freebsd-dev/sys/security/mac/mac_syscalls.c
Robert Watson a9d2f8d84f Second-to-last commit implementing Capsicum capabilities in the FreeBSD
kernel for FreeBSD 9.0:

Add a new capability mask argument to fget(9) and friends, allowing system
call code to declare what capabilities are required when an integer file
descriptor is converted into an in-kernel struct file *.  With options
CAPABILITIES compiled into the kernel, this enforces capability
protection; without, this change is effectively a no-op.

Some cases require special handling, such as mmap(2), which must preserve
information about the maximum rights at the time of mapping in the memory
map so that they can later be enforced in mprotect(2) -- this is done by
narrowing the rights in the existing max_protection field used for similar
purposes with file permissions.

In namei(9), we assert that the code is not reached from within capability
mode, as we're not yet ready to enforce namespace capabilities there.
This will follow in a later commit.

Update two capability names: CAP_EVENT and CAP_KEVENT become
CAP_POST_KEVENT and CAP_POLL_KEVENT to more accurately indicate what they
represent.

Approved by:	re (bz)
Submitted by:	jonathan
Sponsored by:	Google Inc
2011-08-11 12:30:23 +00:00

732 lines
16 KiB
C

/*-
* Copyright (c) 1999-2002, 2006, 2009 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").
*
* This software was developed at the University of Cambridge Computer
* Laboratory with support from a grant from Google, Inc.
*
* 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/capability.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/sysctl.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
FEATURE(security_mac, "Mandatory Access Control Framework support");
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;
PROC_UNLOCK(p);
crfree(oldcred);
mac_proc_vm_revoke(td);
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, CAP_MAC_GET, &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, CAP_MAC_SET, &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 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 (!LIST_EMPTY(&mac_policy_list)) {
mac_policy_slock_sleep();
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_sunlock_sleep();
}
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 */