ndisc: Calculate message body length and option length separately.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 9 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 62b1415bec25..c2b16ffeb1a8 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -426,6 +426,7 @@ static struct sk_buff *ndisc_build_skb(struct net_device *dev,
         struct sk_buff *skb;
         struct icmp6hdr *hdr;
         int len;
+        int optlen = 0;
         u8 *opt;
 
         if (!dev->addr_len)
@@ -433,13 +434,13 @@ static struct sk_buff *ndisc_build_skb(struct net_device *dev,
 
         len = sizeof(struct icmp6hdr) + (target ? sizeof(*target) : 0);
         if (llinfo)
-                len += ndisc_opt_addr_space(dev);
+                optlen += ndisc_opt_addr_space(dev);
 
-        skb = ndisc_alloc_skb(dev, len);
+        skb = ndisc_alloc_skb(dev, len + optlen);
         if (!skb)
                 return NULL;
 
-        skb_put(skb, len);
+        skb_put(skb, len + optlen);
 
         hdr = (struct icmp6hdr *)skb_transport_header(skb);
         memcpy(hdr, icmp6h, sizeof(*hdr));
@@ -1396,7 +1397,7 @@ void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
         struct net_device *dev = skb->dev;
         struct net *net = dev_net(dev);
         struct sock *sk = net->ipv6.ndisc_sk;
-        int len = sizeof(struct rd_msg);
+        int optlen = 0;
         struct inet_peer *peer;
         struct sk_buff *buff;
         struct rd_msg *msg;
@@ -1463,7 +1464,7 @@ void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
                         memcpy(ha_buf, neigh->ha, dev->addr_len);
                         read_unlock_bh(&neigh->lock);
                         ha = ha_buf;
-                        len += ndisc_opt_addr_space(dev);
+                        optlen += ndisc_opt_addr_space(dev);
                 } else
                         read_unlock_bh(&neigh->lock);
 
@@ -1471,15 +1472,16 @@ void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
         }
 
         rd_len = min_t(unsigned int,
-                     IPV6_MIN_MTU-sizeof(struct ipv6hdr)-len, skb->len + 8);
+                       IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen,
+                       skb->len + 8);
         rd_len &= ~0x7;
-        len += rd_len;
+        optlen += rd_len;
 
-        buff = ndisc_alloc_skb(dev, len);
+        buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
         if (!buff)
                 goto release;
 
-        skb_put(buff, len);
+        skb_put(buff, sizeof(*msg) + optlen);
         msg = (struct rd_msg *)icmp6_hdr(buff);
 
         memset(&msg->icmph, 0, sizeof(struct icmp6hdr));