FreeBSD/Linux Kernel Cross Reference
sys/security/mac/mac_net.c

     /*-
      * Copyright (c) 1999-2002, 2009, 2019 Robert N. M. Watson
      * Copyright (c) 2001 Ilmar S. Habibulin
      * Copyright (c) 2001-2004 Networks Associates Technology, Inc.
      * Copyright (c) 2006 SPARTA, Inc.
      * Copyright (c) 2008 Apple Inc.
      * All rights reserved.
      *
      * This software was developed by Robert Watson and Ilmar Habibulin for the
     * TrustedBSD Project.
     *
     * This software was enhanced by SPARTA ISSO under SPAWAR contract
     * N66001-04-C-6019 ("SEFOS").
     *
     * This software was developed for the FreeBSD Project in part by Network
     * Associates Laboratories, the Security Research Division of Network
     * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
     * as part of the DARPA CHATS research program.
     *
     * This software was developed at the University of Cambridge Computer
     * Laboratory with support from a grant from Google, Inc. 
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include "opt_mac.h"
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/mutex.h>
    #include <sys/mac.h>
    #include <sys/priv.h>
    #include <sys/sbuf.h>
    #include <sys/sdt.h>
    #include <sys/systm.h>
    #include <sys/mount.h>
    #include <sys/file.h>
    #include <sys/namei.h>
    #include <sys/protosw.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/sysctl.h>
    
    #include <net/bpfdesc.h>
    #include <net/if.h>
    #include <net/if_var.h>
    
    #include <security/mac/mac_framework.h>
    #include <security/mac/mac_internal.h>
    #include <security/mac/mac_policy.h>
    
    /*
     * XXXRW: struct ifnet locking is incomplete in the network code, so we use
     * our own global mutex for struct ifnet.  Non-ideal, but should help in the
     * SMP environment.
     *
     * This lock is acquired only if a loaded policy is using ifnet labeling.
     * This should not ever change during a MAC policy check, itself, but could
     * change during setup/return from a check, so we have to condition unlock on
     * previous lock.
     */
    struct mtx mac_ifnet_mtx;
    MTX_SYSINIT(mac_ifnet_mtx, &mac_ifnet_mtx, "mac_ifnet", MTX_DEF);
    
    /*
     * Retrieve the label associated with an mbuf by searching for the tag.
     * Depending on the value of mac_labelmbufs, it's possible that a label will
     * not be present, in which case NULL is returned.  Policies must handle the
     * possibility of an mbuf not having label storage if they do not enforce
     * early loading.
     */
    struct label *
    mac_mbuf_to_label(struct mbuf *m)
    {
            struct m_tag *tag;
           struct label *label;
   
           if (m == NULL)
                   return (NULL);
           tag = m_tag_find(m, PACKET_TAG_MACLABEL, NULL);
           if (tag == NULL)
                   return (NULL);
           label = (struct label *)(tag+1);
           return (label);
   }
   
   static struct label *
   mac_bpfdesc_label_alloc(void)
   {
           struct label *label;
   
           label = mac_labelzone_alloc(M_WAITOK);
           MAC_POLICY_PERFORM(bpfdesc_init_label, label);
           return (label);
   }
   
   void
   mac_bpfdesc_init(struct bpf_d *d)
   {
   
           if (mac_labeled & MPC_OBJECT_BPFDESC)
                   d->bd_label = mac_bpfdesc_label_alloc();
           else
                   d->bd_label = NULL;
   }
   
   static struct label *
   mac_ifnet_label_alloc(void)
   {
           struct label *label;
   
           label = mac_labelzone_alloc(M_WAITOK);
           MAC_POLICY_PERFORM(ifnet_init_label, label);
           return (label);
   }
   
   void
   mac_ifnet_init(struct ifnet *ifp)
   {
   
           if (mac_labeled & MPC_OBJECT_IFNET)
                   ifp->if_label = mac_ifnet_label_alloc();
           else
                   ifp->if_label = NULL;
   }
   
   int
   mac_mbuf_tag_init(struct m_tag *tag, int flag)
   {
           struct label *label;
           int error;
   
           label = (struct label *) (tag + 1);
           mac_init_label(label);
   
           if (flag & M_WAITOK)
                   MAC_POLICY_CHECK(mbuf_init_label, label, flag);
           else
                   MAC_POLICY_CHECK_NOSLEEP(mbuf_init_label, label, flag);
           if (error) {
                   MAC_POLICY_PERFORM_NOSLEEP(mbuf_destroy_label, label);
                   mac_destroy_label(label);
           }
           return (error);
   }
   
   int
   mac_mbuf_init(struct mbuf *m, int flag)
   {
           struct m_tag *tag;
           int error;
   
