ipv6: Copy cork options in ip6_append_data

As the options passed to ip6_append_data may be ephemeral, we need
to duplicate it for corking.  This patch applies the simplest fix
which is to memdup all the relevant bits.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 52 insertions, 15 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 4b15938bef4d..9fb49c3b518a 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1105,6 +1105,18 @@ static inline int ip6_ufo_append_data(struct sock *sk,
         return err;
 }
 
+static inline struct ipv6_opt_hdr *ip6_opt_dup(struct ipv6_opt_hdr *src,
+                                               gfp_t gfp)
+{
+        return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
+}
+
+static inline struct ipv6_rt_hdr *ip6_rthdr_dup(struct ipv6_rt_hdr *src,
+                                                gfp_t gfp)
+{
+        return src ? kmemdup(src, (src->hdrlen + 1) * 8, gfp) : NULL;
+}
+
 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
         int offset, int len, int odd, struct sk_buff *skb),
         void *from, int length, int transhdrlen,
@@ -1130,17 +1142,37 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
                  * setup for corking
                  */
                 if (opt) {
-                        if (np->cork.opt == NULL) {
-                                np->cork.opt = kmalloc(opt->tot_len,
-                                                       sk->sk_allocation);
-                                if (unlikely(np->cork.opt == NULL))
-                                        return -ENOBUFS;
-                        } else if (np->cork.opt->tot_len < opt->tot_len) {
-                                printk(KERN_DEBUG "ip6_append_data: invalid option length\n");
+                        if (WARN_ON(np->cork.opt))
                                 return -EINVAL;
-                        }
-                        memcpy(np->cork.opt, opt, opt->tot_len);
-                        inet->cork.flags |= IPCORK_OPT;
+
+                        np->cork.opt = kmalloc(opt->tot_len, sk->sk_allocation);
+                        if (unlikely(np->cork.opt == NULL))
+                                return -ENOBUFS;
+
+                        np->cork.opt->tot_len = opt->tot_len;
+                        np->cork.opt->opt_flen = opt->opt_flen;
+                        np->cork.opt->opt_nflen = opt->opt_nflen;
+
+                        np->cork.opt->dst0opt = ip6_opt_dup(opt->dst0opt,
+                                                            sk->sk_allocation);
+                        if (opt->dst0opt && !np->cork.opt->dst0opt)
+                                return -ENOBUFS;
+
+                        np->cork.opt->dst1opt = ip6_opt_dup(opt->dst1opt,
+                                                            sk->sk_allocation);
+                        if (opt->dst1opt && !np->cork.opt->dst1opt)
+                                return -ENOBUFS;
+
+                        np->cork.opt->hopopt = ip6_opt_dup(opt->hopopt,
+                                                           sk->sk_allocation);
+                        if (opt->hopopt && !np->cork.opt->hopopt)
+                                return -ENOBUFS;
+
+                        np->cork.opt->srcrt = ip6_rthdr_dup(opt->srcrt,
+                                                            sk->sk_allocation);
+                        if (opt->srcrt && !np->cork.opt->srcrt)
+                                return -ENOBUFS;
+
                         /* need source address above miyazawa*/
                 }
                 dst_hold(&rt->u.dst);
@@ -1167,8 +1199,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
         } else {
                 rt = (struct rt6_info *)inet->cork.dst;
                 fl = &inet->cork.fl;
-                if (inet->cork.flags & IPCORK_OPT)
-                        opt = np->cork.opt;
+                opt = np->cork.opt;
                 transhdrlen = 0;
                 exthdrlen = 0;
                 mtu = inet->cork.fragsize;
@@ -1407,9 +1438,15 @@ error:
 
 static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np)
 {
-        inet->cork.flags &= ~IPCORK_OPT;
-        kfree(np->cork.opt);
-        np->cork.opt = NULL;
+        if (np->cork.opt) {
+                kfree(np->cork.opt->dst0opt);
+                kfree(np->cork.opt->dst1opt);
+                kfree(np->cork.opt->hopopt);
+                kfree(np->cork.opt->srcrt);
+                kfree(np->cork.opt);
+                np->cork.opt = NULL;
+        }
+
         if (inet->cork.dst) {
                 dst_release(inet->cork.dst);
                 inet->cork.dst = NULL;