600 lines
14 KiB
C
600 lines
14 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 1999-2006, 2016-2017 Robert N. M. Watson
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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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* Portions of this software were developed by BAE Systems, the University of
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* Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL
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* contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent
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* Computing (TC) 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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/*
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* Developed by the TrustedBSD Project.
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*
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* ACL system calls and other functions common across different ACL types.
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* Type-specific routines go into subr_acl_<type>.c.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/capsicum.h>
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#include <sys/fcntl.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/vnode.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/namei.h>
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#include <sys/file.h>
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#include <sys/filedesc.h>
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#include <sys/proc.h>
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#include <sys/acl.h>
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#include <security/audit/audit.h>
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#include <security/mac/mac_framework.h>
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CTASSERT(ACL_MAX_ENTRIES >= OLDACL_MAX_ENTRIES);
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MALLOC_DEFINE(M_ACL, "acl", "Access Control Lists");
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static int kern___acl_aclcheck_path(struct thread *td, const char *path,
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acl_type_t type, struct acl *aclp, int follow);
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static int kern___acl_delete_path(struct thread *td, const char *path,
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acl_type_t type, int follow);
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static int kern___acl_get_path(struct thread *td, const char *path,
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acl_type_t type, struct acl *aclp, int follow);
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static int kern___acl_set_path(struct thread *td, const char *path,
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acl_type_t type, const struct acl *aclp, int follow);
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static int vacl_set_acl(struct thread *td, struct vnode *vp,
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acl_type_t type, const struct acl *aclp);
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static int vacl_get_acl(struct thread *td, struct vnode *vp,
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acl_type_t type, struct acl *aclp);
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static int vacl_aclcheck(struct thread *td, struct vnode *vp,
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acl_type_t type, const struct acl *aclp);
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int
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acl_copy_oldacl_into_acl(const struct oldacl *source, struct acl *dest)
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{
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int i;
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if (source->acl_cnt < 0 || source->acl_cnt > OLDACL_MAX_ENTRIES)
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return (EINVAL);
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bzero(dest, sizeof(*dest));
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dest->acl_cnt = source->acl_cnt;
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dest->acl_maxcnt = ACL_MAX_ENTRIES;
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for (i = 0; i < dest->acl_cnt; i++) {
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dest->acl_entry[i].ae_tag = source->acl_entry[i].ae_tag;
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dest->acl_entry[i].ae_id = source->acl_entry[i].ae_id;
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dest->acl_entry[i].ae_perm = source->acl_entry[i].ae_perm;
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}
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return (0);
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}
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int
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acl_copy_acl_into_oldacl(const struct acl *source, struct oldacl *dest)
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{
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int i;
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if (source->acl_cnt > OLDACL_MAX_ENTRIES)
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return (EINVAL);
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bzero(dest, sizeof(*dest));
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dest->acl_cnt = source->acl_cnt;
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for (i = 0; i < dest->acl_cnt; i++) {
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dest->acl_entry[i].ae_tag = source->acl_entry[i].ae_tag;
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dest->acl_entry[i].ae_id = source->acl_entry[i].ae_id;
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dest->acl_entry[i].ae_perm = source->acl_entry[i].ae_perm;
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}
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return (0);
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}
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/*
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* At one time, "struct ACL" was extended in order to add support for NFSv4
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* ACLs. Instead of creating compatibility versions of all the ACL-related
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* syscalls, they were left intact. It's possible to find out what the code
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* calling these syscalls (libc) expects basing on "type" argument - if it's
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* either ACL_TYPE_ACCESS_OLD or ACL_TYPE_DEFAULT_OLD (which previously were
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* known as ACL_TYPE_ACCESS and ACL_TYPE_DEFAULT), then it's the "struct
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* oldacl". If it's something else, then it's the new "struct acl". In the
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* latter case, the routines below just copyin/copyout the contents. In the
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* former case, they copyin the "struct oldacl" and convert it to the new
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* format.
