142 lines
4.5 KiB
C
142 lines
4.5 KiB
C
/* $NetBSD: kern_pax.c,v 1.7 2006/11/22 00:41:38 elad Exp $ */
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/*-
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* Copyright (c) 2006 Elad Efrat <elad@NetBSD.org>
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* All rights reserved.
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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. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Elad Efrat.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "opt_pax.h"
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/exec_elf.h>
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#include <sys/pax.h>
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#include <sys/sysctl.h>
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#ifdef PAX_MPROTECT
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static int pax_mprotect_enabled = 1;
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static int pax_mprotect_global = PAX_MPROTECT;
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specificdata_key_t pax_mprotect_key;
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#endif /* PAX_MPROTECT */
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/* PaX internal setspecific flags */
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#define PAX_MPROTECT_EXPLICIT_ENABLE (void *)0x01
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#define PAX_MPROTECT_EXPLICIT_DISABLE (void *)0x02
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SYSCTL_SETUP(sysctl_security_pax_setup, "sysctl security.pax setup")
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{
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const struct sysctlnode *rnode = NULL;
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sysctl_createv(clog, 0, NULL, &rnode,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "security", NULL,
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NULL, 0, NULL, 0,
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CTL_CREATE, CTL_EOL);
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sysctl_createv(clog, 0, &rnode, &rnode,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "pax",
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SYSCTL_DESCR("PaX (exploit mitigation) features."),
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NULL, 0, NULL, 0,
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CTL_CREATE, CTL_EOL);
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#ifdef PAX_MPROTECT
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sysctl_createv(clog, 0, &rnode, &rnode,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "mprotect",
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SYSCTL_DESCR("mprotect(2) W^X restrictions."),
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NULL, 0, NULL, 0,
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CTL_CREATE, CTL_EOL);
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sysctl_createv(clog, 0, &rnode, NULL,
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CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
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CTLTYPE_INT, "enabled",
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SYSCTL_DESCR("Restrictions enabled."),
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NULL, 0, &pax_mprotect_enabled, 0,
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CTL_CREATE, CTL_EOL);
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sysctl_createv(clog, 0, &rnode, NULL,
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CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
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CTLTYPE_INT, "global",
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SYSCTL_DESCR("When enabled, unless explicitly "
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"specified, apply restrictions to "
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"all processes."),
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NULL, 0, &pax_mprotect_global, 0,
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CTL_CREATE, CTL_EOL);
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#endif /* PAX_MPROTECT */
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}
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/*
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* Initialize PaX.
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*/
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void
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pax_init(void)
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{
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#ifdef PAX_MPROTECT
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proc_specific_key_create(&pax_mprotect_key, NULL);
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#endif /* PAX_MPROTECT */
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}
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void
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pax_adjust(struct lwp *l, int f)
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{
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#ifdef PAX_MPROTECT
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if (pax_mprotect_enabled) {
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if (f & PF_PAXMPROTECT)
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proc_setspecific(l->l_proc, pax_mprotect_key,
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PAX_MPROTECT_EXPLICIT_ENABLE);
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if (f & PF_PAXNOMPROTECT)
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proc_setspecific(l->l_proc, pax_mprotect_key,
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PAX_MPROTECT_EXPLICIT_DISABLE);
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}
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#endif /* PAX_MPROTECT */
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}
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#ifdef PAX_MPROTECT
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void
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pax_mprotect(struct lwp *l, vm_prot_t *prot, vm_prot_t *maxprot)
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{
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void *t;
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if (!pax_mprotect_enabled)
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return;
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t = proc_getspecific(l->l_proc, pax_mprotect_key);
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if ((pax_mprotect_global && t == PAX_MPROTECT_EXPLICIT_DISABLE) ||
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(!pax_mprotect_global && t != PAX_MPROTECT_EXPLICIT_ENABLE))
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return;
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if ((*prot & (VM_PROT_WRITE|VM_PROT_EXECUTE)) != VM_PROT_EXECUTE) {
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*prot &= ~VM_PROT_EXECUTE;
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*maxprot &= ~VM_PROT_EXECUTE;
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} else {
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*prot &= ~VM_PROT_WRITE;
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*maxprot &= ~VM_PROT_WRITE;
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}
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}
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#endif /* PAX_MPROTECT */
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