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freebsd-skq/sys/security/mac/mac_syscalls.c
Robert Watson 6356dba0b4 Introduce two related changes to the TrustedBSD MAC Framework: 
(1) Abstract interpreter vnode labeling in execve(2) and mac_execve(2)
    so that the general exec code isn't aware of the details of
    allocating, copying, and freeing labels, rather, simply passes in
    a void pointer to start and stop functions that will be used by
    the framework.  This change will be MFC'd.

(2) Introduce a new flags field to the MAC_POLICY_SET(9) interface
    allowing policies to declare which types of objects require label
    allocation, initialization, and destruction, and define a set of
    flags covering various supported object types (MPC_OBJECT_PROC,
    MPC_OBJECT_VNODE, MPC_OBJECT_INPCB, ...).  This change reduces the
    overhead of compiling the MAC Framework into the kernel if policies
    aren't loaded, or if policies require labels on only a small number
    or even no object types.  Each time a policy is loaded or unloaded,
    we recalculate a mask of labeled object types across all policies
    present in the system.  Eliminate MAC_ALWAYS_LABEL_MBUF option as it
    is no longer required.

MFC after:	1 week ((1) only)
Reviewed by:	csjp
Obtained from:	TrustedBSD Project
Sponsored by:	Apple, Inc.
2008-08-23 15:26:36 +00:00

732 lines
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/*-
* Copyright (c) 1999-2002, 2006 Robert N. M. Watson
* Copyright (c) 2001 Ilmar S. Habibulin
* Copyright (c) 2001-2005 Networks Associates Technology, Inc.
* Copyright (c) 2005-2006 SPARTA, Inc.
* Copyright (c) 2008 Apple Inc.
* All rights reserved.
*
* This software was developed by Robert Watson and Ilmar Habibulin for the
* TrustedBSD Project.
*
* This software was developed for the FreeBSD Project in part by Network
* Associates Laboratories, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
* as part of the DARPA CHATS research program.
*
* This software was enhanced by SPARTA ISSO under SPAWAR contract
* N66001-04-C-6019 ("SEFOS").
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mac.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/sysent.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/file.h>
#include <sys/namei.h>
#include <sys/socket.h>
#include <sys/pipe.h>
#include <sys/socketvar.h>
#include <security/mac/mac_framework.h>
#include <security/mac/mac_internal.h>
#include <security/mac/mac_policy.h>
#ifdef MAC
int
__mac_get_pid(struct thread *td, struct __mac_get_pid_args *uap)
{
char *elements, *buffer;
struct mac mac;
struct proc *tproc;
struct ucred *tcred;
int error;
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
tproc = pfind(uap->pid);
if (tproc == NULL)
return (ESRCH);
tcred = NULL; /* Satisfy gcc. */
error = p_cansee(td, tproc);
if (error == 0)
tcred = crhold(tproc->p_ucred);
PROC_UNLOCK(tproc);
if (error)
return (error);
elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
if (error) {
free(elements, M_MACTEMP);
crfree(tcred);
return (error);
}
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
error = mac_cred_externalize_label(tcred->cr_label, elements,
buffer, mac.m_buflen);
if (error == 0)
error = copyout(buffer, mac.m_string, strlen(buffer)+1);
free(buffer, M_MACTEMP);
free(elements, M_MACTEMP);
crfree(tcred);
return (error);
}
int
__mac_get_proc(struct thread *td, struct __mac_get_proc_args *uap)
{
char *elements, *buffer;
struct mac mac;
int error;
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
if (error) {
free(elements, M_MACTEMP);
return (error);
}
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
error = mac_cred_externalize_label(td->td_ucred->cr_label,
elements, buffer, mac.m_buflen);
if (error == 0)
error = copyout(buffer, mac.m_string, strlen(buffer)+1);
free(buffer, M_MACTEMP);
free(elements, M_MACTEMP);
return (error);
}
int
__mac_set_proc(struct thread *td, struct __mac_set_proc_args *uap)
{
struct ucred *newcred, *oldcred;
struct label *intlabel;
struct proc *p;
struct mac mac;
char *buffer;
int error;
if (!(mac_labeled & MPC_OBJECT_CRED))
return (EINVAL);
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
if (error) {
free(buffer, M_MACTEMP);
return (error);
}
intlabel = mac_cred_label_alloc();
error = mac_cred_internalize_label(intlabel, buffer);
free(buffer, M_MACTEMP);
if (error)
goto out;
newcred = crget();
p = td->td_proc;
PROC_LOCK(p);
oldcred = p->p_ucred;
error = mac_cred_check_relabel(oldcred, intlabel);
if (error) {
PROC_UNLOCK(p);
crfree(newcred);
goto out;
}
setsugid(p);
crcopy(newcred, oldcred);
mac_cred_relabel(newcred, intlabel);
p->p_ucred = newcred;
/*
* Grab additional reference for use while revoking mmaps, prior to
* releasing the proc lock and sharing the cred.
