gerd Hoffmann , Prasad J Pandit Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Prasad J Pandit While accessing VGA registers via ati_mm_read/write routines, a guest may set 's->regs.mm_index' such that it leads to infinite recursion. Check mm_index value to avoid such recursion. Log an error message for wrong values. Reported-by: Ren Ding Reported-by: Hanqing Zhao Reported-by: Yi Ren Message-id: 20200604090830.33885-1-ppandit@redhat.com Suggested-by: BALATON Zoltan Suggested-by: Philippe Mathieu-Daudé Signed-off-by: Prasad J Pandit Signed-off-by: Gerd Hoffmann --- hw/display/ati.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/hw/display/ati.c b/hw/display/ati.c index 065f197678e4..67604e68deb1 100644 --- a/hw/display/ati.c +++ b/hw/display/ati.c @@ -285,8 +285,11 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr, unsigned int size) if (idx <= s->vga.vram_size - size) { val = ldn_le_p(s->vga.vram_ptr + idx, size); } - } else { + } else if (s->regs.mm_index > MM_DATA + 3) { val = ati_mm_read(s, s->regs.mm_index + addr - MM_DATA, size); + } else { + qemu_log_mask(LOG_GUEST_ERROR, + "ati_mm_read: mm_index too small: %u\n", s->regs.mm_index); } break; case BIOS_0_SCRATCH ... BUS_CNTL - 1: @@ -520,8 +523,11 @@ static void ati_mm_write(void *opaque, hwaddr addr, if (idx <= s->vga.vram_size - size) { stn_le_p(s->vga.vram_ptr + idx, size, data); } - } else { + } else if (s->regs.mm_index > MM_DATA + 3) { ati_mm_write(s, s->regs.mm_index + addr - MM_DATA, data, size); + } else { + qemu_log_mask(LOG_GUEST_ERROR, + "ati_mm_write: mm_index too small: %u\n", s->regs.mm_index); } break; case BIOS_0_SCRATCH ... BUS_CNTL - 1: