2087a58ca2
privilege grants so that dtrace can be more easily used to monitor the security decisions being generated by the MAC Framework following policy invocation. Successful access control checks will be reported by: mac_framework:kernel:<entrypoint>:mac_check_ok Failed access control checks will be reported by: mac_framework:kernel:<entrypoint>:mac_check_err Successful privilege grants will be reported by: mac_framework:kernel:priv_grant:mac_grant_ok Failed privilege grants will be reported by: mac_framework:kernel:priv_grant:mac_grant_err In all cases, the return value (always 0 for _ok, otherwise an errno for _err) will be reported via arg0 on the probe, and subsequent arguments will hold entrypoint-specific data, in a style similar to privilege tracing. Obtained from: TrustedBSD Project Sponsored by: Google, Inc.
588 lines
14 KiB
C
588 lines
14 KiB
C
/*-
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* Copyright (c) 1999-2002, 2008-2009 Robert N. M. Watson
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* Copyright (c) 2001 Ilmar S. Habibulin
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* Copyright (c) 2001-2003 Networks Associates Technology, Inc.
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* Copyright (c) 2005 Samy Al Bahra
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* Copyright (c) 2006 SPARTA, Inc.
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* Copyright (c) 2008 Apple Inc.
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* All rights reserved.
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*
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* This software was developed by Robert Watson and Ilmar Habibulin for the
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* TrustedBSD Project.
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*
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* This software was developed for the FreeBSD Project in part by Network
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* Associates Laboratories, the Security Research Division of Network
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* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
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* as part of the DARPA CHATS research program.
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*
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* This software was enhanced by SPARTA ISSO under SPAWAR contract
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* N66001-04-C-6019 ("SEFOS").
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*
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* This software was developed at the University of Cambridge Computer
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* Laboratory with support from a grant from Google, Inc.
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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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*
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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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_kdtrace.h"
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#include "opt_mac.h"
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#include <sys/param.h>
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#include <sys/condvar.h>
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#include <sys/imgact.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/mac.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/sdt.h>
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#include <sys/systm.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/file.h>
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#include <sys/namei.h>
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#include <sys/sysctl.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 <vm/vm_object.h>
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#include <security/mac/mac_framework.h>
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#include <security/mac/mac_internal.h>
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#include <security/mac/mac_policy.h>
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static int mac_mmap_revocation = 1;
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SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation, CTLFLAG_RW,
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&mac_mmap_revocation, 0, "Revoke mmap access to files on subject "
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"relabel");
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static int mac_mmap_revocation_via_cow = 0;
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SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW,
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&mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via "
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"copy-on-write semantics, or by removing all write access");
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static void mac_proc_vm_revoke_recurse(struct thread *td,
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struct ucred *cred, struct vm_map *map);
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static struct label *
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mac_proc_label_alloc(void)
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{
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struct label *label;
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label = mac_labelzone_alloc(M_WAITOK);
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MAC_PERFORM(proc_init_label, label);
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return (label);
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}
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void
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mac_proc_init(struct proc *p)
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{
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if (mac_labeled & MPC_OBJECT_PROC)
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p->p_label = mac_proc_label_alloc();
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else
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p->p_label = NULL;
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}
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static void
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mac_proc_label_free(struct label *label)
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{
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MAC_PERFORM(proc_destroy_label, label);
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mac_labelzone_free(label);
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}
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void
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mac_proc_destroy(struct proc *p)
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{
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if (p->p_label != NULL) {
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mac_proc_label_free(p->p_label);
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p->p_label = NULL;
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}
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}
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void
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mac_thread_userret(struct thread *td)
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{
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MAC_PERFORM(thread_userret, td);
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}
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int
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mac_execve_enter(struct image_params *imgp, struct mac *mac_p)
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{
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struct label *label;
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struct mac mac;
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char *buffer;
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int error;
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if (mac_p == NULL)
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return (0);
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if (!(mac_labeled & MPC_OBJECT_CRED))
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return (EINVAL);
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error = copyin(mac_p, &mac, sizeof(mac));
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if (error)
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return (error);
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error = mac_check_structmac_consistent(&mac);
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if (error)
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return (error);
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buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
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error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
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if (error) {
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free(buffer, M_MACTEMP);
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return (error);
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}
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label = mac_cred_label_alloc();
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error = mac_cred_internalize_label(label, buffer);
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free(buffer, M_MACTEMP);
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if (error) {
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mac_cred_label_free(label);