*/
crhold(newcred);
PROC_UNLOCK(p);
mac_cred_mmapped_drop_perms(td, newcred);
crfree(newcred); /* Free revocation reference. */
crfree(oldcred);
out:
mac_cred_label_free(intlabel);
return (error);
}
int
__mac_get_fd(struct thread *td, struct __mac_get_fd_args *uap)
{
char *elements, *buffer;
struct label *intlabel;
struct file *fp;
struct mac mac;
struct vnode *vp;
struct pipe *pipe;
struct socket *so;
short label_type;
int vfslocked, error;
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
if (error) {
free(elements, M_MACTEMP);
return (error);
}
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
error = fget(td, uap->fd, &fp);
if (error)
goto out;
label_type = fp->f_type;
switch (fp->f_type) {
case DTYPE_FIFO:
case DTYPE_VNODE:
if (!(mac_labeled & MPC_OBJECT_VNODE))
return (EINVAL);
vp = fp->f_vnode;
intlabel = mac_vnode_label_alloc();
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
mac_vnode_copy_label(vp->v_label, intlabel);
VOP_UNLOCK(vp, 0);
VFS_UNLOCK_GIANT(vfslocked);
error = mac_vnode_externalize_label(intlabel, elements,
buffer, mac.m_buflen);
mac_vnode_label_free(intlabel);
break;
case DTYPE_PIPE:
if (!(mac_labeled & MPC_OBJECT_PIPE))
return (EINVAL);
pipe = fp->f_data;
intlabel = mac_pipe_label_alloc();
PIPE_LOCK(pipe);
mac_pipe_copy_label(pipe->pipe_pair->pp_label, intlabel);
PIPE_UNLOCK(pipe);
error = mac_pipe_externalize_label(intlabel, elements,
buffer, mac.m_buflen);
mac_pipe_label_free(intlabel);
break;
case DTYPE_SOCKET:
if (!(mac_labeled & MPC_OBJECT_SOCKET))
return (EINVAL);
so = fp->f_data;
intlabel = mac_socket_label_alloc(M_WAITOK);
SOCK_LOCK(so);
mac_socket_copy_label(so->so_label, intlabel);
SOCK_UNLOCK(so);
error = mac_socket_externalize_label(intlabel, elements,
buffer, mac.m_buflen);
mac_socket_label_free(intlabel);
break;
default:
error = EINVAL;
}
fdrop(fp, td);
if (error == 0)
error = copyout(buffer, mac.m_string, strlen(buffer)+1);
out:
free(buffer, M_MACTEMP);
free(elements, M_MACTEMP);
return (error);
}
int
__mac_get_file(struct thread *td, struct __mac_get_file_args *uap)
{
char *elements, *buffer;
struct nameidata nd;
struct label *intlabel;
struct mac mac;
int vfslocked, error;
if (!(mac_labeled & MPC_OBJECT_VNODE))
return (EINVAL);
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
if (error) {
free(elements, M_MACTEMP);
return (error);
}
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
NDINIT(&nd, LOOKUP, MPSAFE | LOCKLEAF | FOLLOW, UIO_USERSPACE,
uap->path_p, td);
error = namei(&nd);
if (error)
goto out;
intlabel = mac_vnode_label_alloc();
vfslocked = NDHASGIANT(&nd);
mac_vnode_copy_label(nd.ni_vp->v_label, intlabel);
error = mac_vnode_externalize_label(intlabel, elements, buffer,
mac.m_buflen);
NDFREE(&nd, 0);
VFS_UNLOCK_GIANT(vfslocked);
mac_vnode_label_free(intlabel);
if (error == 0)
error = copyout(buffer, mac.m_string, strlen(buffer)+1);
out:
free(buffer, M_MACTEMP);
free(elements, M_MACTEMP);
return (error);
}
int
__mac_get_link(struct thread *td, struct __mac_get_link_args *uap)
{
char *elements, *buffer;
struct nameidata nd;
struct label *intlabel;
struct mac mac;
int vfslocked, error;
