lsm: infrastructure management of the sock security

Move management of the sock->sk_security blob out
of the individual security modules and into the security
infrastructure. Instead of allocating the blobs from within
the modules the modules tell the infrastructure how much
space is required, and the space is allocated there.

Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>

3 files changed, 54 insertions, 54 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 55c78c318ccd..e08ffb1ddd5a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4584,7 +4584,7 @@ static int socket_sockcreate_sid(const struct task_security_struct *tsec,
 
 static int sock_has_perm(struct sock *sk, u32 perms)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net;
 
@@ -4652,7 +4652,7 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 	isec->initialized = LABEL_INITIALIZED;
 
 	if (sock->sk) {
-		sksec = sock->sk->sk_security;
+		sksec = selinux_sock(sock->sk);
 		sksec->sclass = sclass;
 		sksec->sid = sid;
 		/* Allows detection of the first association on this socket */
@@ -4668,8 +4668,8 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 static int selinux_socket_socketpair(struct socket *socka,
 				     struct socket *sockb)
 {
-	struct sk_security_struct *sksec_a = socka->sk->sk_security;
-	struct sk_security_struct *sksec_b = sockb->sk->sk_security;
+	struct sk_security_struct *sksec_a = selinux_sock(socka->sk);
+	struct sk_security_struct *sksec_b = selinux_sock(sockb->sk);
 
 	sksec_a->peer_sid = sksec_b->sid;
 	sksec_b->peer_sid = sksec_a->sid;
@@ -4684,7 +4684,7 @@ static int selinux_socket_socketpair(struct socket *socka,
 static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
 {
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 family;
 	int err;
 
@@ -4824,7 +4824,7 @@ 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;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	int err;
 
 	err = sock_has_perm(sk, SOCKET__CONNECT);
@@ -5002,9 +5002,9 @@ static int selinux_socket_unix_stream_connect(struct sock *sock,
 					      struct sock *other,
 					      struct sock *newsk)
 {
-	struct sk_security_struct *sksec_sock = sock->sk_security;
-	struct sk_security_struct *sksec_other = other->sk_security;
-	struct sk_security_struct *sksec_new = newsk->sk_security;
+	struct sk_security_struct *sksec_sock = selinux_sock(sock);
+	struct sk_security_struct *sksec_other = selinux_sock(other);
+	struct sk_security_struct *sksec_new = selinux_sock(newsk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net;
 	int err;
@@ -5033,8 +5033,8 @@ static int selinux_socket_unix_stream_connect(struct sock *sock,
 static int selinux_socket_unix_may_send(struct socket *sock,
 					struct socket *other)
 {
-	struct sk_security_struct *ssec = sock->sk->sk_security;
-	struct sk_security_struct *osec = other->sk->sk_security;
+	struct sk_security_struct *ssec = selinux_sock(sock->sk);
+	struct sk_security_struct *osec = selinux_sock(other->sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net;
 
@@ -5071,7 +5071,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
 				       u16 family)
 {
 	int err = 0;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u32 sk_sid = sksec->sid;
 	struct common_audit_data ad;
 	struct lsm_network_audit net;
@@ -5100,7 +5100,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
 static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
 	int err, peerlbl_active, secmark_active;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 family = sk->sk_family;
 	u32 sk_sid = sksec->sid;
 	struct common_audit_data ad;
@@ -5168,7 +5168,7 @@ static int selinux_socket_getpeersec_stream(struct socket *sock,
 	int err = 0;
 	char *scontext = NULL;
 	u32 scontext_len;
-	struct sk_security_struct *sksec = sock->sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sock->sk);
 	u32 peer_sid = SECSID_NULL;
 
 	if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET ||
@@ -5228,34 +5228,27 @@ static int selinux_socket_getpeersec_dgram(struct socket *sock,
 
 static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority)
 {
-	struct sk_security_struct *sksec;
-
-	sksec = kzalloc(sizeof(*sksec), priority);
-	if (!sksec)
-		return -ENOMEM;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	sksec->peer_sid = SECINITSID_UNLABELED;
 	sksec->sid = SECINITSID_UNLABELED;
 	sksec->sclass = SECCLASS_SOCKET;
 	selinux_netlbl_sk_security_reset(sksec);
-	sk->sk_security = sksec;
 
 	return 0;
 }
 
 static void selinux_sk_free_security(struct sock *sk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
-	sk->sk_security = NULL;
 	selinux_netlbl_sk_security_free(sksec);
-	kfree(sksec);
 }
 
 static void selinux_sk_clone_security(const struct sock *sk, struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->sid = sksec->sid;
 	newsksec->peer_sid = sksec->peer_sid;
@@ -5269,7 +5262,7 @@ static void selinux_sk_getsecid(const struct sock *sk, u32 *secid)
 	if (!sk)
 		*secid = SECINITSID_ANY_SOCKET;
 	else {
-		const struct sk_security_struct *sksec = sk->sk_security;
+		const struct sk_security_struct *sksec = selinux_sock(sk);
 
