126 lines
3.7 KiB
C
126 lines
3.7 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/systm.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/module.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/syscall.h>
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#include <sys/sysent.h>
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#include <machine/frame.h>
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#include "syscall_gate.h"
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void syscall_gate_init(void);
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int syscall_gate(struct thread *td, caddr_t params);
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static struct syscall_gate sg;
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void
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syscall_gate_init(void) {
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sg.sg_table = curthread->td_proc->p_sysent->sv_table;
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bzero(sg.sg_oldsyscalls, sizeof(sg.sg_oldsyscalls));
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}
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int
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syscall_gate_register(int offset, sy_call_t *call, int narg, int mpsafe) {
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struct sysent *se;
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int error = 0;
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if (offset <= 0 || offset >= SYS_MAXSYSCALL) {
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error = EINVAL;
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goto out;
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}
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if (sg.sg_oldsyscalls[offset].sy_call != NULL) {
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error = EEXIST;
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goto out;
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}
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se = &sg.sg_table[offset];
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sg.sg_oldsyscalls[offset] = *se;
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se->sy_call = (sy_call_t *)call;
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se->sy_narg = narg | (mpsafe ? SYF_MPSAFE : 0);
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out:
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return (error);
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}
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void
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syscall_gate_deregister(int offset) {
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KASSERT(offset > 0 && offset < SYS_MAXSYSCALL, ("syscall offset %d out of range",
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offset));
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KASSERT(sg.sg_oldsyscalls[offset].sy_call != NULL, ("deregistering nonexistant syscall %d",
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offset));
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sg.sg_table[offset] = sg.sg_oldsyscalls[offset];
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sg.sg_oldsyscalls[offset].sy_call = NULL;
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sg.sg_oldsyscalls[offset].sy_narg = 0;
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}
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static int
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syscall_gate_modevent(module_t module, int event, void *unused) {
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int i;
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switch ((enum modeventtype)event) {
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case MOD_LOAD:
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syscall_gate_init();
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break;
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case MOD_UNLOAD:
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for (i = 1; i < SYS_MAXSYSCALL; i++) {
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struct sysent *se;
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se = &sg.sg_oldsyscalls[i];
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if (se->sy_call != NULL)
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sg.sg_table[i] = *se;
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}
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break;
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case MOD_SHUTDOWN:
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break;
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}
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return (0);
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}
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static moduledata_t syscall_gate_moduledata = {
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"syscall_gate",
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&syscall_gate_modevent,
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NULL
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};
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DECLARE_MODULE(syscall_gate, syscall_gate_moduledata, SI_SUB_DRIVERS, SI_ORDER_ANY);
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MODULE_VERSION(syscall_gate, 1);
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