selinux: Add SCTP support
The SELinux SCTP implementation is explained in:
Documentation/security/SELinux-sctp.rst
Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 8644d86..28a5c4e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -67,6 +67,8 @@
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
+#include <linux/sctp.h>
+#include <net/sctp/structs.h>
#include <linux/quota.h>
#include <linux/un.h> /* for Unix socket types */
#include <net/af_unix.h> /* for Unix socket types */
@@ -4134,6 +4136,23 @@ static int selinux_parse_skb_ipv4(struct sk_buff *skb,
break;
}
+#if IS_ENABLED(CONFIG_IP_SCTP)
+ case IPPROTO_SCTP: {
+ struct sctphdr _sctph, *sh;
+
+ if (ntohs(ih->frag_off) & IP_OFFSET)
+ break;
+
+ offset += ihlen;
+ sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
+ if (sh == NULL)
+ break;
+
+ ad->u.net->sport = sh->source;
+ ad->u.net->dport = sh->dest;
+ break;
+ }
+#endif
default:
break;
}
@@ -4207,6 +4226,19 @@ static int selinux_parse_skb_ipv6(struct sk_buff *skb,
break;
}
+#if IS_ENABLED(CONFIG_IP_SCTP)
+ case IPPROTO_SCTP: {
+ struct sctphdr _sctph, *sh;
+
+ sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
+ if (sh == NULL)
+ break;
+
+ ad->u.net->sport = sh->source;
+ ad->u.net->dport = sh->dest;
+ break;
+ }
+#endif
/* includes fragments */
default:
break;
@@ -4396,6 +4428,10 @@ static int selinux_socket_post_create(struct socket *sock, int family,
sksec = sock->sk->sk_security;
sksec->sclass = sclass;
sksec->sid = sid;
+ /* Allows detection of the first association on this socket */
+ if (sksec->sclass == SECCLASS_SCTP_SOCKET)
+ sksec->sctp_assoc_state = SCTP_ASSOC_UNSET;
+
err = selinux_netlbl_socket_post_create(sock->sk, family);
}
@@ -4416,11 +4452,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
if (err)
goto out;
- /*
- * If PF_INET or PF_INET6, check name_bind permission for the port.
- * Multiple address binding for SCTP is not supported yet: we just
- * check the first address now.
- */
+ /* If PF_INET or PF_INET6, check name_bind permission for the port. */
family = sk->sk_family;
if (family == PF_INET || family == PF_INET6) {
char *addrp;
@@ -4432,7 +4464,13 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
unsigned short snum;
u32 sid, node_perm;
- if (family == PF_INET) {
+ /*
+ * sctp_bindx(3) calls via selinux_sctp_bind_connect()
+ * that validates multiple binding addresses. Because of this
+ * need to check address->sa_family as it is possible to have
+ * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
+ */
+ if (address->sa_family == AF_INET) {
if (addrlen < sizeof(struct sockaddr_in)) {
err = -EINVAL;
goto out;
@@ -4486,6 +4524,10 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
node_perm = DCCP_SOCKET__NODE_BIND;
break;
+ case SECCLASS_SCTP_SOCKET:
+ node_perm = SCTP_SOCKET__NODE_BIND;
+ break;
+
default:
node_perm = RAWIP_SOCKET__NODE_BIND;
break;
@@ -4500,7 +4542,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
ad.u.net->sport = htons(snum);
ad.u.net->family = family;
- if (family == PF_INET)
+ if (address->sa_family == AF_INET)
ad.u.net->v4info.saddr = addr4->sin_addr.s_addr;
else
ad.u.net->v6info.saddr = addr6->sin6_addr;
@@ -4514,7 +4556,11 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
return err;
}
-static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen)
+/* This supports connect(2) and SCTP connect services such as sctp_connectx(3)
+ * and sctp_sendmsg(3) as described in Documentation/security/LSM-sctp.txt
+ */
+static int selinux_socket_connect_helper(struct socket *sock,
+ struct sockaddr *address, int addrlen)
{
struct sock *sk = sock->sk;
struct sk_security_struct *sksec = sk->sk_security;
@@ -4525,10 +4571,12 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address,
return err;
/*
- * If a TCP or DCCP socket, check name_connect permission for the port.
+ * If a TCP, DCCP or SCTP socket, check name_connect permission
+ * for the port.
