507 lines
13 KiB
C
507 lines
13 KiB
C
/*-
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* Copyright (c) 2001 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project by NAI Labs, the
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* Security Research Division of Network Associates, Inc. under
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* DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
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* CHATS research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id$
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/systm.h>
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#include <sys/vnode.h>
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#include <sys/pipe.h>
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#include <sys/socketvar.h>
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#include <vm/vm.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include "kernel_interface.h"
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#include "lomacfs.h"
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#include "kernel_log.h"
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/*
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* Reuse the eflags field of proc.p_vmspace->vm_map.header (since it is
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* currently not used for anything but a placeholder, and won't change
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* generally...) as storage for our process-based information.
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*
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* This is the only really effective way to make thread-based MAC
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* easy.
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*/
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#define p_eflags p_vmspace->vm_map.header.eflags
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#define EF_HIGHEST_LEVEL 0x00010000
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#define EF_LOWEST_LEVEL 0x00020000
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#define EF_LEVEL_MASK 0x00030000
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#define EF_ATTR_NONETDEMOTE 0x00040000
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#define EF_ATTR_NODEMOTE 0x00080000
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#define EF_ATTR_MASK 0x000c0000
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static u_int
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level2subjectbits(level_t level) {
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switch (level) {
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case LOMAC_HIGHEST_LEVEL:
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return (EF_HIGHEST_LEVEL);
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case LOMAC_LOWEST_LEVEL:
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return (EF_LOWEST_LEVEL);
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default:
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panic("level2subjectbits: invalid level %d\n", level);
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}
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}
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static level_t
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subjectbits2level(u_int flags) {
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switch (flags & EF_LEVEL_MASK) {
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case EF_HIGHEST_LEVEL:
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/*
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* During an execve(), the kernel's original execve() creates a
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* new vmspace and puts it into use before it has been initialized
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* by us to contain a subject level. Since this is the only case
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* when a subject may have a level not set, pretend that it
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* is just a high-level file, and allow the lomacfs_open() to then
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* succeed.
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*/
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case 0:
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return (LOMAC_HIGHEST_LEVEL);
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case EF_LOWEST_LEVEL:
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return (LOMAC_LOWEST_LEVEL);
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default:
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panic("subjectbits2level: invalid flags %#x\n", flags);
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}
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}
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static u_int
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attr2subjectbits(u_int attr) {
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u_int bits = 0;
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if (attr & LOMAC_ATTR_NONETDEMOTE)
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bits |= EF_ATTR_NONETDEMOTE;
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if (attr & LOMAC_ATTR_NODEMOTE)
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bits |= EF_ATTR_NODEMOTE;
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return (bits);
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}
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static u_int
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subjectbits2attr(u_int bits) {
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u_int attr = 0;
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if (bits & EF_ATTR_NONETDEMOTE)
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attr |= LOMAC_ATTR_NONETDEMOTE;
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if (bits & EF_ATTR_NODEMOTE)
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attr |= LOMAC_ATTR_NODEMOTE;
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return (attr);
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}
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static int
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subject_lock(lomac_subject_t *p, int read) {
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#ifdef USES_LOCKMGR
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int hadlock;
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hadlock = PROC_LOCKED(p);
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if (hadlock)
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PROC_UNLOCK(p);
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#endif
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if (read)
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vm_map_lock_read(&p->p_vmspace->vm_map);
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else
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vm_map_lock(&p->p_vmspace->vm_map);
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#ifdef USES_LOCKMGR
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return (hadlock);
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#else
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return (0);
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#endif
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}
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static void
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subject_unlock(lomac_subject_t *p, int read, int hadlock) {
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if (read)
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vm_map_unlock_read(&p->p_vmspace->vm_map);
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else
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vm_map_unlock(&p->p_vmspace->vm_map);
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#ifdef USES_LOCKMGR
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if (hadlock)
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PROC_LOCK(p);
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#endif
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}
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void
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init_subject_lattr(lomac_subject_t *p, lattr_t *lattr) {
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int s;
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s = subject_lock(p, 0);
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p->p_eflags = level2subjectbits(lattr->level) |
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attr2subjectbits(lattr->flags);
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subject_unlock(p, 0, s);
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}
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/*
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* Set/get the subject level on a process. The process must not be able
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* to change, so either the process must be locked on entry or it must
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* be held in exclusivity otherwise (executing on behalf of via a syscall,
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* including as EITHER child or parent in a fork).
