From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756977Ab3KYOCd (ORCPT ); Mon, 25 Nov 2013 09:02:33 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:58968 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754020Ab3KYNxu (ORCPT ); Mon, 25 Nov 2013 08:53:50 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David S. Miller" , "Dan Carpenter" , "=?UTF-8?Q?J=C3=BCri=20?=Aedla" Date: Mon, 25 Nov 2013 13:44:29 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 04/87] net: heap overflow in __audit_sockaddr() In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.212 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.53-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter [ Upstream commit 1661bf364ae9c506bc8795fef70d1532931be1e8 ] 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 Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/compat.c | 2 ++ net/socket.c | 24 ++++++++++++++++++++---- 2 files changed, 22 insertions(+), 4 deletions(-) diff --git a/net/compat.c b/net/compat.c index 8c979cc..3139ef2 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); diff --git a/net/socket.c b/net/socket.c index cf546a3..bf7adaa 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1876,6 +1876,16 @@ 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 flags, struct used_address *used_address) @@ -1894,8 +1904,11 @@ 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; + } /* do not move before msg_sys is valid */ err = -EMSGSIZE; @@ -2110,8 +2123,11 @@ 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; + } err = -EMSGSIZE; if (msg_sys->msg_iovlen > UIO_MAXIOV)