*/
if (sksec->sclass == SECCLASS_TCP_SOCKET ||
- sksec->sclass == SECCLASS_DCCP_SOCKET) {
+ sksec->sclass == SECCLASS_DCCP_SOCKET ||
+ sksec->sclass == SECCLASS_SCTP_SOCKET) {
struct common_audit_data ad;
struct lsm_network_audit net = {0,};
struct sockaddr_in *addr4 = NULL;
@@ -4536,7 +4584,12 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address,
unsigned short snum;
u32 sid, perm;
- if (sk->sk_family == PF_INET) {
+ /* sctp_connectx(3) calls via selinux_sctp_bind_connect()
+ * that validates multiple connect addresses. Because of this
+ * need to check address->sa_family as it is possible to have
+ * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
+ */
+ if (address->sa_family == AF_INET) {
addr4 = (struct sockaddr_in *)address;
if (addrlen < sizeof(struct sockaddr_in))
return -EINVAL;
@@ -4550,10 +4603,19 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address,
err = sel_netport_sid(sk->sk_protocol, snum, &sid);
if (err)
- goto out;
+ return err;
- perm = (sksec->sclass == SECCLASS_TCP_SOCKET) ?
- TCP_SOCKET__NAME_CONNECT : DCCP_SOCKET__NAME_CONNECT;
+ switch (sksec->sclass) {
+ case SECCLASS_TCP_SOCKET:
+ perm = TCP_SOCKET__NAME_CONNECT;
+ break;
+ case SECCLASS_DCCP_SOCKET:
+ perm = DCCP_SOCKET__NAME_CONNECT;
+ break;
+ case SECCLASS_SCTP_SOCKET:
+ perm = SCTP_SOCKET__NAME_CONNECT;
+ break;
+ }
ad.type = LSM_AUDIT_DATA_NET;
ad.u.net = &net;
@@ -4561,13 +4623,24 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address,
ad.u.net->family = sk->sk_family;
err = avc_has_perm(sksec->sid, sid, sksec->sclass, perm, &ad);
if (err)
- goto out;
+ return err;
}
- err = selinux_netlbl_socket_connect(sk, address);
+ return 0;
+}
-out:
- return err;
+/* Supports connect(2), see comments in selinux_socket_connect_helper() */
+static int selinux_socket_connect(struct socket *sock,
+ struct sockaddr *address, int addrlen)
+{
+ int err;
+ struct sock *sk = sock->sk;
+
+ err = selinux_socket_connect_helper(sock, address, addrlen);
+ if (err)
+ return err;
+
+ return selinux_netlbl_socket_connect(sk, address);
}
static int selinux_socket_listen(struct socket *sock, int backlog)
@@ -4830,7 +4903,8 @@ static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *op
u32 peer_sid = SECSID_NULL;
if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET ||
- sksec->sclass == SECCLASS_TCP_SOCKET)
+ sksec->sclass == SECCLASS_TCP_SOCKET ||
+ sksec->sclass == SECCLASS_SCTP_SOCKET)
peer_sid = sksec->peer_sid;
if (peer_sid == SECSID_NULL)
return -ENOPROTOOPT;
@@ -4943,6 +5017,171 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
sksec->sclass = isec->sclass;
}
+/* Called whenever SCTP receives an INIT chunk. This happens when an incoming
+ * connect(2), sctp_connectx(3) or sctp_sendmsg(3) (with no association
+ * already present).
+ */
+static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
+ struct sk_buff *skb)
+{
+ struct sk_security_struct *sksec = ep->base.sk->sk_security;
+ struct common_audit_data ad;
+ struct lsm_network_audit net = {0,};
+ u8 peerlbl_active;
+ u32 peer_sid = SECINITSID_UNLABELED;
+ u32 conn_sid;
+ int err = 0;
+
+ if (!selinux_policycap_extsockclass)
+ return 0;
+
+ peerlbl_active = selinux_peerlbl_enabled();
+
+ if (peerlbl_active) {
+ /* This will return peer_sid = SECSID_NULL if there are
+ * no peer labels, see security_net_peersid_resolve().
+ */
+ err = selinux_skb_peerlbl_sid(skb, ep->base.sk->sk_family,
+ &peer_sid);
+ if (err)
+ return err;
+
+ if (peer_sid == SECSID_NULL)
+ peer_sid = SECINITSID_UNLABELED;
+ }
+
+ if (sksec->sctp_assoc_state == SCTP_ASSOC_UNSET) {
+ sksec->sctp_assoc_state = SCTP_ASSOC_SET;
+
+ /* Here as first association on socket. As the peer SID
+ * was allowed by peer recv (and the netif/node checks),
+ * then it is approved by policy and used as the primary
+ * peer SID for getpeercon(3).
+ */
+ sksec->peer_sid = peer_sid;
+ } else if (sksec->peer_sid != peer_sid) {
+ /* Other association peer SIDs are checked to enforce
+ * consistency among the peer SIDs.
