5 files changed, 98 insertions, 19 deletions

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index fbe7714f21d0..3cef12835c4b 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -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_hashinfo *hashinfo,
 
         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)];
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index fb662621c54e..fac6398e4367 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -279,19 +279,18 @@ int inet_hash_connect(struct inet_timewait_death_row *death_row,
         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);
 
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 53ef0f4bbdaa..eb286abcf5dc 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -12,6 +12,7 @@
 #include <linux/sysctl.h>
 #include <linux/igmp.h>
 #include <linux/inetdevice.h>
+#include <linux/seqlock.h>
 #include <net/snmp.h>
 #include <net/icmp.h>
 #include <net/ip.h>
@@ -89,6 +90,74 @@ static int ipv4_sysctl_forward_strategy(ctl_table *table,
         return 1;
 }
 
+extern seqlock_t sysctl_port_range_lock;
+extern int sysctl_local_port_range[2];
+
+/* Update system visible IP port range */
+static void set_local_port_range(int range[2])
+{
+        write_seqlock(&sysctl_port_range_lock);
+        sysctl_local_port_range[0] = range[0];
+        sysctl_local_port_range[1] = range[1];
+        write_sequnlock(&sysctl_port_range_lock);
+}
+
+/* Validate changes from /proc interface. */
+static int ipv4_local_port_range(ctl_table *table, int write, struct file *filp,
+                                 void __user *buffer,
+                                 size_t *lenp, loff_t *ppos)
+{
+        int ret;
+        int range[2] = { sysctl_local_port_range[0],
+                         sysctl_local_port_range[1] };
+        ctl_table tmp = {
+                .data = &range,
+                .maxlen = sizeof(range),
+                .mode = table->mode,
+                .extra1 = &ip_local_port_range_min,
+                .extra2 = &ip_local_port_range_max,
+        };
+
+        ret = proc_dointvec_minmax(&tmp, write, filp, buffer, lenp, ppos);
+
+        if (write && ret == 0) {
+                if (range[1] <= range[0])
+                        ret = -EINVAL;
+                else
+                        set_local_port_range(range);
+        }
+
+        return ret;
+}
+
+/* Validate changes from sysctl interface. */
+static int ipv4_sysctl_local_port_range(ctl_table *table, int __user *name,
+                                         int nlen, void __user *oldval,
+                                         size_t __user *oldlenp,
+                                        void __user *newval, size_t newlen)
+{
+        int ret;
+        int range[2] = { sysctl_local_port_range[0],
+                         sysctl_local_port_range[1] };
+        ctl_table tmp = {
+                .data = &range,
+                .maxlen = sizeof(range),
+                .mode = table->mode,
+                .extra1 = &ip_local_port_range_min,
+                .extra2 = &ip_local_port_range_max,
+        };
+
+        ret = sysctl_intvec(&tmp, name, nlen, oldval, oldlenp, newval, newlen);
+        if (ret == 0 && newval && newlen) {
+                if (range[1] <= range[0])
+                        ret = -EINVAL;
+                else
+                        set_local_port_range(range);
+        }
+        return ret;
+}
+
+
 static int proc_tcp_congestion_control(ctl_table *ctl, int write, struct file * filp,
                                        void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -427,10 +496,8 @@ ctl_table ipv4_table[] = {
                 .data           = &sysctl_local_port_range,
                 .maxlen         = sizeof(sysctl_local_port_range),
                 .mode           = 0644,
-                .proc_handler   = &proc_dointvec_minmax,
-                .strategy       = &sysctl_intvec,
-                .extra1         = ip_local_port_range_min,
-                .extra2         = ip_local_port_range_max
+                .proc_handler   = &ipv4_local_port_range,
+                .strategy       = &ipv4_sysctl_local_port_range,
         },
         {
                 .ctl_name       = NET_IPV4_ICMP_ECHO_IGNORE_ALL,
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 8855e640e958..38cf73a56731 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -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);
 
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ef4d901ee9ad..cb9fc58efb2f 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -147,11 +147,11 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
         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;