90f62cf30a
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>
159 lines
3.5 KiB
C
159 lines
3.5 KiB
C
/*
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* scsi_netlink.c - SCSI Transport Netlink Interface
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*
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* Copyright (C) 2006 James Smart, Emulex Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/time.h>
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#include <linux/jiffies.h>
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#include <linux/security.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <net/sock.h>
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#include <net/netlink.h>
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#include <scsi/scsi_netlink.h>
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#include "scsi_priv.h"
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struct sock *scsi_nl_sock = NULL;
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EXPORT_SYMBOL_GPL(scsi_nl_sock);
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/**
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* scsi_nl_rcv_msg - Receive message handler.
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* @skb: socket receive buffer
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*
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* Description: Extracts message from a receive buffer.
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* Validates message header and calls appropriate transport message handler
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*
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*
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**/
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static void
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scsi_nl_rcv_msg(struct sk_buff *skb)
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{
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struct nlmsghdr *nlh;
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struct scsi_nl_hdr *hdr;
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u32 rlen;
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int err, tport;
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while (skb->len >= NLMSG_HDRLEN) {
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err = 0;
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nlh = nlmsg_hdr(skb);
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if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
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(skb->len < nlh->nlmsg_len)) {
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printk(KERN_WARNING "%s: discarding partial skb\n",
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__func__);
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return;
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}
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rlen = NLMSG_ALIGN(nlh->nlmsg_len);
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if (rlen > skb->len)
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rlen = skb->len;
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if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
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err = -EBADMSG;
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goto next_msg;
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}
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hdr = nlmsg_data(nlh);
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if ((hdr->version != SCSI_NL_VERSION) ||
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(hdr->magic != SCSI_NL_MAGIC)) {
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err = -EPROTOTYPE;
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goto next_msg;
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}
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if (!netlink_capable(skb, CAP_SYS_ADMIN)) {
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err = -EPERM;
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goto next_msg;
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}
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if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
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printk(KERN_WARNING "%s: discarding partial message\n",
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__func__);
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goto next_msg;
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}
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/*
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* Deliver message to the appropriate transport
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*/
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tport = hdr->transport;
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if (tport == SCSI_NL_TRANSPORT) {
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switch (hdr->msgtype) {
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case SCSI_NL_SHOST_VENDOR:
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/* Locate the driver that corresponds to the message */
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err = -ESRCH;
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break;
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default:
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err = -EBADR;
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break;
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}
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if (err)
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printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
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__func__, hdr->msgtype, err);
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}
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else
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err = -ENOENT;
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next_msg:
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if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
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netlink_ack(skb, nlh, err);
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skb_pull(skb, rlen);
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}
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}
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/**
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* scsi_netlink_init - Called by SCSI subsystem to initialize
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* the SCSI transport netlink interface
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*
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**/
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void
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scsi_netlink_init(void)
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{
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struct netlink_kernel_cfg cfg = {
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.input = scsi_nl_rcv_msg,
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.groups = SCSI_NL_GRP_CNT,
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};
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scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
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&cfg);
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if (!scsi_nl_sock) {
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printk(KERN_ERR "%s: register of receive handler failed\n",
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__func__);
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return;
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}
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return;
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}
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/**
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* scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
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*
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**/
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void
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scsi_netlink_exit(void)
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{
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if (scsi_nl_sock) {
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netlink_kernel_release(scsi_nl_sock);
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}
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return;
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}
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