From patchwork Mon Jan 27 20:24:51 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 13952189 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id B60DDC0218D for ; Tue, 28 Jan 2025 08:14:13 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tcgXV-0001w0-D5; Tue, 28 Jan 2025 03:01:42 -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 1tcgX5-0000mD-Cp; Tue, 28 Jan 2025 03:01:19 -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 1tcgX3-0001pL-JJ; Tue, 28 Jan 2025 03:01:14 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 90F1FE1B4C; Tue, 28 Jan 2025 10:57:08 +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 0CB511A62FF; Tue, 28 Jan 2025 10:57:34 +0300 (MSK) Received: by localhost.tls.msk.ru (Postfix, from userid 1000) id E508D5208F; Tue, 28 Jan 2025 10:57:33 +0300 (MSK) To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Akihiko Odaki , Jason Wang , Michael Tokarev Subject: [Stable-9.1.3 05/58] virtio-net: Fix size check in dhclient workaround Date: Mon, 27 Jan 2025 23:24:51 +0300 Message-Id: <20250127202547.3723716-5-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.5 In-Reply-To: References: MIME-Version: 1.0 From: Michael Tokarev 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org 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 ed33a32877..cf27d5cbe5 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1692,8 +1692,11 @@ 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 = 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 >= csum_size && size < 1500) && /* normal sized MTU */ (buf[12] == 0x08 && buf[13] == 0x00) && /* ethertype == IPv4 */ (buf[23] == 17) && /* ip.protocol == UDP */ (buf[34] == 0 && buf[35] == 67)) { /* udp.srcport == bootps */