           M_ASSERTPKTHDR(m);
   
           if (mac_labeled & MPC_OBJECT_MBUF) {
                   tag = m_tag_get(PACKET_TAG_MACLABEL, sizeof(struct label),
                       flag);
                   if (tag == NULL)
                           return (ENOMEM);
                   error = mac_mbuf_tag_init(tag, flag);
                   if (error) {
                           m_tag_free(tag);
                           return (error);
                   }
                   m_tag_prepend(m, tag);
           }
           return (0);
   }
   
   static void
   mac_bpfdesc_label_free(struct label *label)
   {
   
           MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_destroy_label, label);
           mac_labelzone_free(label);
   }
   
   void
   mac_bpfdesc_destroy(struct bpf_d *d)
   {
   
           if (d->bd_label != NULL) {
                   mac_bpfdesc_label_free(d->bd_label);
                   d->bd_label = NULL;
           }
   }
   
   static void
   mac_ifnet_label_free(struct label *label)
   {
   
           MAC_POLICY_PERFORM_NOSLEEP(ifnet_destroy_label, label);
           mac_labelzone_free(label);
   }
   
   void
   mac_ifnet_destroy(struct ifnet *ifp)
   {
   
           if (ifp->if_label != NULL) {
                   mac_ifnet_label_free(ifp->if_label);
                   ifp->if_label = NULL;
           }
   }
   
   void
   mac_mbuf_tag_destroy(struct m_tag *tag)
   {
           struct label *label;
   
           label = (struct label *)(tag+1);
   
           MAC_POLICY_PERFORM_NOSLEEP(mbuf_destroy_label, label);
           mac_destroy_label(label);
   }
   
   /*
    * mac_mbuf_tag_copy is called when an mbuf header is duplicated, in which
    * case the labels must also be duplicated.
    */
   void
   mac_mbuf_tag_copy(struct m_tag *src, struct m_tag *dest)
   {
           struct label *src_label, *dest_label;
   
           src_label = (struct label *)(src+1);
           dest_label = (struct label *)(dest+1);
   
           /*
            * mac_mbuf_tag_init() is called on the target tag in m_tag_copy(),
            * so we don't need to call it here.
            */
           MAC_POLICY_PERFORM_NOSLEEP(mbuf_copy_label, src_label, dest_label);
   }
   
   void
   mac_mbuf_copy(struct mbuf *m_from, struct mbuf *m_to)
   {
           struct label *src_label, *dest_label;
   
           if (mac_policy_count == 0)
                   return;
   
           src_label = mac_mbuf_to_label(m_from);
           dest_label = mac_mbuf_to_label(m_to);
   
           MAC_POLICY_PERFORM_NOSLEEP(mbuf_copy_label, src_label, dest_label);
   }
   
   static void
   mac_ifnet_copy_label(struct label *src, struct label *dest)
   {
   
           MAC_POLICY_PERFORM_NOSLEEP(ifnet_copy_label, src, dest);
   }
   
   static int
   mac_ifnet_externalize_label(struct label *label, char *elements,
       char *outbuf, size_t outbuflen)
   {
           int error;
   
           MAC_POLICY_EXTERNALIZE(ifnet, label, elements, outbuf, outbuflen);
   
           return (error);
   }
   
   static int
   mac_ifnet_internalize_label(struct label *label, char *string)
   {
           int error;
   
           MAC_POLICY_INTERNALIZE(ifnet, label, string);
   
           return (error);
   }
   
   void
   mac_ifnet_create(struct ifnet *ifp)
   {
           int locked;
   
           if (mac_policy_count == 0)
                   return;
   
           MAC_IFNET_LOCK(ifp, locked);
           MAC_POLICY_PERFORM_NOSLEEP(ifnet_create, ifp, ifp->if_label);
           MAC_IFNET_UNLOCK(ifp, locked);
   }
   
   void
   mac_bpfdesc_create(struct ucred *cred, struct bpf_d *d)
   {
   
           MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_create, cred, d, d->bd_label);
   }
   
   void
   mac_bpfdesc_create_mbuf(struct bpf_d *d, struct mbuf *m)
   {
           struct label *label;
   
           /* Assume reader lock is enough. */
           BPFD_LOCK_ASSERT(d);
   
           if (mac_policy_count == 0)
                   return;
   
           label = mac_mbuf_to_label(m);
   
           MAC_POLICY_PERFORM_NOSLEEP(bpfdesc_create_mbuf, d, d->bd_label, m,
               label);
   }
   
   void
   mac_ifnet_create_mbuf_impl(struct ifnet *ifp, struct mbuf *m)
   {
           struct label *label;
           int locked;
   
           label = mac_mbuf_to_label(m);
   
           MAC_IFNET_LOCK(ifp, locked);
           MAC_POLICY_PERFORM_NOSLEEP(ifnet_create_mbuf, ifp, ifp->if_label, m,
               label);
           MAC_IFNET_UNLOCK(ifp, locked);
   }
   
