SCTP: port randomization

@@ -197,8 +197,6 @@ extern struct sctp_globals {
 
 	/* This is the sctp port control hash.	*/
 	int port_hashsize;
-	int port_rover;
-	spinlock_t port_alloc_lock;  /* Protects port_rover. */
 	struct sctp_bind_hashbucket *port_hashtable;
 
 	/* This is the global local address list.

@@ -1172,9 +1172,6 @@ SCTP_STATIC __init int sctp_init(void)
 		sctp_port_hashtable[i].chain = NULL;
 	}
 
-	spin_lock_init(&sctp_port_alloc_lock);
-	sctp_port_rover = sysctl_local_port_range[0] - 1;
-
 	printk(KERN_INFO "SCTP: Hash tables configured "
 			 "(established %d bind %d)\n",
 		sctp_assoc_hashsize, sctp_port_hashsize);

@@ -5314,22 +5314,13 @@ static long sctp_get_port_local(struct s
 	sctp_local_bh_disable();
 
 	if (snum == 0) {
-		/* Search for an available port.
-		 *
-		 * 'sctp_port_rover' was the last port assigned, so
-		 * we start to search from 'sctp_port_rover +
-		 * 1'. What we do is first check if port 'rover' is
-		 * already in the hash table; if not, we use that; if
-		 * it is, we try next.
-		 */
-		int low = sysctl_local_port_range[0];
-		int high = sysctl_local_port_range[1];
-		int remaining = (high - low) + 1;
-		int rover;
+		/* Search for an available port. */
+		unsigned int low = sysctl_local_port_range[0];
+		unsigned int high = sysctl_local_port_range[1];
+		unsigned int remaining = (high - low) + 1;
+		unsigned int rover = net_random() % remaining + low;
 		int index;
 
-		sctp_spin_lock(&sctp_port_alloc_lock);
-		rover = sctp_port_rover;
 		do {
 			rover++;
 			if ((rover < low) || (rover > high))

@@ -5344,8 +5335,6 @@ static long sctp_get_port_local(struct s
 		next:
 			sctp_spin_unlock(&head->lock);
 		} while (--remaining > 0);
-		sctp_port_rover = rover;
-		sctp_spin_unlock(&sctp_port_alloc_lock);
 
 		/* Exhausted local port range during search? */
 		ret = 1;

@@ -171,7 +171,8 @@ extern unsigned long snmp_fold_field(voi
 extern int snmp_mib_init(void *ptr[2], size_t mibsize, size_t mibalign);
 extern void snmp_mib_free(void *ptr[2]);
 
-extern int sysctl_local_port_range[2];
+extern void inet_get_local_port_range(int *low, int *high);
+
 extern int sysctl_ip_default_ttl;
 extern int sysctl_ip_nonlocal_bind;
 

@@ -33,6 +33,19 @@ EXPORT_SYMBOL(inet_csk_timer_bug_msg);
  * This array holds the first and last local port number.
  */
 int sysctl_local_port_range[2] = { 32768, 61000 };
+DEFINE_SEQLOCK(sysctl_port_range_lock);
+
+void inet_get_local_port_range(int *low, int *high)
+{
+	unsigned seq;
+	do {
+		seq = read_seqbegin(&sysctl_port_range_lock);
+
+		*low = sysctl_local_port_range[0];
+		*high = sysctl_local_port_range[1];
+	} while (read_seqretry(&sysctl_port_range_lock, seq));
+}
+EXPORT_SYMBOL(inet_get_local_port_range);
 
 int inet_csk_bind_conflict(const struct sock *sk,
 			   const struct inet_bind_bucket *tb)

@@ -77,10 +90,11 @@ int inet_csk_get_port(struct inet_hashin
 
 	local_bh_disable();
 	if (!snum) {
-		int low = sysctl_local_port_range[0];
-		int high = sysctl_local_port_range[1];
-		int remaining = (high - low) + 1;
-		int rover = net_random() % (high - low) + low;
+		int remaining, rover, low, high;
+
+		inet_get_local_port_range(&low, &high);
+		remaining = high - low;
+		rover = net_random() % remaining + low;
 
 		do {
 			head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];