+ */
+ ad.type = LSM_AUDIT_DATA_NET;
+ ad.u.net = &net;
+ ad.u.net->sk = ep->base.sk;
+ err = avc_has_perm(sksec->peer_sid, peer_sid, sksec->sclass,
+ SCTP_SOCKET__ASSOCIATION, &ad);
+ if (err)
+ return err;
+ }
+
+ /* Compute the MLS component for the connection and store
+ * the information in ep. This will be used by SCTP TCP type
+ * sockets and peeled off connections as they cause a new
+ * socket to be generated. selinux_sctp_sk_clone() will then
+ * plug this into the new socket.
+ */
+ err = selinux_conn_sid(sksec->sid, peer_sid, &conn_sid);
+ if (err)
+ return err;
+
+ ep->secid = conn_sid;
+ ep->peer_secid = peer_sid;
+
+ /* Set any NetLabel labels including CIPSO/CALIPSO options. */
+ return selinux_netlbl_sctp_assoc_request(ep, skb);
+}
+
+/* Check if sctp IPv4/IPv6 addresses are valid for binding or connecting
+ * based on their @optname.
+ */
+static int selinux_sctp_bind_connect(struct sock *sk, int optname,
+ struct sockaddr *address,
+ int addrlen)
+{
+ int len, err = 0, walk_size = 0;
+ void *addr_buf;
+ struct sockaddr *addr;
+ struct socket *sock;
+
+ if (!selinux_policycap_extsockclass)
+ return 0;
+
+ /* Process one or more addresses that may be IPv4 or IPv6 */
+ sock = sk->sk_socket;
+ addr_buf = address;
+
+ while (walk_size < addrlen) {
+ addr = addr_buf;
+ switch (addr->sa_family) {
+ case AF_INET:
+ len = sizeof(struct sockaddr_in);
+ break;
+ case AF_INET6:
+ len = sizeof(struct sockaddr_in6);
+ break;
+ default:
+ return -EAFNOSUPPORT;
+ }
+
+ err = -EINVAL;
+ switch (optname) {
+ /* Bind checks */
+ case SCTP_PRIMARY_ADDR:
+ case SCTP_SET_PEER_PRIMARY_ADDR:
+ case SCTP_SOCKOPT_BINDX_ADD:
+ err = selinux_socket_bind(sock, addr, len);
+ break;
+ /* Connect checks */
+ case SCTP_SOCKOPT_CONNECTX:
+ case SCTP_PARAM_SET_PRIMARY:
+ case SCTP_PARAM_ADD_IP:
+ case SCTP_SENDMSG_CONNECT:
+ err = selinux_socket_connect_helper(sock, addr, len);
+ if (err)
+ return err;
+
+ /* As selinux_sctp_bind_connect() is called by the
+ * SCTP protocol layer, the socket is already locked,
+ * therefore selinux_netlbl_socket_connect_locked() is
+ * is called here. The situations handled are:
+ * sctp_connectx(3), sctp_sendmsg(3), sendmsg(2),
+ * whenever a new IP address is added or when a new
+ * primary address is selected.
+ * Note that an SCTP connect(2) call happens before
+ * the SCTP protocol layer and is handled via
+ * selinux_socket_connect().
+ */
+ err = selinux_netlbl_socket_connect_locked(sk, addr);
+ break;
+ }
+
+ if (err)
+ return err;
+
+ addr_buf += len;
+ walk_size += len;
+ }
+
+ return 0;
+}
+
+/* Called whenever a new socket is created by accept(2) or sctp_peeloff(3). */
+static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
+ struct sock *newsk)
+{
+ struct sk_security_struct *sksec = sk->sk_security;
+ struct sk_security_struct *newsksec = newsk->sk_security;
+
+ /* If policy does not support SECCLASS_SCTP_SOCKET then call
+ * the non-sctp clone version.
+ */
+ if (!selinux_policycap_extsockclass)
+ return selinux_sk_clone_security(sk, newsk);
+
+ newsksec->sid = ep->secid;
+ newsksec->peer_sid = ep->peer_secid;
+ newsksec->sclass = sksec->sclass;
+ selinux_netlbl_sctp_sk_clone(sk, newsk);
+}
+
static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
@@ -6563,6 +6802,9 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(sk_clone_security, selinux_sk_clone_security),
LSM_HOOK_INIT(sk_getsecid, selinux_sk_getsecid),
LSM_HOOK_INIT(sock_graft, selinux_sock_graft),
+ LSM_HOOK_INIT(sctp_assoc_request, selinux_sctp_assoc_request),
+ LSM_HOOK_INIT(sctp_sk_clone, selinux_sctp_sk_clone),
+ LSM_HOOK_INIT(sctp_bind_connect, selinux_sctp_bind_connect),
LSM_HOOK_INIT(inet_conn_request, selinux_inet_conn_request),
LSM_HOOK_INIT(inet_csk_clone, selinux_inet_csk_clone),
LSM_HOOK_INIT(inet_conn_established, selinux_inet_conn_established),