freebsd-skq/sys/security/mac/mac_socket.c
rwatson f1bc833e95 Socket MAC labels so_label and so_peerlabel are now protected by
SOCK_LOCK(so):

- Hold socket lock over calls to MAC entry points reading or
  manipulating socket labels.

- Assert socket lock in MAC entry point implementations.

- When externalizing the socket label, first make a thread-local
  copy while holding the socket lock, then release the socket lock
  to externalize to userspace.
2004-06-13 02:50:07 +00:00

537 lines
12 KiB
C

/*-
* Copyright (c) 1999-2002 Robert N. M. Watson
* Copyright (c) 2001 Ilmar S. Habibulin
* Copyright (c) 2001-2004 Networks Associates Technology, 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.
*
* 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/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mac.h>
#include <sys/sbuf.h>
#include <sys/systm.h>
#include <sys/mount.h>
#include <sys/file.h>
#include <sys/namei.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/mac_policy.h>
#include <net/bpfdesc.h>
#include <net/if.h>
#include <net/if_var.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <security/mac/mac_internal.h>
/*
* mac_enforce_socket is used by the inet code when delivering to an inpcb
* without hitting the socket layer, and has to be non-static for now.
*/
int mac_enforce_socket = 1;
SYSCTL_INT(_security_mac, OID_AUTO, enforce_socket, CTLFLAG_RW,
&mac_enforce_socket, 0, "Enforce MAC policy on socket operations");
TUNABLE_INT("security.mac.enforce_socket", &mac_enforce_socket);
#ifdef MAC_DEBUG
static unsigned int nmacsockets;
SYSCTL_UINT(_security_mac_debug_counters, OID_AUTO, sockets, CTLFLAG_RD,
&nmacsockets, 0, "number of sockets in use");
#endif
struct label *
mac_socket_label_alloc(int flag)
{
struct label *label;
int error;
label = mac_labelzone_alloc(flag);
if (label == NULL)
return (NULL);
MAC_CHECK(init_socket_label, label, flag);
if (error) {
MAC_PERFORM(destroy_socket_label, label);
mac_labelzone_free(label);
return (NULL);
}
MAC_DEBUG_COUNTER_INC(&nmacsockets);
return (label);
}
static struct label *
mac_socket_peer_label_alloc(int flag)
{
struct label *label;
int error;
label = mac_labelzone_alloc(flag);
if (label == NULL)
return (NULL);
MAC_CHECK(init_socket_peer_label, label, flag);
if (error) {
MAC_PERFORM(destroy_socket_peer_label, label);
mac_labelzone_free(label);
return (NULL);
}
MAC_DEBUG_COUNTER_INC(&nmacsockets);
return (label);
}
int
mac_init_socket(struct socket *so, int flag)
{
so->so_label = mac_socket_label_alloc(flag);
if (so->so_label == NULL)
return (ENOMEM);
so->so_peerlabel = mac_socket_peer_label_alloc(flag);
if (so->so_peerlabel == NULL) {
mac_socket_label_free(so->so_label);
so->so_label = NULL;
return (ENOMEM);
}
return (0);
}
void
mac_socket_label_free(struct label *label)
{
MAC_PERFORM(destroy_socket_label, label);
mac_labelzone_free(label);
MAC_DEBUG_COUNTER_DEC(&nmacsockets);
}
static void
mac_socket_peer_label_free(struct label *label)
{
MAC_PERFORM(destroy_socket_peer_label, label);
mac_labelzone_free(label);
MAC_DEBUG_COUNTER_DEC(&nmacsockets);
}
void
mac_destroy_socket(struct socket *socket)
{
mac_socket_label_free(socket->so_label);
socket->so_label = NULL;
mac_socket_peer_label_free(socket->so_peerlabel);
socket->so_peerlabel = NULL;
}
void
