From patchwork Mon Nov 30 10:04:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dan Carpenter X-Patchwork-Id: 11940069 X-Patchwork-Delegate: kuba@kernel.org 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=-18.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 CE828C71156 for ; Mon, 30 Nov 2020 10:06:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F94720855 for ; Mon, 30 Nov 2020 10:06:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="v3Cb2GUa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728798AbgK3KGl (ORCPT ); Mon, 30 Nov 2020 05:06:41 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:37450 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726579AbgK3KGl (ORCPT ); Mon, 30 Nov 2020 05:06:41 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0AU9xBhm078632; Mon, 30 Nov 2020 10:04:42 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type : content-transfer-encoding : in-reply-to; s=corp-2020-01-29; bh=89d0xM4SUH4a0fX74f4jEtNnPihawrq2u89AGEQ/K1I=; b=v3Cb2GUa5tO1ck9uZJVgTSfz+Rqgf8BbP8CWZySuiRS1/MNhwFWwNMtwQlb6BS0HJNpX ZojXTgzG2Fvtwb7uvXkg9ITVM0TglIFIXygOBQ1NyY1YoVigALg05yrXDCMyvbfG0wAG jOqphwIZGcajIQ39bHzyLoIvcq8boyKIl3UUA/ouDVTu0y7192w5r74TANPHlVZnQ3AL ET1ROYKM8FjYAvM9Kg2RmmZlLLYXmibim+fYLMlBx33AVDAJ91GP4Q0XdXRqqn0pyWzA Cx5stsAD6qWNtAKI/54XICGwfGBrlFS817x6+GJnGSdhnNyJoM2SyqMh+rWv2pvCu3Q5 VA== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 353dyqc9sh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 30 Nov 2020 10:04:42 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0AUA1GcJ076901; Mon, 30 Nov 2020 10:04:42 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 3540fuucxc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 30 Nov 2020 10:04:42 +0000 Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0AUA4b0q001002; Mon, 30 Nov 2020 10:04:37 GMT Received: from kadam (/102.36.221.92) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 30 Nov 2020 02:04:36 -0800 Date: Mon, 30 Nov 2020 13:04:25 +0300 From: Dan Carpenter To: Andrew Hendry , =?utf-8?b?a2l5aW4o5bC55LquKQ==?= , Martin Schiller Cc: "security@kernel.org" , "linux-distros@vs.openwall.org" , =?utf-8?b?aHVudGNoZW4o6ZmI6ZizKQ==?= , =?utf-8?b?ZGFu?= =?utf-8?b?bnl3YW5nKOeOi+Wuhyk=?= , "David S. Miller" , Jakub Kicinski , linux-x25@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH net] net/x25: prevent a couple of overflows Message-ID: <20201130100425.GB2789@kadam> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <61d3e7e75f704996bf312ef5d271bcea@tencent.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9820 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 suspectscore=0 phishscore=0 mlxlogscore=999 adultscore=0 mlxscore=0 bulkscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011300063 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9820 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 bulkscore=0 clxscore=1011 mlxscore=0 spamscore=0 priorityscore=1501 mlxlogscore=999 suspectscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011300063 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: "kiyin(尹亮)" The .x25_addr[] address comes from the user and is not necessarily NUL terminated. This leads to a couple problems. The first problem is that the strlen() in x25_bind() can read beyond the end of the buffer. The second problem is more subtle and could result in memory corruption. The call tree is: x25_connect() --> x25_write_internal() --> x25_addr_aton() The .x25_addr[] buffers are copied to the "addresses" buffer from x25_write_internal() so it will lead to stack corruption. The x25 protocol only allows 15 character addresses so putting a NUL terminator as the 16th character is safe and obviously preferable to reading out of bounds. Signed-off-by: "kiyin(尹亮)" Signed-off-by: Dan Carpenter --- net/x25/af_x25.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index 0bbb283f23c9..3180f15942fe 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -686,6 +686,8 @@ static int x25_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) goto out; } + addr->sx25_addr.x25_addr[X25_ADDR_LEN - 1] = '\0'; + /* check for the null_x25_address */ if (strcmp(addr->sx25_addr.x25_addr, null_x25_address.x25_addr)) { @@ -779,6 +781,7 @@ static int x25_connect(struct socket *sock, struct sockaddr *uaddr, goto out; rc = -ENETUNREACH; + addr->sx25_addr.x25_addr[X25_ADDR_LEN - 1] = '\0'; rt = x25_get_route(&addr->sx25_addr); if (!rt) goto out;