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*/
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static int
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acl_copyin(const void *user_acl, struct acl *kernel_acl, acl_type_t type)
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{
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int error;
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struct oldacl old;
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switch (type) {
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case ACL_TYPE_ACCESS_OLD:
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case ACL_TYPE_DEFAULT_OLD:
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error = copyin(user_acl, &old, sizeof(old));
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if (error != 0)
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break;
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acl_copy_oldacl_into_acl(&old, kernel_acl);
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break;
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default:
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error = copyin(user_acl, kernel_acl, sizeof(*kernel_acl));
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if (kernel_acl->acl_maxcnt != ACL_MAX_ENTRIES)
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return (EINVAL);
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}
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return (error);
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}
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static int
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acl_copyout(const struct acl *kernel_acl, void *user_acl, acl_type_t type)
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{
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uint32_t am;
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int error;
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struct oldacl old;
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switch (type) {
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case ACL_TYPE_ACCESS_OLD:
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case ACL_TYPE_DEFAULT_OLD:
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error = acl_copy_acl_into_oldacl(kernel_acl, &old);
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if (error != 0)
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break;
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error = copyout(&old, user_acl, sizeof(old));
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break;
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default:
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error = fueword32((char *)user_acl +
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offsetof(struct acl, acl_maxcnt), &am);
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if (error == -1)
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return (EFAULT);
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if (am != ACL_MAX_ENTRIES)
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return (EINVAL);
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error = copyout(kernel_acl, user_acl, sizeof(*kernel_acl));
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}
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return (error);
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}
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/*
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* Convert "old" type - ACL_TYPE_{ACCESS,DEFAULT}_OLD - into its "new"
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* counterpart. It's required for old (pre-NFSv4 ACLs) libc to work
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* with new kernel. Fixing 'type' for old binaries with new libc
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* is being done in lib/libc/posix1e/acl_support.c:_acl_type_unold().
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*/
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static int
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acl_type_unold(int type)
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{
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switch (type) {
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case ACL_TYPE_ACCESS_OLD:
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return (ACL_TYPE_ACCESS);
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case ACL_TYPE_DEFAULT_OLD:
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return (ACL_TYPE_DEFAULT);
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default:
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return (type);
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}
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}
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/*
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* These calls wrap the real vnode operations, and are called by the syscall
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* code once the syscall has converted the path or file descriptor to a vnode
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* (unlocked). The aclp pointer is assumed still to point to userland, so
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* this should not be consumed within the kernel except by syscall code.
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* Other code should directly invoke VOP_{SET,GET}ACL.
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*/
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/*
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* Given a vnode, set its ACL.
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*/
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static int
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vacl_set_acl(struct thread *td, struct vnode *vp, acl_type_t type,
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const struct acl *aclp)
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{
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struct acl *inkernelacl;
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struct mount *mp;
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int error;
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AUDIT_ARG_VALUE(type);
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inkernelacl = acl_alloc(M_WAITOK);
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error = acl_copyin(aclp, inkernelacl, type);
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if (error != 0)
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goto out;
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error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH);
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if (error != 0)
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goto out;
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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AUDIT_ARG_VNODE1(vp);
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#ifdef MAC
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error = mac_vnode_check_setacl(td->td_ucred, vp, type, inkernelacl);
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if (error != 0)
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goto out_unlock;
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#endif
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error = VOP_SETACL(vp, acl_type_unold(type), inkernelacl,
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td->td_ucred, td);
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#ifdef MAC
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out_unlock:
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#endif
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VOP_UNLOCK(vp);
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vn_finished_write(mp);
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out:
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acl_free(inkernelacl);
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return (error);
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}
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/*
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* Given a vnode, get its ACL.
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*/
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static int
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vacl_get_acl(struct thread *td, struct vnode *vp, acl_type_t type,
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struct acl *aclp)
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{
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struct acl *inkernelacl;
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int error;
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AUDIT_ARG_VALUE(type);
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inkernelacl = acl_alloc(M_WAITOK | M_ZERO);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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AUDIT_ARG_VNODE1(vp);
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#ifdef MAC
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error = mac_vnode_check_getacl(td->td_ucred, vp, type);
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if (error != 0)
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goto out;
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#endif
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error = VOP_GETACL(vp, acl_type_unold(type), inkernelacl,
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td->td_ucred, td);
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#ifdef MAC
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out:
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#endif
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VOP_UNLOCK(vp);
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if (error == 0)
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error = acl_copyout(inkernelacl, aclp, type);
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acl_free(inkernelacl);
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return (error);
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}
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/*
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* Given a vnode, delete its ACL.
