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

     /*-
      * Copyright (c) 1999-2002 Robert N. M. Watson
      * Copyright (c) 2001 Ilmar S. Habibulin
      * Copyright (c) 2001-2004 Networks Associates Technology, Inc.
      * All rights reserved.
      *
      * This software was developed by Robert Watson and Ilmar Habibulin for the
      * TrustedBSD Project.
      *
     * 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.
     *
     * 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/sbuf.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 <sys/mac_policy.h>
    
    #include <net/bpfdesc.h>
    #include <net/if.h>
    #include <net/if_var.h>
    
    #include <security/mac/mac_internal.h>
    
    /*
     * mac_enforce_network is used by IPv4 and IPv6 checks, and so must
     * be non-static for now.
     */
    int     mac_enforce_network = 1;
    SYSCTL_INT(_security_mac, OID_AUTO, enforce_network, CTLFLAG_RW,
        &mac_enforce_network, 0, "Enforce MAC policy on network packets");
    TUNABLE_INT("security.mac.enforce_network", &mac_enforce_network);
    
    #ifdef MAC_DEBUG
    static unsigned int nmacbpfdescs, nmacifnets, nmacmbufs;
    
    SYSCTL_UINT(_security_mac_debug_counters, OID_AUTO, bpfdescs, CTLFLAG_RD,
        &nmacbpfdescs, 0, "number of bpfdescs in use");
    SYSCTL_UINT(_security_mac_debug_counters, OID_AUTO, ifnets, CTLFLAG_RD,
        &nmacifnets, 0, "number of ifnets in use");
    SYSCTL_UINT(_security_mac_debug_counters, OID_AUTO, mbufs, CTLFLAG_RD,
        &nmacmbufs, 0, "number of mbufs in use");
    #endif
    
    /*
     * 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.
     */
    static struct mtx mac_ifnet_mtx;
    MTX_SYSINIT(mac_ifnet_mtx, &mac_ifnet_mtx, "mac_ifnet", MTX_DEF);
    #define MAC_IFNET_LOCK(ifp)     mtx_lock(&mac_ifnet_mtx)
    #define MAC_IFNET_UNLOCK(ifp)   mtx_unlock(&mac_ifnet_mtx)
    
    struct label *
    mac_mbuf_to_label(struct mbuf *mbuf)
    {
            struct m_tag *tag;
           struct label *label;
   
           if (mbuf == NULL)
                   return (NULL);
           tag = m_tag_find(mbuf, 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_PERFORM(init_bpfdesc_label, label);
           MAC_DEBUG_COUNTER_INC(&nmacbpfdescs);
           return (label);
   }
   
   void
   mac_init_bpfdesc(struct bpf_d *bpf_d)
   {
   
           bpf_d->bd_label = mac_bpfdesc_label_alloc();
   }
   
   static struct label *
   mac_ifnet_label_alloc(void)
   {
           struct label *label;
   
           label = mac_labelzone_alloc(M_WAITOK);
           MAC_PERFORM(init_ifnet_label, label);
           MAC_DEBUG_COUNTER_INC(&nmacifnets);
           return (label);
   }
   
   void
   mac_init_ifnet(struct ifnet *ifp)
   {
   
           ifp->if_label = mac_ifnet_label_alloc();
   }
   
   int
   mac_init_mbuf_tag(struct m_tag *tag, int flag)
   {
           struct label *label;
           int error;
   
           label = (struct label *) (tag + 1);
           mac_init_label(label);
   
           MAC_CHECK(init_mbuf_label, label, flag);
           if (error) {
                   MAC_PERFORM(destroy_mbuf_label, label);
                   mac_destroy_label(label);
           } else {
                   MAC_DEBUG_COUNTER_INC(&nmacmbufs);
           }
           return (error);
   }
   
   int
   mac_init_mbuf(struct mbuf *m, int flag)
   {
           struct m_tag *tag;
           int error;
   
           M_ASSERTPKTHDR(m);
   