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return (error);
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}
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imgp->execlabel = label;
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return (0);
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}
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void
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mac_execve_exit(struct image_params *imgp)
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{
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if (imgp->execlabel != NULL) {
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mac_cred_label_free(imgp->execlabel);
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imgp->execlabel = NULL;
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}
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}
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void
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mac_execve_interpreter_enter(struct vnode *interpvp,
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struct label **interpvplabel)
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{
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if (mac_labeled & MPC_OBJECT_VNODE) {
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*interpvplabel = mac_vnode_label_alloc();
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mac_vnode_copy_label(interpvp->v_label, *interpvplabel);
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} else
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*interpvplabel = NULL;
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}
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void
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mac_execve_interpreter_exit(struct label *interpvplabel)
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{
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if (interpvplabel != NULL)
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mac_vnode_label_free(interpvplabel);
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}
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/*
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* When relabeling a process, call out to the policies for the maximum
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* permission allowed for each object type we know about in its memory space,
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* and revoke access (in the least surprising ways we know) when necessary.
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* The process lock is not held here.
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*/
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void
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mac_proc_vm_revoke(struct thread *td)
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{
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struct ucred *cred;
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PROC_LOCK(td->td_proc);
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cred = crhold(td->td_proc->p_ucred);
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PROC_UNLOCK(td->td_proc);
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/* XXX freeze all other threads */
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mac_proc_vm_revoke_recurse(td, cred,
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&td->td_proc->p_vmspace->vm_map);
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/* XXX allow other threads to continue */
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crfree(cred);
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}
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static __inline const char *
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prot2str(vm_prot_t prot)
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{
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switch (prot & VM_PROT_ALL) {
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case VM_PROT_READ:
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return ("r--");
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case VM_PROT_READ | VM_PROT_WRITE:
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return ("rw-");
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case VM_PROT_READ | VM_PROT_EXECUTE:
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return ("r-x");
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case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE:
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return ("rwx");
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case VM_PROT_WRITE:
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return ("-w-");
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case VM_PROT_EXECUTE:
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return ("--x");
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case VM_PROT_WRITE | VM_PROT_EXECUTE:
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return ("-wx");
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default:
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return ("---");
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}
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}
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static void
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mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
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struct vm_map *map)
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{
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vm_map_entry_t vme;
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int vfslocked, result;
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vm_prot_t revokeperms;
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vm_object_t backing_object, object;
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vm_ooffset_t offset;
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struct vnode *vp;
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struct mount *mp;
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if (!mac_mmap_revocation)
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return;
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vm_map_lock(map);
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for (vme = map->header.next; vme != &map->header; vme = vme->next) {
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if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
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mac_proc_vm_revoke_recurse(td, cred,
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vme->object.sub_map);
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continue;
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}
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/*
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* Skip over entries that obviously are not shared.
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*/
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if (vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC) ||
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!vme->max_protection)
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continue;
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/*
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* Drill down to the deepest backing object.
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*/
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offset = vme->offset;
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object = vme->object.vm_object;
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if (object == NULL)
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continue;
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VM_OBJECT_LOCK(object);
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while ((backing_object = object->backing_object) != NULL) {
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VM_OBJECT_LOCK(backing_object);
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offset += object->backing_object_offset;
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VM_OBJECT_UNLOCK(object);
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object = backing_object;
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}
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VM_OBJECT_UNLOCK(object);
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/*
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* At the moment, vm_maps and objects aren't considered by
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* the MAC system, so only things with backing by a normal
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* object (read: vnodes) are checked.
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*/
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if (object->type != OBJT_VNODE)
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continue;
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vp = (struct vnode *)object->handle;
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vfslocked = VFS_LOCK_GIANT(vp->v_mount);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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result = vme->max_protection;
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mac_vnode_check_mmap_downgrade(cred, vp, &result);
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VOP_UNLOCK(vp, 0);
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/*
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* Find out what maximum protection we may be allowing now
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* but a policy needs to get removed.
