014ab19a69
Previous work enabled the use of address based NetLabel selectors, which while highly useful, brought the potential for additional per-packet overhead when used. This patch attempts to solve that by applying NetLabel socket labels when sockets are connect()'d. This should alleviate the per-packet NetLabel labeling for all connected sockets (yes, it even works for connected DGRAM sockets). Signed-off-by: Paul Moore <paul.moore@hp.com> Reviewed-by: James Morris <jmorris@namei.org>
504 lines
13 KiB
C
504 lines
13 KiB
C
/*
|
|
* SELinux NetLabel Support
|
|
*
|
|
* This file provides the necessary glue to tie NetLabel into the SELinux
|
|
* subsystem.
|
|
*
|
|
* Author: Paul Moore <paul.moore@hp.com>
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* (c) Copyright Hewlett-Packard Development Company, L.P., 2007, 2008
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
|
|
* the GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*
|
|
*/
|
|
|
|
#include <linux/spinlock.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/ipv6.h>
|
|
#include <net/sock.h>
|
|
#include <net/netlabel.h>
|
|
#include <net/ip.h>
|
|
#include <net/ipv6.h>
|
|
|
|
#include "objsec.h"
|
|
#include "security.h"
|
|
#include "netlabel.h"
|
|
|
|
/**
|
|
* selinux_netlbl_sidlookup_cached - Cache a SID lookup
|
|
* @skb: the packet
|
|
* @secattr: the NetLabel security attributes
|
|
* @sid: the SID
|
|
*
|
|
* Description:
|
|
* Query the SELinux security server to lookup the correct SID for the given
|
|
* security attributes. If the query is successful, cache the result to speed
|
|
* up future lookups. Returns zero on success, negative values on failure.
|
|
*
|
|
*/
|
|
static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
|
|
struct netlbl_lsm_secattr *secattr,
|
|
u32 *sid)
|
|
{
|
|
int rc;
|
|
|
|
rc = security_netlbl_secattr_to_sid(secattr, sid);
|
|
if (rc == 0 &&
|
|
(secattr->flags & NETLBL_SECATTR_CACHEABLE) &&
|
|
(secattr->flags & NETLBL_SECATTR_CACHE))
|
|
netlbl_cache_add(skb, secattr);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_sock_setsid - Label a socket using the NetLabel mechanism
|
|
* @sk: the socket to label
|
|
*
|
|
* Description:
|
|
* Attempt to label a socket using the NetLabel mechanism. Returns zero values
|
|
* on success, negative values on failure.
|
|
*
|
|
*/
|
|
static int selinux_netlbl_sock_setsid(struct sock *sk)
|
|
{
|
|
int rc;
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
struct netlbl_lsm_secattr secattr;
|
|
|
|
if (sksec->nlbl_state != NLBL_REQUIRE)
|
|
return 0;
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
|
|
rc = security_netlbl_sid_to_secattr(sksec->sid, &secattr);
|
|
if (rc != 0)
|
|
goto sock_setsid_return;
|
|
rc = netlbl_sock_setattr(sk, &secattr);
|
|
switch (rc) {
|
|
case 0:
|
|
sksec->nlbl_state = NLBL_LABELED;
|
|
break;
|
|
case -EDESTADDRREQ:
|
|
sksec->nlbl_state = NLBL_REQSKB;
|
|
rc = 0;
|
|
break;
|
|
}
|
|
|
|
sock_setsid_return:
|
|
netlbl_secattr_destroy(&secattr);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_cache_invalidate - Invalidate the NetLabel cache
|
|
*
|
|
* Description:
|
|
* Invalidate the NetLabel security attribute mapping cache.
|
|
*
|
|
*/
|
|
void selinux_netlbl_cache_invalidate(void)
|
|
{
|
|
netlbl_cache_invalidate();
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_err - Handle a NetLabel packet error
|
|
* @skb: the packet
|
|
* @error: the error code
|
|
* @gateway: true if host is acting as a gateway, false otherwise
|
|
*
|
|
* Description:
|
|
* When a packet is dropped due to a call to avc_has_perm() pass the error
|
|
* code to the NetLabel subsystem so any protocol specific processing can be
|
|
* done. This is safe to call even if you are unsure if NetLabel labeling is
|
|
* present on the packet, NetLabel is smart enough to only act when it should.