   #ifndef MAC_ALWAYS_LABEL_MBUF
           /*
            * If conditionally allocating mbuf labels, don't allocate unless
            * they are required.
            */
           if (!mac_labelmbufs)
                   return (0);
   #endif
           tag = m_tag_get(PACKET_TAG_MACLABEL, sizeof(struct label),
               flag);
           if (tag == NULL)
                   return (ENOMEM);
           error = mac_init_mbuf_tag(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_PERFORM(destroy_bpfdesc_label, label);
           mac_labelzone_free(label);
           MAC_DEBUG_COUNTER_DEC(&nmacbpfdescs);
   }
   
   void
   mac_destroy_bpfdesc(struct bpf_d *bpf_d)
   {
   
           mac_bpfdesc_label_free(bpf_d->bd_label);
           bpf_d->bd_label = NULL;
   }
   
   static void
   mac_ifnet_label_free(struct label *label)
   {
   
           MAC_PERFORM(destroy_ifnet_label, label);
           mac_labelzone_free(label);
           MAC_DEBUG_COUNTER_DEC(&nmacifnets);
   }
   
   void
   mac_destroy_ifnet(struct ifnet *ifp)
   {
   
           mac_ifnet_label_free(ifp->if_label);
           ifp->if_label = NULL;
   }
   
   void
   mac_destroy_mbuf_tag(struct m_tag *tag)
   {
           struct label *label;
   
           label = (struct label *)(tag+1);
   
           MAC_PERFORM(destroy_mbuf_label, label);
           mac_destroy_label(label);
           MAC_DEBUG_COUNTER_DEC(&nmacmbufs);
   }
   
   void
   mac_copy_mbuf_tag(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_init_mbuf_tag() is called on the target tag in
            * m_tag_copy(), so we don't need to call it here.
            */
           MAC_PERFORM(copy_mbuf_label, src_label, dest_label);
   }
   
   void
   mac_copy_mbuf(struct mbuf *m_from, struct mbuf *m_to)
   {
           struct label *src_label, *dest_label;
   
           src_label = mac_mbuf_to_label(m_from);
           dest_label = mac_mbuf_to_label(m_to);
   
           MAC_PERFORM(copy_mbuf_label, src_label, dest_label);
   }
   
   static void
   mac_copy_ifnet_label(struct label *src, struct label *dest)
   {
   
           MAC_PERFORM(copy_ifnet_label, src, dest);
   }
   
   static int
   mac_externalize_ifnet_label(struct label *label, char *elements,
       char *outbuf, size_t outbuflen)
   {
           int error;
   
           MAC_EXTERNALIZE(ifnet, label, elements, outbuf, outbuflen);
   
           return (error);
   }
   
   static int
   mac_internalize_ifnet_label(struct label *label, char *string)
   {
           int error;
   
           MAC_INTERNALIZE(ifnet, label, string);
   
           return (error);
   }
   
   void
   mac_create_ifnet(struct ifnet *ifnet)
   {
   
           MAC_IFNET_LOCK(ifnet);
           MAC_PERFORM(create_ifnet, ifnet, ifnet->if_label);
           MAC_IFNET_UNLOCK(ifnet);
   }
   
   void
   mac_create_bpfdesc(struct ucred *cred, struct bpf_d *bpf_d)
   {
   
           MAC_PERFORM(create_bpfdesc, cred, bpf_d, bpf_d->bd_label);
   }
   
   void
   mac_create_mbuf_from_bpfdesc(struct bpf_d *bpf_d, struct mbuf *mbuf)
   {
           struct label *label;
   
           BPFD_LOCK_ASSERT(bpf_d);
   
           label = mac_mbuf_to_label(mbuf);
   
           MAC_PERFORM(create_mbuf_from_bpfdesc, bpf_d, bpf_d->bd_label, mbuf,
               label);
   }
   
   void
   mac_create_mbuf_linklayer(struct ifnet *ifnet, struct mbuf *mbuf)
   {
           struct label *label;
   
           label = mac_mbuf_to_label(mbuf);
   
           MAC_IFNET_LOCK(ifnet);
           MAC_PERFORM(create_mbuf_linklayer, ifnet, ifnet->if_label, mbuf,
               label);
           MAC_IFNET_UNLOCK(ifnet);
   }
   
   void
   mac_create_mbuf_from_ifnet(struct ifnet *ifnet, struct mbuf *mbuf)
   {
           struct label *label;
   
           label = mac_mbuf_to_label(mbuf);
   
