/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1999-2006, 2016-2017 Robert N. M. Watson
* All rights reserved.
*
* This software was developed by Robert Watson for the TrustedBSD Project.
*
* Portions of this software were developed by BAE Systems, the University of
* Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL
* contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent
* Computing (TC) research program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Developed by the TrustedBSD Project.
*
* ACL system calls and other functions common across different ACL types.
* Type-specific routines go into subr_acl_<type>.c.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/capsicum.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/proc.h>
#include <sys/sysent.h>
#include <sys/acl.h>
#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>
CTASSERT(ACL_MAX_ENTRIES >= OLDACL_MAX_ENTRIES);
MALLOC_DEFINE(M_ACL, "acl", "Access Control Lists");
static int kern___acl_aclcheck_path(struct thread *td, const char *path,
acl_type_t type, struct acl *aclp, int follow);
static int kern___acl_delete_path(struct thread *td, const char *path,
acl_type_t type, int follow);
static int kern___acl_get_path(struct thread *td, const char *path,
acl_type_t type, struct acl *aclp, int follow);
static int kern___acl_set_path(struct thread *td, const char *path,
acl_type_t type, const struct acl *aclp, int follow);
static int vacl_set_acl(struct thread *td, struct vnode *vp,
acl_type_t type, const struct acl *aclp);
static int vacl_get_acl(struct thread *td, struct vnode *vp,
acl_type_t type, struct acl *aclp);
static int vacl_aclcheck(struct thread *td, struct vnode *vp,
acl_type_t type, const struct acl *aclp);
int
acl_copy_oldacl_into_acl(const struct oldacl *source, struct acl *dest)
{
int i;
if (source->acl_cnt < 0 || source->acl_cnt > OLDACL_MAX_ENTRIES)
return (EINVAL);
bzero(dest, sizeof(*dest));
dest->acl_cnt = source->acl_cnt;
dest->acl_maxcnt = ACL_MAX_ENTRIES;
for (i = 0; i < dest->acl_cnt; i++) {
dest->acl_entry[i].ae_tag = source->acl_entry[i].ae_tag;
dest->acl_entry[i].ae_id = source->acl_entry[i].ae_id;
dest->acl_entry[i].ae_perm = source->acl_entry[i].ae_perm;
}
return (0);
}
int
acl_copy_acl_into_oldacl(const struct acl *source, struct oldacl *dest)
{
int i;
if (source->acl_cnt > OLDACL_MAX_ENTRIES)
return (EINVAL);
bzero(dest, sizeof(*dest));
dest->acl_cnt = source->acl_cnt;
for (i = 0; i < dest->acl_cnt; i++) {
dest->acl_entry[i].ae_tag = source->acl_entry[i].ae_tag;
dest->acl_entry[i].ae_id = source->acl_entry[i].ae_id;
dest->acl_entry[i].ae_perm = source->acl_entry[i].ae_perm;
}
return (0);
}
/*
* At one time, "struct ACL" was extended in order to add support for NFSv4
* ACLs. Instead of creating compatibility versions of all the ACL-related
* syscalls, they were left intact. It's possible to find out what the code
* calling these syscalls (libc) expects basing on "type" argument - if it's
* either ACL_TYPE_ACCESS_OLD or ACL_TYPE_DEFAULT_OLD (which previously were
* known as ACL_TYPE_ACCESS and ACL_TYPE_DEFAULT), then it's the "struct
* oldacl". If it's something else, then it's the new "struct acl". In the
* latter case, the routines below just copyin/copyout the contents. In the
* former case, they copyin the "struct oldacl" and convert it to the new
* format.