|
|
*
|
|
*/
|
|
void selinux_netlbl_err(struct sk_buff *skb, int error, int gateway)
|
|
{
|
|
netlbl_skbuff_err(skb, error, gateway);
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_sk_security_reset - Reset the NetLabel fields
|
|
* @ssec: the sk_security_struct
|
|
* @family: the socket family
|
|
*
|
|
* Description:
|
|
* Called when the NetLabel state of a sk_security_struct needs to be reset.
|
|
* The caller is responsibile for all the NetLabel sk_security_struct locking.
|
|
*
|
|
*/
|
|
void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec,
|
|
int family)
|
|
{
|
|
if (family == PF_INET)
|
|
ssec->nlbl_state = NLBL_REQUIRE;
|
|
else
|
|
ssec->nlbl_state = NLBL_UNSET;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel
|
|
* @skb: the packet
|
|
* @family: protocol family
|
|
* @type: NetLabel labeling protocol type
|
|
* @sid: the SID
|
|
*
|
|
* Description:
|
|
* Call the NetLabel mechanism to get the security attributes of the given
|
|
* packet and use those attributes to determine the correct context/SID to
|
|
* assign to the packet. Returns zero on success, negative values on failure.
|
|
*
|
|
*/
|
|
int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
|
|
u16 family,
|
|
u32 *type,
|
|
u32 *sid)
|
|
{
|
|
int rc;
|
|
struct netlbl_lsm_secattr secattr;
|
|
|
|
if (!netlbl_enabled()) {
|
|
*sid = SECSID_NULL;
|
|
return 0;
|
|
}
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
rc = netlbl_skbuff_getattr(skb, family, &secattr);
|
|
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
|
|
rc = selinux_netlbl_sidlookup_cached(skb, &secattr, sid);
|
|
else
|
|
*sid = SECSID_NULL;
|
|
*type = secattr.type;
|
|
netlbl_secattr_destroy(&secattr);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_skbuff_setsid - Set the NetLabel on a packet given a sid
|
|
* @skb: the packet
|
|
* @family: protocol family
|
|
* @sid: the SID
|
|
*
|
|
* Description
|
|
* Call the NetLabel mechanism to set the label of a packet using @sid.
|
|
* Returns zero on auccess, negative values on failure.
|
|
*
|
|
*/
|
|
int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
|
|
u16 family,
|
|
u32 sid)
|
|
{
|
|
int rc;
|
|
struct netlbl_lsm_secattr secattr;
|
|
struct sock *sk;
|
|
|
|
/* if this is a locally generated packet check to see if it is already
|
|
* being labeled by it's parent socket, if it is just exit */
|
|
sk = skb->sk;
|
|
if (sk != NULL) {
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
if (sksec->nlbl_state != NLBL_REQSKB)
|
|
return 0;
|
|
}
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
rc = security_netlbl_sid_to_secattr(sid, &secattr);
|
|
if (rc != 0)
|
|
goto skbuff_setsid_return;
|
|
rc = netlbl_skbuff_setattr(skb, family, &secattr);
|
|
|
|
skbuff_setsid_return:
|
|
netlbl_secattr_destroy(&secattr);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_inet_conn_established - Netlabel the newly accepted connection
|
|
* @sk: the new connection
|
|
*
|
|
* Description:
|
|
* A new connection has been established on @sk so make sure it is labeled
|
|
* correctly with the NetLabel susbsystem.
