FreeBSD/Linux Kernel Cross Reference
sys/security/mac_partition/mac_partition.c

     /*-
      * Copyright (c) 1999-2002, 2007-2008 Robert N. M. Watson
      * Copyright (c) 2001-2002 Networks Associates Technology, Inc.
      * Copyright (c) 2006 SPARTA, Inc.
      * Copyright (c) 2008 Apple Inc.
      * All rights reserved.
      *
      * This software was developed by Robert Watson 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.
     *
     * This software was enhanced by SPARTA ISSO under SPAWAR contract
     * N66001-04-C-6019 ("SEFOS").
     *
     * 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.
     *
     * $FreeBSD$
     */
    
    /*
     * Developed by the TrustedBSD Project.
     *
     * Experiment with a partition-like model.
     */
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/priv.h>
    #include <sys/proc.h>
    #include <sys/sbuf.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/systm.h>
    #include <sys/sysctl.h>
    
    #include <net/route.h>
    #include <netinet/in.h>
    #include <netinet/in_pcb.h>
    
    #include <security/mac/mac_policy.h>
    #include <security/mac_partition/mac_partition.h>
    
    SYSCTL_DECL(_security_mac);
    
    static SYSCTL_NODE(_security_mac, OID_AUTO, partition,
        CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
        "TrustedBSD mac_partition policy controls");
    
    static int      partition_enabled = 1;
    SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
        &partition_enabled, 0, "Enforce partition policy");
    
    static int      partition_slot;
    #define SLOT(l) mac_label_get((l), partition_slot)
    #define SLOT_SET(l, v)  mac_label_set((l), partition_slot, (v))
    
    static int
    partition_check(struct label *subject, struct label *object)
    {
    
            if (partition_enabled == 0)
                    return (0);
    
            if (subject == NULL)
                    return (0);
    
            if (SLOT(subject) == 0)
                    return (0);
    
            /*
             * If the object label hasn't been allocated, then it's effectively
             * not in a partition, and we know the subject is as it has a label
             * and it's not 0, so reject.
             */
            if (object == NULL)
                    return (EPERM);
   
           if (SLOT(subject) == SLOT(object))
                   return (0);
   
           return (EPERM);
   }
   
   /*
    * Object-specific entry points are sorted alphabetically by object type name
    * and then by operation.
    */
   static int
   partition_cred_check_relabel(struct ucred *cred, struct label *newlabel)
   {
           int error;
   
           error = 0;
   
           /*
            * Treat "" as a no-op request because it reflects an unset
            * partition label.  If we ever want to support switching back to an
            * unpartitioned state for a process, we'll need to differentiate the
            * "not in a partition" and "no partition defined during internalize"
            * conditions.
            */
           if (SLOT(newlabel) != 0) {
                   /*
                    * Require BSD privilege in order to change the partition.
                    * Originally we also required that the process not be in a
                    * partition in the first place, but this didn't interact
                    * well with sendmail.
                    */
                   error = priv_check_cred(cred, PRIV_MAC_PARTITION);
           }
   
           return (error);
   }
   
   static int
   partition_cred_check_visible(struct ucred *cr1, struct ucred *cr2)
   {
           int error;
   
           error = partition_check(cr1->cr_label, cr2->cr_label);
   
           return (error == 0 ? 0 : ESRCH);
   }
   
   static void
   partition_cred_copy_label(struct label *src, struct label *dest)
   {
   
           if (src != NULL && dest != NULL)
                   SLOT_SET(dest, SLOT(src));
           else if (dest != NULL)
                   SLOT_SET(dest, 0);
   }
   
   static void
   partition_cred_create_init(struct ucred *cred)
   {
   
           SLOT_SET(cred->cr_label, 0);
   }
   
   static void
   partition_cred_create_swapper(struct ucred *cred)
   {
   
           SLOT_SET(cred->cr_label, 0);
   }
   
   static void
   partition_cred_destroy_label(struct label *label)
   {
   
           SLOT_SET(label, 0);
   }
   
   static int
   partition_cred_externalize_label(struct label *label, char *element_name,
       struct sbuf *sb, int *claimed)
   {
   
           if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
                   return (0);
   
