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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDDD1C433FE for ; Wed, 23 Feb 2022 02:30:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230453AbiBWCas (ORCPT ); Tue, 22 Feb 2022 21:30:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237105AbiBWCaT (ORCPT ); Tue, 22 Feb 2022 21:30:19 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE7F256C3C; Tue, 22 Feb 2022 18:29:28 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 55CD1B81E1D; Wed, 23 Feb 2022 02:29:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0BB9C340F9; Wed, 23 Feb 2022 02:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645583365; bh=HFHNgNb2sk/EDRKrFsACtTis3QDI7ANP8TMbbBEU5EU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=syccDILwiWvGj8wtn1maN7VU0lHxFaJpT4BZ6Xo6G5eUcY3ZSQ5VgJIo8+yYr53E7 sclSfBe0gQSmeE8J/n6jXBZBXPjcOMgTbHXcYeqQUS1EAmxGH5mhn06GBkXeP2aoQN fSZhpg/v/paxv+9Ivae9LT61l4GH6ce7Xa5wx0zdqbYT3tUd33twuRl7KlfS0IwaZe 5+vvTJB46lyiYZAupbx4g5U16vD1En2/7EAjUnmHaimjA2HKEmx8KiD/Lhlm5L4+k8 aY9Ot95FGEeW0oYYlm2sve1Hewl0AgXcHv+Lfk3nETNYGp72tlQohgyNWOEpWG31D+ WTFxAsiIyRbAw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Oliver Neukum , Greg Kroah-Hartman , "David S . Miller" , Sasha Levin , oliver@neukum.org, kuba@kernel.org, linux-usb@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.16 28/30] CDC-NCM: avoid overflow in sanity checking Date: Tue, 22 Feb 2022 21:28:17 -0500 Message-Id: <20220223022820.240649-28-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220223022820.240649-1-sashal@kernel.org> References: <20220223022820.240649-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oliver Neukum [ Upstream commit 8d2b1a1ec9f559d30b724877da4ce592edc41fdc ] A broken device may give an extreme offset like 0xFFF0 and a reasonable length for a fragment. In the sanity check as formulated now, this will create an integer overflow, defeating the sanity check. Both offset and offset + len need to be checked in such a manner that no overflow can occur. And those quantities should be unsigned. Signed-off-by: Oliver Neukum Reviewed-by: Greg Kroah-Hartman Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/usb/cdc_ncm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index e303b522efb50..15f91d691bba3 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -1715,10 +1715,10 @@ int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in) { struct sk_buff *skb; struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0]; - int len; + unsigned int len; int nframes; int x; - int offset; + unsigned int offset; union { struct usb_cdc_ncm_ndp16 *ndp16; struct usb_cdc_ncm_ndp32 *ndp32; @@ -1790,8 +1790,8 @@ int cdc_ncm_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in) break; } - /* sanity checking */ - if (((offset + len) > skb_in->len) || + /* sanity checking - watch out for integer wrap*/ + if ((offset > skb_in->len) || (len > skb_in->len - offset) || (len > ctx->rx_max) || (len < ETH_HLEN)) { netif_dbg(dev, rx_err, dev->net, "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n", -- 2.34.1