selinux: Set socket NetLabel based on connection endpoint
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>
diff --git a/include/net/cipso_ipv4.h b/include/net/cipso_ipv4.h
index 2ce093b..811febf 100644
--- a/include/net/cipso_ipv4.h
+++ b/include/net/cipso_ipv4.h
@@ -207,6 +207,7 @@
int cipso_v4_sock_setattr(struct sock *sk,
const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr);
+void cipso_v4_sock_delattr(struct sock *sk);
int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr);
int cipso_v4_skbuff_setattr(struct sk_buff *skb,
const struct cipso_v4_doi *doi_def,
@@ -230,6 +231,10 @@
return -ENOSYS;
}
+static inline void cipso_v4_sock_delattr(struct sock *sk)
+{
+}
+
static inline int cipso_v4_sock_getattr(struct sock *sk,
struct netlbl_lsm_secattr *secattr)
{
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index 3f67e6d..074cad4 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -380,8 +380,12 @@
int netlbl_enabled(void);
int netlbl_sock_setattr(struct sock *sk,
const struct netlbl_lsm_secattr *secattr);
+void netlbl_sock_delattr(struct sock *sk);
int netlbl_sock_getattr(struct sock *sk,
struct netlbl_lsm_secattr *secattr);
+int netlbl_conn_setattr(struct sock *sk,
+ struct sockaddr *addr,
+ const struct netlbl_lsm_secattr *secattr);
int netlbl_skbuff_setattr(struct sk_buff *skb,
u16 family,
const struct netlbl_lsm_secattr *secattr);
@@ -449,11 +453,20 @@
{
return -ENOSYS;
}
+static inline void netlbl_sock_delattr(struct sock *sk)
+{
+}
static inline int netlbl_sock_getattr(struct sock *sk,
struct netlbl_lsm_secattr *secattr)
{
return -ENOSYS;
}
+static inline int netlbl_conn_setattr(struct sock *sk,
+ struct sockaddr *addr,
+ const struct netlbl_lsm_secattr *secattr)
+{
+ return -ENOSYS;
+}
static inline int netlbl_skbuff_setattr(struct sk_buff *skb,
u16 family,
const struct netlbl_lsm_secattr *secattr)
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index e13d6db..23768b9 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1810,6 +1810,80 @@
}
/**
+ * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
+ * @sk: the socket
+ *
+ * Description:
+ * Removes the CIPSO option from a socket, if present.
+ *
+ */
+void cipso_v4_sock_delattr(struct sock *sk)
+{
+ u8 hdr_delta;
+ struct ip_options *opt;
+ struct inet_sock *sk_inet;
+
+ sk_inet = inet_sk(sk);
+ opt = sk_inet->opt;
+ if (opt == NULL || opt->cipso == 0)
+ return;
+
+ if (opt->srr || opt->rr || opt->ts || opt->router_alert) {
+ u8 cipso_len;
+ u8 cipso_off;
+ unsigned char *cipso_ptr;
+ int iter;
+ int optlen_new;
+
+ cipso_off = opt->cipso - sizeof(struct iphdr);
+ cipso_ptr = &opt->__data[cipso_off];
+ cipso_len = cipso_ptr[1];
+
+ if (opt->srr > opt->cipso)
+ opt->srr -= cipso_len;
+ if (opt->rr > opt->cipso)
+ opt->rr -= cipso_len;
+ if (opt->ts > opt->cipso)
+ opt->ts -= cipso_len;
+ if (opt->router_alert > opt->cipso)
+ opt->router_alert -= cipso_len;
+ opt->cipso = 0;
+
+ memmove(cipso_ptr, cipso_ptr + cipso_len,
+ opt->optlen - cipso_off - cipso_len);
+
+ /* determining the new total option length is tricky because of
+ * the padding necessary, the only thing i can think to do at
+ * this point is walk the options one-by-one, skipping the
+ * padding at the end to determine the actual option size and
+ * from there we can determine the new total option length */
+ iter = 0;
+ optlen_new = 0;
+ while (iter < opt->optlen)
+ if (opt->__data[iter] != IPOPT_NOP) {
+ iter += opt->__data[iter + 1];
+ optlen_new = iter;
+ } else
+ iter++;
+ hdr_delta = opt->optlen;
+ opt->optlen = (optlen_new + 3) & ~3;
+ hdr_delta -= opt->optlen;
+ } else {
+ /* only the cipso option was present on the socket so we can
+ * remove the entire option struct */
+ sk_inet->opt = NULL;
+ hdr_delta = opt->optlen;
+ kfree(opt);
+ }
+
+ if (sk_inet->is_icsk && hdr_delta > 0) {
+ struct inet_connection_sock *sk_conn = inet_csk(sk);
+ sk_conn->icsk_ext_hdr_len -= hdr_delta;
+ sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
+ }
+}
+
+/**
* cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
* @cipso: the CIPSO v4 option
* @secattr: the security attributes
diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
index cc8047d..78fc557 100644
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -10,7 +10,7 @@
*/
/*
- * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 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
@@ -456,6 +456,20 @@
}
/**
+ * netlbl_sock_delattr - Delete all the NetLabel labels on a socket
+ * @sk: the socket
+ *
+ * Description:
+ * Remove all the NetLabel labeling from @sk. The caller is responsible for
+ * ensuring that @sk is locked.