@@ -279,19 +279,18 @@ int inet_hash_connect(struct inet_timewa
 	int ret;
 
 	if (!snum) {
-		int low = sysctl_local_port_range[0];
-		int high = sysctl_local_port_range[1];
-		int range = high - low;
-		int i;
-		int port;
+		int i, remaining, low, high, port;
 		static u32 hint;
 		u32 offset = hint + inet_sk_port_offset(sk);
 		struct hlist_node *node;
 		struct inet_timewait_sock *tw = NULL;
 
+		inet_get_local_port_range(&low, &high);
+		remaining = high - low;
+
 		local_bh_disable();
-		for (i = 1; i <= range; i++) {
-			port = low + (i + offset) % range;
+		for (i = 1; i <= remaining; i++) {
+			port = low + (i + offset) % remaining;
 			head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
 			spin_lock(&head->lock);
 

93 lines not on this page · raw message

@@ -2470,6 +2470,5 @@ EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
 EXPORT_SYMBOL(tcp_proc_register);
 EXPORT_SYMBOL(tcp_proc_unregister);
 #endif
-EXPORT_SYMBOL(sysctl_local_port_range);
 EXPORT_SYMBOL(sysctl_tcp_low_latency);
 

@@ -147,11 +147,11 @@ int __udp_lib_get_port(struct sock *sk, 
 	write_lock_bh(&udp_hash_lock);
 
 	if (!snum) {
-		int i;
-		int low = sysctl_local_port_range[0];
-		int high = sysctl_local_port_range[1];
+		int i, low, high;
 		unsigned rover, best, best_size_so_far;
 
+		inet_get_local_port_range(&low, &high);
+
 		best_size_so_far = UINT_MAX;
 		best = rover = net_random() % (high - low) + low;
 

@@ -254,18 +254,18 @@ int inet6_hash_connect(struct inet_timew
 	int ret;
 
 	if (snum == 0) {
-		const int low = sysctl_local_port_range[0];
-		const int high = sysctl_local_port_range[1];
-		const int range = high - low;
-		int i, port;
+		int i, port, low, high, remaining;
 		static u32 hint;
 		const u32 offset = hint + inet6_sk_port_offset(sk);
 		struct hlist_node *node;
 		struct inet_timewait_sock *tw = NULL;
 
+		inet_get_local_port_range(&low, &high);
+		remaining = high - low;
+
 		local_bh_disable();
-		for (i = 1; i <= range; i++) {
-			port = low + (i + offset) % range;
+		for (i = 1; i <= remaining; i++) {
+			port = low + (i + offset) % remaining;
 			head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
 			spin_lock(&head->lock);
 

@@ -47,7 +47,7 @@
 #include <linux/netfilter_ipv6.h>
 #include <linux/tty.h>
 #include <net/icmp.h>
-#include <net/ip.h>		/* for sysctl_local_port_range[] */
+#include <net/ip.h>		/* for local_port_range[] */
 #include <net/tcp.h>		/* struct or_callable used in sock_rcv_skb */
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>

@@ -3232,8 +3232,6 @@ static int selinux_socket_post_create(st
 /* Range of port numbers used to automatically bind.
    Need to determine whether we should perform a name_bind
    permission check between the socket and the port number. */
-#define ip_local_port_range_0 sysctl_local_port_range[0]
-#define ip_local_port_range_1 sysctl_local_port_range[1]
 
 static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
 {

@@ -3276,20 +3274,27 @@ static int selinux_socket_bind(struct so
 			addrp = (char *)&addr6->sin6_addr.s6_addr;
 		}
 
