[IPV6]: Lost locking when inserting a flowlabel in ipv6_fl_list

The new flowlabels should be inserted into the sock list
under the ip6_sk_fl_lock. This was lost in one place.

This list is naturally protected with the socket lock, but
the fl6_sock_lookup() is called without it, so another
protection is required.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 8 deletions

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index 217d60f9fc80..8550df20f984 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -409,6 +409,16 @@ static int ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
         return 0;
 }
 
+static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
+                struct ip6_flowlabel *fl)
+{
+        write_lock_bh(&ip6_sk_fl_lock);
+        sfl->fl = fl;
+        sfl->next = np->ipv6_fl_list;
+        np->ipv6_fl_list = sfl;
+        write_unlock_bh(&ip6_sk_fl_lock);
+}
+
 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 {
         int err;
@@ -513,11 +523,7 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
                                         fl1->linger = fl->linger;
                                 if ((long)(fl->expires - fl1->expires) > 0)
                                         fl1->expires = fl->expires;
-                                write_lock_bh(&ip6_sk_fl_lock);
-                                sfl1->fl = fl1;
-                                sfl1->next = np->ipv6_fl_list;
-                                np->ipv6_fl_list = sfl1;
-                                write_unlock_bh(&ip6_sk_fl_lock);
+                                fl_link(np, sfl1, fl1);
                                 fl_free(fl);
                                 return 0;
 
@@ -545,9 +551,7 @@ release:
                         }
                 }
 
-                sfl1->fl = fl;
-                sfl1->next = np->ipv6_fl_list;
-                np->ipv6_fl_list = sfl1;
+                fl_link(np, sfl1, fl);
                 return 0;
 
         default: