FreeBSD/Linux Kernel Cross Reference
sys/security/mac/mac_socket.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: releng/5.4/sys/security/mac/mac_socket.c 130398 2004-06-13 02:50:07Z rwatson $");
    
    #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 <netinet/in.h>
    #include <netinet/in_pcb.h>
    #include <netinet/ip_var.h>
    
    #include <security/mac/mac_internal.h>
    
    /*
     * mac_enforce_socket is used by the inet code when delivering to an inpcb
     * without hitting the socket layer, and has to be non-static for now.
     */
    int     mac_enforce_socket = 1;
    SYSCTL_INT(_security_mac, OID_AUTO, enforce_socket, CTLFLAG_RW,
        &mac_enforce_socket, 0, "Enforce MAC policy on socket operations");
    TUNABLE_INT("security.mac.enforce_socket", &mac_enforce_socket);
    
    #ifdef MAC_DEBUG
    static unsigned int nmacsockets;
    
    SYSCTL_UINT(_security_mac_debug_counters, OID_AUTO, sockets, CTLFLAG_RD,
        &nmacsockets, 0, "number of sockets in use");
    #endif
    
    struct label *
    mac_socket_label_alloc(int flag)
    {
            struct label *label;
            int error;
    
            label = mac_labelzone_alloc(flag);
            if (label == NULL)
                    return (NULL);
    
            MAC_CHECK(init_socket_label, label, flag);
            if (error) {
                    MAC_PERFORM(destroy_socket_label, label);
                    mac_labelzone_free(label);
                   return (NULL);
           }
           MAC_DEBUG_COUNTER_INC(&nmacsockets);
           return (label);
   }
   
   static struct label *
   mac_socket_peer_label_alloc(int flag)
   {
           struct label *label;
           int error;
   
           label = mac_labelzone_alloc(flag);
           if (label == NULL)
                   return (NULL);
   
           MAC_CHECK(init_socket_peer_label, label, flag);
           if (error) {
                   MAC_PERFORM(destroy_socket_peer_label, label);
                   mac_labelzone_free(label);
                   return (NULL);
           }
           MAC_DEBUG_COUNTER_INC(&nmacsockets);
           return (label);
   }
   
   int
   mac_init_socket(struct socket *so, int flag)
   {
   
           so->so_label = mac_socket_label_alloc(flag);
           if (so->so_label == NULL)
                   return (ENOMEM);
           so->so_peerlabel = mac_socket_peer_label_alloc(flag);
           if (so->so_peerlabel == NULL) {
                   mac_socket_label_free(so->so_label);
                   so->so_label = NULL;
                   return (ENOMEM);
           }
           return (0);
   }
   
   void
   mac_socket_label_free(struct label *label)
   {
   
           MAC_PERFORM(destroy_socket_label, label);
           mac_labelzone_free(label);
           MAC_DEBUG_COUNTER_DEC(&nmacsockets);
   }
   
   static void
   mac_socket_peer_label_free(struct label *label)
   {
   
           MAC_PERFORM(destroy_socket_peer_label, label);
           mac_labelzone_free(label);
           MAC_DEBUG_COUNTER_DEC(&nmacsockets);
   }
   
   void
   mac_destroy_socket(struct socket *socket)
   {
   
           mac_socket_label_free(socket->so_label);
           socket->so_label = NULL;
           mac_socket_peer_label_free(socket->so_peerlabel);
           socket->so_peerlabel = NULL;
   }
   
   void
   mac_copy_socket_label(struct label *src, struct label *dest)
   {
   
           MAC_PERFORM(copy_socket_label, src, dest);
   }
   
   int
   mac_externalize_socket_label(struct label *label, char *elements,
       char *outbuf, size_t outbuflen)
   {
           int error;
   
           MAC_EXTERNALIZE(socket, label, elements, outbuf, outbuflen);
   
           return (error);
   }
   
   static int
   mac_externalize_socket_peer_label(struct label *label, char *elements,
       char *outbuf, size_t outbuflen)
   {
           int error;
   
           MAC_EXTERNALIZE(socket_peer, label, elements, outbuf, outbuflen);
   
           return (error);
   }
   
   int
   mac_internalize_socket_label(struct label *label, char *string)
   {
           int error;
   
           MAC_INTERNALIZE(socket, label, string);
   
           return (error);
   }
   
   void
   mac_create_socket(struct ucred *cred, struct socket *socket)
   {
   
           MAC_PERFORM(create_socket, cred, socket, socket->so_label);
   }
   
   void
   mac_create_socket_from_socket(struct socket *oldsocket,
       struct socket *newsocket)
   {
   
           SOCK_LOCK_ASSERT(oldsocket);
           MAC_PERFORM(create_socket_from_socket, oldsocket, oldsocket->so_label,
               newsocket, newsocket->so_label);
   }
   
   static void
   mac_relabel_socket(struct ucred *cred, struct socket *socket,
       struct label *newlabel)
   {
   
           SOCK_LOCK_ASSERT(socket);
           MAC_PERFORM(relabel_socket, cred, socket, socket->so_label, newlabel);
   }
   
   void
   mac_set_socket_peer_from_mbuf(struct mbuf *mbuf, struct socket *socket)
   {
           struct label *label;
   
           SOCK_LOCK_ASSERT(socket);
   
           label = mac_mbuf_to_label(mbuf);
   
           MAC_PERFORM(set_socket_peer_from_mbuf, mbuf, label, socket,
               socket->so_peerlabel);
   }
   
   void
   mac_set_socket_peer_from_socket(struct socket *oldsocket,
       struct socket *newsocket)
   {
   
           /*
            * XXXRW: only hold the socket lock on one at a time, as one
            * socket is the original, and one is the new.  However, it's
            * called in both directions, so we can't assert the lock
            * here currently.
            */
           MAC_PERFORM(set_socket_peer_from_socket, oldsocket,
               oldsocket->so_label, newsocket, newsocket->so_peerlabel);
   }
   
   void
   mac_create_mbuf_from_socket(struct socket *socket, struct mbuf *mbuf)
   {
           struct label *label;
   
           label = mac_mbuf_to_label(mbuf);
   
           SOCK_LOCK_ASSERT(socket);
           MAC_PERFORM(create_mbuf_from_socket, socket, socket->so_label, mbuf,
               label);
   }
   
   int
   mac_check_socket_bind(struct ucred *ucred, struct socket *socket,
       struct sockaddr *sockaddr)
   {
           int error;
   
           SOCK_LOCK_ASSERT(socket);
   
           if (!mac_enforce_socket)
                   return (0);
   
           MAC_CHECK(check_socket_bind, ucred, socket, socket->so_label,
               sockaddr);
   
           return (error);
   }
   
   int
   mac_check_socket_connect(struct ucred *cred, struct socket *socket,
       struct sockaddr *sockaddr)
   {
           int error;
   
           SOCK_LOCK_ASSERT(socket);
   
           if (!mac_enforce_socket)
                   return (0);
   
           MAC_CHECK(check_socket_connect, cred, socket, socket->so_label,
               sockaddr);
   
           return (error);
   }
   
   int
   mac_check_socket_deliver(struct socket *socket, struct mbuf *mbuf)
   {
           struct label *label;
           int error;
   
           SOCK_LOCK_ASSERT(socket);
   
           if (!mac_enforce_socket)
                   return (0);
   
           label = mac_mbuf_to_label(mbuf);
   
           MAC_CHECK(check_socket_deliver, socket, socket->so_label, mbuf,
               label);
   
           return (error);
   }
   
   int
   mac_check_socket_listen(struct ucred *cred, struct socket *socket)
   {
           int error;
   
           SOCK_LOCK_ASSERT(socket);
   
           if (!mac_enforce_socket)
                   return (0);
   
           MAC_CHECK(check_socket_listen, cred, socket, socket->so_label);
           return (error);
   }
   
   int
   mac_check_socket_receive(struct ucred *cred, struct socket *so)
   {
           int error;
   