if (!(mac_labeled & MPC_OBJECT_VNODE))
return (EINVAL);
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
elements = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, elements, mac.m_buflen, NULL);
if (error) {
free(elements, M_MACTEMP);
return (error);
}
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK | M_ZERO);
NDINIT(&nd, LOOKUP, MPSAFE | LOCKLEAF | NOFOLLOW, UIO_USERSPACE,
uap->path_p, td);
error = namei(&nd);
if (error)
goto out;
intlabel = mac_vnode_label_alloc();
vfslocked = NDHASGIANT(&nd);
mac_vnode_copy_label(nd.ni_vp->v_label, intlabel);
error = mac_vnode_externalize_label(intlabel, elements, buffer,
mac.m_buflen);
NDFREE(&nd, 0);
VFS_UNLOCK_GIANT(vfslocked);
mac_vnode_label_free(intlabel);
if (error == 0)
error = copyout(buffer, mac.m_string, strlen(buffer)+1);
out:
free(buffer, M_MACTEMP);
free(elements, M_MACTEMP);
return (error);
}
int
__mac_set_fd(struct thread *td, struct __mac_set_fd_args *uap)
{
struct label *intlabel;
struct pipe *pipe;
struct socket *so;
struct file *fp;
struct mount *mp;
struct vnode *vp;
struct mac mac;
char *buffer;
int error, vfslocked;
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
if (error) {
free(buffer, M_MACTEMP);
return (error);
}
error = fget(td, uap->fd, &fp);
if (error)
goto out;
switch (fp->f_type) {
case DTYPE_FIFO:
case DTYPE_VNODE:
if (!(mac_labeled & MPC_OBJECT_VNODE))
return (EINVAL);
intlabel = mac_vnode_label_alloc();
error = mac_vnode_internalize_label(intlabel, buffer);
if (error) {
mac_vnode_label_free(intlabel);
break;
}
vp = fp->f_vnode;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
if (error != 0) {
VFS_UNLOCK_GIANT(vfslocked);
mac_vnode_label_free(intlabel);
break;
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = vn_setlabel(vp, intlabel, td->td_ucred);
VOP_UNLOCK(vp, 0);
vn_finished_write(mp);
VFS_UNLOCK_GIANT(vfslocked);
mac_vnode_label_free(intlabel);
break;
case DTYPE_PIPE:
if (!(mac_labeled & MPC_OBJECT_PIPE))
return (EINVAL);
intlabel = mac_pipe_label_alloc();
error = mac_pipe_internalize_label(intlabel, buffer);
if (error == 0) {
pipe = fp->f_data;
PIPE_LOCK(pipe);
error = mac_pipe_label_set(td->td_ucred,
pipe->pipe_pair, intlabel);
PIPE_UNLOCK(pipe);
}
mac_pipe_label_free(intlabel);
break;
case DTYPE_SOCKET:
if (!(mac_labeled & MPC_OBJECT_SOCKET))
return (EINVAL);
intlabel = mac_socket_label_alloc(M_WAITOK);
error = mac_socket_internalize_label(intlabel, buffer);
if (error == 0) {
so = fp->f_data;
error = mac_socket_label_set(td->td_ucred, so,
intlabel);
}
mac_socket_label_free(intlabel);
break;
default:
error = EINVAL;
}
fdrop(fp, td);
out:
free(buffer, M_MACTEMP);
return (error);
}
int
__mac_set_file(struct thread *td, struct __mac_set_file_args *uap)
{
struct label *intlabel;
struct nameidata nd;
struct mount *mp;
struct mac mac;
char *buffer;
int vfslocked, error;
if (!(mac_labeled & MPC_OBJECT_VNODE))
return (EINVAL);
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
if (error) {
free(buffer, M_MACTEMP);
return (error);
}
intlabel = mac_vnode_label_alloc();
error = mac_vnode_internalize_label(intlabel, buffer);
free(buffer, M_MACTEMP);
