From patchwork Wed Oct 2 21:27:20 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dan Carpenter X-Patchwork-Id: 280185 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 92F702C00A6 for ; Thu, 3 Oct 2013 07:27:34 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754164Ab3JBV1b (ORCPT ); Wed, 2 Oct 2013 17:27:31 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:33775 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753602Ab3JBV1a (ORCPT ); Wed, 2 Oct 2013 17:27:30 -0400 Received: from ucsinet21.oracle.com (ucsinet21.oracle.com [156.151.31.93]) by userp1040.oracle.com (Sentrion-MTA-4.3.1/Sentrion-MTA-4.3.1) with ESMTP id r92LRQu5028891 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 2 Oct 2013 21:27:27 GMT Received: from aserz7021.oracle.com (aserz7021.oracle.com [141.146.126.230]) by ucsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id r92LRPYI006469 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 2 Oct 2013 21:27:26 GMT Received: from abhmt108.oracle.com (abhmt108.oracle.com [141.146.116.60]) by aserz7021.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id r92LRPtm007327; Wed, 2 Oct 2013 21:27:25 GMT Received: from elgon.mountain (/41.202.233.186) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 02 Oct 2013 14:27:24 -0700 Date: Thu, 3 Oct 2013 00:27:20 +0300 From: Dan Carpenter To: "David S. Miller" Cc: netdev@vger.kernel.org, security@kernel.org, =?iso-8859-1?Q?J=FCri?= Aedla Subject: [patch v2] net: heap overflow in __audit_sockaddr() Message-ID: <20131002212720.GA30492@elgon.mountain> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1380748306.1795.67.camel@bwh-desktop.uk.level5networks.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We need to cap ->msg_namelen or it leads to a buffer overflow when we to the memcpy() in __audit_sockaddr(). It requires CAP_AUDIT_CONTROL to exploit this bug. The call tree is: ___sys_recvmsg() move_addr_to_user() audit_sockaddr() __audit_sockaddr() Reported-by: Jüri Aedla Signed-off-by: Dan Carpenter --- v2: The limit check to the compat code was missing as pointed out by Ben Hutchings. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/net/socket.c b/net/socket.c index ebed4b6..c226ace 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1964,6 +1964,16 @@ struct used_address { unsigned int name_len; }; +static int copy_msghdr_from_user(struct msghdr *kmsg, + struct msghdr __user *umsg) +{ + if (copy_from_user(kmsg, umsg, sizeof(struct msghdr))) + return -EFAULT; + if (kmsg->msg_namelen > sizeof(struct sockaddr_storage)) + return -EINVAL; + return 0; +} + static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg, struct msghdr *msg_sys, unsigned int flags, struct used_address *used_address) @@ -1982,8 +1992,11 @@ static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg, if (MSG_CMSG_COMPAT & flags) { if (get_compat_msghdr(msg_sys, msg_compat)) return -EFAULT; - } else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr))) - return -EFAULT; + } else { + err = copy_msghdr_from_user(msg_sys, msg); + if (err) + return err; + } if (msg_sys->msg_iovlen > UIO_FASTIOV) { err = -EMSGSIZE; @@ -2191,8 +2204,11 @@ static int ___sys_recvmsg(struct socket *sock, struct msghdr __user *msg, if (MSG_CMSG_COMPAT & flags) { if (get_compat_msghdr(msg_sys, msg_compat)) return -EFAULT; - } else if (copy_from_user(msg_sys, msg, sizeof(struct msghdr))) - return -EFAULT; + } else { + err = copy_msghdr_from_user(msg_sys, msg); + if (err) + return err; + } if (msg_sys->msg_iovlen > UIO_FASTIOV) { err = -EMSGSIZE; diff --git a/net/compat.c b/net/compat.c index f0a1ba6..8903258 100644 --- a/net/compat.c +++ b/net/compat.c @@ -71,6 +71,8 @@ int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg) __get_user(kmsg->msg_controllen, &umsg->msg_controllen) || __get_user(kmsg->msg_flags, &umsg->msg_flags)) return -EFAULT; + if (kmsg->msg_namelen > sizeof(struct sockaddr_storage)) + return -EINVAL; kmsg->msg_name = compat_ptr(tmp1); kmsg->msg_iov = compat_ptr(tmp2); kmsg->msg_control = compat_ptr(tmp3);