 		*secid = sksec->sid;
 	}
@@ -5279,7 +5272,7 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
 {
 	struct inode_security_struct *isec =
 		inode_security_novalidate(SOCK_INODE(parent));
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6 ||
 	    sk->sk_family == PF_UNIX)
@@ -5296,7 +5289,7 @@ static int selinux_sctp_process_new_assoc(struct sctp_association *asoc,
 {
 	struct sock *sk = asoc->base.sk;
 	u16 family = sk->sk_family;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct common_audit_data ad;
 	struct lsm_network_audit net;
 	int err;
@@ -5351,7 +5344,7 @@ static int selinux_sctp_process_new_assoc(struct sctp_association *asoc,
 static int selinux_sctp_assoc_request(struct sctp_association *asoc,
 				      struct sk_buff *skb)
 {
-	struct sk_security_struct *sksec = asoc->base.sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(asoc->base.sk);
 	u32 conn_sid;
 	int err;
 
@@ -5384,7 +5377,7 @@ static int selinux_sctp_assoc_request(struct sctp_association *asoc,
 static int selinux_sctp_assoc_established(struct sctp_association *asoc,
 					  struct sk_buff *skb)
 {
-	struct sk_security_struct *sksec = asoc->base.sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(asoc->base.sk);
 
 	if (!selinux_policycap_extsockclass())
 		return 0;
@@ -5483,8 +5476,8 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname,
 static void selinux_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk,
 				  struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	/* If policy does not support SECCLASS_SCTP_SOCKET then call
 	 * the non-sctp clone version.
@@ -5500,8 +5493,8 @@ static void selinux_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk
 
 static int selinux_mptcp_add_subflow(struct sock *sk, struct sock *ssk)
 {
-	struct sk_security_struct *ssksec = ssk->sk_security;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *ssksec = selinux_sock(ssk);
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	ssksec->sclass = sksec->sclass;
 	ssksec->sid = sksec->sid;
@@ -5516,7 +5509,7 @@ static int selinux_mptcp_add_subflow(struct sock *sk, struct sock *ssk)
 static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 				     struct request_sock *req)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	int err;
 	u16 family = req->rsk_ops->family;
 	u32 connsid;
@@ -5537,7 +5530,7 @@ static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 static void selinux_inet_csk_clone(struct sock *newsk,
 				   const struct request_sock *req)
 {
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->sid = req->secid;
 	newsksec->peer_sid = req->peer_secid;
@@ -5554,7 +5547,7 @@ static void selinux_inet_csk_clone(struct sock *newsk,
 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;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	/* handle mapped IPv4 packets arriving via IPv6 sockets */
 	if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
@@ -5629,7 +5622,7 @@ static int selinux_tun_dev_attach_queue(void *security)
 static int selinux_tun_dev_attach(struct sock *sk, void *security)
 {
 	struct tun_security_struct *tunsec = security;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	/* we don't currently perform any NetLabel based labeling here and it
 	 * isn't clear that we would want to do so anyway; while we could apply
@@ -5752,7 +5745,7 @@ static unsigned int selinux_ip_output(void *priv, struct sk_buff *skb,
 			return NF_ACCEPT;
 
 		/* standard practice, label using the parent socket */
-		sksec = sk->sk_security;
+		sksec = selinux_sock(sk);
 		sid = sksec->sid;
 	} else
 		sid = SECINITSID_KERNEL;
@@ -5775,7 +5768,7 @@ static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb,
 	sk = skb_to_full_sk(skb);
 	if (sk == NULL)
 		return NF_ACCEPT;
-	sksec = sk->sk_security;
+	sksec = selinux_sock(sk);
 
 	ad_net_init_from_iif(&ad, &net, state->out->ifindex, state->pf);
 	if (selinux_parse_skb(skb, &ad, NULL, 0, &proto))
@@ -5864,7 +5857,7 @@ static unsigned int selinux_ip_postroute(void *priv,
 		u32 skb_sid;
 		struct sk_security_struct *sksec;
 