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*/
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void
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set_subject_lattr(lomac_subject_t *p, lattr_t lattr) {
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int s;
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#ifdef INVARIANTS
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do {
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lattr_t oslattr;
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get_subject_lattr(p, &oslattr);
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if (lomac_must_demote(&lattr, &oslattr))
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panic("raising subject level");
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} while (0);
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#endif /* !INVARIANTS */
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s = subject_lock(p, 0);
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p->p_eflags = (p->p_eflags & ~(EF_LEVEL_MASK | EF_ATTR_MASK)) |
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level2subjectbits(lattr.level) |
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attr2subjectbits(lattr.flags);
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subject_unlock(p, 0, s);
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kernel_vm_drop_perms(curthread, &lattr);
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}
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void
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get_subject_lattr(lomac_subject_t *p, lattr_t *lattr) {
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int s;
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s = subject_lock(p, 1);
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lattr->level = subjectbits2level(p->p_eflags);
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lattr->flags = subjectbits2attr(p->p_eflags);
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subject_unlock(p, 1, s);
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}
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static __inline u_int
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level2lvnodebits(level_t level) {
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switch (level) {
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case LOMAC_HIGHEST_LEVEL:
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return (LN_HIGHEST_LEVEL);
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case LOMAC_LOWEST_LEVEL:
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return (LN_LOWEST_LEVEL);
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default:
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panic("level2lvnodebits: invalid level %d\n", level);
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}
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}
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static __inline level_t
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lvnodebits2level(u_int flags) {
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switch (flags & LN_LEVEL_MASK) {
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case LN_HIGHEST_LEVEL:
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return (LOMAC_HIGHEST_LEVEL);
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case LN_LOWEST_LEVEL:
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return (LOMAC_LOWEST_LEVEL);
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default:
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panic("lvnodebits2level: invalid flags %#x\n", flags);
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}
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}
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static __inline unsigned int
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attr2lvnodebits(unsigned int attr) {
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unsigned int bits = 0;
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if (attr & LOMAC_ATTR_LOWWRITE)
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bits |= LN_ATTR_LOWWRITE;
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if (attr & LOMAC_ATTR_LOWNOOPEN)
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bits |= LN_ATTR_LOWNOOPEN;
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if (attr & LOMAC_ATTR_NONETDEMOTE)
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bits |= LN_ATTR_NONETDEMOTE;
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if (attr & LOMAC_ATTR_NODEMOTE)
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bits |= LN_ATTR_NODEMOTE;
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return (bits);
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}
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static __inline unsigned int
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lvnodebits2attr(unsigned int bits) {
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unsigned int attr = 0;
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if (bits & LN_ATTR_LOWWRITE)
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attr |= LOMAC_ATTR_LOWWRITE;
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if (bits & LN_ATTR_LOWNOOPEN)
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attr |= LOMAC_ATTR_LOWNOOPEN;
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if (bits & LN_ATTR_NONETDEMOTE)
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attr |= LOMAC_ATTR_NONETDEMOTE;
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if (bits & LN_ATTR_NODEMOTE)
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attr |= LOMAC_ATTR_NODEMOTE;
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return (attr);
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}
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/*
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* These flags correspond to the same ones set in lomac_node{}s.