*/
static int
acl_copyin(const void *user_acl, struct acl *kernel_acl, acl_type_t type)
{
int error;
struct oldacl old;
switch (type) {
case ACL_TYPE_ACCESS_OLD:
case ACL_TYPE_DEFAULT_OLD:
error = copyin(user_acl, &old, sizeof(old));
if (error != 0)
break;
acl_copy_oldacl_into_acl(&old, kernel_acl);
break;
default:
error = copyin(user_acl, kernel_acl, sizeof(*kernel_acl));
if (kernel_acl->acl_maxcnt != ACL_MAX_ENTRIES)
return (EINVAL);
}
return (error);
}
static int
acl_copyout(const struct acl *kernel_acl, void *user_acl, acl_type_t type)
{
uint32_t am;
int error;
struct oldacl old;
switch (type) {
case ACL_TYPE_ACCESS_OLD:
case ACL_TYPE_DEFAULT_OLD:
error = acl_copy_acl_into_oldacl(kernel_acl, &old);
if (error != 0)
break;
error = copyout(&old, user_acl, sizeof(old));
break;
default:
error = fueword32((char *)user_acl +
offsetof(struct acl, acl_maxcnt), &am);
if (error == -1)
return (EFAULT);
if (am != ACL_MAX_ENTRIES)
return (EINVAL);
error = copyout(kernel_acl, user_acl, sizeof(*kernel_acl));
}
return (error);
}
/*
* Convert "old" type - ACL_TYPE_{ACCESS,DEFAULT}_OLD - into its "new"
* counterpart. It's required for old (pre-NFSv4 ACLs) libc to work
* with new kernel. Fixing 'type' for old binaries with new libc
* is being done in lib/libc/posix1e/acl_support.c:_acl_type_unold().
*/
static int
acl_type_unold(int type)
{
switch (type) {
case ACL_TYPE_ACCESS_OLD:
return (ACL_TYPE_ACCESS);
case ACL_TYPE_DEFAULT_OLD:
return (ACL_TYPE_DEFAULT);
default:
return (type);
}
}
/*
* These calls wrap the real vnode operations, and are called by the syscall
* code once the syscall has converted the path or file descriptor to a vnode
* (unlocked). The aclp pointer is assumed still to point to userland, so
* this should not be consumed within the kernel except by syscall code.
* Other code should directly invoke VOP_{SET,GET}ACL.
*/
/*
* Given a vnode, set its ACL.
*/
static int
vacl_set_acl(struct thread *td, struct vnode *vp, acl_type_t type,
const struct acl *aclp)
{
struct acl *inkernelacl;
struct mount *mp;
int error;
AUDIT_ARG_VALUE(type);
inkernelacl = acl_alloc(M_WAITOK);
error = acl_copyin(aclp, inkernelacl, type);
if (error != 0)
goto out;
error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
if (error != 0)
goto out;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
#ifdef MAC
error = mac_vnode_check_setacl(td->td_ucred, vp, type, inkernelacl);
if (error != 0)
goto out_unlock;
#endif
error = VOP_SETACL(vp, acl_type_unold(type), inkernelacl,
td->td_ucred, td);
#ifdef MAC
out_unlock:
#endif
VOP_UNLOCK(vp);
vn_finished_write(mp);
out:
acl_free(inkernelacl);
return (error);
}
/*
* Given a vnode, get its ACL.
*/
static int
vacl_get_acl(struct thread *td, struct vnode *vp, acl_type_t type,
struct acl *aclp)
{
struct acl *inkernelacl;
int error;
AUDIT_ARG_VALUE(type);
inkernelacl = acl_alloc(M_WAITOK | M_ZERO);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
#ifdef MAC
error = mac_vnode_check_getacl(td->td_ucred, vp, type);
if (error != 0)
goto out;
#endif
error = VOP_GETACL(vp, acl_type_unold(type), inkernelacl,
td->td_ucred, td);
#ifdef MAC
out:
#endif
VOP_UNLOCK(vp);
if (error == 0)
error = acl_copyout(inkernelacl, aclp, type);
acl_free(inkernelacl);
return (error);
}
/*
* Given a vnode, delete its ACL.
*/
static int
vacl_delete(struct thread *td, struct vnode *vp, acl_type_t type)
{
struct mount *mp;
int error;
AUDIT_ARG_VALUE(type);
error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
if (error != 0)
return (error);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
#ifdef MAC
error = mac_vnode_check_deleteacl(td->td_ucred, vp, type);
if (error != 0)
goto out;
#endif
error = VOP_SETACL(vp, acl_type_unold(type), 0, td->td_ucred, td);
#ifdef MAC
out:
#endif
VOP_UNLOCK(vp);
vn_finished_write(mp);
return (error);
}
/*
* Given a vnode, check whether an ACL is appropriate for it
*
* XXXRW: No vnode lock held so can't audit vnode state...?
*/
static int
vacl_aclcheck(struct thread *td, struct vnode *vp, acl_type_t type,
const struct acl *aclp)
{
struct acl *inkernelacl;
int error;
inkernelacl = acl_alloc(M_WAITOK);
error = acl_copyin(aclp, inkernelacl, type);
if (error != 0)
goto out;
error = VOP_ACLCHECK(vp, acl_type_unold(type), inkernelacl,
td->td_ucred, td);
out:
acl_free(inkernelacl);
return (error);
}
/*
* syscalls -- convert the path/fd to a vnode, and call vacl_whatever. Don't
* need to lock, as the vacl_ code will get/release any locks required.