|
|
*
|
|
*/
|
|
void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family)
|
|
{
|
|
int rc;
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
struct netlbl_lsm_secattr secattr;
|
|
struct inet_sock *sk_inet = inet_sk(sk);
|
|
struct sockaddr_in addr;
|
|
|
|
if (sksec->nlbl_state != NLBL_REQUIRE)
|
|
return;
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
if (security_netlbl_sid_to_secattr(sksec->sid, &secattr) != 0)
|
|
goto inet_conn_established_return;
|
|
|
|
rc = netlbl_sock_setattr(sk, &secattr);
|
|
switch (rc) {
|
|
case 0:
|
|
sksec->nlbl_state = NLBL_LABELED;
|
|
break;
|
|
case -EDESTADDRREQ:
|
|
/* no PF_INET6 support yet because we don't support any IPv6
|
|
* labeling protocols */
|
|
if (family != PF_INET) {
|
|
sksec->nlbl_state = NLBL_UNSET;
|
|
goto inet_conn_established_return;
|
|
}
|
|
|
|
addr.sin_family = family;
|
|
addr.sin_addr.s_addr = sk_inet->daddr;
|
|
if (netlbl_conn_setattr(sk, (struct sockaddr *)&addr,
|
|
&secattr) != 0) {
|
|
/* we failed to label the connected socket (could be
|
|
* for a variety of reasons, the actual "why" isn't
|
|
* important here) so we have to go to our backup plan,
|
|
* labeling the packets individually in the netfilter
|
|
* local output hook. this is okay but we need to
|
|
* adjust the MSS of the connection to take into
|
|
* account any labeling overhead, since we don't know
|
|
* the exact overhead at this point we'll use the worst
|
|
* case value which is 40 bytes for IPv4 */
|
|
struct inet_connection_sock *sk_conn = inet_csk(sk);
|
|
sk_conn->icsk_ext_hdr_len += 40 -
|
|
(sk_inet->opt ? sk_inet->opt->optlen : 0);
|
|
sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
|
|
|
|
sksec->nlbl_state = NLBL_REQSKB;
|
|
} else
|
|
sksec->nlbl_state = NLBL_CONNLABELED;
|
|
break;
|
|
default:
|
|
/* note that we are failing to label the socket which could be
|
|
* a bad thing since it means traffic could leave the system
|
|
* without the desired labeling, however, all is not lost as
|
|
* we have a check in selinux_netlbl_inode_permission() to
|
|
* pick up the pieces that we might drop here because we can't
|
|
* return an error code */
|
|
break;
|
|
}
|
|
|
|
inet_conn_established_return:
|
|
netlbl_secattr_destroy(&secattr);
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_socket_post_create - Label a socket using NetLabel
|
|
* @sock: the socket to label
|
|
*
|
|
* Description:
|
|
* Attempt to label a socket using the NetLabel mechanism using the given
|
|
* SID. Returns zero values on success, negative values on failure.
|
|
*
|
|
*/
|
|
int selinux_netlbl_socket_post_create(struct socket *sock)
|
|
{
|
|
return selinux_netlbl_sock_setsid(sock->sk);
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_inode_permission - Verify the socket is NetLabel labeled
|
|
* @inode: the file descriptor's inode
|
|
* @mask: the permission mask
|
|
*
|
|
* Description:
|
|
* Looks at a file's inode and if it is marked as a socket protected by
|
|
* NetLabel then verify that the socket has been labeled, if not try to label
|
|
* the socket now with the inode's SID. Returns zero on success, negative
|
|
* values on failure.
|
|
*
|
|
*/
|
|
int selinux_netlbl_inode_permission(struct inode *inode, int mask)
|
|
{
|
|
int rc;
|
|
struct sock *sk;
|
|
struct socket *sock;
|
|
struct sk_security_struct *sksec;
|
|
|
|
if (!S_ISSOCK(inode->i_mode) ||
|
|
((mask & (MAY_WRITE | MAY_APPEND)) == 0))
|
|
return 0;
|
|
|
|
sock = SOCKET_I(inode);
|
|
sk = sock->sk;
|
|
sksec = sk->sk_security;
|
|
if (sksec->nlbl_state != NLBL_REQUIRE)
|
|
return 0;
|
|
|
|
local_bh_disable();
|
|
bh_lock_sock_nested(sk);
|
|
if (likely(sksec->nlbl_state == NLBL_REQUIRE))
|
|
rc = selinux_netlbl_sock_setsid(sk);
|
|
else
|
|
rc = 0;
|
|
bh_unlock_sock(sk);
|
|
local_bh_enable();
|
|
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel
|
|
* @sksec: the sock's sk_security_struct
|
|
* @skb: the packet
|
|
* @family: protocol family
|
|
* @ad: the audit data
|
|
*
|
|
* Description:
|
|
* Fetch the NetLabel security attributes from @skb and perform an access check
|
|
* against the receiving socket. Returns zero on success, negative values on
|
|
* error.