           (*claimed)++;
   
           if (label != NULL) {
                   if (sbuf_printf(sb, "%jd", (intmax_t)SLOT(label)) == -1)
                           return (EINVAL);
           } else {
                   if (sbuf_printf(sb, "") == -1)
                           return (EINVAL);
           }
           return (0);
   }
   
   static void
   partition_cred_init_label(struct label *label)
   {
   
           SLOT_SET(label, 0);
   }
   
   static int
   partition_cred_internalize_label(struct label *label, char *element_name,
       char *element_data, int *claimed)
   {
   
           if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
                   return (0);
   
           (*claimed)++;
           SLOT_SET(label, strtol(element_data, NULL, 10));
           return (0);
   }
   
   static void
   partition_cred_relabel(struct ucred *cred, struct label *newlabel)
   {
   
           if (newlabel != NULL && SLOT(newlabel) != 0)
                   SLOT_SET(cred->cr_label, SLOT(newlabel));
   }
   
   static int
   partition_inpcb_check_visible(struct ucred *cred, struct inpcb *inp,
       struct label *inplabel)
   {
           int error;
   
           error = partition_check(cred->cr_label, inp->inp_cred->cr_label);
   
           return (error ? ENOENT : 0);
   }
   
   static int
   partition_proc_check_debug(struct ucred *cred, struct proc *p)
   {
           int error;
   
           error = partition_check(cred->cr_label, p->p_ucred->cr_label);
   
           return (error ? ESRCH : 0);
   }
   
   static int
   partition_proc_check_sched(struct ucred *cred, struct proc *p)
   {
           int error;
   
           error = partition_check(cred->cr_label, p->p_ucred->cr_label);
   
           return (error ? ESRCH : 0);
   }
   
   static int
   partition_proc_check_signal(struct ucred *cred, struct proc *p,
       int signum)
   {
           int error;
   
           error = partition_check(cred->cr_label, p->p_ucred->cr_label);
   
           return (error ? ESRCH : 0);
   }
   
   static int
   partition_socket_check_visible(struct ucred *cred, struct socket *so,
       struct label *solabel)
   {
           int error;
   
           error = partition_check(cred->cr_label, so->so_cred->cr_label);
   
           return (error ? ENOENT : 0);
   }
   
   static int
   partition_vnode_check_exec(struct ucred *cred, struct vnode *vp,
       struct label *vplabel, struct image_params *imgp,
       struct label *execlabel)
   {
   
           if (execlabel != NULL) {
                   /*
                    * We currently don't permit labels to be changed at
                    * exec-time as part of the partition model, so disallow
                    * non-NULL partition label changes in execlabel.
                    */
                   if (SLOT(execlabel) != 0)
                           return (EINVAL);
           }
   
           return (0);
   }
   
   static struct mac_policy_ops partition_ops =
   {
           .mpo_cred_check_relabel = partition_cred_check_relabel,
           .mpo_cred_check_visible = partition_cred_check_visible,
           .mpo_cred_copy_label = partition_cred_copy_label,
           .mpo_cred_create_init = partition_cred_create_init,
           .mpo_cred_create_swapper = partition_cred_create_swapper,
           .mpo_cred_destroy_label = partition_cred_destroy_label,
           .mpo_cred_externalize_label = partition_cred_externalize_label,
           .mpo_cred_init_label = partition_cred_init_label,
           .mpo_cred_internalize_label = partition_cred_internalize_label,
           .mpo_cred_relabel = partition_cred_relabel,
           .mpo_inpcb_check_visible = partition_inpcb_check_visible,
           .mpo_proc_check_debug = partition_proc_check_debug,
           .mpo_proc_check_sched = partition_proc_check_sched,
           .mpo_proc_check_signal = partition_proc_check_signal,
           .mpo_socket_check_visible = partition_socket_check_visible,
           .mpo_vnode_check_exec = partition_vnode_check_exec,
   };
   
   MAC_POLICY_SET(&partition_ops, mac_partition, "TrustedBSD MAC/Partition",
       MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);

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