+ *
+ */
+void netlbl_sock_delattr(struct sock *sk)
+{
+ cipso_v4_sock_delattr(sk);
+}
+
+/**
* netlbl_sock_getattr - Determine the security attributes of a sock
* @sk: the sock
* @secattr: the security attributes
@@ -473,6 +487,68 @@
}
/**
+ * netlbl_conn_setattr - Label a connected socket using the correct protocol
+ * @sk: the socket to label
+ * @addr: the destination address
+ * @secattr: the security attributes
+ *
+ * Description:
+ * Attach the correct label to the given connected socket using the security
+ * attributes specified in @secattr. The caller is responsible for ensuring
+ * that @sk is locked. Returns zero on success, negative values on failure.
+ *
+ */
+int netlbl_conn_setattr(struct sock *sk,
+ struct sockaddr *addr,
+ const struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val;
+ struct sockaddr_in *addr4;
+ struct netlbl_domaddr4_map *af4_entry;
+
+ rcu_read_lock();
+ switch (addr->sa_family) {
+ case AF_INET:
+ addr4 = (struct sockaddr_in *)addr;
+ af4_entry = netlbl_domhsh_getentry_af4(secattr->domain,
+ addr4->sin_addr.s_addr);
+ if (af4_entry == NULL) {
+ ret_val = -ENOENT;
+ goto conn_setattr_return;
+ }
+ switch (af4_entry->type) {
+ case NETLBL_NLTYPE_CIPSOV4:
+ ret_val = cipso_v4_sock_setattr(sk,
+ af4_entry->type_def.cipsov4,
+ secattr);
+ break;
+ case NETLBL_NLTYPE_UNLABELED:
+ /* just delete the protocols we support for right now
+ * but we could remove other protocols if needed */
+ cipso_v4_sock_delattr(sk);
+ ret_val = 0;
+ break;
+ default:
+ ret_val = -ENOENT;
+ }
+ break;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+ case AF_INET6:
+ /* since we don't support any IPv6 labeling protocols right
+ * now we can optimize everything away until we do */
+ ret_val = 0;
+ break;
+#endif /* IPv6 */
+ default:
+ ret_val = 0;
+ }
+
+conn_setattr_return:
+ rcu_read_unlock();
+ return ret_val;
+}
+
+/**
* netlbl_skbuff_setattr - Label a packet using the correct protocol
* @skb: the packet
* @family: protocol family
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 7432bdd..632ac3e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3794,6 +3794,7 @@
static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen)
{
+ struct sock *sk = sock->sk;
struct inode_security_struct *isec;
int err;
@@ -3807,7 +3808,6 @@
isec = SOCK_INODE(sock)->i_security;
if (isec->sclass == SECCLASS_TCP_SOCKET ||
isec->sclass == SECCLASS_DCCP_SOCKET) {
- struct sock *sk = sock->sk;
struct avc_audit_data ad;
struct sockaddr_in *addr4 = NULL;
struct sockaddr_in6 *addr6 = NULL;
@@ -3841,6 +3841,8 @@
goto out;
}
+ err = selinux_netlbl_socket_connect(sk, address);
+
out:
return err;
}
@@ -4290,8 +4292,6 @@
sk->sk_family == PF_UNIX)
isec->sid = sksec->sid;
sksec->sclass = isec->sclass;
-
- selinux_netlbl_sock_graft(sk, parent);
}
static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
@@ -4342,8 +4342,7 @@
selinux_netlbl_sk_security_reset(newsksec, req->rsk_ops->family);
}
-static void selinux_inet_conn_established(struct sock *sk,
- struct sk_buff *skb)
+static void selinux_inet_conn_established(struct sock *sk, struct sk_buff *skb)
{
u16 family = sk->sk_family;
struct sk_security_struct *sksec = sk->sk_security;
@@ -4353,6 +4352,8 @@
family = PF_INET;
selinux_skb_peerlbl_sid(skb, family, &sksec->peer_sid);
+
+ selinux_netlbl_inet_conn_established(sk, family);
}
static void selinux_req_classify_flow(const struct request_sock *req,
diff --git a/security/selinux/include/netlabel.h b/security/selinux/include/netlabel.h
index b3e6ae0..982bac0 100644
--- a/security/selinux/include/netlabel.h
+++ b/security/selinux/include/netlabel.h
@@ -52,7 +52,7 @@
u16 family,
u32 sid);
-void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock);