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*/
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#define UV_LEVEL_MASK 0x08000000
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#define UV_LOWEST_LEVEL 0x00000000
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#define UV_HIGHEST_LEVEL 0x08000000
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#define UV_ATTR_LOWWRITE 0x10000000
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#define UV_ATTR_LOWNOOPEN 0x20000000
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#define UV_ATTR_NONETDEMOTE 0x40000000
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#define UV_ATTR_NODEMOTE 0x80000000
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#define UV_ATTR_MASK 0xf0000000
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static __inline u_int
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level2uvnodebits(level_t level) {
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switch (level) {
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case LOMAC_HIGHEST_LEVEL:
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return (UV_HIGHEST_LEVEL);
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case LOMAC_LOWEST_LEVEL:
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return (UV_LOWEST_LEVEL);
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default:
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panic("level2uvnodebits: invalid level %d\n", level);
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}
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}
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static __inline level_t
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uvnodebits2level(u_int flags) {
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switch (flags & UV_LEVEL_MASK) {
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case UV_HIGHEST_LEVEL:
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return (LOMAC_HIGHEST_LEVEL);
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case UV_LOWEST_LEVEL:
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return (LOMAC_LOWEST_LEVEL);
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default:
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panic("uvnodebits2level: invalid flags %#x\n", flags);
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}
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}
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static __inline u_int
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attr2uvnodebits(u_int attr) {
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unsigned int bits = 0;
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if (attr & LOMAC_ATTR_LOWWRITE)
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bits |= UV_ATTR_LOWWRITE;
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if (attr & LOMAC_ATTR_LOWNOOPEN)
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bits |= UV_ATTR_LOWNOOPEN;
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if (attr & LOMAC_ATTR_NONETDEMOTE)
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bits |= UV_ATTR_NONETDEMOTE;
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if (attr & LOMAC_ATTR_NODEMOTE)
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bits |= UV_ATTR_NODEMOTE;
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return (bits);
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}
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static __inline u_int
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uvnodebits2attr(u_int bits) {
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unsigned int attr = 0;
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if (bits & UV_ATTR_LOWWRITE)
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attr |= LOMAC_ATTR_LOWWRITE;
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if (bits & UV_ATTR_LOWNOOPEN)
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attr |= LOMAC_ATTR_LOWNOOPEN;
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if (bits & UV_ATTR_NONETDEMOTE)
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attr |= LOMAC_ATTR_NONETDEMOTE;
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if (bits & UV_ATTR_NODEMOTE)
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attr |= LOMAC_ATTR_NODEMOTE;
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return (attr);
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}
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#define OBJ_LOWEST_LEVEL 0x8000 /* the highest level is implicit */
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/*
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* This code marks pipes with levels. We use a previously unnused bit
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* in the pipe_state field of struct pipe to store the level
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* information. Bit clear means LOMAC_HIGHEST_LEVEL, bit set means
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* LOMAC_LOWEST_LEVEL. Since new pipes have clear bits by default,
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* using clear bit as highest causes new pipes to start at the highest
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* level automatically.
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*/
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#define PIPE_LEVEL_LOWEST 0x10000000
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/* This code marks sockets created by socketpair() with levels. It
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* uses a previouslt unused bit in the so_state field of struct socket
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* to store the level information. Bit clear means
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* LOMAC_HIGHEST_LEVEL, bit set means LOMAC_LOWEST_LEVEL. Since new
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* sockets have clear bits by default, using clear bit as highest
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* causes new sockets to start at the highest level automatically.
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*/
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#define SOCKET_LEVEL_LOWEST 0x4000
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void
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set_object_lattr(lomac_object_t *obj, lattr_t lattr) {
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struct vnode *vp;
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struct lomac_node *ln;
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vm_object_t object;
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struct pipe *pipe;
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struct socket *socket;
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switch (obj->lo_type) {
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case LO_TYPE_LVNODE:
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KASSERT(VISLOMAC(obj->lo_object.vnode),
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("not a LOMACFS vnode"));
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ln = VTOLOMAC(obj->lo_object.vnode);
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ln->ln_flags =
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(ln->ln_flags & ~(LN_LEVEL_MASK | LN_ATTR_MASK)) |
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level2lvnodebits(lattr.level) |
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attr2lvnodebits(lattr.flags);
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break;
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case LO_TYPE_UVNODE:
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vp = obj->lo_object.vnode;
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KASSERT(!VISLOMAC(vp), ("is a LOMACFS vnode"));
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VI_LOCK(vp);
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vp->v_flag = (vp->v_flag & ~(UV_LEVEL_MASK | UV_ATTR_MASK)) |
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level2uvnodebits(lattr.level) |
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attr2uvnodebits(lattr.flags);
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VI_UNLOCK(vp);
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break;
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case LO_TYPE_VM_OBJECT:
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object = obj->lo_object.vm_object;
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KASSERT(object->type != OBJT_VNODE, ("object has a vnode"));
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KASSERT(object->backing_object == NULL,