if (error)
goto out;
NDINIT(&nd, LOOKUP, MPSAFE | LOCKLEAF | FOLLOW, UIO_USERSPACE,
uap->path_p, td);
error = namei(&nd);
vfslocked = NDHASGIANT(&nd);
if (error == 0) {
error = vn_start_write(nd.ni_vp, &mp, V_WAIT | PCATCH);
if (error == 0) {
error = vn_setlabel(nd.ni_vp, intlabel,
td->td_ucred);
vn_finished_write(mp);
}
}
NDFREE(&nd, 0);
VFS_UNLOCK_GIANT(vfslocked);
out:
mac_vnode_label_free(intlabel);
return (error);
}
int
__mac_set_link(struct thread *td, struct __mac_set_link_args *uap)
{
struct label *intlabel;
struct nameidata nd;
struct mount *mp;
struct mac mac;
char *buffer;
int vfslocked, error;
if (!(mac_labeled & MPC_OBJECT_VNODE))
return (EINVAL);
error = copyin(uap->mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
if (error) {
free(buffer, M_MACTEMP);
return (error);
}
intlabel = mac_vnode_label_alloc();
error = mac_vnode_internalize_label(intlabel, buffer);
free(buffer, M_MACTEMP);
if (error)
goto out;
NDINIT(&nd, LOOKUP, MPSAFE | LOCKLEAF | NOFOLLOW, UIO_USERSPACE,
uap->path_p, td);
error = namei(&nd);
vfslocked = NDHASGIANT(&nd);
if (error == 0) {
error = vn_start_write(nd.ni_vp, &mp, V_WAIT | PCATCH);
if (error == 0) {
error = vn_setlabel(nd.ni_vp, intlabel,
td->td_ucred);
vn_finished_write(mp);
}
}
NDFREE(&nd, 0);
VFS_UNLOCK_GIANT(vfslocked);
out:
mac_vnode_label_free(intlabel);
return (error);
}
int
mac_syscall(struct thread *td, struct mac_syscall_args *uap)
{
struct mac_policy_conf *mpc;
char target[MAC_MAX_POLICY_NAME];
int entrycount, error;
error = copyinstr(uap->policy, target, sizeof(target), NULL);
if (error)
return (error);
error = ENOSYS;
LIST_FOREACH(mpc, &mac_static_policy_list, mpc_list) {
if (strcmp(mpc->mpc_name, target) == 0 &&
mpc->mpc_ops->mpo_syscall != NULL) {
error = mpc->mpc_ops->mpo_syscall(td,
uap->call, uap->arg);
goto out;
}
}
if ((entrycount = mac_policy_list_conditional_busy()) != 0) {
LIST_FOREACH(mpc, &mac_policy_list, mpc_list) {
if (strcmp(mpc->mpc_name, target) == 0 &&
mpc->mpc_ops->mpo_syscall != NULL) {
error = mpc->mpc_ops->mpo_syscall(td,
uap->call, uap->arg);
break;
}
}
mac_policy_list_unbusy();
}
out:
return (error);
}
#else /* !MAC */
int
__mac_get_pid(struct thread *td, struct __mac_get_pid_args *uap)
{
return (ENOSYS);
}
int
__mac_get_proc(struct thread *td, struct __mac_get_proc_args *uap)
{
return (ENOSYS);
}
int
__mac_set_proc(struct thread *td, struct __mac_set_proc_args *uap)
{
return (ENOSYS);
}
int
__mac_get_fd(struct thread *td, struct __mac_get_fd_args *uap)
{
return (ENOSYS);
}
int
__mac_get_file(struct thread *td, struct __mac_get_file_args *uap)
{
return (ENOSYS);
}
int
__mac_get_link(struct thread *td, struct __mac_get_link_args *uap)
{
return (ENOSYS);
}
int
__mac_set_fd(struct thread *td, struct __mac_set_fd_args *uap)
{
return (ENOSYS);
}
int
__mac_set_file(struct thread *td, struct __mac_set_file_args *uap)
{
return (ENOSYS);
}
int
__mac_set_link(struct thread *td, struct __mac_set_link_args *uap)
{
return (ENOSYS);
}
int
mac_syscall(struct thread *td, struct mac_syscall_args *uap)
{
return (ENOSYS);
}
#endif /* !MAC */
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