           SOCK_LOCK_ASSERT(so);
   
           if (!mac_enforce_socket)
                   return (0);
   
           MAC_CHECK(check_socket_receive, cred, so, so->so_label);
   
           return (error);
   }
   
   static int
   mac_check_socket_relabel(struct ucred *cred, struct socket *socket,
       struct label *newlabel)
   {
           int error;
   
           SOCK_LOCK_ASSERT(socket);
   
           MAC_CHECK(check_socket_relabel, cred, socket, socket->so_label,
               newlabel);
   
           return (error);
   }
   
   int
   mac_check_socket_send(struct ucred *cred, struct socket *so)
   {
           int error;
   
           SOCK_LOCK_ASSERT(so);
   
           if (!mac_enforce_socket)
                   return (0);
   
           MAC_CHECK(check_socket_send, cred, so, so->so_label);
   
           return (error);
   }
   
   int
   mac_check_socket_visible(struct ucred *cred, struct socket *socket)
   {
           int error;
   
           SOCK_LOCK_ASSERT(socket);
   
           if (!mac_enforce_socket)
                   return (0);
   
           MAC_CHECK(check_socket_visible, cred, socket, socket->so_label);
   
           return (error);
   }
   
   int
   mac_socket_label_set(struct ucred *cred, struct socket *so,
       struct label *label)
   {
           int error;
   
           /*
            * We acquire the socket lock when we perform the test and set,
            * but have to release it as the pcb code needs to acquire the
            * pcb lock, which will precede the socket lock in the lock
            * order.  However, this is fine, as any race will simply
            * result in the inpcb being refreshed twice, but still
            * consistently, as the inpcb code will acquire the socket lock
            * before refreshing, holding both locks.
            */
           SOCK_LOCK(so);
           error = mac_check_socket_relabel(cred, so, label);
           if (error) {
                   SOCK_UNLOCK(so);
                   return (error);
           }
   
           mac_relabel_socket(cred, so, label);
           SOCK_UNLOCK(so);
           /*
            * If the protocol has expressed interest in socket layer changes,
            * such as if it needs to propagate changes to a cached pcb
            * label from the socket, notify it of the label change while
            * holding the socket lock.
            */
           if (so->so_proto->pr_usrreqs->pru_sosetlabel != NULL)
                   (so->so_proto->pr_usrreqs->pru_sosetlabel)(so);
   
           return (0);
   }
   
   int
   mac_setsockopt_label(struct ucred *cred, struct socket *so, struct mac *mac)
   {
           struct label *intlabel;
           char *buffer;
           int 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_socket_label_alloc(M_WAITOK);
           error = mac_internalize_socket_label(intlabel, buffer);
           free(buffer, M_MACTEMP);
           if (error)
                   goto out;
   
           error = mac_socket_label_set(cred, so, intlabel);
   out:
           mac_socket_label_free(intlabel);
           return (error);
   }
   
   int
   mac_getsockopt_label(struct ucred *cred, struct socket *so, struct mac *mac)
   {
           char *buffer, *elements;
           struct label *intlabel;
           int 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_socket_label_alloc(M_WAITOK);
           SOCK_LOCK(so);
           mac_copy_socket_label(so->so_label, intlabel);
           SOCK_UNLOCK(so);
           error = mac_externalize_socket_label(intlabel, elements, buffer,
               mac->m_buflen);
           mac_socket_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_getsockopt_peerlabel(struct ucred *cred, struct socket *so,
       struct mac *mac)
   {
           char *elements, *buffer;
           struct label *intlabel;
           int 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_socket_label_alloc(M_WAITOK);
           SOCK_LOCK(so);
           mac_copy_socket_label(so->so_peerlabel, intlabel);
           SOCK_UNLOCK(so);
           error = mac_externalize_socket_peer_label(intlabel, elements, buffer,
               mac->m_buflen);
           mac_socket_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);
   }

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