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*/
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revokeperms = vme->max_protection & ~result;
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if (!revokeperms) {
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VFS_UNLOCK_GIANT(vfslocked);
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continue;
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}
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printf("pid %ld: revoking %s perms from %#lx:%ld "
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"(max %s/cur %s)\n", (long)td->td_proc->p_pid,
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prot2str(revokeperms), (u_long)vme->start,
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(long)(vme->end - vme->start),
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prot2str(vme->max_protection), prot2str(vme->protection));
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/*
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* This is the really simple case: if a map has more
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* max_protection than is allowed, but it's not being
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* actually used (that is, the current protection is still
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* allowed), we can just wipe it out and do nothing more.
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*/
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if ((vme->protection & revokeperms) == 0) {
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vme->max_protection -= revokeperms;
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} else {
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if (revokeperms & VM_PROT_WRITE) {
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/*
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* In the more complicated case, flush out all
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* pending changes to the object then turn it
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* copy-on-write.
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*/
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vm_object_reference(object);
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(void) vn_start_write(vp, &mp, V_WAIT);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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VM_OBJECT_LOCK(object);
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vm_object_page_clean(object,
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OFF_TO_IDX(offset),
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OFF_TO_IDX(offset + vme->end - vme->start +
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PAGE_MASK),
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OBJPC_SYNC);
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VM_OBJECT_UNLOCK(object);
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VOP_UNLOCK(vp, 0);
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vn_finished_write(mp);
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vm_object_deallocate(object);
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/*
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* Why bother if there's no read permissions
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* anymore? For the rest, we need to leave
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* the write permissions on for COW, or
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* remove them entirely if configured to.
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*/
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if (!mac_mmap_revocation_via_cow) {
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vme->max_protection &= ~VM_PROT_WRITE;
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vme->protection &= ~VM_PROT_WRITE;
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} if ((revokeperms & VM_PROT_READ) == 0)
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vme->eflags |= MAP_ENTRY_COW |
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MAP_ENTRY_NEEDS_COPY;
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}
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if (revokeperms & VM_PROT_EXECUTE) {
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vme->max_protection &= ~VM_PROT_EXECUTE;
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vme->protection &= ~VM_PROT_EXECUTE;
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}
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if (revokeperms & VM_PROT_READ) {
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vme->max_protection = 0;
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vme->protection = 0;
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}
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pmap_protect(map->pmap, vme->start, vme->end,
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vme->protection & ~revokeperms);
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vm_map_simplify_entry(map, vme);
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}
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VFS_UNLOCK_GIANT(vfslocked);
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}
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vm_map_unlock(map);
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}
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MAC_CHECK_PROBE_DEFINE2(proc_check_debug, "struct ucred *", "struct proc *");
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int
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mac_proc_check_debug(struct ucred *cred, struct proc *p)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_debug, cred, p);
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MAC_CHECK_PROBE2(proc_check_debug, error, cred, p);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE2(proc_check_sched, "struct ucred *", "struct proc *");
