1 files changed, 16 insertions, 1 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 783bccfcc060..88d2cf0cae52 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4935,6 +4935,21 @@ int addrconf_sysctl_forward(struct ctl_table *ctl, int write,
         return ret;
 }
 
+static
+int addrconf_sysctl_mtu(struct ctl_table *ctl, int write,
+                        void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        struct inet6_dev *idev = ctl->extra1;
+        int min_mtu = IPV6_MIN_MTU;
+        struct ctl_table lctl;
+
+        lctl = *ctl;
+        lctl.extra1 = &min_mtu;
+        lctl.extra2 = idev ? &idev->dev->mtu : NULL;
+
+        return proc_dointvec_minmax(&lctl, write, buffer, lenp, ppos);
+}
+
 static void dev_disable_change(struct inet6_dev *idev)
 {
         struct netdev_notifier_info info;
@@ -5086,7 +5101,7 @@ static struct addrconf_sysctl_table
                         .data           = &ipv6_devconf.mtu6,
                         .maxlen         = sizeof(int),
                         .mode           = 0644,
-                        .proc_handler   = proc_dointvec,
+                        .proc_handler   = addrconf_sysctl_mtu,
                 },
                 {
                         .procname       = "accept_ra",