-		if (snum&&(snum < max(PROT_SOCK,ip_local_port_range_0) ||
-			   snum > ip_local_port_range_1)) {
-			err = security_port_sid(sk->sk_family, sk->sk_type,
-						sk->sk_protocol, snum, &sid);
-			if (err)
-				goto out;
-			AVC_AUDIT_DATA_INIT(&ad,NET);
-			ad.u.net.sport = htons(snum);
-			ad.u.net.family = family;
-			err = avc_has_perm(isec->sid, sid,
-					   isec->sclass,
-					   SOCKET__NAME_BIND, &ad);
-			if (err)
-				goto out;
+		if (snum) {
+			int low, high;
+
+			inet_get_local_port_range(&low, &high);
+
+			if (snum < max(PROT_SOCK, low) || snum > high) {
+				err = security_port_sid(sk->sk_family,
+							sk->sk_type,
+							sk->sk_protocol, snum,
+							&sid);
+				if (err)
+					goto out;
+				AVC_AUDIT_DATA_INIT(&ad,NET);
+				ad.u.net.sport = htons(snum);
+				ad.u.net.family = family;
+				err = avc_has_perm(isec->sid, sid,
+						   isec->sclass,
+						   SOCKET__NAME_BIND, &ad);
+				if (err)
+					goto out;
+			}
 		}
 		
 		switch(isec->sclass) {

@@ -1866,13 +1866,14 @@ err1:
 static int cma_alloc_any_port(struct idr *ps, struct rdma_id_private *id_priv)
 {
 	struct rdma_bind_list *bind_list;
-	int port, ret;
+	int port, ret, low, high;
 
 	bind_list = kzalloc(sizeof *bind_list, GFP_KERNEL);
 	if (!bind_list)
 		return -ENOMEM;
 
 retry:
+	/* FIXME: add proper port randomization per like inet_csk_get_port */
 	do {
 		ret = idr_get_new_above(ps, bind_list, next_port, &port);
 	} while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL));

@@ -1880,18 +1881,19 @@ retry:
 	if (ret)
 		goto err1;
 
-	if (port > sysctl_local_port_range[1]) {
-		if (next_port != sysctl_local_port_range[0]) {
+	inet_get_local_port_range(&low, &high);
+	if (port > high) {
+		if (next_port != low) {
 			idr_remove(ps, port);
-			next_port = sysctl_local_port_range[0];
+			next_port = low;
 			goto retry;
 		}
 		ret = -EADDRNOTAVAIL;
 		goto err2;
 	}
 
-	if (port == sysctl_local_port_range[1])
-		next_port = sysctl_local_port_range[0];
+	if (port == high)
+		next_port = low;
 	else
 		next_port = port + 1;
 

@@ -2769,12 +2771,12 @@ static void cma_remove_one(struct ib_dev
 
 static int cma_init(void)
 {
-	int ret;
+	int ret, low, high;
 
 	get_random_bytes(&next_port, sizeof next_port);
-	next_port = ((unsigned int) next_port %
-		    (sysctl_local_port_range[1] - sysctl_local_port_range[0])) +
-		    sysctl_local_port_range[0];
+	inet_get_local_port_range(&low, &high);
+	next_port = ((unsigned int) next_port % (high - low)) + low;
+
 	cma_wq = create_singlethread_workqueue("rdma_cm");
 	if (!cma_wq)
 		return -ENOMEM;

@@ -5315,11 +5315,12 @@ static long sctp_get_port_local(struct s
 
 	if (snum == 0) {
 		/* Search for an available port. */
-		unsigned int low = sysctl_local_port_range[0];
-		unsigned int high = sysctl_local_port_range[1];
-		unsigned int remaining = (high - low) + 1;
-		unsigned int rover = net_random() % remaining + low;
-		int index;
+		int low, high, remaining, index;
+		unsigned int rover;
+
+		inet_get_local_port_range(&low, &high);
+		remaining = (high - low) + 1;
+		rover = net_random() % remaining + low;
 
 		do {
 			rover++;