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It is possible by passing a netlink socket to a more privileged executable and then to fool that executable into writing to the socket data that happens to be valid netlink message to do something that privileged executable did not intend to do. To keep this from happening replace bare capable and ns_capable calls with netlink_capable, netlink_net_calls and netlink_ns_capable calls. Which act the same as the previous calls except they verify that the opener of the socket had the desired permissions as well. Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
102 lines
3.3 KiB
C
102 lines
3.3 KiB
C
/*
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* net/tipc/netlink.c: TIPC configuration handling
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*
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* Copyright (c) 2005-2006, Ericsson AB
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* Copyright (c) 2005-2007, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "config.h"
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#include <net/genetlink.h>
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static int handle_cmd(struct sk_buff *skb, struct genl_info *info)
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{
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struct sk_buff *rep_buf;
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struct nlmsghdr *rep_nlh;
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struct nlmsghdr *req_nlh = info->nlhdr;
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struct tipc_genlmsghdr *req_userhdr = info->userhdr;
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int hdr_space = nlmsg_total_size(GENL_HDRLEN + TIPC_GENL_HDRLEN);
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u16 cmd;
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if ((req_userhdr->cmd & 0xC000) && (!netlink_capable(skb, CAP_NET_ADMIN)))
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cmd = TIPC_CMD_NOT_NET_ADMIN;
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else
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cmd = req_userhdr->cmd;
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rep_buf = tipc_cfg_do_cmd(req_userhdr->dest, cmd,
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nlmsg_data(req_nlh) + GENL_HDRLEN + TIPC_GENL_HDRLEN,
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nlmsg_attrlen(req_nlh, GENL_HDRLEN + TIPC_GENL_HDRLEN),
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hdr_space);
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if (rep_buf) {
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skb_push(rep_buf, hdr_space);
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rep_nlh = nlmsg_hdr(rep_buf);
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memcpy(rep_nlh, req_nlh, hdr_space);
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rep_nlh->nlmsg_len = rep_buf->len;
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genlmsg_unicast(&init_net, rep_buf, NETLINK_CB(skb).portid);
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}
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return 0;
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}
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static struct genl_family tipc_genl_family = {
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.id = GENL_ID_GENERATE,
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.name = TIPC_GENL_NAME,
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.version = TIPC_GENL_VERSION,
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.hdrsize = TIPC_GENL_HDRLEN,
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.maxattr = 0,
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};
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static struct genl_ops tipc_genl_ops[] = {
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{
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.cmd = TIPC_GENL_CMD,
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.doit = handle_cmd,
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},
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};
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int tipc_netlink_start(void)
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{
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int res;
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res = genl_register_family_with_ops(&tipc_genl_family, tipc_genl_ops);
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if (res) {
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pr_err("Failed to register netlink interface\n");
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return res;
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}
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return 0;
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}
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void tipc_netlink_stop(void)
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{
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genl_unregister_family(&tipc_genl_family);
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}
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