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("is a backing object"));
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if (lattr.level == LOMAC_HIGHEST_LEVEL)
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vm_object_clear_flag(object, OBJ_LOWEST_LEVEL);
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else
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vm_object_set_flag(object, OBJ_LOWEST_LEVEL);
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KASSERT(lattr.flags == 0,
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("cannot set attr on a vm_object"));
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break;
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case LO_TYPE_PIPE:
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pipe = obj->lo_object.pipe;
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KASSERT(pipe->pipe_peer == NULL ||
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(pipe->pipe_state & PIPE_LEVEL_LOWEST) ==
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(pipe->pipe_peer->pipe_state & PIPE_LEVEL_LOWEST),
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("pipe attrs unsynchronized"));
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if (lattr.level == LOMAC_HIGHEST_LEVEL)
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pipe->pipe_state &= ~PIPE_LEVEL_LOWEST;
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else
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pipe->pipe_state |= PIPE_LEVEL_LOWEST;
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pipe = pipe->pipe_peer;
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if (pipe != NULL) {
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if (lattr.level == LOMAC_HIGHEST_LEVEL)
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pipe->pipe_state &= ~PIPE_LEVEL_LOWEST;
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else
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pipe->pipe_state |= PIPE_LEVEL_LOWEST;
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}
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KASSERT(lattr.flags == 0, ("cannot set attr on a pipe"));
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break;
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case LO_TYPE_SOCKETPAIR:
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socket = obj->lo_object.socket;
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/* KASSERT that socket peer levels are synchronized */
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if (lattr.level == LOMAC_HIGHEST_LEVEL)
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socket->so_state &= ~SOCKET_LEVEL_LOWEST;
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else
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socket->so_state |= SOCKET_LEVEL_LOWEST;
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#ifdef NOT_YET
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pipe = pipe->pipe_peer;
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if (pipe != NULL) {
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if (lattr.level == LOMAC_HIGHEST_LEVEL)
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pipe->pipe_state &= ~PIPE_LEVEL_LOWEST;
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else
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pipe->pipe_state |= PIPE_LEVEL_LOWEST;
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}
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KASSERT(lattr.flags == 0, ("cannot set attr on a pipe"));
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#endif
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break;
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default:
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panic("set_object_lattr: invalid lo_type %d", obj->lo_type);
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}
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}
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void
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get_object_lattr(const lomac_object_t *obj, lattr_t *lattr) {
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struct vnode *vp;
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struct lomac_node *ln;
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vm_object_t object;
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struct pipe *pipe;
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struct socket *socket;
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switch (obj->lo_type) {
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case LO_TYPE_LVNODE:
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KASSERT(VISLOMAC(obj->lo_object.vnode),
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("not a LOMACFS vnode"));
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ln = VTOLOMAC(obj->lo_object.vnode);
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lattr->level = lvnodebits2level(ln->ln_flags);
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lattr->flags = lvnodebits2attr(ln->ln_flags);
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break;
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case LO_TYPE_UVNODE:
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vp = obj->lo_object.vnode;
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KASSERT(!VISLOMAC(vp), ("is a LOMACFS vnode"));
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VI_LOCK(vp);
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lattr->level = uvnodebits2level(vp->v_flag);
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lattr->flags = uvnodebits2attr(vp->v_flag);
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VI_UNLOCK(vp);
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break;
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case LO_TYPE_VM_OBJECT:
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object = obj->lo_object.vm_object;
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KASSERT(object->type != OBJT_VNODE, ("object has a vnode"));
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KASSERT(object->backing_object == NULL,
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("is a backing object"));
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lattr->level = (object->flags & OBJ_LOWEST_LEVEL) ?
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LOMAC_LOWEST_LEVEL : LOMAC_HIGHEST_LEVEL;
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lattr->flags = 0;
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break;
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case LO_TYPE_PIPE:
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pipe = obj->lo_object.pipe;
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lattr->level = (pipe->pipe_state & PIPE_LEVEL_LOWEST) ?
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LOMAC_LOWEST_LEVEL : LOMAC_HIGHEST_LEVEL;
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lattr->flags = 0;
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break;
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case LO_TYPE_SOCKETPAIR:
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socket = obj->lo_object.socket;
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lattr->level = (socket->so_state & SOCKET_LEVEL_LOWEST) ?
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LOMAC_LOWEST_LEVEL : LOMAC_HIGHEST_LEVEL;
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lattr->flags = 0;
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break;
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default:
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panic("get_object_level: invalid lo_type %d", obj->lo_type);
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}
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}
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/*
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* Flag certain procs, like init(8) and kthreads, as "invincible".
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*/
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int
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subject_do_not_demote(lomac_subject_t *subj) {
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int inv = 0;
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if (subj->p_pid == 1) {
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inv = 1;
|
|
} else {
|
|
int had_lock = PROC_LOCKED(subj);
|
|
|
|
if (!had_lock)
|
|
PROC_LOCK(subj);
|
|
if (subj->p_flag & P_SYSTEM)
|
|
inv = 1;
|
|
if (!had_lock)
|
|
PROC_UNLOCK(subj);
|
|
}
|
|
return (inv);
|
|
}
|