|
|
*
|
|
*/
|
|
int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
|
|
struct sk_buff *skb,
|
|
u16 family,
|
|
struct avc_audit_data *ad)
|
|
{
|
|
int rc;
|
|
u32 nlbl_sid;
|
|
u32 perm;
|
|
struct netlbl_lsm_secattr secattr;
|
|
|
|
if (!netlbl_enabled())
|
|
return 0;
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
rc = netlbl_skbuff_getattr(skb, family, &secattr);
|
|
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
|
|
rc = selinux_netlbl_sidlookup_cached(skb, &secattr, &nlbl_sid);
|
|
else
|
|
nlbl_sid = SECINITSID_UNLABELED;
|
|
netlbl_secattr_destroy(&secattr);
|
|
if (rc != 0)
|
|
return rc;
|
|
|
|
switch (sksec->sclass) {
|
|
case SECCLASS_UDP_SOCKET:
|
|
perm = UDP_SOCKET__RECVFROM;
|
|
break;
|
|
case SECCLASS_TCP_SOCKET:
|
|
perm = TCP_SOCKET__RECVFROM;
|
|
break;
|
|
default:
|
|
perm = RAWIP_SOCKET__RECVFROM;
|
|
}
|
|
|
|
rc = avc_has_perm(sksec->sid, nlbl_sid, sksec->sclass, perm, ad);
|
|
if (rc == 0)
|
|
return 0;
|
|
|
|
if (nlbl_sid != SECINITSID_UNLABELED)
|
|
netlbl_skbuff_err(skb, rc, 0);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel
|
|
* @sock: the socket
|
|
* @level: the socket level or protocol
|
|
* @optname: the socket option name
|
|
*
|
|
* Description:
|
|
* Check the setsockopt() call and if the user is trying to replace the IP
|
|
* options on a socket and a NetLabel is in place for the socket deny the
|
|
* access; otherwise allow the access. Returns zero when the access is
|
|
* allowed, -EACCES when denied, and other negative values on error.
|
|
*
|
|
*/
|
|
int selinux_netlbl_socket_setsockopt(struct socket *sock,
|
|
int level,
|
|
int optname)
|
|
{
|
|
int rc = 0;
|
|
struct sock *sk = sock->sk;
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
struct netlbl_lsm_secattr secattr;
|
|
|
|
if (level == IPPROTO_IP && optname == IP_OPTIONS &&
|
|
(sksec->nlbl_state == NLBL_LABELED ||
|
|
sksec->nlbl_state == NLBL_CONNLABELED)) {
|
|
netlbl_secattr_init(&secattr);
|
|
lock_sock(sk);
|
|
rc = netlbl_sock_getattr(sk, &secattr);
|
|
release_sock(sk);
|
|
if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
|
|
rc = -EACCES;
|
|
netlbl_secattr_destroy(&secattr);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* selinux_netlbl_socket_connect - Label a client-side socket on connect
|
|
* @sk: the socket to label
|
|
* @addr: the destination address
|
|
*
|
|
* Description:
|
|
* Attempt to label a connected socket with NetLabel using the given address.
|
|
* Returns zero values on success, negative values on failure.
|
|
*
|
|
*/
|
|
int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr)
|
|
{
|
|
int rc;
|
|
struct sk_security_struct *sksec = sk->sk_security;
|
|
struct netlbl_lsm_secattr secattr;
|
|
|
|
if (sksec->nlbl_state != NLBL_REQSKB &&
|
|
sksec->nlbl_state != NLBL_CONNLABELED)
|
|
return 0;
|
|
|
|
netlbl_secattr_init(&secattr);
|
|
local_bh_disable();
|
|
bh_lock_sock_nested(sk);
|
|
|
|
/* connected sockets are allowed to disconnect when the address family
|
|
* is set to AF_UNSPEC, if that is what is happening we want to reset
|
|
* the socket */
|
|
if (addr->sa_family == AF_UNSPEC) {
|
|
netlbl_sock_delattr(sk);
|
|
sksec->nlbl_state = NLBL_REQSKB;
|
|
rc = 0;
|
|
goto socket_connect_return;
|
|
}
|
|
rc = security_netlbl_sid_to_secattr(sksec->sid, &secattr);
|
|
if (rc != 0)
|
|
goto socket_connect_return;
|
|
rc = netlbl_conn_setattr(sk, addr, &secattr);
|
|
if (rc != 0)
|
|
goto socket_connect_return;
|
|
sksec->nlbl_state = NLBL_CONNLABELED;
|
|
|
|
socket_connect_return:
|
|
bh_unlock_sock(sk);
|
|
local_bh_enable();
|
|
netlbl_secattr_destroy(&secattr);
|
|
return rc;
|
|
}
|