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 177C9C433F5 for ; Wed, 23 Feb 2022 02:36:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237504AbiBWCg1 (ORCPT ); Tue, 22 Feb 2022 21:36:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237569AbiBWCdO (ORCPT ); Tue, 22 Feb 2022 21:33:14 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE39A5E164; Tue, 22 Feb 2022 18:31:18 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 4DF6261581; Wed, 23 Feb 2022 02:31:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A58DAC36AE3; Wed, 23 Feb 2022 02:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645583475; bh=ETgDXuiQzFhaFNdJSbiMHIBC9RzGUFsPHvvMRY++lxw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A/VSV66QN+XPOq+12ou+UM7N+w+zxtlB1Lfb5YW+8Hhm3kHNlUrzlZMvz9Z6h1bqD 1wEQhlMqQr5Vaid4bVawe6DXi8zjwcijLwQ+VrU4gW3z2C2/4bXv2cqAVcwNbA989u fcXFaWG+ueg4/Fv7U+fs/gM/mmDkb9LfbI+R0Cb1ymbiaV52zpotiy4YkiSBGz5AuB nGxwg9/wW/Ni4Kq0UKVzM2FT0uOxsrMgTXdVLGGBEloCSPjPsA9BS+CrTN4wuJ+Usu 480lkv6UBHRE2/Dy04dgXqpWPLu2GysycYOxGQn0PVwQ39iyvNadYtGuJtH5ZS/5dw b+MIcmD96iGXQ== 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 5.10 17/18] CDC-NCM: avoid overflow in sanity checking Date: Tue, 22 Feb 2022 21:30:34 -0500 Message-Id: <20220223023035.241551-17-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220223023035.241551-1-sashal@kernel.org> References: <20220223023035.241551-1-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 eaaa5aee58251..ab91fa5b0194d 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -1702,10 +1702,10 @@ 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; @@ -1777,8 +1777,8 @@ 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