From nobody Sat Apr 5 15:44:02 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1738051187041855.46113183533; Mon, 27 Jan 2025 23:59:47 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tcgPg-0000xg-57; Tue, 28 Jan 2025 02:53:36 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tcgPc-0000vJ-K2; Tue, 28 Jan 2025 02:53:32 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tcgPb-0007nM-1U; Tue, 28 Jan 2025 02:53:32 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id AAD42E1ABE; Tue, 28 Jan 2025 10:52:59 +0300 (MSK) Received: from localhost.tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with ESMTP id 259E81A62AD; Tue, 28 Jan 2025 10:53:25 +0300 (MSK) Received: by localhost.tls.msk.ru (Postfix, from userid 1000) id 15E1D51FF1; Tue, 28 Jan 2025 10:53:25 +0300 (MSK) To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Akihiko Odaki , Jason Wang , Michael Tokarev Subject: [Stable-7.2.16 05/31] virtio-net: Fix size check in dhclient workaround Date: Tue, 28 Jan 2025 00:40:57 +0300 Message-Id: <20250127214124.3730126-5-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.5 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable From: Michael Tokarev Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -53 X-Spam_score: -5.4 X-Spam_bar: ----- X-Spam_report: (-5.4 / 5.0 requ) BAYES_00=-1.9, DATE_IN_PAST_06_12=1.543, RCVD_IN_DNSWL_HI=-5, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1738051189608019000 Content-Type: text/plain; charset="utf-8" work_around_broken_dhclient() accesses IP and UDP headers to detect relevant packets and to calculate checksums, but it didn't check if the packet has size sufficient to accommodate them, causing out-of-bound access hazards. Fix this by correcting the size requirement. Fixes: 1d41b0c1ec66 ("Work around dhclient brokenness") Cc: qemu-stable@nongnu.org Signed-off-by: Akihiko Odaki Signed-off-by: Jason Wang (cherry picked from commit a8575f7fb2f213e6690b23160b04271d47fdfaa8) Signed-off-by: Michael Tokarev diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 925a5c319e..204a80ec71 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1647,8 +1647,11 @@ static void virtio_net_hdr_swap(VirtIODevice *vdev, = struct virtio_net_hdr *hdr) static void work_around_broken_dhclient(struct virtio_net_hdr *hdr, uint8_t *buf, size_t size) { + size_t csum_size =3D ETH_HLEN + sizeof(struct ip_header) + + sizeof(struct udp_header); + if ((hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && /* missing csum */ - (size > 27 && size < 1500) && /* normal sized MTU */ + (size >=3D csum_size && size < 1500) && /* normal sized MTU */ (buf[12] =3D=3D 0x08 && buf[13] =3D=3D 0x00) && /* ethertype =3D= =3D IPv4 */ (buf[23] =3D=3D 17) && /* ip.protocol =3D=3D UDP */ (buf[34] =3D=3D 0 && buf[35] =3D=3D 67)) { /* udp.srcport =3D=3D b= ootps */ --=20 2.39.5