+void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family);
int selinux_netlbl_socket_post_create(struct socket *sock);
int selinux_netlbl_inode_permission(struct inode *inode, int mask);
int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
@@ -62,6 +62,8 @@
int selinux_netlbl_socket_setsockopt(struct socket *sock,
int level,
int optname);
+int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr);
+
#else
static inline void selinux_netlbl_cache_invalidate(void)
{
@@ -98,8 +100,14 @@
return 0;
}
-static inline void selinux_netlbl_sock_graft(struct sock *sk,
- struct socket *sock)
+static inline int selinux_netlbl_conn_setsid(struct sock *sk,
+ struct sockaddr *addr)
+{
+ return 0;
+}
+
+static inline void selinux_netlbl_inet_conn_established(struct sock *sk,
+ u16 family)
{
return;
}
@@ -125,6 +133,11 @@
{
return 0;
}
+static inline int selinux_netlbl_socket_connect(struct sock *sk,
+ struct sockaddr *addr)
+{
+ return 0;
+}
#endif /* CONFIG_NETLABEL */
#endif
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index f46dd1c..ad34787 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -118,6 +118,7 @@
NLBL_REQUIRE,
NLBL_LABELED,
NLBL_REQSKB,
+ NLBL_CONNLABELED,
} nlbl_state;
#endif
};
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index 090404d..b22b7da 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -29,10 +29,12 @@
#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/inet_sock.h>
-#include <net/inet_connection_sock.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
#include "objsec.h"
#include "security.h"
@@ -79,8 +81,6 @@
int rc;
struct sk_security_struct *sksec = sk->sk_security;
struct netlbl_lsm_secattr secattr;
- struct inet_sock *sk_inet;
- struct inet_connection_sock *sk_conn;
if (sksec->nlbl_state != NLBL_REQUIRE)
return 0;
@@ -96,20 +96,6 @@
sksec->nlbl_state = NLBL_LABELED;
break;
case -EDESTADDRREQ:
- /* we are going to possibly end up labeling the individual
- * packets later which is problematic for stream sockets
- * because of the additional IP header size, our solution is to
- * allow for the maximum IP header length (40 bytes for IPv4,
- * we don't have to worry about IPv6 yet) just in case */
- sk_inet = inet_sk(sk);
- if (sk_inet->is_icsk) {
- sk_conn = inet_csk(sk);
- if (sk_inet->opt)
- sk_conn->icsk_ext_hdr_len -=
- sk_inet->opt->optlen;
- sk_conn->icsk_ext_hdr_len += 40;
- sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
- }
sksec->nlbl_state = NLBL_REQSKB;
rc = 0;
break;
@@ -247,21 +233,77 @@
}
/**
- * selinux_netlbl_sock_graft - Netlabel the new socket
+ * selinux_netlbl_inet_conn_established - Netlabel the newly accepted connection
* @sk: the new connection
- * @sock: the new socket
*
* Description:
- * The connection represented by @sk is being grafted onto @sock so set the
- * socket's NetLabel to match the SID of @sk.
+ * A new connection has been established on @sk so make sure it is labeled
+ * correctly with the NetLabel susbsystem.
*
*/
-void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock)
+void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family)
{
- /* Try to set the NetLabel on the socket to save time later, if we fail
- * here we will pick up the pieces in later calls to
- * selinux_netlbl_inode_permission(). */
- selinux_netlbl_sock_setsid(sk);
+ 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;
}
/**
@@ -398,7 +440,8 @@
struct netlbl_lsm_secattr secattr;
if (level == IPPROTO_IP && optname == IP_OPTIONS &&
- sksec->nlbl_state == NLBL_LABELED) {
+ (sksec->nlbl_state == NLBL_LABELED ||
+ sksec->nlbl_state == NLBL_CONNLABELED)) {
netlbl_secattr_init(&secattr);
lock_sock(sk);
rc = netlbl_sock_getattr(sk, &secattr);
@@ -410,3 +453,51 @@
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;
+}