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*/
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static int
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vacl_delete(struct thread *td, struct vnode *vp, acl_type_t type)
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{
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struct mount *mp;
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int error;
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AUDIT_ARG_VALUE(type);
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error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH);
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if (error != 0)
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return (error);
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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AUDIT_ARG_VNODE1(vp);
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#ifdef MAC
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error = mac_vnode_check_deleteacl(td->td_ucred, vp, type);
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if (error != 0)
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goto out;
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#endif
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error = VOP_SETACL(vp, acl_type_unold(type), 0, td->td_ucred, td);
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#ifdef MAC
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out:
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#endif
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VOP_UNLOCK(vp);
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vn_finished_write(mp);
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return (error);
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}
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/*
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* Given a vnode, check whether an ACL is appropriate for it
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*
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* XXXRW: No vnode lock held so can't audit vnode state...?
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*/
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static int
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vacl_aclcheck(struct thread *td, struct vnode *vp, acl_type_t type,
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const struct acl *aclp)
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{
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struct acl *inkernelacl;
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int error;
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inkernelacl = acl_alloc(M_WAITOK);
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error = acl_copyin(aclp, inkernelacl, type);
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if (error != 0)
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goto out;
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error = VOP_ACLCHECK(vp, acl_type_unold(type), inkernelacl,
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td->td_ucred, td);
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out:
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acl_free(inkernelacl);
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return (error);
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}
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/*
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* syscalls -- convert the path/fd to a vnode, and call vacl_whatever. Don't
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* need to lock, as the vacl_ code will get/release any locks required.
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*/
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/*
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* Given a file path, get an ACL for it
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*/
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int
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sys___acl_get_file(struct thread *td, struct __acl_get_file_args *uap)
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{
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return (kern___acl_get_path(td, uap->path, uap->type, uap->aclp,
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FOLLOW));
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}
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/*
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* Given a file path, get an ACL for it; don't follow links.
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*/
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int
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sys___acl_get_link(struct thread *td, struct __acl_get_link_args *uap)
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{
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return(kern___acl_get_path(td, uap->path, uap->type, uap->aclp,
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NOFOLLOW));
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}
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static int
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kern___acl_get_path(struct thread *td, const char *path, acl_type_t type,
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struct acl *aclp, int follow)
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{
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struct nameidata nd;
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int error;
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NDINIT(&nd, LOOKUP, follow | AUDITVNODE1, UIO_USERSPACE, path);
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error = namei(&nd);
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if (error == 0) {
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error = vacl_get_acl(td, nd.ni_vp, type, aclp);
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vrele(nd.ni_vp);
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NDFREE_PNBUF(&nd);
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}
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return (error);
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}
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/*
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* Given a file path, set an ACL for it.
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*/
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int
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sys___acl_set_file(struct thread *td, struct __acl_set_file_args *uap)
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{
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return(kern___acl_set_path(td, uap->path, uap->type, uap->aclp,
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FOLLOW));
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}
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/*
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* Given a file path, set an ACL for it; don't follow links.
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*/
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int
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sys___acl_set_link(struct thread *td, struct __acl_set_link_args *uap)
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{
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return(kern___acl_set_path(td, uap->path, uap->type, uap->aclp,
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NOFOLLOW));
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}
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static int
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kern___acl_set_path(struct thread *td, const char *path,
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acl_type_t type, const struct acl *aclp, int follow)
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{
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struct nameidata nd;
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int error;
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NDINIT(&nd, LOOKUP, follow | AUDITVNODE1, UIO_USERSPACE, path);
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error = namei(&nd);
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if (error == 0) {
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error = vacl_set_acl(td, nd.ni_vp, type, aclp);
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vrele(nd.ni_vp);
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NDFREE_PNBUF(&nd);
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}
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return (error);
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}
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/*
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* Given a file descriptor, get an ACL for it.
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*/
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int
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sys___acl_get_fd(struct thread *td, struct __acl_get_fd_args *uap)
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{
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struct file *fp;
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cap_rights_t rights;
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int error;
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AUDIT_ARG_FD(uap->filedes);
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error = getvnode_path(td, uap->filedes,
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cap_rights_init_one(&rights, CAP_ACL_GET), &fp);
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if (error == 0) {
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error = vacl_get_acl(td, fp->f_vnode, uap->type, uap->aclp);
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fdrop(fp, td);
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}
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return (error);
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}
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/*
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* Given a file descriptor, set an ACL for it.
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*/
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int
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sys___acl_set_fd(struct thread *td, struct __acl_set_fd_args *uap)
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{
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struct file *fp;
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cap_rights_t rights;
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int error;
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AUDIT_ARG_FD(uap->filedes);
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error = getvnode(td, uap->filedes,
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cap_rights_init_one(&rights, CAP_ACL_SET), &fp);
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if (error == 0) {
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error = vacl_set_acl(td, fp->f_vnode, uap->type, uap->aclp);
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fdrop(fp, td);
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}
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return (error);
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}
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/*
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* Given a file path, delete an ACL from it.
