[IPV6] SIT: Fix locking issues in PRL management.

To protect PRL list, use ipip6_lock.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 4786419..ee0cc28 100644 (file)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -198,7 +198,7 @@ failed:
 }
 
 static struct ip_tunnel_prl_entry *
-ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
+__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 {
        struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
 
@@ -213,34 +213,46 @@ static int
 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 {
        struct ip_tunnel_prl_entry *p;
+       int err = 0;
+
+       write_lock(&ipip6_lock);
 
        for (p = t->prl; p; p = p->next) {
                if (p->entry.addr == a->addr) {
-                       if (chg) {
-                               p->entry = *a;
-                               return 0;
-                       }
-                       return -EEXIST;
+                       if (chg)
+                               goto update;
+                       err = -EEXIST;
+                       goto out;
                }
        }
 
-       if (chg)
-               return -ENXIO;
+       if (chg) {
+               err = -ENXIO;
+               goto out;
+       }
 
        p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
-       if (!p)
-               return -ENOBUFS;
+       if (!p) {
+               err = -ENOBUFS;
+               goto out;
+       }
 
-       p->entry = *a;
        p->next = t->prl;
        t->prl = p;
-       return 0;
+update:
+       p->entry = *a;
+out:
+       write_unlock(&ipip6_lock);
+       return err;
 }
 
 static int
 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 {
        struct ip_tunnel_prl_entry *x, **p;
+       int err = 0;
+
+       write_lock(&ipip6_lock);
 
        if (a) {
                for (p = &t->prl; *p; p = &(*p)->next) {
@@ -248,10 +260,10 @@ ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
                                x = *p;
                                *p = x->next;
                                kfree(x);
-                               return 0;
+                               goto out;
                        }
                }
-               return -ENXIO;
+               err = -ENXIO;
        } else {
                while (t->prl) {
                        x = t->prl;
@@ -259,6 +271,8 @@ ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
                        kfree(x);
                }
        }
+out:
+       write_unlock(&ipip6_lock);
        return 0;
 }
 
@@ -290,9 +304,11 @@ ipip6_onlink(struct in6_addr *addr, struct net_device *dev)
 static int
 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
 {
-       struct ip_tunnel_prl_entry *p = ipip6_tunnel_locate_prl(t, iph->saddr);
+       struct ip_tunnel_prl_entry *p;
        int ok = 1;
 
+       read_lock(&ipip6_lock);
+       p = __ipip6_tunnel_locate_prl(t, iph->saddr);
        if (p) {
                if (p->entry.flags & PRL_DEFAULT)
                        skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
@@ -307,6 +323,7 @@ isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
                else
                        ok = 0;
        }
+       read_unlock(&ipip6_lock);
        return ok;
 }
 
@@ -895,12 +912,10 @@ ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
                if (!(t = netdev_priv(dev)))
                        goto done;
 
-               ipip6_tunnel_unlink(t);
                if (cmd == SIOCDELPRL)
                        err = ipip6_tunnel_del_prl(t, &prl);
                else
                        err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
-               ipip6_tunnel_link(t);
                netdev_state_change(dev);
                break;