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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF910C2D0DB for ; Thu, 30 Jan 2020 18:39:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C31D20CC7 for ; Thu, 30 Jan 2020 18:39:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580409598; bh=3OppFeTIC5EGVmWme2JxnhZ9O/cxokC45JreOYg3EiA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=If4GQbcjOeABec8bOXezsxLkqIpQ0rPVgXenqRoyBUwf6OpIXH4FtVSF+ThYZz07B DTXMndHwKvz7c7EB1QSW9qFYJUAax8gttwq33oAWjUFuiyF/j381dOidCZukrlu0In w/TbU8R4srxfWCQDkZamBodN07K1X8J2y4ZyEkFc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727974AbgA3Sj6 (ORCPT ); Thu, 30 Jan 2020 13:39:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:47244 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727928AbgA3Sjw (ORCPT ); Thu, 30 Jan 2020 13:39:52 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 96E1A2083E; Thu, 30 Jan 2020 18:39:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580409592; bh=3OppFeTIC5EGVmWme2JxnhZ9O/cxokC45JreOYg3EiA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gj+8l0urHI1d2IzT5NZpU3iJhF1bG1UfNTXgQsJ2vECMjzmu7LO1IkQLdTLVA1RKa i2A7gWczLCrNwyjOPOUbP8C5+j6ustWXnIYycDdKeVWv9P0i4tIg4+QtwgOCnm74WX mScmiHm8zhOEXb06WYL7ZTWdErh/dstzn1SKMLjU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Shvetsov Subject: [PATCH 5.5 12/56] staging: most: net: fix buffer overflow Date: Thu, 30 Jan 2020 19:38:29 +0100 Message-Id: <20200130183611.429347579@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200130183608.849023566@linuxfoundation.org> References: <20200130183608.849023566@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrey Shvetsov commit 4d1356ac12f4d5180d0df345d85ff0ee42b89c72 upstream. If the length of the socket buffer is 0xFFFFFFFF (max size for an unsigned int), then payload_len becomes 0xFFFFFFF1 after subtracting 14 (ETH_HLEN). Then, mdp_len is set to payload_len + 16 (MDP_HDR_LEN) which overflows and results in a value of 2. These values for payload_len and mdp_len will pass current buffer size checks. This patch checks if derived from skb->len sum may overflow. The check is based on the following idea: For any `unsigned V1, V2` and derived `unsigned SUM = V1 + V2`, `V1 + V2` overflows iif `SUM < V1`. Reported-by: Greg Kroah-Hartman Signed-off-by: Andrey Shvetsov Cc: stable Link: https://lore.kernel.org/r/20200116172238.6046-1-andrey.shvetsov@microchip.com Signed-off-by: Greg Kroah-Hartman --- drivers/staging/most/net/net.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/drivers/staging/most/net/net.c +++ b/drivers/staging/most/net/net.c @@ -81,6 +81,11 @@ static int skb_to_mamac(const struct sk_ unsigned int payload_len = skb->len - ETH_HLEN; unsigned int mdp_len = payload_len + MDP_HDR_LEN; + if (mdp_len < skb->len) { + pr_err("drop: too large packet! (%u)\n", skb->len); + return -EINVAL; + } + if (mbo->buffer_length < mdp_len) { pr_err("drop: too small buffer! (%d for %d)\n", mbo->buffer_length, mdp_len); @@ -128,6 +133,11 @@ static int skb_to_mep(const struct sk_bu u8 *buff = mbo->virt_address; unsigned int mep_len = skb->len + MEP_HDR_LEN; + if (mep_len < skb->len) { + pr_err("drop: too large packet! (%u)\n", skb->len); + return -EINVAL; + } + if (mbo->buffer_length < mep_len) { pr_err("drop: too small buffer! (%d for %d)\n", mbo->buffer_length, mep_len);