           MAC_IFNET_LOCK(ifnet);
           MAC_PERFORM(create_mbuf_from_ifnet, ifnet, ifnet->if_label, mbuf,
               label);
           MAC_IFNET_UNLOCK(ifnet);
   }
   
   void
   mac_create_mbuf_multicast_encap(struct mbuf *oldmbuf, struct ifnet *ifnet,
       struct mbuf *newmbuf)
   {
           struct label *oldmbuflabel, *newmbuflabel;
   
           oldmbuflabel = mac_mbuf_to_label(oldmbuf);
           newmbuflabel = mac_mbuf_to_label(newmbuf);
   
           MAC_IFNET_LOCK(ifnet);
           MAC_PERFORM(create_mbuf_multicast_encap, oldmbuf, oldmbuflabel,
               ifnet, ifnet->if_label, newmbuf, newmbuflabel);
           MAC_IFNET_UNLOCK(ifnet);
   }
   
   void
   mac_create_mbuf_netlayer(struct mbuf *oldmbuf, struct mbuf *newmbuf)
   {
           struct label *oldmbuflabel, *newmbuflabel;
   
           oldmbuflabel = mac_mbuf_to_label(oldmbuf);
           newmbuflabel = mac_mbuf_to_label(newmbuf);
   
           MAC_PERFORM(create_mbuf_netlayer, oldmbuf, oldmbuflabel, newmbuf,
               newmbuflabel);
   }
   
   int
   mac_check_bpfdesc_receive(struct bpf_d *bpf_d, struct ifnet *ifnet)
   {
           int error;
   
           BPFD_LOCK_ASSERT(bpf_d);
   
           if (!mac_enforce_network)
                   return (0);
   
           MAC_IFNET_LOCK(ifnet);
           MAC_CHECK(check_bpfdesc_receive, bpf_d, bpf_d->bd_label, ifnet,
               ifnet->if_label);
           MAC_IFNET_UNLOCK(ifnet);
   
           return (error);
   }
   
   int
   mac_check_ifnet_transmit(struct ifnet *ifnet, struct mbuf *mbuf)
   {
           struct label *label;
           int error;
   
           M_ASSERTPKTHDR(mbuf);
   
           if (!mac_enforce_network)
                   return (0);
   
           label = mac_mbuf_to_label(mbuf);
   
           MAC_IFNET_LOCK(ifnet);
           MAC_CHECK(check_ifnet_transmit, ifnet, ifnet->if_label, mbuf,
               label);
           MAC_IFNET_UNLOCK(ifnet);
   
           return (error);
   }
   
   int
   mac_ioctl_ifnet_get(struct ucred *cred, struct ifreq *ifr,
       struct ifnet *ifnet)
   {
           char *elements, *buffer;
           struct label *intlabel;
           struct mac mac;
           int error;
   
           error = copyin(ifr->ifr_ifru.ifru_data, &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(ifnet);
           mac_copy_ifnet_label(ifnet->if_label, intlabel);
           MAC_IFNET_UNLOCK(ifnet);
           error = mac_externalize_ifnet_label(ifnet->if_label, 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_ioctl_ifnet_set(struct ucred *cred, struct ifreq *ifr,
       struct ifnet *ifnet)
   {
           struct label *intlabel;
           struct mac mac;
           char *buffer;
           int error;
   
           error = copyin(ifr->ifr_ifru.ifru_data, &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_internalize_ifnet_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 = suser_cred(cred, 0);
           if (error) {
                   mac_ifnet_label_free(intlabel);
                   return (error);
           }
   
           MAC_IFNET_LOCK(ifnet);
           MAC_CHECK(check_ifnet_relabel, cred, ifnet, ifnet->if_label,
               intlabel);
           if (error) {
                   MAC_IFNET_UNLOCK(ifnet);
                   mac_ifnet_label_free(intlabel);
                   return (error);
           }
   
           MAC_PERFORM(relabel_ifnet, cred, ifnet, ifnet->if_label, intlabel);
           MAC_IFNET_UNLOCK(ifnet);
   
           mac_ifnet_label_free(intlabel);
           return (0);
   }

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