*/
/*
* Given a file path, get an ACL for it
*/
int
sys___acl_get_file(struct thread *td, struct __acl_get_file_args *uap)
{
return (kern___acl_get_path(td, uap->path, uap->type, uap->aclp,
FOLLOW));
}
/*
* Given a file path, get an ACL for it; don't follow links.
*/
int
sys___acl_get_link(struct thread *td, struct __acl_get_link_args *uap)
{
return(kern___acl_get_path(td, uap->path, uap->type, uap->aclp,
NOFOLLOW));
}
static int
kern___acl_get_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 | AUDITVNODE1, UIO_USERSPACE, path, td);
error = namei(&nd);
if (error == 0) {
error = vacl_get_acl(td, nd.ni_vp, type, aclp);
NDFREE(&nd, 0);
}
return (error);
}
/*
* Given a file path, set an ACL for it.
*/
int
sys___acl_set_file(struct thread *td, struct __acl_set_file_args *uap)
{
return(kern___acl_set_path(td, uap->path, uap->type, uap->aclp,
FOLLOW));
}
/*
* Given a file path, set an ACL for it; don't follow links.
*/
int
sys___acl_set_link(struct thread *td, struct __acl_set_link_args *uap)
{
return(kern___acl_set_path(td, uap->path, uap->type, uap->aclp,
NOFOLLOW));
}
static int
kern___acl_set_path(struct thread *td, const char *path,
acl_type_t type, const struct acl *aclp, int follow)
{
struct nameidata nd;
int error;
NDINIT(&nd, LOOKUP, follow | AUDITVNODE1, UIO_USERSPACE, path, td);
error = namei(&nd);
if (error == 0) {
error = vacl_set_acl(td, nd.ni_vp, type, aclp);
NDFREE(&nd, 0);
}
return (error);
}
/*
* Given a file descriptor, get an ACL for it.
*/
int
sys___acl_get_fd(struct thread *td, struct __acl_get_fd_args *uap)
{
struct file *fp;
cap_rights_t rights;
int error;
AUDIT_ARG_FD(uap->filedes);
error = getvnode(td, uap->filedes,
cap_rights_init_one(&rights, CAP_ACL_GET), &fp);
if (error == 0) {
error = vacl_get_acl(td, fp->f_vnode, uap->type, uap->aclp);
fdrop(fp, td);
}
return (error);
}
/*
* Given a file descriptor, set an ACL for it.
*/
int
sys___acl_set_fd(struct thread *td, struct __acl_set_fd_args *uap)
{
struct file *fp;
cap_rights_t rights;
int error;
AUDIT_ARG_FD(uap->filedes);
error = getvnode(td, uap->filedes,
cap_rights_init_one(&rights, CAP_ACL_SET), &fp);
if (error == 0) {
error = vacl_set_acl(td, fp->f_vnode, uap->type, uap->aclp);
fdrop(fp, td);
}
return (error);
}
/*
* Given a file path, delete an ACL from it.
*/
int
sys___acl_delete_file(struct thread *td, struct __acl_delete_file_args *uap)
{
return (kern___acl_delete_path(td, uap->path, uap->type, FOLLOW));
}
/*
* Given a file path, delete an ACL from it; don't follow links.
*/
int
sys___acl_delete_link(struct thread *td, struct __acl_delete_link_args *uap)
{
return (kern___acl_delete_path(td, uap->path, uap->type, NOFOLLOW));
}
static int
kern___acl_delete_path(struct thread *td, const char *path,
acl_type_t type, int follow)
{
struct nameidata nd;
int error;
NDINIT(&nd, LOOKUP, follow, UIO_USERSPACE, path, td);
error = namei(&nd);
if (error == 0) {
error = vacl_delete(td, nd.ni_vp, type);
NDFREE(&nd, 0);
}
return (error);
}
/*
* Given a file path, delete an ACL from it.
*/
int
sys___acl_delete_fd(struct thread *td, struct __acl_delete_fd_args *uap)
{
struct file *fp;
cap_rights_t rights;
int error;
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, td);
error = namei(&nd);
if (error == 0) {
error = vacl_aclcheck(td, nd.ni_vp, type, aclp);
NDFREE(&nd, 0);
}
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(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);
}