-		sksec = sk->sk_security;
+		sksec = selinux_sock(sk);
 		if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
 			return NF_DROP;
 		/* At this point, if the returned skb peerlbl is SECSID_NULL
@@ -5893,7 +5886,7 @@ static unsigned int selinux_ip_postroute(void *priv,
 	} else {
 		/* Locally generated packet, fetch the security label from the
 		 * associated socket. */
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 		peer_sid = sksec->sid;
 		secmark_perm = PACKET__SEND;
 	}
@@ -5936,7 +5929,7 @@ static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
 	unsigned int data_len = skb->len;
 	unsigned char *data = skb->data;
 	struct nlmsghdr *nlh;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	u16 sclass = sksec->sclass;
 	u32 perm;
 
@@ -6994,6 +6987,7 @@ struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = {
 	.lbs_inode = sizeof(struct inode_security_struct),
 	.lbs_ipc = sizeof(struct ipc_security_struct),
 	.lbs_msg_msg = sizeof(struct msg_security_struct),
+	.lbs_sock = sizeof(struct sk_security_struct),
 	.lbs_superblock = sizeof(struct superblock_security_struct),
 	.lbs_xattr_count = SELINUX_INODE_INIT_XATTRS,
 };
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index dea1d6f3ed2d..b074099acbaf 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -195,4 +195,9 @@ selinux_superblock(const struct super_block *superblock)
 	return superblock->s_security + selinux_blob_sizes.lbs_superblock;
 }
 
+static inline struct sk_security_struct *selinux_sock(const struct sock *sock)
+{
+	return sock->sk_security + selinux_blob_sizes.lbs_sock;
+}
+
 #endif /* _SELINUX_OBJSEC_H_ */
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index 55885634e880..fbe5f8c29f81 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -17,6 +17,7 @@
 #include <linux/gfp.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
+#include <linux/lsm_hooks.h>
 #include <net/sock.h>
 #include <net/netlabel.h>
 #include <net/ip.h>
@@ -68,7 +69,7 @@ static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
 static struct netlbl_lsm_secattr *selinux_netlbl_sock_genattr(struct sock *sk)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	if (sksec->nlbl_secattr != NULL)
@@ -100,7 +101,7 @@ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr(
 							const struct sock *sk,
 							u32 sid)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr = sksec->nlbl_secattr;
 
 	if (secattr == NULL)
@@ -240,7 +241,7 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
 	 * being labeled by it's parent socket, if it is just exit */
 	sk = skb_to_full_sk(skb);
 	if (sk != NULL) {
-		struct sk_security_struct *sksec = sk->sk_security;
+		struct sk_security_struct *sksec = selinux_sock(sk);
 
 		if (sksec->nlbl_state != NLBL_REQSKB)
 			return 0;
@@ -277,7 +278,7 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_association *asoc,
 {
 	int rc;
 	struct netlbl_lsm_secattr secattr;
-	struct sk_security_struct *sksec = asoc->base.sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(asoc->base.sk);
 	struct sockaddr_in addr4;
 	struct sockaddr_in6 addr6;
 
@@ -356,7 +357,7 @@ inet_conn_request_return:
  */
 void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (family == PF_INET)
 		sksec->nlbl_state = NLBL_LABELED;
@@ -374,8 +375,8 @@ void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
  */
 void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct sk_security_struct *newsksec = newsk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
+	struct sk_security_struct *newsksec = selinux_sock(newsk);
 
 	newsksec->nlbl_state = sksec->nlbl_state;
 }
@@ -393,7 +394,7 @@ void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk)
 int selinux_netlbl_socket_post_create(struct sock *sk, u16 family)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	if (family != PF_INET && family != PF_INET6)
@@ -510,7 +511,7 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock,
 {
 	int rc = 0;
 	struct sock *sk = sock->sk;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr secattr;
 
 	if (selinux_netlbl_option(level, optname) &&
@@ -548,7 +549,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk,
 						struct sockaddr *addr)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 	struct netlbl_lsm_secattr *secattr;
 
 	/* connected sockets are allowed to disconnect when the address family
@@ -587,7 +588,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk,
 int selinux_netlbl_socket_connect_locked(struct sock *sk,
 					 struct sockaddr *addr)
 {
-	struct sk_security_struct *sksec = sk->sk_security;
+	struct sk_security_struct *sksec = selinux_sock(sk);
 
 	if (sksec->nlbl_state != NLBL_REQSKB &&
 	    sksec->nlbl_state != NLBL_CONNLABELED)