From patchwork Thu Nov 5 10:56:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Matteo Cascella X-Patchwork-Id: 11883941 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 0CF716A2 for ; Thu, 5 Nov 2020 10:57:26 +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 5060920729 for ; Thu, 5 Nov 2020 10:57:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WjJnLokI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5060920729 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]:52932 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kacxI-0005k4-2w for patchwork-qemu-devel@patchwork.kernel.org; Thu, 05 Nov 2020 05:57:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:56352) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kacws-0005JP-Eu for qemu-devel@nongnu.org; Thu, 05 Nov 2020 05:56:58 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:28198) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kacwq-0005g1-BT for qemu-devel@nongnu.org; Thu, 05 Nov 2020 05:56:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604573814; 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; bh=ZqIH+9Hw3cw0MS/CqZluoRm1gWD3ILVjGDMEQqYVTjI=; b=WjJnLokIsjwx75SwZNG+4syjg8+h05aR4k1vZFMPQIG6u/zWtssQwiskXrqxO1q+2pXn4g OEa9vlu9s/w91AcoD3otsyuasVG9u11IwxpChTsXzK0CyTg6tAqB7xdv3DAgJy+IAUPoOg uhzckTin0trnIdlAGRW4PCAQl+oW5N0= 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-74-8I531HTAPymnAZ5s7G0kBw-1; Thu, 05 Nov 2020 05:56:39 -0500 X-MC-Unique: 8I531HTAPymnAZ5s7G0kBw-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 A53D81006C92; Thu, 5 Nov 2020 10:56:37 +0000 (UTC) Received: from f32-work.redhat.com (unknown [10.40.194.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C4A326CE54; Thu, 5 Nov 2020 10:56:35 +0000 (UTC) From: Mauro Matteo Cascella To: qemu-devel@nongnu.org Subject: [PATCH] net/e1000e_core: make sure RDH never exceeds RDT in e1000e_ring_advance() Date: Thu, 5 Nov 2020 11:56:16 +0100 Message-Id: <20201105105616.327593-1-mcascell@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mcascell@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=63.128.21.124; envelope-from=mcascell@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/04 22:46:30 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: mcascell@redhat.com, dmitry.fleytman@gmail.com, gaoning.pgn@antgroup.com, jasowang@redhat.com, lersek@redhat.com, 330cjfdn@gmail.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" The e1000e_write_packet_to_guest() function iterates over a set of receive descriptors by advancing rx descriptor head register (RDH) from its initial value to rx descriptor tail register (RDT). The check in e1000e_ring_empty() is responsible for detecting whether RDH has reached RDT, terminating the loop if that's the case. Additional checks have been added in the past to deal with bogus values submitted by the guest to prevent possible infinite loop. This is done by "wrapping around" RDH at some point and detecting whether it assumes the original value during the loop. However, when e1000e is configured to use the packet split feature, RDH is incremented by two instead of one, as the packet split descriptors are 32 bytes while regular descriptors are 16 bytes. A malicious or buggy guest may set RDT to an odd value and transmit only null RX descriptors. This corner case would prevent RDH from ever matching RDT, leading to an infinite loop. This patch adds a check in e1000e_ring_advance() to make sure RDH does never exceed RDT. This issue was independently reported by Gaoning Pan (Zhejiang University) and Cheolwoo Myung. Signed-off-by: Mauro Matteo Cascella Reported-by: Gaoning Pan Reported-by: Cheolwoo Myung <330cjfdn@gmail.com> Tested-by: Mauro Matteo Cascella --- References: https://git.qemu.org/?p=qemu.git;a=commit;h=dd793a74882477ca38d49e191110c17dfe https://git.qemu.org/?p=qemu.git;a=commit;h=4154c7e03fa55b4cf52509a83d50d6c09d743b7 http://www.intel.com/content/dam/doc/datasheet/82574l-gbe-controller-datasheet.pdf hw/net/e1000e_core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c index bcd186cac5..4c4d14b6ed 100644 --- a/hw/net/e1000e_core.c +++ b/hw/net/e1000e_core.c @@ -831,6 +831,10 @@ e1000e_ring_advance(E1000ECore *core, const E1000E_RingInfo *r, uint32_t count) { core->mac[r->dh] += count; + if (core->mac[r->dh] > core->mac[r->dt]) { + core->mac[r->dh] = core->mac[r->dt]; + } + if (core->mac[r->dh] * E1000_RING_DESC_LEN >= core->mac[r->dlen]) { core->mac[r->dh] = 0; }