net/ipv6: factor out a ipv6_set_opt_hdr helper

Factour out a helper to set the IPv6 option headers from
do_ipv6_setsockopt.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 3897fb5..90442c8 100644 (file)
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -315,6 +315,80 @@ static int compat_ipv6_mcast_join_leave(struct sock *sk, int optname,
        return ipv6_sock_mc_drop(sk, gr32.gr_interface, &psin6->sin6_addr);
 }
 
+static int ipv6_set_opt_hdr(struct sock *sk, int optname, void __user *optval,
+               int optlen)
+{
+       struct ipv6_pinfo *np = inet6_sk(sk);
+       struct ipv6_opt_hdr *new = NULL;
+       struct net *net = sock_net(sk);
+       struct ipv6_txoptions *opt;
+       int err;
+
+       /* hop-by-hop / destination options are privileged option */
+       if (optname != IPV6_RTHDR && !ns_capable(net->user_ns, CAP_NET_RAW))
+               return -EPERM;
+
+       /* remove any sticky options header with a zero option
+        * length, per RFC3542.
+        */
+       if (optlen > 0) {
+               if (!optval)
+                       return -EINVAL;
+               if (optlen < sizeof(struct ipv6_opt_hdr) ||
+                   optlen & 0x7 ||
+                   optlen > 8 * 255)
+                       return -EINVAL;
+
+               new = memdup_user(optval, optlen);
+               if (IS_ERR(new))
+                       return PTR_ERR(new);
+               if (unlikely(ipv6_optlen(new) > optlen)) {
+                       kfree(new);
+                       return -EINVAL;
+               }
+       }
+
+       opt = rcu_dereference_protected(np->opt, lockdep_sock_is_held(sk));
+       opt = ipv6_renew_options(sk, opt, optname, new);
+       kfree(new);
+       if (IS_ERR(opt))
+               return PTR_ERR(opt);
+
+       /* routing header option needs extra check */
+       err = -EINVAL;
+       if (optname == IPV6_RTHDR && opt && opt->srcrt) {
+               struct ipv6_rt_hdr *rthdr = opt->srcrt;
+               switch (rthdr->type) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+               case IPV6_SRCRT_TYPE_2:
+                       if (rthdr->hdrlen != 2 || rthdr->segments_left != 1)
+                               goto sticky_done;
+                       break;
+#endif
+               case IPV6_SRCRT_TYPE_4:
+               {
+                       struct ipv6_sr_hdr *srh =
+                               (struct ipv6_sr_hdr *)opt->srcrt;
+
+                       if (!seg6_validate_srh(srh, optlen, false))
+                               goto sticky_done;
+                       break;
+               }
+               default:
+                       goto sticky_done;
+               }
+       }
+
+       err = 0;
+       opt = ipv6_update_options(sk, opt);
+sticky_done:
+       if (opt) {
+               atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
+               txopt_put(opt);
+       }
+       return err;
+}
+
 static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
                    char __user *optval, unsigned int optlen)
 {
@@ -580,82 +654,8 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
        case IPV6_RTHDRDSTOPTS:
        case IPV6_RTHDR:
        case IPV6_DSTOPTS:
-       {
-               struct ipv6_txoptions *opt;
-               struct ipv6_opt_hdr *new = NULL;
-
-               /* hop-by-hop / destination options are privileged option */
-               retv = -EPERM;
-               if (optname != IPV6_RTHDR && !ns_capable(net->user_ns, CAP_NET_RAW))
-                       break;
-
-               /* remove any sticky options header with a zero option
-                * length, per RFC3542.
-                */
-               if (optlen == 0)
-                       optval = NULL;
-               else if (!optval)
-                       goto e_inval;
-               else if (optlen < sizeof(struct ipv6_opt_hdr) ||
-                        optlen & 0x7 || optlen > 8 * 255)
-                       goto e_inval;
-               else {
-                       new = memdup_user(optval, optlen);
-                       if (IS_ERR(new)) {
-                               retv = PTR_ERR(new);
-                               break;
-                       }
-                       if (unlikely(ipv6_optlen(new) > optlen)) {
-                               kfree(new);
-                               goto e_inval;
-                       }
-               }
-
-               opt = rcu_dereference_protected(np->opt,
-                                               lockdep_sock_is_held(sk));
-               opt = ipv6_renew_options(sk, opt, optname, new);
-               kfree(new);
-               if (IS_ERR(opt)) {
-                       retv = PTR_ERR(opt);
-                       break;
-               }
-
-               /* routing header option needs extra check */
-               retv = -EINVAL;
-               if (optname == IPV6_RTHDR && opt && opt->srcrt) {
-                       struct ipv6_rt_hdr *rthdr = opt->srcrt;
-                       switch (rthdr->type) {
-#if IS_ENABLED(CONFIG_IPV6_MIP6)
-                       case IPV6_SRCRT_TYPE_2:
-                               if (rthdr->hdrlen != 2 ||
-                                   rthdr->segments_left != 1)
-                                       goto sticky_done;
-
-                               break;
-#endif
-                       case IPV6_SRCRT_TYPE_4:
-                       {
-                               struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)
-                                                         opt->srcrt;
-
-                               if (!seg6_validate_srh(srh, optlen, false))
-                                       goto sticky_done;
-                               break;
-                       }
-                       default:
-                               goto sticky_done;
-                       }
-               }
-
-               retv = 0;
-               opt = ipv6_update_options(sk, opt);
-sticky_done:
-               if (opt) {
-                       atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
-                       txopt_put(opt);
-               }
+               retv = ipv6_set_opt_hdr(sk, optname, optval, optlen);
                break;
-       }
 
        case IPV6_PKTINFO:
        {