   MAC_CHECK_PROBE_DEFINE2(bpfdesc_check_receive, "struct bpf_d *",
       "struct ifnet *");
   
   int
   mac_bpfdesc_check_receive(struct bpf_d *d, struct ifnet *ifp)
   {
           int error, locked;
   
           /* Assume reader lock is enough. */
           BPFD_LOCK_ASSERT(d);
   
           if (mac_policy_count == 0)
                   return (0);
   
           MAC_IFNET_LOCK(ifp, locked);
           MAC_POLICY_CHECK_NOSLEEP(bpfdesc_check_receive, d, d->bd_label, ifp,
               ifp->if_label);
           MAC_CHECK_PROBE2(bpfdesc_check_receive, error, d, ifp);
           MAC_IFNET_UNLOCK(ifp, locked);
   
           return (error);
   }
   
   MAC_CHECK_PROBE_DEFINE2(ifnet_check_transmit, "struct ifnet *",
       "struct mbuf *");
   
   int
   mac_ifnet_check_transmit_impl(struct ifnet *ifp, struct mbuf *m)
   {
           struct label *label;
           int error, locked;
   
           M_ASSERTPKTHDR(m);
   
           label = mac_mbuf_to_label(m);
   
           MAC_IFNET_LOCK(ifp, locked);
           MAC_POLICY_CHECK_NOSLEEP(ifnet_check_transmit, ifp, ifp->if_label, m,
               label);
           MAC_CHECK_PROBE2(ifnet_check_transmit, error, ifp, m);
           MAC_IFNET_UNLOCK(ifp, locked);
   
           return (error);
   }
   
   int
   mac_ifnet_ioctl_get(struct ucred *cred, struct ifreq *ifr,
       struct ifnet *ifp)
   {
           char *elements, *buffer;
           struct label *intlabel;
           struct mac mac;
           int error, locked;
   
           if (!(mac_labeled & MPC_OBJECT_IFNET))
                   return (EINVAL);
   
           error = copyin(ifr_data_get_ptr(ifr), &mac, sizeof(mac));
           if (error)
                   return (error);
   
           error = mac_check_structmac_consistent(&mac);
           if (error)
                   return (error);
   
           elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
           error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
           if (error) {
                   free(elements, M_MACTEMP);
                   return (error);
           }
   
           buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
           intlabel = mac_ifnet_label_alloc();
           MAC_IFNET_LOCK(ifp, locked);
           mac_ifnet_copy_label(ifp->if_label, intlabel);
           MAC_IFNET_UNLOCK(ifp, locked);
           error = mac_ifnet_externalize_label(intlabel, elements, buffer,
               mac.m_buflen);
           mac_ifnet_label_free(intlabel);
           if (error == 0)
                   error = copyout(buffer, mac.m_string, strlen(buffer)+1);
   
           free(buffer, M_MACTEMP);
           free(elements, M_MACTEMP);
   
           return (error);
   }
   
   int
   mac_ifnet_ioctl_set(struct ucred *cred, struct ifreq *ifr, struct ifnet *ifp)
   {
           struct label *intlabel;
           struct mac mac;
           char *buffer;
           int error, locked;
   
           if (!(mac_labeled & MPC_OBJECT_IFNET))
                   return (EINVAL);
   
           error = copyin(ifr_data_get_ptr(ifr), &mac, sizeof(mac));
           if (error)
                   return (error);
   
           error = mac_check_structmac_consistent(&mac);
           if (error)
                   return (error);
   
           buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
           error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
           if (error) {
                   free(buffer, M_MACTEMP);
                   return (error);
           }
   
           intlabel = mac_ifnet_label_alloc();
           error = mac_ifnet_internalize_label(intlabel, buffer);
           free(buffer, M_MACTEMP);
           if (error) {
                   mac_ifnet_label_free(intlabel);
                   return (error);
           }
   
           /*
            * XXX: Note that this is a redundant privilege check, since policies
            * impose this check themselves if required by the policy
            * Eventually, this should go away.
            */
           error = priv_check_cred(cred, PRIV_NET_SETIFMAC);
           if (error) {
                   mac_ifnet_label_free(intlabel);
                   return (error);
           }
   
           MAC_IFNET_LOCK(ifp, locked);
           MAC_POLICY_CHECK_NOSLEEP(ifnet_check_relabel, cred, ifp,
               ifp->if_label, intlabel);
           if (error) {
                   MAC_IFNET_UNLOCK(ifp, locked);
                   mac_ifnet_label_free(intlabel);
                   return (error);
           }
   
           MAC_POLICY_PERFORM_NOSLEEP(ifnet_relabel, cred, ifp, ifp->if_label,
               intlabel);
           MAC_IFNET_UNLOCK(ifp, locked);
   
           mac_ifnet_label_free(intlabel);
           return (0);
   }

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