mac_copy_socket_label(struct label *src, struct label *dest)
{
MAC_PERFORM(copy_socket_label, src, dest);
}
int
mac_externalize_socket_label(struct label *label, char *elements,
char *outbuf, size_t outbuflen)
{
int error;
MAC_EXTERNALIZE(socket, label, elements, outbuf, outbuflen);
return (error);
}
static int
mac_externalize_socket_peer_label(struct label *label, char *elements,
char *outbuf, size_t outbuflen)
{
int error;
MAC_EXTERNALIZE(socket_peer, label, elements, outbuf, outbuflen);
return (error);
}
int
mac_internalize_socket_label(struct label *label, char *string)
{
int error;
MAC_INTERNALIZE(socket, label, string);
return (error);
}
void
mac_create_socket(struct ucred *cred, struct socket *socket)
{
MAC_PERFORM(create_socket, cred, socket, socket->so_label);
}
void
mac_create_socket_from_socket(struct socket *oldsocket,
struct socket *newsocket)
{
SOCK_LOCK_ASSERT(oldsocket);
MAC_PERFORM(create_socket_from_socket, oldsocket, oldsocket->so_label,
newsocket, newsocket->so_label);
}
static void
mac_relabel_socket(struct ucred *cred, struct socket *socket,
struct label *newlabel)
{
SOCK_LOCK_ASSERT(socket);
MAC_PERFORM(relabel_socket, cred, socket, socket->so_label, newlabel);
}
void
mac_set_socket_peer_from_mbuf(struct mbuf *mbuf, struct socket *socket)
{
struct label *label;
SOCK_LOCK_ASSERT(socket);
label = mac_mbuf_to_label(mbuf);
MAC_PERFORM(set_socket_peer_from_mbuf, mbuf, label, socket,
socket->so_peerlabel);
}
void
mac_set_socket_peer_from_socket(struct socket *oldsocket,
struct socket *newsocket)
{
/*
* XXXRW: only hold the socket lock on one at a time, as one
* socket is the original, and one is the new. However, it's
* called in both directions, so we can't assert the lock
* here currently.
*/
MAC_PERFORM(set_socket_peer_from_socket, oldsocket,
oldsocket->so_label, newsocket, newsocket->so_peerlabel);
}
void
mac_create_mbuf_from_socket(struct socket *socket, struct mbuf *mbuf)
{
struct label *label;
label = mac_mbuf_to_label(mbuf);
SOCK_LOCK_ASSERT(socket);
MAC_PERFORM(create_mbuf_from_socket, socket, socket->so_label, mbuf,
label);
}
int
mac_check_socket_bind(struct ucred *ucred, struct socket *socket,
struct sockaddr *sockaddr)
{
int error;
SOCK_LOCK_ASSERT(socket);
if (!mac_enforce_socket)
return (0);
MAC_CHECK(check_socket_bind, ucred, socket, socket->so_label,
sockaddr);
return (error);
}
int
mac_check_socket_connect(struct ucred *cred, struct socket *socket,
struct sockaddr *sockaddr)
{
int error;
SOCK_LOCK_ASSERT(socket);
if (!mac_enforce_socket)
return (0);
MAC_CHECK(check_socket_connect, cred, socket, socket->so_label,
sockaddr);
return (error);
}
int
mac_check_socket_deliver(struct socket *socket, struct mbuf *mbuf)
{
struct label *label;
int error;
SOCK_LOCK_ASSERT(socket);
if (!mac_enforce_socket)
return (0);
label = mac_mbuf_to_label(mbuf);
MAC_CHECK(check_socket_deliver, socket, socket->so_label, mbuf,
label);
return (error);
}
int
mac_check_socket_listen(struct ucred *cred, struct socket *socket)
{
int error;
SOCK_LOCK_ASSERT(socket);
if (!mac_enforce_socket)
return (0);
MAC_CHECK(check_socket_listen, cred, socket, socket->so_label);
return (error);
}
int
mac_check_socket_receive(struct ucred *cred, struct socket *so)
{
int error;
SOCK_LOCK_ASSERT(so);
if (!mac_enforce_socket)
return (0);
MAC_CHECK(check_socket_receive, cred, so, so->so_label);
