b3e7e1b010
code and not trying to use temporary solutions. Lots of comments and help from YAMAMOTO Takashi, also thanks to the PaX author for being quick to recognize that something fishy's going on. :) Hook up in mmap/vmcmd rather than (ugh!) uvm_map_protect(). Next time I suggest to commit a temporary solution just revoke my commit bit.
112 lines
3.9 KiB
C
112 lines
3.9 KiB
C
/* $NetBSD: kern_pax.c,v 1.3 2006/05/20 15:45:37 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 <uvm/uvm_extern.h>
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#include <sys/pax.h>
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#include <sys/sysctl.h>
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int pax_mprotect_enabled = 1;
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int pax_mprotect_global = PAX_MPROTECT;
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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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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_protection",
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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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}
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void
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pax_mprotect_adjust(struct lwp *l, int f)
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{
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if (!pax_mprotect_enabled)
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return;
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if (f & PF_PAXMPROTECT)
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l->l_proc->p_flag |= P_PAXMPROTECT;
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if (f & PF_PAXNOMPROTECT)
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l->l_proc->p_flag |= P_PAXNOMPROTECT;
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}
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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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if (!pax_mprotect_enabled ||
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(pax_mprotect_global && (l->l_proc->p_flag & P_PAXNOMPROTECT)) ||
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(!pax_mprotect_global && !(l->l_proc->p_flag & P_PAXMPROTECT)))
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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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