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int
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mac_proc_check_sched(struct ucred *cred, struct proc *p)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_sched, cred, p);
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MAC_CHECK_PROBE2(proc_check_sched, error, cred, p);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE3(proc_check_signal, "struct ucred *", "struct proc *",
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"int");
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int
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mac_proc_check_signal(struct ucred *cred, struct proc *p, int signum)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_signal, cred, p, signum);
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MAC_CHECK_PROBE3(proc_check_signal, error, cred, p, signum);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE2(proc_check_setuid, "struct ucred *", "uid_t");
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int
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mac_proc_check_setuid(struct proc *p, struct ucred *cred, uid_t uid)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_setuid, cred, uid);
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MAC_CHECK_PROBE2(proc_check_setuid, error, cred, uid);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE2(proc_check_seteuid, "struct ucred *", "uid_t");
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int
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mac_proc_check_seteuid(struct proc *p, struct ucred *cred, uid_t euid)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_seteuid, cred, euid);
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MAC_CHECK_PROBE2(proc_check_seteuid, error, cred, euid);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE2(proc_check_setgid, "struct ucred *", "gid_t");
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int
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mac_proc_check_setgid(struct proc *p, struct ucred *cred, gid_t gid)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_setgid, cred, gid);
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MAC_CHECK_PROBE2(proc_check_setgid, error, cred, gid);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE2(proc_check_setegid, "struct ucred *", "gid_t");
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int
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mac_proc_check_setegid(struct proc *p, struct ucred *cred, gid_t egid)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_setegid, cred, egid);
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MAC_CHECK_PROBE2(proc_check_setegid, error, cred, egid);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE3(proc_check_setgroups, "struct ucred *", "int",
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"gid_t *");
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int
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mac_proc_check_setgroups(struct proc *p, struct ucred *cred, int ngroups,
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gid_t *gidset)
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{
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int error;
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PROC_LOCK_ASSERT(p, MA_OWNED);
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MAC_CHECK(proc_check_setgroups, cred, ngroups, gidset);
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MAC_CHECK_PROBE3(proc_check_setgroups, error, cred, ngroups, gidset);
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return (error);
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}
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MAC_CHECK_PROBE_DEFINE3(proc_check_setreuid, "struct ucred *", "uid_t",
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"uid_t");
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|
|
int
|
|
mac_proc_check_setreuid(struct proc *p, struct ucred *cred, uid_t ruid,
|
|
uid_t euid)
|
|
{
|
|
int error;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
|
|
MAC_CHECK(proc_check_setreuid, cred, ruid, euid);
|
|
MAC_CHECK_PROBE3(proc_check_setreuid, error, cred, ruid, euid);
|
|
|
|
return (error);
|
|
}
|
|
|
|
MAC_CHECK_PROBE_DEFINE3(proc_check_setregid, "struct ucred *", "gid_t",
|
|
"gid_t");
|
|
|
|
int
|
|
mac_proc_check_setregid(struct proc *proc, struct ucred *cred, gid_t rgid,
|
|
gid_t egid)
|
|
{
|
|
int error;
|
|
|
|
PROC_LOCK_ASSERT(proc, MA_OWNED);
|
|
|
|
MAC_CHECK(proc_check_setregid, cred, rgid, egid);
|
|
MAC_CHECK_PROBE3(proc_check_setregid, error, cred, rgid, egid);
|
|
|
|
return (error);
|
|
}
|
|
|
|
MAC_CHECK_PROBE_DEFINE4(proc_check_setresuid, "struct ucred *", "uid_t",
|
|
"uid_t", "uid_t");
|
|
|
|
int
|
|
mac_proc_check_setresuid(struct proc *p, struct ucred *cred, uid_t ruid,
|
|
uid_t euid, uid_t suid)
|
|
{
|
|
int error;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
|
|
MAC_CHECK(proc_check_setresuid, cred, ruid, euid, suid);
|
|
MAC_CHECK_PROBE4(proc_check_setresuid, error, cred, ruid, euid,
|
|
suid);
|
|
|
|
return (error);
|
|
}
|
|
|
|
MAC_CHECK_PROBE_DEFINE4(proc_check_setresgid, "struct ucred *", "gid_t",
|
|
"gid_t", "gid_t");
|
|
|
|
int
|
|
mac_proc_check_setresgid(struct proc *p, struct ucred *cred, gid_t rgid,
|
|
gid_t egid, gid_t sgid)
|
|
{
|
|
int error;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
|
|
MAC_CHECK(proc_check_setresgid, cred, rgid, egid, sgid);
|
|
MAC_CHECK_PROBE4(proc_check_setresgid, error, cred, rgid, egid,
|
|
sgid);
|
|
|
|
return (error);
|
|
}
|
|
|
|
MAC_CHECK_PROBE_DEFINE2(proc_check_wait, "struct ucred *", "struct proc *");
|
|
|
|
int
|
|
mac_proc_check_wait(struct ucred *cred, struct proc *p)
|
|
{
|
|
int error;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
|
|
MAC_CHECK(proc_check_wait, cred, p);
|
|
MAC_CHECK_PROBE2(proc_check_wait, error, cred, p);
|
|
|
|
return (error);
|
|
}
|