return (error);
}
static int
mac_check_socket_relabel(struct ucred *cred, struct socket *socket,
struct label *newlabel)
{
int error;
SOCK_LOCK_ASSERT(socket);
MAC_CHECK(check_socket_relabel, cred, socket, socket->so_label,
newlabel);
return (error);
}
int
mac_check_socket_send(struct ucred *cred, struct socket *so)
{
int error;
SOCK_LOCK_ASSERT(so);
if (!mac_enforce_socket)
return (0);
MAC_CHECK(check_socket_send, cred, so, so->so_label);
return (error);
}
int
mac_check_socket_visible(struct ucred *cred, struct socket *socket)
{
int error;
SOCK_LOCK_ASSERT(socket);
if (!mac_enforce_socket)
return (0);
MAC_CHECK(check_socket_visible, cred, socket, socket->so_label);
return (error);
}
int
mac_socket_label_set(struct ucred *cred, struct socket *so,
struct label *label)
{
int error;
/*
* We acquire the socket lock when we perform the test and set,
* but have to release it as the pcb code needs to acquire the
* pcb lock, which will precede the socket lock in the lock
* order. However, this is fine, as any race will simply
* result in the inpcb being refreshed twice, but still
* consistently, as the inpcb code will acquire the socket lock
* before refreshing, holding both locks.
*/
SOCK_LOCK(so);
error = mac_check_socket_relabel(cred, so, label);
if (error) {
SOCK_UNLOCK(so);
return (error);
}
mac_relabel_socket(cred, so, label);
SOCK_UNLOCK(so);
/*
* If the protocol has expressed interest in socket layer changes,
* such as if it needs to propagate changes to a cached pcb
* label from the socket, notify it of the label change while
* holding the socket lock.
*/
if (so->so_proto->pr_usrreqs->pru_sosetlabel != NULL)
(so->so_proto->pr_usrreqs->pru_sosetlabel)(so);
return (0);
}
int
mac_setsockopt_label(struct ucred *cred, struct socket *so, struct mac *mac)
{
struct label *intlabel;
char *buffer;
int 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_socket_label_alloc(M_WAITOK);
error = mac_internalize_socket_label(intlabel, buffer);
free(buffer, M_MACTEMP);
if (error)
goto out;
error = mac_socket_label_set(cred, so, intlabel);
out:
mac_socket_label_free(intlabel);
return (error);
}
int
mac_getsockopt_label(struct ucred *cred, struct socket *so, struct mac *mac)
{
char *buffer, *elements;
struct label *intlabel;
int 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);
intlabel = mac_socket_label_alloc(M_WAITOK);
SOCK_LOCK(so);
mac_copy_socket_label(so->so_label, intlabel);
SOCK_UNLOCK(so);
error = mac_externalize_socket_label(intlabel, elements, buffer,
mac->m_buflen);
mac_socket_label_free(intlabel);
if (error == 0)
error = copyout(buffer, mac->m_string, strlen(buffer)+1);
free(buffer, M_MACTEMP);
free(elements, M_MACTEMP);
return (error);
}
int
mac_getsockopt_peerlabel(struct ucred *cred, struct socket *so,
struct mac *mac)
{
char *elements, *buffer;
struct label *intlabel;
int 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);
intlabel = mac_socket_label_alloc(M_WAITOK);
SOCK_LOCK(so);
mac_copy_socket_label(so->so_peerlabel, intlabel);
SOCK_UNLOCK(so);
error = mac_externalize_socket_peer_label(intlabel, elements, buffer,
mac->m_buflen);
mac_socket_label_free(intlabel);
if (error == 0)
error = copyout(buffer, mac->m_string, strlen(buffer)+1);
free(buffer, M_MACTEMP);
free(elements, M_MACTEMP);
return (error);
}