1 files changed, 40 insertions, 21 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index a225d5ee3c2f..c02280a4d126 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -502,29 +502,31 @@ static void addrconf_forward_change(struct net *net, __s32 newf)
         rcu_read_unlock();
 }
 
-static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old)
+static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int newf)
 {
         struct net *net;
+        int old;
+
+        if (!rtnl_trylock())
+                return restart_syscall();
 
         net = (struct net *)table->extra2;
-        if (p == &net->ipv6.devconf_dflt->forwarding)
-                return 0;
+        old = *p;
+        *p = newf;
 
-        if (!rtnl_trylock()) {
-                /* Restore the original values before restarting */
-                *p = old;
-                return restart_syscall();
+        if (p == &net->ipv6.devconf_dflt->forwarding) {
+                rtnl_unlock();
+                return 0;
         }
 
         if (p == &net->ipv6.devconf_all->forwarding) {
-                __s32 newf = net->ipv6.devconf_all->forwarding;
                 net->ipv6.devconf_dflt->forwarding = newf;
                 addrconf_forward_change(net, newf);
-        } else if ((!*p) ^ (!old))
+        } else if ((!newf) ^ (!old))
                 dev_forward_change((struct inet6_dev *)table->extra1);
         rtnl_unlock();
 
-        if (*p)
+        if (newf)
                 rt6_purge_dflt_routers(net);
         return 1;
 }
@@ -4260,9 +4262,17 @@ int addrconf_sysctl_forward(ctl_table *ctl, int write,
         int *valp = ctl->data;
         int val = *valp;
         loff_t pos = *ppos;
+        ctl_table lctl;
         int ret;
 
-        ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
+        /*
+         * ctl->data points to idev->cnf.forwarding, we should
+         * not modify it until we get the rtnl lock.
+         */
+        lctl = *ctl;
+        lctl.data = &val;
+
+        ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);
 
         if (write)
                 ret = addrconf_fixup_forwarding(ctl, valp, val);
@@ -4300,26 +4310,27 @@ static void addrconf_disable_change(struct net *net, __s32 newf)
         rcu_read_unlock();
 }
 
-static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int old)
+static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
 {
         struct net *net;
+        int old;
+
+        if (!rtnl_trylock())
+                return restart_syscall();
 
         net = (struct net *)table->extra2;
+        old = *p;
+        *p = newf;
 
-        if (p == &net->ipv6.devconf_dflt->disable_ipv6)
+        if (p == &net->ipv6.devconf_dflt->disable_ipv6) {
+                rtnl_unlock();
                 return 0;
-
-        if (!rtnl_trylock()) {
-                /* Restore the original values before restarting */
-                *p = old;
-                return restart_syscall();
         }
 
         if (p == &net->ipv6.devconf_all->disable_ipv6) {
-                __s32 newf = net->ipv6.devconf_all->disable_ipv6;
                 net->ipv6.devconf_dflt->disable_ipv6 = newf;
                 addrconf_disable_change(net, newf);
-        } else if ((!*p) ^ (!old))
+        } else if ((!newf) ^ (!old))
                 dev_disable_change((struct inet6_dev *)table->extra1);
 
         rtnl_unlock();
@@ -4333,9 +4344,17 @@ int addrconf_sysctl_disable(ctl_table *ctl, int write,
         int *valp = ctl->data;
         int val = *valp;
         loff_t pos = *ppos;
+        ctl_table lctl;
         int ret;
 
-        ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
+        /*
+         * ctl->data points to idev->cnf.disable_ipv6, we should
+         * not modify it until we get the rtnl lock.
+         */
+        lctl = *ctl;
+        lctl.data = &val;
+
+        ret = proc_dointvec(&lctl, write, buffer, lenp, ppos);
 
         if (write)
                 ret = addrconf_disable_ipv6(ctl, valp, val);