f51e58036e
the MAC policy modules to improve robustness against C string bugs and vulnerabilities. Following these revisions, all string construction of labels for export to userspace (or elsewhere) is performed using the sbuf API, which prevents the consumer from having to perform laborious and intricate pointer and buffer checks. This substantially simplifies the externalization logic, both at the MAC Framework level, and in individual policies; this becomes especially useful when policies export more complex label data, such as with compartments in Biba and MLS. Bundled in here are some other minor fixes associated with externalization: including avoiding malloc while holding the process mutex in mac_lomac, and hence avoid a failure mode when printing labels during a downgrade operation due to the removal of the M_NOWAIT case. This has been running in the MAC development tree for about three weeks without problems. Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
291 lines
7.2 KiB
C
291 lines
7.2 KiB
C
/*-
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* Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
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* Copyright (c) 2001, 2002 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed by Robert Watson for the 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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* 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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* $FreeBSD$
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*/
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/*
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* Developed by the TrustedBSD Project.
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* Experiment with a partition-like model.
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*/
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/mac.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/sysent.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.h>
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#include <fs/devfs/devfs.h>
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#include <net/bpfdesc.h>
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#include <net/if.h>
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#include <net/if_types.h>
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#include <net/if_var.h>
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#include <vm/vm.h>
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#include <sys/mac_policy.h>
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#include <security/mac_partition/mac_partition.h>
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SYSCTL_DECL(_security_mac);
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SYSCTL_NODE(_security_mac, OID_AUTO, partition, CTLFLAG_RW, 0,
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"TrustedBSD mac_partition policy controls");
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static int mac_partition_enabled = 1;
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SYSCTL_INT(_security_mac_partition, OID_AUTO, enabled, CTLFLAG_RW,
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&mac_partition_enabled, 0, "Enforce partition policy");
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static int partition_slot;
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#define SLOT(l) (LABEL_TO_SLOT((l), partition_slot).l_long)
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static void
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mac_partition_init(struct mac_policy_conf *conf)
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{
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}
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static void
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mac_partition_init_label(struct label *label)
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{
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SLOT(label) = 0;
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}
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static void
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mac_partition_destroy_label(struct label *label)
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{
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SLOT(label) = 0;
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}
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static int
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mac_partition_externalize_label(struct label *label, char *element_name,
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struct sbuf *sb, int *claimed)
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{
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if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
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return (0);
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(*claimed)++;
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if (sbuf_printf(sb, "%ld", SLOT(label)) == -1)
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return (EINVAL);
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else
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return (0);
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}
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static int
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mac_partition_internalize_label(struct label *label, char *element_name,
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char *element_data, int *claimed)
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{
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if (strcmp(MAC_PARTITION_LABEL_NAME, element_name) != 0)
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return (0);
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(*claimed)++;
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SLOT(label) = strtol(element_data, NULL, 10);
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return (0);
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}
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static void
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mac_partition_create_cred(struct ucred *cred_parent, struct ucred *cred_child)
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{
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SLOT(&cred_child->cr_label) = SLOT(&cred_parent->cr_label);
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}
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static void
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mac_partition_create_proc0(struct ucred *cred)
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{
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SLOT(&cred->cr_label) = 0;
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}
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static void
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mac_partition_create_proc1(struct ucred *cred)
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{
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SLOT(&cred->cr_label) = 0;
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}
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static void
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mac_partition_relabel_cred(struct ucred *cred, struct label *newlabel)
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{
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if (SLOT(newlabel) != 0)
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SLOT(&cred->cr_label) = SLOT(newlabel);
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}
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static int
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label_on_label(struct label *subject, struct label *object)
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{
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if (mac_partition_enabled == 0)
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return (0);
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if (SLOT(subject) == 0)
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return (0);
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if (SLOT(subject) == SLOT(object))
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return (0);
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return (EPERM);
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}
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static int
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mac_partition_check_cred_relabel(struct ucred *cred, struct label *newlabel)
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{
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int error;
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error = 0;
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/* Treat "0" as a no-op request. */
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if (SLOT(newlabel) != 0) {
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/*
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* Require BSD privilege in order to change the partition.
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* Originally we also required that the process not be
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* in a partition in the first place, but this didn't
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* interact well with sendmail.
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*/
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error = suser_cred(cred, 0);
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}
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return (error);
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}
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static int
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mac_partition_check_cred_visible(struct ucred *u1, struct ucred *u2)
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{
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int error;
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error = label_on_label(&u1->cr_label, &u2->cr_label);
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return (error == 0 ? 0 : ESRCH);
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}
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static int
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mac_partition_check_proc_debug(struct ucred *cred, struct proc *proc)
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{
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int error;
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error = label_on_label(&cred->cr_label, &proc->p_ucred->cr_label);
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return (error ? ESRCH : 0);
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}
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static int
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mac_partition_check_proc_sched(struct ucred *cred, struct proc *proc)
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{
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int error;
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error = label_on_label(&cred->cr_label, &proc->p_ucred->cr_label);
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return (error ? ESRCH : 0);
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}
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static int
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mac_partition_check_proc_signal(struct ucred *cred, struct proc *proc,
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int signum)
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{
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int error;
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error = label_on_label(&cred->cr_label, &proc->p_ucred->cr_label);
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return (error ? ESRCH : 0);
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}
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static int
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mac_partition_check_socket_visible(struct ucred *cred, struct socket *socket,
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struct label *socketlabel)
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{
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int error;
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error = label_on_label(&cred->cr_label, socketlabel);
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return (error ? ENOENT : 0);
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}
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static int
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mac_partition_check_vnode_exec(struct ucred *cred, struct vnode *vp,
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struct label *label, struct image_params *imgp, struct label *execlabel)
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{
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if (execlabel != NULL) {
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/*
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* We currently don't permit labels to be changed at
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* exec-time as part of the partition model, so disallow
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* non-NULL partition label changes in execlabel.
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*/
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if (SLOT(execlabel) != 0)
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return (EINVAL);
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}
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return (0);
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}
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static struct mac_policy_ops mac_partition_ops =
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{
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.mpo_init = mac_partition_init,
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.mpo_init_cred_label = mac_partition_init_label,
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.mpo_destroy_cred_label = mac_partition_destroy_label,
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.mpo_externalize_cred_label = mac_partition_externalize_label,
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.mpo_internalize_cred_label = mac_partition_internalize_label,
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.mpo_create_cred = mac_partition_create_cred,
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.mpo_create_proc0 = mac_partition_create_proc0,
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.mpo_create_proc1 = mac_partition_create_proc1,
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.mpo_relabel_cred = mac_partition_relabel_cred,
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.mpo_check_cred_relabel = mac_partition_check_cred_relabel,
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.mpo_check_cred_visible = mac_partition_check_cred_visible,
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.mpo_check_proc_debug = mac_partition_check_proc_debug,
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.mpo_check_proc_sched = mac_partition_check_proc_sched,
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.mpo_check_proc_signal = mac_partition_check_proc_signal,
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.mpo_check_socket_visible = mac_partition_check_socket_visible,
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.mpo_check_vnode_exec = mac_partition_check_vnode_exec,
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};
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MAC_POLICY_SET(&mac_partition_ops, mac_partition, "TrustedBSD MAC/Partition",
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MPC_LOADTIME_FLAG_UNLOADOK, &partition_slot);
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