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*/
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int
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sys___acl_delete_file(struct thread *td, struct __acl_delete_file_args *uap)
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{
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return (kern___acl_delete_path(td, uap->path, uap->type, FOLLOW));
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}
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/*
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* Given a file path, delete an ACL from it; don't follow links.
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*/
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int
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sys___acl_delete_link(struct thread *td, struct __acl_delete_link_args *uap)
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{
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return (kern___acl_delete_path(td, uap->path, uap->type, NOFOLLOW));
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}
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static int
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kern___acl_delete_path(struct thread *td, const char *path,
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acl_type_t type, int follow)
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{
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struct nameidata nd;
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int error;
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NDINIT(&nd, LOOKUP, follow, UIO_USERSPACE, path);
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error = namei(&nd);
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if (error == 0) {
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error = vacl_delete(td, nd.ni_vp, type);
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vrele(nd.ni_vp);
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NDFREE_PNBUF(&nd);
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}
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return (error);
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}
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/*
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* Given a file path, delete an ACL from it.
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*/
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int
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sys___acl_delete_fd(struct thread *td, struct __acl_delete_fd_args *uap)
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{
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struct file *fp;
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cap_rights_t rights;
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int error;
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|
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AUDIT_ARG_FD(uap->filedes);
|
|
error = getvnode(td, uap->filedes,
|
|
cap_rights_init_one(&rights, CAP_ACL_DELETE), &fp);
|
|
if (error == 0) {
|
|
error = vacl_delete(td, fp->f_vnode, uap->type);
|
|
fdrop(fp, td);
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Given a file path, check an ACL for it.
|
|
*/
|
|
int
|
|
sys___acl_aclcheck_file(struct thread *td, struct __acl_aclcheck_file_args *uap)
|
|
{
|
|
|
|
return (kern___acl_aclcheck_path(td, uap->path, uap->type, uap->aclp,
|
|
FOLLOW));
|
|
}
|
|
|
|
/*
|
|
* Given a file path, check an ACL for it; don't follow links.
|
|
*/
|
|
int
|
|
sys___acl_aclcheck_link(struct thread *td, struct __acl_aclcheck_link_args *uap)
|
|
{
|
|
return (kern___acl_aclcheck_path(td, uap->path, uap->type, uap->aclp,
|
|
NOFOLLOW));
|
|
}
|
|
|
|
static int
|
|
kern___acl_aclcheck_path(struct thread *td, const char *path, acl_type_t type,
|
|
struct acl *aclp, int follow)
|
|
{
|
|
struct nameidata nd;
|
|
int error;
|
|
|
|
NDINIT(&nd, LOOKUP, follow, UIO_USERSPACE, path);
|
|
error = namei(&nd);
|
|
if (error == 0) {
|
|
error = vacl_aclcheck(td, nd.ni_vp, type, aclp);
|
|
NDFREE_PNBUF(&nd);
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Given a file descriptor, check an ACL for it.
|
|
*/
|
|
int
|
|
sys___acl_aclcheck_fd(struct thread *td, struct __acl_aclcheck_fd_args *uap)
|
|
{
|
|
struct file *fp;
|
|
cap_rights_t rights;
|
|
int error;
|
|
|
|
AUDIT_ARG_FD(uap->filedes);
|
|
error = getvnode_path(td, uap->filedes,
|
|
cap_rights_init_one(&rights, CAP_ACL_CHECK), &fp);
|
|
if (error == 0) {
|
|
error = vacl_aclcheck(td, fp->f_vnode, uap->type, uap->aclp);
|
|
fdrop(fp, td);
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
struct acl *
|
|
acl_alloc(int flags)
|
|
{
|
|
struct acl *aclp;
|
|
|
|
aclp = malloc(sizeof(*aclp), M_ACL, flags);
|
|
if (aclp == NULL)
|
|
return (NULL);
|
|
|
|
aclp->acl_maxcnt = ACL_MAX_ENTRIES;
|
|
|
|
return (aclp);
|
|
}
|
|
|
|
void
|
|
acl_free(struct acl *aclp)
|
|
{
|
|
|
|
free(aclp, M_ACL);
|
|
}
|